Oily fish, EFAs and health
Why are oily fish promoted as essential for good health? The answer lies, partly, in the role EFAs may have in lowering the risk of heart disease and stroke.
Oily fish first got the nutritional thumbs up when it was observed that populations such as the Japanese and Inuit (Eskimo) people, with their fish-rich diets, have much lower rates of CVD. Further investigation suggested that the EPA and DHA fatty acids found in fish can help reduce blood-clotting, lower blood pressure and cholesterol levels and lower triglyceride (fat) levels in the body. All these effects can help lower the risk of CVD. However, the promotion of oily fish ignores the fact that EPA and DHA can also be formed within the body from plant sources of ALA. Not to mention the toxic pollutants found in fish and the environmental catastrophe of industrial fishing.
Numerous studies have looked at the benefits of eating polyunsaturated fatty acids (particularly the omega-3s: ALA, EPA and/or DHA) to reduce the risk of heart disease. Three major studies are frequently referred to: the DART, GISSI and LYON studies. The DART and GISSI trials demonstrated how fish oils could reduce mortality in people with CVD. However, there is now a large body of evidence showing how plant-based ALA can do the same without exposure to harmful toxins found in oily fish. The third well-known study, the LYON study, clearly demonstrated this.
DART - using dietary fish to prevent secondary heart disease
One of the best-known early studies was the Diet and Reinfarcation Trial (DART) (Burr et al., 1989). This study looked at the effects of dietary intervention in the secondary prevention of heart attacks in patients who had previously recovered from one. In this study 2,033 men who had recovered from a heart attack were allocated to receive or not receive advice to eat around 300 grams of oily fish per week, or take fish oil supplements giving an equivalent amount of omega-3 fats.
Results showed that the fish group had a 29 per cent reduction in death during the two year recovery period following a heart attack. So it was concluded that fish oil may reduce CVD mortality; the effect being greatest during the period of recovery following a heart attack.
Burr suggested that omega-3 fats may help normalise heartbeat rhythms by exerting what is called a beneficial anti-arrhythmic effect. In other words, omega-3s may help your heart beat more regularly and calm irregular activity (arrhythmia). Others agree that the most likely mechanism by which EPA and DHA reduce the recurrence of heart disease is by stabilising arrhythmias (Marchiolo et al., 2002). Research suggests that the anti-arrhythmic effect of omega-3 fats is partly due to their ability to reduce the electrical excitability of cells.
As stated, fish oils (or components of them) may also offer benefit by reducing blood-clotting. Platelet cells found in the blood ensure that blood becomes sticky (platelet aggregation or blood-clotting). This is important for stopping bleeding, for instance, if you are wounded. However, too much clotting can cause the cells to clump together and stick to the walls of blood vessels. This can lead to heart disease and stroke. EPA appears to reduce the tendency of blood platelets to clump together. Consequently, it may prevent the formation of blood clots and the narrowing of coronary arteries, which can lead to a heart attack. However, extensive reduction in platelet aggregation can lead to prolonged bleeding times following injury. It is important that blood is neither too thick nor too thin.
Those taking blood-thinning medication (such as daily aspirin or warfarin), should speak to their GP before eating lots of food that has added omega-3 or before taking fish oil supplements, as this can also reduce blood-clotting.
Interestingly, although there were less fatal heart attacks among the DART fish group, the total number of attacks was not reduced. So although eating oily fish reduced the risk of dying after a heart attack, it did not prevent a secondary heart attack. Whereas a large body of evidence shows that plant-based diets can be used to both prevent and even reverse heart disease (see the guide Have a Heart for further information).
GISSI - using fish oil supplements to prevent secondary heart disease
The GISSI-Prevenzione trial similarly looked at the effect of EPA and DHA on 11,324 patients (primarily men) who had recently survived a heart attack. Half the participants received a daily supplement (1 gram per day) of omega-3 fish oil capsules, while the other half did not (GISSI, 1999).
After three-and-a-half years, results showed a 20 per cent reduction in the overall death rate among the fish oil group. However, like the DART trial, the rate of non-fatal heart attacks was unchanged. It should also be noted that the large amount of omega-3 fats given (1 gram) is the equivalent of consuming a very large amount (around 100 grams) of oily fish per day. This exceeds the 'safe' amount the UK government recommends (FSA, 2009).
More recently, a Finnish study looking at the relationship between omega-3 levels and the five-year risk of heart attack and death in patients with heart disease found that relatively high blood levels of omega-3 fats were associated with a lower risk of death (Erkkilä et al., 2003). However, like the previous trials, omega-3s did not prevent the recurrence of a heart attack. This finding fits well with those from earlier studies showing that fish consumption and omega-3s may be associated with decreased death rates but do not necessarily prevent a secondary heart attack in high-risk subjects. Conversely, there is a huge body of evidence (see below) showing how vegetarian or vegan diets can actually reverse heart disease in patients and so reduce both death rates and secondary heart attacks.
No benefit from fish for low-risk heart disease populations
While the DART and GISSI trials suggested that fish oils may reduce death rates in people who have already had a heart attack, the same cannot be said for the wider population. A major review of studies examining the relationship between fish intake and heart disease found that fish consumption is not associated with a reduced risk in low-risk populations (people with no history of heart problems) (Marckmann and Gronbaek, 1999). This review concluded that healthy people (at low-risk of heart disease) do not gain any additional protection for the heart from eating fish. The authors question whether the apparent protection in high-risk individuals is attributable to eating fish or whether the link might be explained by other dietary or non-dietary confounding factors.
In a later editorial, one of the review authors reaffirmed that while an average daily intake of 50 grams of fish may lower heart disease death rate, the apparent protection is limited to high-risk populations (Marckmann, 2003). Marckmann observes that both the DART and GISSI trials were well-designed and performed and the results were convincing. However, he says that their conclusion, that heart disease patients should be prescribed oily fish or fish oil supplements, has been seriously challenged by more recent research.
No long-term protection against heart disease
A long-term follow-up to the DART study (Ness et al., 2002), showed that the death rate in the two groups (fish and no fish) after an average follow-up of 15 years was almost identical. So the dietary advice given to former DART participants, over a decade previously, offered no long-term protective effect. So while fish oil may offer short-term protection to people who have suffered a heart attack, this protection does not appear to stand the test of time.
A further study looked at whether dietary advice (to eat oily fish or fish oil supplements) could reduce the death rate among men with angina (Burr et al, 2003). Another surprising result was found: advice to consume fish and the intake of fish oil capsules was associated with an increase in mortality of 20 per cent and 45 per cent respectively! Furthermore, this increase was even more prominent for sudden death. Such results should make health organisations and the Government sit up and rethink their position on fish and fish oil in the primary and secondary prevention of heart disease.
More recently, in 2006, a major review published in the British Medical Journal drew the evidence together by reviewing all the relevant studies published over the previous four years (Hooper et al., 2006). It looked at 89 studies on omega-3 fats and health and concluded that long chain and shorter chain omega-3 fats do not have a clear effect on total mortality, combined cardiovascular events or cancer.
The review noted that the 2003 study by Burr contradicts the other large studies by not suggesting a benefit of omega-3s in patients with angina. One possible explanation the researchers suggest for this is that as this trial had the longest follow-up period of all the studies reviewed it could be that the negative effects of oily fish and fish oil supplements were due to the cumulative harmful effects of mercury. In other words, the pollutants in fish and fish oil supplements taken over time may cancel out the beneficial effects of the omega-3 fats they contain.
Another study found fish oil supplements increased life-threatening abnormal heart rhythms in patients with implanted defibrillators (Raitt et al., 2005). This study actually found that fish oil supplementation did not reduce the risk of abnormal or irregular heart rhythm and may even be pro-arrhythmic in some patients.
LYON - using plant-derived ALA to prevent secondary heart disease
The Lyon Diet Heart Study investigated whether a Mediterranean-type diet could reduce secondary heart disease (a second heart attack) compared to a prudent Western-type diet (de Lorgeril et al., 1999).
In this study, 423 patients with a history of heart attack were randomly assigned either a Mediterranean diet or a prudent Western diet (as recommended by the American Heart Association). The Mediterranean diet was largely plant-based containing more bread, pulses (peas, beans and lentils), vegetables (both root and green vegetables) and fruit. Butter and cream were replaced with healthier fats including olive oil and rapeseed oil margarine. The diet did contain fish, but less red meat, and overall it was lower in animal fat.
The Mediterranean diet was significantly lower in cholesterol and higher in a number of beneficial substances such as ALA. Earlier work with this group revealed a 70 per cent increase in circulating levels of ALA and a 40 per cent rise in EPA (de Lorgeril et al., 1994). Although fish intake was encouraged, the experimental group ate only seven grams a day more fish than the control group, leading the researchers to conclude that the favourable EPA level seen in the test group was due to plant-ALA intake rather than the fish in the diet.
Results showed a striking drop in death rates (due to a reduction in heart disease) of close to 70 per cent. Compared with the DART trial, the protective effect was associated with ALA instead of EPA. Another important difference was that the protection ALA offered extended to non-fatal heart attacks. The authors of this study suggested that moderate amounts of omega-3 fatty acids (such as in the Mediterranean diet), may work in multiple ways to reduce the risk of heart attacks and sudden death.
Just to be clear, the only fatty acid associated with the reduction in heart attacks was ALA. The authors did not find any correlation between the longer-chain omega-3 fatty acids (EPA and DHA) and a reduction in cardiac events. The Lyon Diet Heart Study demonstrated that plant-derived ALA is extremely effective in reducing the risks of secondary heart disease. It demonstrated that plant ALA was superior to fish-derived EPA and DHA in reducing the risk of a second heart attack. This study also confirmed that ALA can confer long-term protection to heart health.
Three years later, in an article published in the journal Circulation, Dr J. David Spence of the Stroke Prevention and Atherosclerosis Research Centre at Robarts Research Institute in London, Canada, asked why the Lyon study was so neglected (Spence, 2002). Spence believes this study should have set the benchmark for dietary recommendations. He stressed how Mediterranean diets have been shown to improve endothelial function (how the internal lining of the blood vessels work). Spence also attributed the protective role of this type of diet to the higher levels of antioxidants they contain. A large body of evidence indicates that antioxidants may be able to reduce atherosclerosis (the progressive thickening and hardening of arterial walls that results from the build up of fatty deposits) (Azen et al., 1996).
Spence also suggested that dietary cholesterol is more harmful to health than previously thought. Cholesterol is a fatty substance mainly produced by the liver (in response to saturated fat intake) but it is also supplied in diets containing animal-based foods (meat and dairy). Plant foods don't contain any cholesterol. It is carried in the bloodstream by molecules called lipoproteins (a mixture of fat and protein). Low-density lipoprotein (LDL) takes cholesterol from the liver to the cells and is often referred to as 'bad' cholesterol because when levels are high, it can accumulate on the walls of the arteries. High-density lipoprotein (HDL) carries excess cholesterol back to the liver for excretion and is therefore called 'good' cholesterol.
Evidence suggests that LDL can also harm the walls of the arteries when it is damaged or oxidised (Galassetti and Pontello, 2006). So what has this to with the diet and what can be done about it? Well, quite a lot. For example, one study showed how eating two eggs a day for three weeks not only raised LDL levels by about 10 per cent but increased oxidised LDL by 34 per cent (Levy et al., 1996). The authors concluded that egg consumption, in addition to raising cholesterol, increased how readily LDL could be oxidised. This, in turn, enhanced the progression of atherosclerosis (the build up of fatty deposits in the arteries). It was concluded that this may contribute to the high levels of heart disease seen in populations with high cholesterol intakes.
The precise mechanism underlying how eggs increase LDL oxidation is unclear, although their relatively high omega-6 intake has been blamed (Shapira and Pinchasov, 2008). Conversely, a healthier diet, such as the Mediterranean diet (rich in antioxidants and flavanoids), appears to reduce how readily LDL is oxidised (Lapointe et al., 2006). Interestingly though, antioxidant supplements and fish oil supplements have not been clearly demonstrated to prevent LDL oxidation.
Research shows that LDL in vegetarians is less susceptible to oxidative damage (Lu et al., 2000). This may be due to the low-fat, high-antioxidant (beta-carotene and vitamins C and E) and/or soya food content of a well-balanced plant-based diet. This could be one of the reasons why the Mediterranean diet is associated with a lower incidence of heart disease (Lapointe et al., 2006). These and other studies provide strong evidence that plant-based omega-3s can protect heart health and that contrary to popular belief, oily fish are not the only (nor indeed the best) source of these valuable nutrients.
Spence states that it is no longer reasonable for patients with heart disease to be prescribed diets containing a daily intake of animal flesh (Spence, 2002). Dietary recommendations, he suggests, should be based on diets similar to that used in the Lyon study.
Plant omega-3s and heart disease
Many other studies indicate that plant omega-3s have a protective effect against heart disease. The Health Professionals' Study looked at 43,757 men over six years (Ascherio et al., 1996). During this time 229 men suffered a fatal heart attack and 505 a non-fatal heart attack. This study found that a one per cent increase in ALA intake lowered the risk of heart attack by 59 per cent. It was concluded that diets high in ALA from plants are associated with a reduced risk of heart disease.
Similar findings were reported in the Nurses' Health Study which looked at over 76,000 women over 10 years (Hu et al., 1999). During this time 232 women suffered a fatal heart attack and 597 a non-fatal attack. Those who consumed the most ALA had a 45 per cent lower risk of fatal heart disease. The risk was further lowered among women who also took vitamin E supplements or who had a lower intake of trans fatty acids. The authors concluded that higher consumption of foods such as oil-based salad dressings that provide polyunsaturated fats, including ALA, may reduce the risk of fatal heart disease.
In the 2001 National Heart, Lung and Blood Institute Family Heart Study, the diets of 4,584 participants were assessed (Djousse et al., 2001). Results showed that men who consumed the most ALA had a 40 per cent lower risk of heart disease and women who consumed the most had a whopping 50-70 per cent reduction.
In 2003, a joint report by WHO/FAO concurred that ALA has a protective effect against heart disease (WHO/FAO, 2003). The report states that several prospective studies have found an inverse association between the intake of ALA (from flaxseed, rapeseed and soya bean oils) and risk of fatal heart disease. In other words, ALA protects against death from heart disease.
It has been suggested that the protective effects of ALA are particularly evident among subjects with low intakes. This may be in parts of Europewhere sunflower oil is used almost exclusively, or in developing countries where palm oil is used (both oils lack ALA).
In 2008, a study published in Circulation, the Journal of the American Heart Association, investigated the role of ALA in heart disease in Costa Rica where ALA intake was low but is increasing due to the switch from palm oil to soya bean oil (Campos et al., 2008). This study found that a 1.79 gram per day intake of (supplying 0.65 per cent of total energy) decreased the risk of a second heart attack in heart disease patients by 57 per cent, compared to a 1.11 gram per day intake (supplying 0.42 per cent of total energy). The authors suggest that the amount of ALA needed to reduce the risk of a second heart attack can be obtained from just 2 teaspoons of soya bean or rapeseed oil, 1-2 millilitres of flaxseed oil or just 6-10 halves of walnuts per day.
The Cochrane Collaboration is an international not-for-profit, independent organisation, dedicated to making up-to-date, accurate information about the effects of healthcare readily available worldwide. The Collaboration's systematic reviews of healthcare studies are published quarterly as part of The Cochrane Library. Cochrane reviews have become known internationally as sources of high quality, reliable health information.
In 2004, the Cochrane Collaboration reviewed the current evidence to see whether dietary or supplemental omega-3 fatty acids alter total mortality (death rate) or cardiovascular events (heart attack and stroke) (Hooper et al., 2004). They concluded that there was no overall benefit either on heart attacks, deaths from heart disease or overall mortality. The authors concluded that there was not enough evidence to say that people should stop taking rich sources of omega-3 fats, but said that further high quality trials are needed to confirm the previously suggested protective effect of omega-3 fats for those at increased cardiovascular risk.
With declining fish stocks, polluted seas and oceans, the role of plant-based omega-3s in heart disease must be further examined. The possibility of a simple and sustainable plant-based solution can no longer be ignored.
Veggie diets and heart disease
Plant-based diets have been shown to prevent and even reverse heart disease. Dr Dean Ornish, Clinical Professor of Medicine at the University of California in San Francisco, is well-known for his Lifestyle Heart Trial in which he treated severe heart disease patients with lifestyle changes alone (Ornish et al., 1990; Ornish et al., 1998). The experimental group ate a low-fat wholegrain plant-based diet containing lots of fruits, vegetables and pulses. They also followed an exercise programme, practised various forms of stress management but did not receive medication. They were monitored against a control group of similar patients who received conventional treatments.
After just one year, 82 per cent of patients on this lifestyle change regime had regression of their heart disease with a 91 per cent reduction in chest pain and reduced cholesterol levels. Whereas the control group experienced a 165 per cent increase in the frequency of chest pain, cholesterol was worse and blockages of their arteries became worse. This trial has continued with similar results and continues to achieve better results than conventional surgical or medical intervention.
More recent work shows that vegetarians generally have a much lower risk of heart disease than meat-eaters. A major review of the scientific evidence shows that vegetarians have a massive 25 per cent lower risk of dying from heart disease! The authors of this study conclude that the widespread adoption of a vegetarian diet could prevent approximately 40,000 deaths from heart disease in Britain each year (Key et al., 1999).
As stated, meat, poultry, fish, eggs and dairy products all contain cholesterol, while a plant-based diet contains little or no cholesterol. It should be no surprise then that a large-scale study investigating cholesterol levels among vegans, vegetarians, fish- and meat-eaters found that the vegans had the lowest levels, vegetarians and fish-eaters had similar values and the meat-eaters had the highest (Appleby et al., 1999).
For vegans it's a win-win situation. Not only do they avoid harmful substances (saturated animal fat, animal protein and cholesterol), they also benefit from a wide range of healthy nutrients including fibre, vitamins and minerals.
It is reported that omega-3 fats can help fight heart disease, asthma, type 1 diabetes and multiple sclerosis. The beneficial effects have also been seen in some cancers, inflammatory bowel disease, arthritis, osteoporosis, mental health, dry eye disease, age-related macular degeneration and psoriasis (Simopoulos, 2008). Many of theses conditions involve inflammation.
Our bodies use inflammation to protect tissues from infection, injury or disease. The inflammatory process usually promotes healing but, when uncontrolled, it can also harm. We now know that the balance of omega-6s to omega-3s is important for regulating inflammation. As a general rule, omega-6 fats are thought to be pro-inflammatory, whereas omega-3 fats are considered anti-inflammatory (GLA is the exception as it is an omega-6 fat with anti-inflammatory properties). The dramatic increase in dietary saturated and omega-6 fats, coupled to the decrease in omega-3 fats is linked to the increasing incidence of numerous inflammatory diseases including asthma, allergy and atherosclerosis (Chilton et al., 2008).
There is evidence that changing the diet can help some people with inflammatory conditions; some of these are discussed below.
Arthritis is a painful condition of the joints and bones. There are many different forms of this condition. The two main types are rheumatoid arthritis and osteoarthritis. Other forms of arthritis include ankylosing spondylitis, cervical spondylitis, fibromyalgia, lupus, gout, psoriatic arthritis and Reiter's syndrome (NHS Direct, 2008).
Osteoarthritis is the most common type of arthritis in the UK, with an estimated 8.5 million people affected by the condition (NHS Direct, 2008a). This degenerative disease is sometimes referred to as 'wear and tear' arthritis. Cartilage is the strong, smooth surface that lines the bones and allows joints to move against each other easily without friction. In osteoarthritis, cartilage gradually breaks down faster than it can be repaired. Eventually the surface of the bones begin to rub together causing them to degenerate.
In osteoarthritis, damage to cartilage can result in bony growths developing around the edge of the joints causing mild inflammation of the tissues (synovitis). Osteoarthritis mostly occurs in the knees, hips and small joints of the hands. However, almost any joint can be affected.
Osteoarthritis generally occurs in the over 50s and is more common in women than men. However, it is not an inevitable part of getting older. It can develop after an injury to a joint; this can happen months or even years after the injury.
Studies have been carried out to try to find whether omega-3 fats and/or fish oils can be helpful for osteoarthritis, but the results so far are inconclusive.
Rheumatoid (inflammatory) arthritis is a more aggressive, but less common condition than osteoarthritis. It is thought to be an autoimmune disease whereby the body's own immune system attacks the joints, causing pain, swelling and the destruction of bone and cartilage.
This chronic condition is characterised by hot painful swelling in the joints. It usually starts in the wrists, hands and feet but can spread to other joints in the body. In some diseases inflammation can help towards healing, but in rheumatoid arthritis it tends to cause damage. For some people the discomfort, pain and loss of mobility caused by this condition can have a serious impact on their lives.
Rheumatoid arthritis affects approximately 350,000 people in the UK and like osteoarthritis, is also more common in women than men. It is most common after the age of 40, but can affect people of any age (NHS Direct, 2008b).
Diet and arthritis
In the past, arthritis patients were told that dietary changes would not help them. Despite this many arthritis patients have found that certain foods can worsen their condition, or improve it.
Arthritis Care is the UK's largest voluntary organisation working with and for people with arthritis. It suggests that a diet high in fruit, vegetables, pasta, fish and white meat, and low in fatty foods such as red meat, cream and cheese can help (Arthritis Care, 2008). Most people would benefit from eating less saturated fat and sugar and eating more complex carbohydrates, fibre, vitamins and minerals. Evidence shows that at least for some people with arthritis, a healthier diet can help considerably.
In 2001, the first controlled study examining the long-term effect of a vegan, gluten-free diet on rheumatoid arthritis found that this diet could improve the signs and symptoms of this condition (Hafström et al., 2001). The authors of this study suggested that a gluten-free vegan diet may, in some people, reduce the immune response that triggers rheumatoid arthritis. Another study tested a low-fat, vegan diet in patients with moderate-to-severe rheumatoid arthritis (McDougall et al., 2002). Results also showed those who switched to this type of diet experienced a significant reduction in symptoms.
A further study showed that an uncooked vegan diet, rich in antioxidants and fibre, decreased joint stiffness and pain in patients with rheumatoid arthritis (Hänninen et al., 2000). Some studies have looked at fasting followed by a vegetarian or vegan diet. A review of these studies concluded that this dietary treatment might also be beneficial for people with rheumatoid arthritis (Müller et al., 2001). Taken together, these studies provide strong evidence that dietary modification can benefit arthritis patients.
It is widely accepted that it is important for people with arthritis to maintain a healthy weight. The extra burden on the joints, in overweight or obese arthritis patients, can make symptoms considerably worse and losing weight can have a dramatic beneficial effect.
The Arthritis Research Campaign (ARC) promotes medical research into the cause, treatment and cure of arthritic conditions. ARC's dietary guidelines for people with arthritis suggest that one of the most important links between diet and arthritis is being overweight (ARC, 2006).
Adopting a plant-based based diet can help people lose weight and maintain a healthy body weight. Numerous studies show that vegetarians and vegans weigh less than meat-eaters. A study of over 55,000 Swedish women revealed that the vegetarian and vegan women were less likely to be overweight or obese than the meat-eaters (Newby et al., 2005). In another study, the effects of a low-fat, plant-based diet on 64 overweight postmenopausal women was compared to a diet based on National Cholesterol Education Program guidelines (Barnard et al., 2005). Results showed that the low-fat, vegan diet was associated with significant weight loss. A subsequent review of 40 studies revealed that, on average, vegetarians and vegans weigh between six pounds and two stones less than meat-eaters (Berkow and Bernard, 2006).
When trying to lose weight, it is important to maintain a good intake of nutrients. A healthy balanced diet containing plenty of fruit and vegetables, pulses and wholegrain foods (wholemeal bread, brown rice and wholemeal pasta) provides a good supply of vitamins, minerals and fibre. A diet lacking in these foods and rich in meat, dairy and processed foods (such as white bread, white rice and white pasta) does not provide such a good source of nutrients. Find out how to achieve and maintain a healthy weight while protecting your health too in the V-Plan Diet guide.
Getting the fats right
ARC states that vegetarian diets have been shown to be helpful in the long-term to some people with rheumatoid arthritis. It also says that a vegan diet (no meat, fish or other animal products such as eggs, milk, cheese or other dairy products) may also be helpful (ARC, 2006). Conversely, studies have shown that people who eat large amounts of red meat seem to have a higher risk of developing inflammatory arthritis.
The key point here is that not only is a plant-based diet helpful because it contains beneficial substances (antioxidants and omega-3 fats), but a typical Western diet, rich in meat, dairy and processed foods, is detrimental as it contains high levels of harmful substances such as saturated fat. This unhealthy type of fat tends to come from animal-based food (particularly meat, poultry and dairy products) and processed foods (cakes, pastry and biscuits). This unhealthy fat is the most important kind to avoid as it can increase pain and inflammation in arthritis (ARC, 2006).
Plant-based diets tend to contain considerably less saturated fat and more healthy polyunsaturated fats. The research suggests that polyunsaturated omega-3 fats may help some people with arthritis and other inflammatory conditions. The fact that people also tend to lose weight on a vegan diet contributes further to its beneficial effects.
Omega-6 fats do not appear to benefit people with arthritis. In fact they may increase inflammation by competing with omega-3s (ARC, 2006). Most people have diets which already contain more omega-6 fats than they need. If you have inflammatory arthritis, it may be helpful to replace some of the omega-6 fats (found in sunflower oil, corn oil and products made from them such as sunflower margarines) with omega-3 fats from flaxseed, hempseed and rapeseed oils and walnuts. Obtaining plant-based omega-3s from these sources will ensure you get this healthy fat without exposing your body to the harmful toxins found in oily fish.
ARC warns that people with gout should not consume oily fish. Gout is a type of arthritis caused by a high level of urate in the body which can crystallise in the joints and cause severe pain and inflammation. Urate is produced from purines, which are chemicals that result from the natural death of cells. Cutting down on foods which are high in purines may be helpful if you have gout. This is best done by replacing animal-based foods (especially meat and fish) with other sources of protein, such as pulses (peas, beans, and lentils). Other dietary measures for gout include losing weight (if you are overweight) and avoiding excessive alcohol consumption, which has been associated with gout for centuries (ARC, 2006).
A well-balanced healthy diet can help you if you are taking strong drugs for arthritis. In fact, ARC states that if you are taking strong drugs for arthritis there is even more reason to eat a good diet as it can help to protect the body against some of the side-effects of the drugs. For example steroids, such as prednisolone, can cause osteoporosis, particularly if you stay on them for a long time. Plenty of calcium in your diet will help to reduce the risk (ARC, 2006).
Arthritis Care points out that people with rheumatoid arthritis are at increased risk of developing osteoporosis and agrees that ensuring an adequate calcium intake is very important (Arthritis Care, 2007). While cow's milk and dairy products are indeed a source of calcium, they are not the best source. This is because they contain animal protein. Excessive amounts of animal protein can upset the acid balance within the body, which then takes calcium from the bones to neutralise the acid. Even the usually pro-dairy National Osteoporosis Society says: "It is a good idea to avoid too much protein, particularly animal protein such as meat and cheese," (NOS, 2008). It is also a good idea to avoid too much salt, fizzy drinks and caffeine for the same reason.
Healthier sources of calcium include green leafy vegetables (broccoli, kale, spring greens, cabbage, parsley and watercress - but not spinach), dried fruits (figs and dates) nuts (almonds and Brazil nuts), seeds (sesame seeds and tahini - sesame seed paste), pulses (peas, beans, lentils and soya products such as calcium-set tofu and calcium-enriched soya milk). For more information on calcium see the fact sheet Boning up on Calcium.
Some arthritis sufferers may be concerned about their iron intake, particularly - they may be told - if they avoid eating red meat. This should not be a concern as the British Medical Association and the American Dietetic Association agree that vegetarians are no more likely to suffer from iron deficiency than meat-eaters (BMA, 1996; American Dietetic Association, 2003). Indeed one of the largest studies of vegetarians and vegans in the world (the EPIC Oxford cohort study) looked at over 33,883 meat-eaters, 18,840 vegetarians and 2,596 vegans and found that the vegans had the highest intake of iron, followed by the fish-eaters, vegetarians then the meat-eaters (Davey et al., 2003). Cow's milk and dairy products are an extremely poor source of iron, containing hardly any, whereas pulses, dried fruits and dark leafy vegetables are all excellent sources. For more information on iron see the fact sheet Ironing out the Facts.
The antioxidant vitamins A, C and E are thought to protect against disease (and aging) by defending the body against attack from harmful molecules called free radicals. These damaging molecules are produced naturally as your body breaks down food, or as a result of exposure to harmful chemicals (including cigarette smoke) or radiation.
The damage caused by free radicals plays a role in many diseases including cancer and arthritis. A particular class of free radicals (called reactive oxygen species) can promote the inflammatory response that occurs in rheumatoid arthritis (Filippin, 2008). A molecular mechanism linking free radicals to inflammation has been proposed. It suggests that free radicals activate molecules called transcription factors (nuclear factor-kappa B or NF-?B). These then activate genes involved in inflammatory and/or autoimmune responses. In other words, free radicals can cause a sequence of events rather like a line of dominos falling down, which may lead to inflammatory arthritis.
There is some evidence that anti-rheumatic drugs may exert their therapeutic effects by acting as antioxidants. For example, non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to act as free radical scavengers (Merry et al., 1991). This means they may protect against the harmful effects of free radicals by 'mopping them up'. However, antioxidants may be more useful in preventing damage before it occurs, rather than treating an already inflamed joint.
Too much iron in the blood can encourage the production of free radicals (McCord, 2004). Unlike the non-haem iron we find in plant foods, haem iron in meat is absorbed into the body whether it is needed or not. Thus meat can supply an overload of iron (but no vitamin C and very little vitamin E). Conversely, vegetables and wholegrains foods can supply as much or as little iron as is required, as well as an abundance of protective antioxidant vitamins, fibre and other nutrients.
Omega-3s and arthritis
For some arthritis patients, omega-3 supplements may be helpful, for example a tablespoon of flaxseed oil twice a day (this exceeds the 1 teaspoon-a-day recommendation for normal consumption). If this is helpful, it may be a good idea to try to reduce your intake to the lowest effective dose.
Some arthritis patients have benefited from taking a herbal remedy isolated from Rosa canina, a type of rose hip (Winther et al., 2005). In a randomised, double-blind, placebo-controlled trial, published in the Journal of Rheumatology, 82 per cent of patients reported a reduction in pain after just three weeks of active treatment with this herbal remedy. The authors of the study concluded that it could alleviate symptoms of osteoarthritis. In fact pain was reduced to such an extent that there was a significant decrease in the consumption of painkillers such as paracetemol, ibuprofen and NSAIDs. This compares favourably to glucosamine, currently the most popular supplement for joint health (Reginster et al., 2001; Matheson and Perry 2003).
Losing weight, eating a healthy plant-based diet that includes a good supply of omega-3 fatty acids (either though foods or supplements) can help reduce the symptoms of arthritis and may help some people reduce their medication (ARC, 2006).
In multiple sclerosis (MS), the protective sheath (called myelin) that surrounds the nerve fibres of the central nervous system becomes damaged. This process is called demyelination. Sclerosis means scarring and multiple refers to the many different sites at which the scarring may occur in the brain and spinal cord. Demyelination interferes with the messages that are sent between the brain and other parts of the body. Symptoms can include blurred vision, paralysis, slurred speech, lack of coordination and incontinence. The severity of symptoms depends on how much damage has occurred.
MS is the most common disease of the central nervous system (the brain and spinal cord) affecting young adults in the UK. It currently affects around 85,000 people in the UK and can occur at any age, but in most cases symptoms first appear between the ages of 20 and 40. Women are almost twice as likely to develop MS as men. The majority of patients with MS have the relapsing-remitting form of the disease, characterised by attacks or relapses interspersed with periods of recovery or remission (Harbige and Sharief, 2007). It is a life-long condition, but it is not terminal and people with MS can expect to live as long as anyone else (NHS Direct, 2008c).
The cause of MS is not yet fully understood but is thought to be an autoimmune disease (like rheumatoid arthritis or type 1 diabetes) whereby the body's immune system attacks its own tissues having 'mistaken' them for an invading (foreign) protein. This process is referred to as 'molecular mimicry' as part of the foreign protein closely resembles part of certain cells in our own body. If this all sounds a bit complicated, just think of it as 'friendly fire' - when a soldier mistakenly attacks one of his own. In autoimmune diseases, the body attacks itself.
As with other autoimmune diseases, it is thought that a combination of genetic factors and environmental factors causes the disease. There is undoubtedly an element of genetic predisposition in MS but the evidence suggests that this disease is more strongly related to environmental factors than genes. In other words, a person may have a genetic predisposition to the disease but not develop it unless exposed to a specific environmental 'trigger'. Such triggers may include bacteria, viruses or components of the diet.
One of the most intriguing features of MS is that it occurs more in countries that are far from the equator. For example, MS is relatively common in the UK, North America and Scandinavia, but hardly ever occurs in countries such as Malaysia and Ecuador (NHS Direct, 2008c). The reason for this is not fully understood, but it could be that MS is triggered by a particular bacteria or virus which thrives in cooler climates. Alternative theories suggest that components of particular foods consumed in these countries may be responsible.
Diet and MS
Research suggests that some components in food can act as causative agents of autoimmune disease. For example, there is strong evidence that proteins found in cow's milk can trigger an autoimmune response leading to type 1 diabetes in genetically susceptible children. The theory with MS is that proteins from certain foods (such as cow's milk) may also prompt the immune system to respond inappropriately and attack the myelin sheath in the brain and central nervous system. A large body of evidence shows that populations that consume high quantities of animal-based foods seem to be most affected by MS (Agnello et al., 2004). This inevitably has drawn attention to the role of meat and dairy foods in the development of MS.
Numerous studies have revealed a striking association between the geographical pattern of MS and that of meat and dairy consumption (Arganoff and Goldberg, 1974; Butcher, 1976; Lauer, 1994). There is also strong evidence linking a high intake of saturated fat to the incidence of MS. Taken together, the evidence shows that foods rich in saturated fats are associated with higher levels of MS while foods rich in polyunsaturated fats are linked to lower levels (Harbige and Sharief, 2007).
The research investigating the links between diet and MS dates back 60 years to Dr Roy Swank's work first at the Montreal Neurological Institute in Norway, then at the Division of Neurology at the University of Oregon Medical School in the US. Swank was intrigued by the geographical distribution of MS and hypothesised that dietary fat intake may contribute to progression of MS.
Swank suspected animal foods high in saturated fats may be responsible as MS seemed to occur most among inland dairy-consuming populations and less among coastal fish-eating populations. His best known trial, published in the Lancet in 1990, followed 144 MS patients for a total of 34 years (Swank and Dugan, 1990). Swank prescribed a low-saturated fat diet to patients with relapsing-remitting MS and observed how their conditions progressed. Results showed that those who adhered most closely to the diet derived the greatest benefits from the intervention. The beneficial effects were strongest in those who began to follow the diet early in their disease.
In 2000, 15 patients who had been on the diet for 50 years were re-assessed. Of these, 13 were able to walk without difficulty, the other two required assistance with walking (Swank and Goodwin, 2003). Swank concluded that if people with MS adhere to the diet, with no more than 10-15 grams of saturated fat per day, they can expect to survive and be ambulant and otherwise normal to an advanced age.
Although Swank's diet restricted meat and dairy foods, it did include fish and fish oils. More recently, another study recommended a co-called 'quasi' vegan diet with fish oil (McCarty, 2001). This study concluded that a whole-food vegan diet, coupled with fish oil and vitamin D supplementation, may represent a practical strategy for the prevention of autoimmune diseases, while concurrently lowering the risk of many other life-threatening Western diseases. Both regimes overlook the fact that you can have an omega-3 rich vegan diet (containing ALA and an algal supplement containing DHA and EPA if desired) without exposing yourself to the toxins found in oily fish and fish oils.
Polyunsaturated fatty acids and MS
Some research indicates that polyunsaturated fatty acids (particularly omega-6 fats) have a role in the chain of events leading to, and the treatment of, MS. Studies show that omega-6 levels are lower in MS patients. It has been suggested that the way omega-6 fatty acids are normally processed in the body is disrupted in people with MS.
In a randomised, double-blind trial of a high dose and low dose omega-6 GLA-rich (borage) oil and a placebo control, the high dose had a marked clinical effect in relapsing-remitting MS. Results showed that the GLA-rich oil significantly decreased the relapse rate and the progression of disease (Harbige and Sharief, 2007). The authors of this study suggested that disturbed omega-6 fatty acid metabolism in MS gives rise to a loss of both long chain omega-6 fatty acids in the membranes and anti-inflammatory cytokines, particularly during the relapse phase.
The loss of these important neural fatty acids in central nervous system structure and function may have long-term consequences in MS. However, this feature of MS can be treated by supplementation (Harbige and Sharief, 2007). In general, it appears that over time, diets low in saturated fat, but containing both some omega-6 and omega-3 fats, can improve the course of MS (Harbige and Sharief, 2007).
In 2007, a Cochrane review concluded that polyunsaturated fatty acids seemed to have no major effect on the main clinical outcome in MS (disease progression) (Farinotti et al., 2007). However, only a limited number of studies was reviewed and they did state that the data available were insufficient to assess any potential benefit or harm from supplementation. Clearly more research is required to assess the effectiveness of dietary interventions in MS. In the meantime, over 50 per cent of people with MS make dietary changes and take supplements (Farinotti et al., 2007).
Polyunsaturated fats and autoimmunity
It is generally accepted that omega-6 fatty acids are pro-inflammatory (Harbige, 2003). However, while they have been shown to increase the severity of some autoimmune and inflammatory diseases, omega-6 fats may actually protect against other (immune-mediated and non-immune-mediated) inflammatory diseases. Therefore, the view that all omega-6 fats are pro-inflammatory is incorrect (Harbige, 2003).
There is some evidence that omega-3 fats can 'dampen down' inflammatory responses. This anti-inflammatory role may offer short-term benefits in some autoimmune diseases. However, this could be an undesirable long-term effect of high-dose fish oils, as it could compromise immunity (Harbige, 2003). As stated earlier, the inflammatory response is a natural part of our immune system and can help fight infection. In other words, a high intake of fish oils may not be beneficial in the long term; it may weaken the immune system while only addressing the secondary consequences of an autoimmune response.
Diets low in saturated fat and relatively high in omega-3 fats (higher than the low amount present in most UK diets) can reduce the severity of some autoimmune diseases. Conversely, diets high in the omega-6 fat LA may increase the severity of these conditions (Harbige, 2003). However, as stated previously, there is convincing evidence for a protective role of both omega-6 and omega-3 fats in MS (Harbige, 2003).
In conclusion, moderate intakes of omega-6 fats and the appropriate ratio between omega-6 and omega-3 fats are important for the correct functioning of the immune system (Harbige, 2003). Adjusting the ratio could be helpful in autoimmune or inflammatory disease. The optimum ratio varies depending on age and the basis of the autoimmune disease.
This all sounds rather complicated but the overall message is that a plant-based diet, low in fat, salt, sugar and processed foods and high in fresh fruit, vegetables, wholegrains, pulses, nuts and seeds can provide all the nutrients required for good health and reduce some of the risk factors for autoimmune diseases or prevent making an already existing condition worse.
As the incidence of most autoimmune diseases correlates directly to the consumption of animal foods, a move towards a more a plant-based diet could help combat the rise in these conditions among populations that currently consume high levels of dairy and meat products.
Some research suggests that the dramatic increase in the consumption of omega-6 fats, coupled to the decrease in omega-3 fats consumed, is a major driver of the increase of a range of inflammatory allergic reactions (Chilton et al., 2008).
Asthma is a chronic inflammatory lung disease characterised by recurrent breathing problems. The UK has one of the highest prevalence rates for asthma in the world, along with New Zealand, Australia and Ireland. Around one in eight children and one in 20 adults are currently being treated for asthma in the UK.
During an asthma attack, the lining of the airways becomes inflamed and the airways constrict. This can lead to the characteristic symptoms of asthma such as coughing, wheezing, difficulty in breathing and tightness across the chest.
The causes of asthma are thought to include a genetic predisposition (asthma in the family) and environmental triggers such as cigarette smoke, chemicals, dust mites and diet. As food allergies are responsible for approximately five per cent of all asthma cases (James et al., 1994) and as cow's milk is a primary cause of food allergies, it seems reasonable to consider avoiding all cow's milk and dairy products in the treatment of asthma.
Asthma may also respond to other dietary modifications, thereby reducing the need for medication. Studies show that supplementing the diet with plant-based fatty acids can inhibit inflammatory responses leading to asthma. One study found that supplementing the diet with omega-6 and omega-3 fats in a ratio of 2:1 helped alleviate symptoms, whereas a ratio of 10:1 made symptoms worse (Broughton et al., 1997).
Another study found that supplementing the diet with borage oil (containing GLA) led to the accumulation of natural inhibitors of leukotrines (hormones that cause the symptoms of asthma) within inflammatory cells (Chilton et al., 2008). This concurs with the research described above that shows that GLA provides an exception to the usual pro-inflammatory role attributed to omega-6 fats.
The overall optimum ratio of omega-6 to omega-3 fats may vary according the disease and the patient (age, sex and physical condition) but the message that we all need to increase our intake of omega-3 fats while not increasing that of omega-6 fats is consistent throughout the research.
The increasing rate of eczema in the West has been linked to a steep rise in the consumption of omega-6 fats and the reduced intake of omega-3s (Koch et al., 2008). Omega-6 fats favour the formation of specific eicosanoids (hormone-like molecules) that are involved in allergic inflammation. The parent omega-6 fatty acid LA is converted into arachidonic acid, a precursor in the production of eicosanoids (Koch at al., 2008). Consequently an increased intake of omega-6 fats can promote allergic reactions, while increasing omega-3 intake competes with omega-6 metabolism and protects against inflammatory conditions.
The results of a recent exploratory trial were published in the British Journal of Dermatology (Koch at al., 2008). This study reported how 53 patients suffering from eczema were randomly allocated supplements of both DHA and EPA, or a control (caprylic acid, otherwise known as octanoic acid, an eight-carbon saturated fatty acid) daily for eight weeks. Results showed a considerable improvement in the group taking DHA/EPA supplements. The authors suggested that these fatty acids may have an anti-inflammatory role as they inhibit arachidonic acid production. While some arachidonic acid is essential for your health, too much may make inflammation worse.
It was noted that plasma DHA and EPA levels rose two- to threefold following supplementation. The authors suggested that the higher level of EPA might have resulted from the small but significant amount of EPA in the supplement or from the retroconversion of DHA to EPA. This is important as it indicates that an algal supplement supplying DHA could be used to increase both DHA and EPA levels. Again this means you could take an algal supplement and avoid the risk of exposing yourself to toxins that may be found in fish oil supplements.
Our genes take a very long time to change and are still very similar to the genes of our ancestors during the Palaeolithic era 40,000 years ago, when the human genetic profile was established (Simopoulos, 2008). The same cannot be said for our diet. Anyone can see our diets have changes hugely - our ancestors would have been hard pushed to find burger, chips and a milkshake! But does this matter? Well, studies on the evolutionary aspects of diet indicate that the major changes that have occurred have altered the type and amount of essential fatty acids in our diets (Simopoulos, 2008). So while in many ways our bodies are potentially the same as those of our ancestors, the way we fuel it has changed drastically. This is like expecting a car to run on a lower grade fuel than it was designed for. There will inevitably be problems with the engine.
The increase in heart disease, arthritis, allergies and other health problems has encouraged some scientists to investigate the role of diet in these and other diseases. Omega-3 fats have been identified as potentially helpful. Many people cannot tolerate the taste or smell of fish oils, even when provided in capsules. Because of this, and dwindling fish stocks, interest in plant-based sources of omega-3 fatty acids has increased tremendously (Chilton et al., 2008).
Most fat eaten in excess of requirements is stored in adipose tissue in the form of triglycerides (three fatty acids combined with glycerol). Many diseases feature elevated levels of triglycerides: cardiovascular diseases, asthma, diabetes, obesity and arthritis. There is tremendous interest in plant-based oils and supplements (as an alternative to fish oil) as a source of omega-3 fatty acids for protection against these chronic diseases. Researchers from the Center for Botanical Lipids at Wake Forest University in North Carolina state that botanical (plant-based) oils hold particular promise for modulating inflammatory responses (Chilton et al., 2008).
A large number of vegetarian and vegan studies show that plant-based diets offer numerous health benefits, including the prevention and therapy of many chronic diseases including arthritis (Leitzmann, 2005). Since vegetarian and vegan diets are more sustainable, environmentally and economically, they certainly deserve more consideration in both the prevention and treatment of disease. This message needs to filter down from the peer-reviewed studies into our hospitals, schools, workplaces and homes.
The human brain grows and develops very rapidly during the first year of life, tripling in size by the age of one. The brain is largely made up of fat (over 60 per cent) and early brain development and function in humans requires a sufficient supply of polyunsaturated EFAs. For humans, the omega-6 fat arachidonic acid and the omega-3 fat DHA are essential for brain development and functioning.
Although human breast milk and cow's milk contain a similar amount of total fat, the proportion of saturated and unsaturated fats in each is very different. This difference contributes to the unsuitability of cow's milk for human infants. The high level of unsaturated fats in human breast milk reflects the crucial role these fats play in human brain development. A rapid increase in body size is more important for cows, so they produce milk high in body-building saturated fats to help their calves grow quickly.
A review of 20 studies of cognitive (brain) function of breast-fed infants compared to that of formula-fed infants concluded that the nutrients in breast milk may have a significant effect on neurological development in infants (Anderson et al., 1999). Indeed, a longer duration of breastfeeding is associated with significantly higher scores in verbal, performance and IQ tests (Mortensen et al., 2002). So breast really is best!
Attempts to alter the fatty acid composition of cow's milk, in order to meet human requirements, have involved experiments feeding cows fish meal and soya beans (Abu-Ghazaleh et al., 2004) and flaxseed (Petit, 2002). Feeding flaxseed resulted in a lower omega-6 to omega-3 fatty acid ratio, which might improve the nutritional value of milk for humans. Of course you could just eat flaxseed oil yourself to improve the balance of omega-3 and omega-6 oils in your diet while avoiding the many undesirable components of cow's milk and oily fish.
Smart enough to be veggie?
Fish oils have been sold as a magic bullet for boosting brain power. As the term 'essential' implies, we certainly do need some EFAs in the diet. However, contrary to the intensive and misleading marketing, fish and fish oils are not essential for good health. In fact, the fatty acids found in fish oil (EPA and DHA) are not defined as 'essential'; only the plant-based fats ALA and LA are. These plant-derived EFAs provide a healthier and safer source. Consider this: if fish oils were a superior source of fatty acids for brain health then vegetarians would come bottom of the intelligence stakes. The reverse appears to be the case.
Links between intelligence and the vegetarian diet were demonstrated in 2006 when a team of vegetarians won the BBC's Test the Nation IQ battle (the butchers came joint fourth; sadly there was not a team of fish-mongers!)
More weighty evidence was provided in a study published in the British Medical Journal which showed that intelligent children are more likely to become vegetarians later in life (Gale et al., 2007). Researchers from Southampton University found that people who are vegetarians by the age of 30 had an IQ five points higher than the average IQ when they were 10. This might explain why people with a higher IQ are healthier: vegetarians generally suffer less heart disease, hypertension, obesity, diabetes, various cancers, diverticular disease, bowel disorders, gallstones, kidney stones, and osteoporosis.
The obvious point here is that if omitting fish and fish oils from the diet led to a lower cognitive ability, non-fish eating children and adults would come bottom in the intelligence stakes. There has never been any study to suggest this is the case and thousands of healthy intelligent vegetarian and non-fish eating families provide proof that brains function perfectly well without fish oils!
Fish oils for brainy kids?
So what is the scientific evidence that fish oils can improve cognitive ability and where does the Government stand on this issue? The evidence comes mainly from trials done using children with behavioural problems and is largely anecdotal.
The Durham-Oxford Study is the most cited work (Richardson and Montgomery, 2005). In this study, 117 children with developmental coordination disorders (DCD) such as attention deficit/hyperactivity disorder (ADHD), dyslexia and dyspraxia were given a daily supplement of fatty acids. The treatment was a supplement containing 80 per cent fish oil and 20 per cent evening primrose oil in gelatine capsules. The daily dose of six capsules provided omega-3 fatty acids (558 mg of EPA and 174 mg of DHA) and the omega-6 fatty acid LA (60 mg), or olive oil (omega-9) as a placebo.
After three months of treatment, results showed significant improvements in reading, spelling and behaviour among those receiving the fish oil supplements. The researchers concluded that fatty acid supplements may be a safe, tolerable, effective treatment for improving academic progress and behaviour among children with DCD. In other words, children who are not fulfilling their potential may benefit from increasing their intake of essential fatty acids. The VVF asked the researchers in Durham if they would consider using flaxseed oil in future trials to see if similar results could be achieved without exposing children to potential toxins but our requests were ignored.
A follow-up trial was conducted in Durham more recently whereby three million fish oil capsules were given to 2,000 children over eight months to see if their GCSE results improved. Unfortunately the GCSE results were rather disappointing, which was not press-released by the County Council. In some very fast back-pedalling they said "...it was never intended, and the County Council never suggested, that it would use this initiative to draw conclusions about the effectiveness or otherwise of using fish oil to boost exam results." So it seems fish oil was not the magic bullet Durham Council was looking for.
It is interesting to note that the fish oil capsules used in the Durham trial cost 80p per child, per day, rather more than the 65p Durham Council was spending per child per day on school meals at the time. In 2008 the cost of ingredients had risen, but to just 80p for a secondary school child per day (Durham Council, 2008). Rather than looking for a magic bullet, improving the quality of school meals and education about diet and health would perhaps have been a better approach.
Most children in the UK eat such appalling diets that nutritional deficiencies are inevitable. Correcting such deficiencies will in many cases improve the symptoms associated with that particular deficiency. This is not the same as saying fish oil will turn all kids into geniuses, which is exactly how the media interpreted the findings. 'Council to include more fruit, vegetable and wholefoods in school meals' just doesn't make such an impressive headline as 'magic pill makes kids clever'.
The Joint Health Claims Initiative (JHCI) operated between 2000 and 2007 to ensure a level playing field for the food industry and to increase consumer protection by investigating the science behind health claims (JHCI, 2007). It is no longer in operation as the new EU 'claims' regulation for foods now verifies health claims. However, during the seven years of investigating health claims, the JHCI approved claims for soya protein, oats and reduced saturated fat all for their cholesterol-lowering effects and for wholegrain foods' benefits to heart health. They also approved health claims for long chain omega-3 fats for maintaining a healthy heart. They did not approve any claims linking omega-3 fats (or fish oils) to cognitive ability.
Unfortunately misleading publicity from this and other research has encouraged companies to produce so-called functional foods such as St Ivel Advance Omega-3 milk. The advertisements implied that this milk may make children more intelligent because it contained omega-3 fatty acids (from fish). The advertisements for this so-called 'clever milk' featured the scientist Professor Robert Winston, lending kudos to the outlandish claims. But following complaints, the Advertising Standards Authority (ASA) ruled that the advertisements were misleading and the claims used for the benefits of the milk unproven. The ASA ruled that as the children in the trial had learning difficulties, there was no basis to claim there would be an improvement in the concentration of all children. Dairy Crest, the firm behind the product, withdrew the adverts following the ruling.
Although the Government has refused to shift its position on recommending fish oils for heart health, it is clearly not convinced about cognitive benefits. The FSA states that: "Evidence on the cognitive benefits of the omega-3 fatty acids, EPA and DHA, which are found in fish oils, is currently uncertain," (FSA, 2008).
Common sense suggests that if the diet provides enough EFAs, fish oils may have no additional effect on cognitive ability at all. Encouraging children to eat oily fish in the pursuit of cleverness may lead to serious health problems due to their exposure to pollutants.