Nutrition: back to our roots

We have eaten plant foods throughout our evolution. This has shaped our current nutritional requirements. Our evolutionary diets would have been high in fibre, vegetable protein, plant sterols and other protective ‘phytochemicals’, and low in harmful saturated and trans fats.

Fruits, green leafy parts of plants, shoots, seeds, nuts, roots and tubers are the fundamental components of the primate eating pattern – and common sense tells us that these foods should be the foods that humans eat, too.

Our Stone Age predecessors ate three or more times the amount of plant foods that we do – about nine servings daily of fruits and vegetables, compared to the UK average of around three. Similarly, while chimpanzees are known to eat 123 different plant varieties in a year, even the most health conscious Westerner rarely consumes more than 20 or 30. Seventy five per cent of our global food supply comes from just 12 crops.

And we consume just a fraction of the antioxidants, calcium, iron and other nutrients that our ancestors ate every day.

Even without cows and yoghurts, our ancestors also managed to get more calcium than we do, primarily because of the dark green leafy vegetables in their diet. They racked up an impressive 1,900 milligrams (mg) a day, compared with the 1,007 mg that most men – and the 777 mg that most women – consume these days!

OUR BODIES NEED PLANT NUTRIENTS

Vitamins are essential micronutrients that cannot be synthesised by the body and must be obtained in the food we consume. Since plants, rich in vitamin C (ascorbic acid) have always been a reliable part of our diet, we have lost the ability to synthesise (make our own) vitamin C. Without it in our diet, our health suffers dramatically. In contrast, carnivores have never had a reliable source of vitamin C in their diets. They are still able to make their own from the basic raw materials in their meat diet. This is one example of many metabolic processes and nutritional needs that clearly say our bodies are designed to thrive on a diet of plant foods (Carpenter, 1992; Milton, 1999; Milton, 2000).

VITAMIN B12

Vitamin B12 is often used as a reason why we cannot possibly be vegetarian in nature since this essential B-vitamin is not found in plants. This vitamin is actually produced by bacteria in the soil and is required in only very tiny amounts by humans. Eating plant foods with B12-containing soil particles attached would have been commonplace in our evolutionary history.

Of course today we cannot rely on unwashed vegetables providing vitamin B12, which is why it is vital that a daily source of this vitamin is provided by fortified foods such as yeast extracts, soya products and many breakfast cereals. In fact, we now know that the B12 found in fortified foods is better absorbed by the body than the B12 found in foods such as meat, fish or eggs!

Scientists have being saying for decades that while designed to subsist on vegetarian foods, man has “perverted his dietary habits to accept the food of the carnivore,” (Collens and Dobkin, 1965). And this is not without serious consequences for our health.

CHOLESTEROL OVERWHELMS A PLANT- EATER’S LIVER

Cholesterol is a type of lipid (fat) called a sterol. The body does need some cholesterol, but the liver can make all of the cholesterol that the body requires.

It is well known that too much cholesterol is harmful to the human body. What is less widely known is that cholesterol is only found in animal foods, and not plant foods.

Meat-eating animals have an unlimited capacity to process and excrete cholesterol from their bodies. For example, you could feed a cat pure egg yolks all day long, and he or she would excrete all of it, never suffering from a build up of cholesterol. On the other hand, people’s (like other plant-eating animals) livers have a very limited capacity for cholesterol removal. Most people have great difficulty eliminating the amounts of cholesterol that they take in from eating animal products.

What appears to be an inefficiency is a result of our evolutionary design. We were made to consume plant foods (containing no cholesterol); therefore we have never needed a highly efficient cholesterol-eliminating system. It is also believed that evolution favoured (and therefore conserved) mechanisms in the body which tend to raise blood cholesterol levels (Jenkins et al., 2003).

Eating animal products – including meats, fish, eggs and dairy foods – can lead to a build up of cholesterol. This can result in deposits in the arteries (atherosclerosis), in the skin or under the eyes (xanthelasma) and in the tendons. Bile supersaturated with cholesterol forms gallstones. Meat-eaters are twice as likely to be afflicted with gallstones, compared to vegetarians. For further information see Viva! Health's report, White Meat Black Mark.

Cholesterol can’t be avoided by choosing lean cuts of meat as it’s mainly found in the lean parts. White and red meat and fish all contain cholesterol. One small, grilled, skinless chicken breast contains around 100 milligrams of cholesterol – an amount that can add roughly 0.13 mmol/L (or 5 mg/dL) to your cholesterol level! Worse still, animal products also contain saturated fat which causes our livers to make even more cholesterol.

It is a sad fact that cholesterol-lowering medications are the order of the day for modern, middle aged humans – a consequence of our Westernised diet and lifestyle.

But scientists have managed to lower people’s cholesterol levels by simply changing their diets. By eating more fibre, vegetable proteins and plant sterols – in the form of leafy vegetables, fruit and nuts – healthy people’s cholesterol levels have dropped by over 30 per cent! This effect is comparable to the effect of standard cholesterol-lowering medications (statins) and simply involves reverting to our evolutionary roots.