Part 2 of 4 (Part 1, Part 3, Part 4)

Toxicity Of Raw Vegetables

The second investigation (10) concerned the inedibility of many of today's plant foods in the raw state. Beans and other legumes although rich in both carbohydrate and protein, also contain a repellent called protease that must be broken down by cooking, and cooking for a long time, before they can be eaten safely.

Starchy roots - yams and cassava - are common staples today, but if not well cooked are very toxic indeed. The cassava even contains cyanide which must be oxidised by heat to make it safe to eat. And the cereals - wheat, rice, barley, oats, and rye - are also inedible in quantity if not cooked first. (See also soybeans below.)

Unlike meat, which can be easily digested in its raw state, vegetables should really infrequently be eaten raw and cereals should be fermented and then cooked for a very long time before being eaten to neutralize the phytic acid and other toxic anti-nutrients. That fact that we don't do these things is the reason for so much atopic disease - asthma, eczema, and so on - around today.

'Homo carnivorus'

There is no doubt whatsoever that we cannot be a vegetarian species. From at least the time that Homo erectus appeared in the cold Eurasian continent some 500,000 years ago, we must have lived on and adapted to a diet almost exclusively of meat.

All this evidence points to our being pure carnivores, as are the big cats. However, we are a remarkably successful species. It is unlikely that we would have been quite so successful if we had been forced to rely on only one source of food.

It is obvious from archaeological remains that we tended to be more opportunist eaters. We hunted and ate meat primarily but, if meat was in short supply, we would eat almost anything - so long as it did not require cooking.

This still precluded some of the roots and most of the legumes and cereals that we eat today. When meat was in short supply, we got our protein from nuts and ate fruits and berries. During our evolution, therefore, when we lived well, our diet was high in protein and fat: during lean times it was richer in carbohydrates.

So, our ideal diet, the one we evolved and adapted to, must also be one which is high in proteins and fats, and low in carbohydrates.

The Diet Revolutions (11)

About 9,000 years ago our ancestors started to domesticate wild grasses. From these we get the cereals we know today: wheat, barley, maize, rice. We could not eat them directly as the starch molecule is too large for our digestive process to cope with.

It had to be broken down first by cooking. This development began a dramatic change in Man's lifestyle. Once our ancestors produced controlled quantities of higher-energy starches which could be stored, their numbers could grow. And as numbers grew, it became more difficult to maintain their supplies through hunting. Thus their basic diet changed from a high protein/fat diet to one largely of carbohydrate.

This radical change of diet brought with it radical changes to our ancestors, both in physique and in health.

As vegetable foods made up an increasing proportion of our diet and intakes of meat declined, so our height also declined. European, meat-eating Homo erectus erectus of 30,000 years ago was some 150 mm (6 inches) taller than his agricultural descendants. Indeed, even today we are still shorter than they were. We see the same pattern in North America. The Paleoindian hunters of 10,000 years ago were much taller than their farming descendants at the time of European conquests of the fifteenth and sixteenth centuries AD.

There is no evidence of nutritional diseases before the advent of agriculture. After it, there is. The cereal crops that became the modern staples, together with root crops that began to be cultivated, are all relatively deficient in protein and the B vitamins.

Additionally, all the cereals contain a substance called phytic acid that binds with a number of minerals and other nutrients and reduces their availability to the digestion. As a consequence, with the coming of agriculture we see the appearance of a number of nutritional diseases such as rickets, pellagra, dental caries, beriberi, obesity, allergies and cancers. We see the emergence of the 'diseases of civilization'.

About two hundred years ago there began a second dietary revolution which was brought about with the introduction of industrialization. This had two powerful but opposite effects on our health. The industrialized countries with their increased wealth no longer had to rely on home-produced food with its seasonal changes, they could import the food they needed.

Thus the populations of those countries could look forward to going through life without ever being hungry. A good thing, you might think, but it brought with it adverse effects.

Many of the imported foods were unnatural to those eating them. The new fruits, in particular, as well as being novel, tasted nice. As a consequence, we changed from eating what we needed to eating what we liked.

And with no previous experience of these foods, our bodies had never learned when to stop. Subsequently, science made possible the production of synthetic foods that had the appearance, texture and taste of the real thing, but with none of the proteins, minerals and vitamins.

Sugar, which contains no useful nutrients whatsoever, became easy and cheap to produce, leading to a 30-fold increase in its consumption.

The industrial revolution, therefore, was something of a two-edged sword. On the one hand it gave people a wider range of nutritious food than had ever before been possible; on the other hand it brought diabetes, peptic ulcers, heart disease and yet more dental caries, cancers and obesity.

In the late twentieth century the speed at which our diet has become increasingly unnatural has quickened. When a music-hall singer at the beginning of the twentieth century sang that 'a little of what you fancy does you good', there was still an element of truth in it - at least as far as diet was concerned.

When hunger signaled that the body needed more nourishment, appetite determined which elements. At one time, we ate what we had an appetite for, and the body's needs were met. Nature told us what to eat and by this means, nature ensured that we ate a balanced diet.

Over the last two centuries, and increasingly during the last several decades, however, the situation has changed dramatically.

During the millions of years that we have been evolving, we have been eating our natural food. We had a sense of taste that told us what was good for us and what was poisonous. Like all animals on this planet, we ate what we liked without danger either from nutritional deficiency or from overindulgence. But when food is changed from its natural state that no longer holds true.

At first, all our food, whether from animal or vegetable sources, was eaten raw. Now cooking food has become a way of life. Most people in Western society today would not eat uncooked meat. Indeed, as possible pathogens would not be killed, it may be unwise to eat raw meat.

But, while boiling parallels the first stages of digestion, and may be helpful in that process, over-cooking in a way that chars food can present the digestive processes with food which it has great difficulty digesting.

In 1838, in Canada, Dr. William Beaumont performed a remarkable series of experiments on a man named Alexis St. Martin. St. Martin had an opening in the front wall of his stomach from a gunshot wound.

Even after the wound had healed, there remained a small opening through which the mucous membrane of his stomach could be seen and, through which, substances could be introduced into the stomach or removed from it. Dr. Beaumont was able to introduce foodstuffs through the opening and observe the rate of digestion.

By so doing, he found that raw beef digested in two hours, well done boiled beef in three hours but well-done roast beef took four hours. Similarly, raw eggs were digested in one-and-a-half hours but hard-boiled eggs took three-and-a-half hours.

In contrast, the cellulose which envelops cereal grains and which is the major constituent of vegetable cell walls, cannot be broken down by the digestive juices at all. Only the process of cooking ruptures them.

Cooking is also the only means of breaking down the large starch molecules so that we can digest them. As a consequence, cereals and many other vegetables need not only to be cooked, but well cooked, before they can be digested.

That is not to say, however, that cooking presents no other problems. Cooked food, for example, can be damaging to the teeth. We know that sugar is a major cause of cavities in teeth, particularly children's teeth.

We also know that the effect is worse if the sugary food is sticky. Dates and toffee are both high in sugars and stick around the teeth. Both, therefore, might be expected to cause cavities. But while toffee does cause dental caries, Arabs who eat sticky, sweet dates have healthy teeth. Why the difference?

All living organisms have immune systems that protect them from invading bacteria. At the time of being eaten, the raw dates are still living organisms and their immune systems are working. The bacteria that would ferment the sugars in the dates and form the acid which attacks teeth, are repelled. That is not the case with cooked and, therefore, dead toffee.

Cooking can also destroy some nutrients: Vitamin C is a good example. Thus nutrients, which might be present when food is 'natural', are lost and their correct balance may also be lost.

Cooking food, therefore, may cause changes to which the body's systems are not entirely adapted and which, as a consequence, may cause us minor problems.

Today, however, food has been changed much more radically and in a shorter time span - a time span much too short for us to have evolved and adapted to it. A large proportion of the food we eat now can no longer be called natural. This is particularly so in the case of carbohydrates - sugars and starches. There is a considerable body of evidence that it this change which is the cause of so many of today's ills.

There are a number of vegetable-based foods that are processed to such a high degree that nothing but pure carbohydrate is left. The obvious example is white, granulated sugar.

Sugar cane and sugar beet contain a significant proportion of protein that is lost during processing. Also lost are other nutrients such as vitamins and fiber. The end product is pure, concentrated carbohydrate. It is this concentration that is so unnatural. This has not happened with protein as it is relatively expensive.

Neither has it happened with fats as they are already concentrated naturally. The concentration of carbohydrate allowed a dramatic and rapid increase in its consumption. Annual sugar consumption in Britain in the middle of the eighteenth century was less than two kilograms (4½ lbs) per person, today it is more than sixty kilograms (130 lbs).

The same is true of cereals, albeit to a lesser degree. Many packaged foods today contain what is euphemistically called 'modified starch'.

This again is highly concentrated carbohydrate, in this case cereal starch. This concentration of sugars and starches is done to make foods cheaper, more attractive and, of course, to make a bigger profit for the manufacturers. But it has had serious effects in large sections of the population.

The body's natural nutrient-requirement signal, the appetite, has not evolved to cope with such unnatural foods. It knows when to stop us eating meat, but not when to stop us eating chocolate bars and cakes. It is also much easier to eat modern white bread than the stodgy, pre-Industrial-Revolution bread.

During The Past Century There Have Been Dramatic Rises In A Number Of Previously Rare Diseases.

These include heart disease, cancers, diabetes, peptic ulcers, tooth decay, constipation and obesity. Although dietary fat is blamed for many of them, a half century of research has failed consistently to provide any convincing evidence in support of this hypothesis (12) .

The fat-and-heart disease hypothesis relies on comparisons between disease patterns in 'civilized' countries and more primitive societies, and the amounts of fat in their respective diets.

They purport to show that where a lot of fat is eaten there is a high incidence of heart disease, while others who eat less fat have lower incidences of the disease. However, if one makes similar comparisons, replacing fat with sugar, one finds similar patterns. And with sugar the argument is much more compelling.

The food that we eat is made up of many different nutrients. We need energy that we measure in calories. Fats, carbohydrates and proteins all contain energy and so lack of energy is generally not a problem. But we also need a variety of minerals, trace elements and vitamins.

Although we need them only in small amounts, they are vital to our health. The diet of the adult lacto-ovo-vegetarian may be more bulky and lower in energy than a mixed diet, but because he is consuming eggs, milk and cheese, his diet generally is nutritionally similar to the mixed diet and there is little problem.

However, while it is possible to meet the body's nutritional requirements with the vegan diet if great care is taken, without that care there is a real risk of deficiencies leading to serious ill-health. This risk increases as diets become more restricted. Historical evidence shows that Man can live healthily on diets which vary enormously in their content.

However, it also tells us that, generally, the further one gets from a diet which includes animal products, the greater is the risk of ill health.

The Meat Vitamin: B-12

The most important deficiency for the vegan is of vitamin B-12. By definition vitamin B-12 is essential to human life. It is essential for the synthesis of nucleic acids, the maintenance of the myelin sheath (the insulation around nerves which when damaged causes Multiple Sclerosis); indeed its presence or deficiency affects nearly all body tissues, particularly those with rapidly dividing cells.

Without it we suffer from pernicious anemia that, as its name suggests, is deadly, and a degeneration of the nervous system.

Vitamin B-12 is unique among vitamins in that while it is found universally in foods of animal origin, where it is derived ultimately from bacteria, there is no active vitamin B-12 in anything that grows out of the ground. Where vitamin B-12 is found on plants it is there only fortuitously in bacterial contamination.

Bacteria in the human colon make prodigious amounts of vitamin B-12. Unfortunately, this is useless as it is not absorbed through the colon wall.

Dr. Sheila Callender (13) tells of treating vegans who had severe vitamin B-12 deficiency by making water extracts of their stools that she fed to them, thus affecting a cure. An Iranian vegan sect unwittingly also makes use of the fact that human stools contain vitamin B-12.

Investigators could not understand how members of this sect remained healthy until their investigations showed that they grew their vegetables in human manure - and then ate the vegetables without being too fussy about washing them first (14) .

To enable vegans to survive, vitamin B-12 is added artificially to breakfast cereals in Britain and may be bought in pill form. This is hardly a natural way to get food and in many cases it is self-defeating. Vitamin B-12 is also unlike all other vitamins in that it occurs as a number of analogues, only one of which, cyanocobalamin, is active for humans.

In collecting human stools for analysis Dr. Victor Herbert found that of each one hundred micrograms of vitamin B-12 extracted, only five micrograms was of the cyanocobalamin analogue (15). Thus even in this most prodigious source of the vitamin ninety-five percent was composed of analogues that were useless.

Several fermented products such as tempeh, a soy bean product, and spirulinas, used by strict vegans as a source of vitamin B-12, either do not contain appreciable amounts of the vitamin or contain analogues of the vitamin which are not active for humans (16).

Vitamin B-12 status was assessed in a group of 110 adults and 42 children from a macrobiotic community in New England. Over half of the adults had low concentrations of vitamin B-12. Children were short in stature and low in weight. The community relied on sea vegetables for the vitamin. However, the researchers say: " We could not show that individuals who reported more of these sea vegetables had increased vitamin B-12 status..."

"Similar null results were obtained with the other sea vegetables, tempeh, and miso, foods considered to contain significant amounts of vitamin B-12 by many individuals in the macrobiotic community.

On the other hand, it is possible that the vitamin B-12 measured in these sea vegetables has no biological activity for humans....only a small fraction of total corrinoids in Spirulina, a genus of blue-green algae contains cobalamin and that the remainder is in the form of analogues that are not biologically active for humans. In these cases the analogues can block metabolism by the body of the ones that are of use."

Dr Herbert suspects that vegans taking the spirulinas as a source of vitamin B-12 actually bring on the symptoms of deficiency quicker.

Yeast is also believed by vegetarians to contain vitamin B-12 - and it does. But even if the yeast is grown on a medium rich in vitamin B-12, unless some of the growing medium is mixed with the yeast, it is unlikely to contain the cyanocobalamin analogue that is the active form for humans.

The amount of vitamin B-12 we need is very small: about five micrograms per day.

Eating more than is needed results in a reserve being built up in the body. When a person becomes a vegan, those stores are depleted - but only gradually. Thus it is possible to live for several years on such a diet before the onset of symptoms of deficiency. In England a carefully conducted study (17) carried out on vegans showed that they all got vitamin B-12 deficiency eventually.

The first manifestation of vitamin B-12 deficiency is usually mental disturbances. These range from abnormal mood swings, mental slowness and memory problems, through hallucinations and depression to severe psychosis.

Physical symptoms include: rapid heartbeat, cardiac pain, facial swellings, jaundice, weakness and fatigue and loss of weight. While a dose of active vitamin B-12 given by injection can cure symptoms very quickly, there is a hidden danger.

A largely vegetable-based diet provides large quantities of folic acid, which works in conjunction with vitamin B-12. In a diet that contains folic acid but is devoid of vitamin B-12 the folic acid can disguise the vitamin's deficiency. In such a case, irreparable damage to nerves and the spinal cord can take place such that by the time symptoms become apparent, death is inevitable.

Continue to Part 3

References