ALLERGY ON STAPLE CROPS: WHEAT

Monday, April 20, 2009 9:35

Posted in category Allergies

A possible suspect in this regard is wheat, which contains defensive proteins called lectins that bind to cells in our bodies. Certain people, known as coeliacs, are made seriously ill by wheat, and the way in which lectins might cause their disease is dealt with on pl36. Coeliac disease is inherited, which suggests that there are genetic differences making some people better able to cope with a wheat-based diet than others. This was confirmed by experiments in which very large amounts of wheat protein were given to healthy volunteers. The relatives of coeliacs were made ill by these large amounts of wheat protein – so were ‘normal’ people, but the relatives of coeliacs suffered more.

It looks very much as if coeliacs are unfortunate casualties of the slow adaptation process between the human race and wheat. Wheat, after all, is a relatively new food – we have only had 10,000 years to get used to it, which is the blinking of an eye in evolutionary terms. Although natural selection should gradually eliminate any genes that make human beings susceptible to wheat (at least among wheat-eating populations) it seems to be a process that has not had time to run to completion.

If this theory is correct, then it is possible that some non-coeliacs are adversely affected (though not as seriously) by lectins orother defensive chemicals found in wheat. Not just affected by very large amounts, as in the experiment described above, but affected by a normal, everyday intake of wheat. Natural selection works more slowly on a gene that has mild ill-effects than on one with serious ill-effects, such as coeliac disease. So it is even more likely that minor problems with a new food would persist for thousands of years.

This could explain why wheat sensitivity is so common, although there are other equally plausible explanations. Wheat, along with milk, is the most commonly eaten food in Western countries, and may appear in every meal and snack of the day. There is little doubt that a food which is consumed frequently is far more likely to cause food intolerance (although no-one knows precisely why) and this alone could account for wheat’s bad record.

Other foods, besides cereals, are a possible source of toxic or damaging chemicals. Some are known to cause false food allergy in susceptible individuals and a few can cause cancer. Others, such as coffee, have a drug-like (pharmacological) action on the body, which means that they produce marked physiological effects even though they are eaten in very small amounts.