¶Hood colorings and flavorings. Butter yellow, Violet No. 1 and Red Dyes Nos. 2 and 4 have been banned by the Food and Drug Administration after they were shown to cause cancer in animal tests. Flavorings for root beer and vermouth and the artificial sweetener cyclamate met a similar fate, and saccharin is likely to join the list soon.
¶Pesticides. Several—including alden, dieldrin, DDT and arsenicals—have been shown to cause cancer in animals. Most of these were banned because residues were found repeatedly in foods sold for human consumption.
Other inadvertent food contaminants that can cause cancer in man as well as in animals include the cattle fattener DES and aflatoxin, a poison produced by a mold that grows on corn, peanuts, rice, wheat and other foods stored under humid conditions.
But in concentrating on food additives and inadvertent contaminants as the main cancer‐causing culprits in the American diet, we may be allowing the most dangerous dietary villain to escape. For a growing body of evidence suggests that the very structure of the typical American diet may be cancerpromoting. The studies show that the heavy reliance on meat and dairy products, laden as they are with saturated fats and cholesterol, and the minimal consumption of fibrous foods (grains, fruits and vegetables) are associated with an increased risk of cancer, particularly cancers of the colon‐rectum and breast, two of the leading cancer killers of Americans.
An international study showed that persons who developed colon‐rectal cancer consumed more meat than persons free of this disease. Throughout the world, in countries where the consumption of meats and dairy products is low, the incidence of colon‐rectal and breast cancer (as well as heart disease) is also low. In Japan, for example, deaths from these diseases are far less common than in the United States. But when Japanese migrate to this country and adopt a more Western diet, their rates of these cancers increase, and in one or two generations JapaneseAmericans have the same cancer rates other Americans.
Among native Americans, Seventhday Adventists and Mormons, most of whom live on vegetarian diets, have much lower rates of cancer of the colonrectum, breast and uterus than the average American. Obese persons have more cancers of the breast, uterus, pancreas and, gallbladder than persons of normal weight.
When the diet is high in animal fats and cholesterol, bacteria that live in the gut break down these foodstuffs into substances that can cause cancer. Since such diets are usually low in bulky, fibrous foods, the stool tends to be more concentrated and to stay longer in the colon, exposing colonic tissues to these carcinogens. Some of the substances produced from cholesterol by intestinal bacteria can mimic the action of female sex hormones and may promote the growth of cancers in hormone‐sensitive tisssues like the breast and uterus.
Thus, the best dietary approach to cancer prevention is not necessarily avoiding food additives and other chemicals found in minute quantities in foods. Rather it lies in keeping your weight down and adopting a prudent diet that may protect you from cancer and heart disease at the same time. You don’t have to become a total vegetarian; instead, consider reorienting your diet to concentrate more on fish, chicken, grains; fruits and vegetables and less on meats, eggs and dairy products containing butterfat.
It would also help to avoid consuming excessive amounts of alcoholic beverages. Heavy drinkers face a much higher than normal risk of developing cancers of the esophagus, mouth and throat, larynx and liver.
As for the much‐touted preventive value of vitamin supplements, none has been shown to protect against cancer unless the diet lacks the normal recommended amounts. However, large doses of certain chemical relatives of vitamin A seem to protect animals against cancers that affect the body’s skin and lining cells. The protective effect of these experimental chemicals will soon be tested in people who face an unusually high risk of developing bladder cancer. But large doses of vitamin A itself are poisonous and should not be used.
Good nutrition is important in resisting most diseases, and it is likely that cancer is among them. But just because a little of something is good, that does not mean a lot of it is better. Currently many nutritionists consider the American diet too rich in fat, sugar and even protein to he maximally healthy, and are advocating a return to a diet that emphasizes complex carbohydrates such as are found in fruits and vegetables.