Does beef cause cancer?
What about the accusation that beef causes cancer, in particular cancer of the colon? The genesis of this myth involves more than just muddied thinking, but actual skulduggery. In 1965 an influential physician, Ernst Wynder, took the data for the mostly processed vegetable oils, called them animal fat (which they were not) and compared them with worldwide colon cancer mortality.6 The table he produced showed high rates of colon cancer in European countries and low rates of colon cancer in Japan, and concluded that there was a positive effect, in other words, that saturated fat, the kind found in beef, caused colon cancer. What the data actually showed was that consumption of polyunsaturated vegetable oils, not saturated animal fats, was associated with the incidence of colon cancer. And Wynder forgot to mention that Asians have much higher rates than Americans of other types of cancers, particularly cancers of the liver, pancreas, stomach, esophagus and lungs.
Then in 1973, William Haenszel and his colleagues from the National Cancer Institute reported the findings from a study that relied on dietary recall and lacked matched controls—in other words, a very poorly designed study.7 The researchers stated that they found a relationship between beef and colon cancer that fit the earlier work of Wynder. Actually, what they really found was that those westernized Japanese Americans who said they consumed lots of macaroni, green beans and peas, as well as beef, had the highest rates of colon cancer; while traditional Japanese Americans who said they consumed lots of dried cuttlefish, Chinese peas, bamboo shoots, rice and fermented soy products had the highest rates of colon cancer. This second-rate and inconclusive study is firmly fixed in the consciousness of the scientific community as providing evidence for the assertion that beef causes colon cancer.
Two American studies conducted in the 1990's have found a higher risk of colon cancer among those who eat red meat.8 However, no study done in Europe has ever shown an association between meat consumption and cancer.9 This suggests that European sausage and luncheon meat, included in the rubric of "meat consumption," are prepared by traditional methods that require few additives, while the similar products in the United States contain many carcinogenic preservatives and flavorings. Unfortunately, the American Cancer Society's 1996 recommendation that Americans cut down on their consumption of meat—particularly fatty meat—in order to avoid cancer makes no distinction between fresh meats and those that have been embalmed with modern chemicals.
While two US studies have implicated meat consumption as a cause of colon cancer, there are several that contradict these findings. In 1975, Rowland Philips compared Seventh-Day Adventists physicians, who do not eat meat, with non-Seventh Day Adventist physicians, and found that the vegetarian doctors had higher rates of gastrointestinal and colon-rectal cancer deaths.10 National Cancer Institute data show that Argentina, with very high levels of beef consumption, has significantly lower rates of colon cancer than other western countries where beef consumption is considerably lower.11 A 1997 study published in the International Journal of Cancer found that increased risk of colon and rectal cancer was positively associated with consumption of bread, cereal dishes, potatoes, cakes, desserts and refined sugars, but not with eggs or meat.12 And a 1978 study published in the Journal of the National Cancer Institute found no greater risk of colon cancer, regardless of the amounts of beef or other meats ingested.13 The study also found that those who ate plenty of cruciferous vegetables, such as cabbage, Brussels sprouts and broccoli, had lower rates of colon cancer. So just because it's all right to eat beef doesn't mean you shouldn't eat your broccoli.
Actually, we know one of the mechanisms whereby colon cancer is initiated, and it does not involve meat per se. Colon cancer occurs when high levels of dietary vegetable oils and hydrogenated fats, along with certain carcinogens, are acted on by certain enzymes in the cells lining the colon, leading to tumor formation.14 This explains the fact that in industrialized countries, where there are many carcinogens in the diet and where consumption of vegetable oils and carcinogens is high, some studies have correlated meat-eating with colon cancer; but in traditional societies, where vegetable oils are absent and the food is free of additives, meat-eating is not associated with cancer.
Riding piggy back on the alleged association of beef with colon cancer are supposed links with other cancers, such as breast cancer. Here the evidence shows a similarly inconsistent pattern. Cancer is a disease of rich countries where numerous factors can be fingered—altered fats, fabricated foods, low levels of protective nutrients, high levels of carcinogens—and rich countries consume lots of beef. But association is not the same as cause. Countries where there are more telephones have more cancer, but that does not mean that telephones cause cancer. Fat consumption in general also gets the blame for high rates of breast cancer. But a recent survey showed that women on lowfat diets have just as much breast cancer as those on high fat diets.15
High protein diets are said to cause osteoporosis and Americans are now being advised to avoid beef in order to protect their bones. Once again, it's important to look at the studies carefully. Research that showed a link with bone loss and protein consumption was done with purified protein powders.16 With meat, a natural protein food, there was no negative calcium balance. New evidence indicates that women who eat lots of meat had fewer hip fractures compared to those who avoided it.17
High protein diets are said to contribute to kidney problems but, again, the evidence is contradictory. Although protein restriction can be helpful for those who are suffering kidney failure, there is no evidence that eating meat causes kidney disease.18 The fat-soluble vitamins found exclusively in animal fats are very important for healthy kidney function.
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