Does saturated fat cause breast, colon and other cancers?
Saturated fat and cancer are widely believed to be closely linked. Many doctors, nutritionists and health authorities believe that a high intake of saturated fat increases the risks of cancer – just as they believe that saturated fat increases the risks of heart disease.
As closer examination of the disease patterns tells us, however, that there is no positive relationship between saturated fat and cancer.
Just as in the case of heart disease, the same situation applies.
Until early last century, people ate large amounts of saturated fat and used it as their main form of cooking oil – pork lard in China, butter in Europe, ghee in India, coconut oil in the tropics. Yet cancer was rare.
The rate of cancer began to rise sharply only in recent decades – when the consumption of saturated fat actually fell.
Thus, we need to seriously re-consider the idea that saturated fat and cancer are closely related.
The McGovern Committee report
The idea that saturated fat causes cancer began to form in the 1950s, when Ancel Keys stated that saturated fat raised cholesterol levels and caused heart disease.
As we saw in the article on causes of coronary heart disease, this idea is badly mistaken. However, many scientists embraced this idea and, by the 1970s, saturated fat acquired a strong reputation as the “bad fat” – even though it is medically known that saturated fat is necessary for many body functions.
In 1977, the US Senate Select Committee on Nutrition and Human Needs, chaired by Senator George McGovern, released its Dietary Goals for the United States.
The Dietary Goals stated categorically that “the over consumption of fat, generally, and saturated fat in particular. . . have been related to six of the ten leading causes of death. . .” in the United States.
The McGovern Committee report claimed that a high fat diet caused cancer. The report said saturated fat and cancer – particularly breast cancer and colon cancer – were closely linked. It urged for Americans to substitute polyunsaturates for saturated fat from animal sources – use margarine and corn oil instead of butter, lard and tallow.
The rest of the world followed America’s example.
Testimony of Dr Fred Kummerow
Among the scientists who testified before the McGovern Committee was Dr Fred Kummerow of the University of Illinois. He disagreed with the view that there were links between saturated fat and heart disease, as well as links between saturated fat and cancer.
Fred Kummerow pointed out that the real harm was caused by trans fat in products like margarine. He also warned against soft drinks, which contained large amounts of sugar.
And, Fred Kummerow pleaded for a return to traditional foods rich in saturated fats.
However, the testimony of Fred Kummerow was buried in the voluminous McGovern Committee report. His views and the scientific evidence he presented were largely ignored.
Saturated fat and cancer – Mary Enig’s research
At the time the McGovern Committee released its Dietary Goals for the United States, Mary Enig was a graduate student at the University of Maryland.
Mary Enig, who was familiar with the research of Fred Kummerow, noted that the McGovern Committee report claiming a strong link between saturated fat and cancer contradicted many real life situations:
- In America, the consumption of saturated fat had been declining steadily since the turn of the century, yet the cancer rate was rising sharply.
- Greece had the same level of dietary fat intake as Israel, but only one-fourth the breast cancer rate.
- Spain had a slightly higher dietary fat intake than France or Italy, but only one-third the mortality rate from breast cancer.
- Puerto Rico, with a high animal fat intake, had a very low rate of breast and colon cancer.
- The Netherlands and Finland both have the same level of animal fat intake – about 100 grams per person per day. But the Netherlands has twice the rate of both breast and colon cancer. The difference was that people in the Netherlands consumed 53 grams of vegetable fat per person compared to 13 grams in Finland.
This seems to suggest that there is a stronger link between vegetable oil, or polyunsaturated fat and cancer, than between saturated fat and cancer.
- A study in Cali, Columbia found a fourfold excess risk for colon cancer in the higher economic classes, which used less animal fat than the lower economic classes.
- A study on Seventh-Day Adventist physicians, who avoid meat found they had a significantly higher rate of colon cancer than non-Seventh Day Adventist physicians.
Mary Enig analyzed the US Department of Agriculture data that the McGovern Committee had used and she reached an opposite conclusion:
|There is a a strong positive correlation between total fat / vegetable fat and cancer. There is a strong negative correlation or no correlation between animal fat or saturated fat and cancer deaths.|
In other words, Mary Enig found that the use of vegetable oils seemed to predispose to cancer and animal fats seemed to protect against cancer.
Saturated fat and cancer – Harvard University Research
More recent research by Prof Walter Willett at the Harvard School of Public Health provides further evidence that there is no real connection between a high fat diet and cancer. Nor is there any link between saturated fat and cancer.
Walter Willett’s research at Harvard includes the Nurses Study II, which monitors the long-term health condition of nearly 116,000 women, and the Health Professionals Study, which monitors the long-term health condition of 52,000 men.
These studies reveal that the type fat has a far greater effect on cancer risks than the amount of fat. In other words, quality matters more than quantity.
The website of the Harvard University School of Public Health reports:
Fat and breast cancer
Initially, international comparisons showed higher breast cancer rates in countries with higher per capita fat intake. But as more detailed studies were performed over the next couple of decades, the apparent link between total fat intake and breast cancer has faded.
Fat and colon cancer
As with breast cancer, international comparisons initially suggested an association between total dietary fat intake and colon cancer risk. But later studies contradicted these earlier findings and revealed instead an association that was weak at best.
However, Harvard researchers found that although fat and saturated fat intake did not seem to increase colon cancer risk, high consumption of red meat appears to increase colon cancer risks.
Fat and prostate Cancer
Here, the evidence is contradictory.There is some evidence that diets high in animal fat and saturated fat increase prostate cancer risk. However, some studies have also shown no association, while others have implicated unsaturated fats.
Fat and other Cancers
In the Nurses’ Health Study, Harvard researchers found that a high intake of trans fats increased the risk for non-Hodgkin’s lymphoma and that a high saturated fat intake increased the risk for endometrial cancer.
Saturated fat and cancer
Although the Harvard website did not specially mention a lack of correlation between saturated fat and cancer, its findings can be taken to include saturated fat as part of overall fat intake.
One of the problems with earlier scientific studies on saturated fat and cancer is that the researchers often do not take into account trans fats.
Even Walter Willett and his team of Harvard researchers failed to make this distinction until the 1990s. Once they took trans fats into account, they discovered that trans fats are often the real culprits in causing heart disease, cancer, diabetes, obseity and other modern, degenerative diseases.
So before the 1990s, Walter Willett found, like most other researchers, that saturated fat “caused” heart disease and cancer. But in the early 1990s, his researchers contacted Mary Enig for data on trans fats.
Working with the refined data, Walter Willett confirmed, in the Nurses Health Study II, that nurses with higher rates of cancer were those who consumed more margarine and vegetable shortenings – not those who ate butter, eggs, cheese and meat.
In other words, he no longer found any link between saturated fat and cancer, but he now found a strong link between trans fats and cancer.
This correlation between trans fat and cancer was never published, but was reported at the Baltimore Data Bank Conference in 1992.
Unfortunately, even many present day research studies continue not to make any distinction between saturated fat and trans fat. And so we continue to get reports every now and then about links between saturated fat and cancer, heart disease and various other diseases.
As more researchers work with better and more accurate data, a clearer picture will emerge showing that, just as there was no link between saturated fat and cancer a hundred years ago, there is no link today.
The problem is not saturated fat – which even protects against cancer in certain cases. In fact, even trans fats that occur naturally – in the milk and meat of cows and other grass-fed animals – are known to protect against cancer.
The real problem is with artificial trans fats, and other types of artificial foods.