An INVITATION to the READER and the INVESTIGATORS OF THE HARVARD NURSES’ HEALTH STUDY
It was June 1982. At a news conference in Washington, a group of internationally recognized scientists had just finished announcing the National Research Council’s report on diet, nutrition, and cancer1. The report received extensive news coverage, lots of criticism from the industry most affected by the report’s conclusion and – according to some authorities-the highest number of requests for a report ever released by the august National Academy of Sciences (NAS), our sponsor.
Why the attention? Spending about two years, six three-day meetings, a million dollars, and a rather substantial amount of time reviewing what turned out to be a rather large amount of information, we had simply summarized the scientific evidence on the association of diet with cancer. The intense interest that followed was due to our rather provocative recommendations to cut down on fat intake and increase the consumption of fruits, vegetables, and whole grain cereal-based products.
Today, seventeen years later, these dietary recommendations for reducing cancer risk-virtually identical with those for cardiovascular disease-sound very familiar. At that time, however, they seemed to be a hefty message for many, for they indicated a fairly major change in dietary practices-away from the esteemed meat and dairy-focused American eating patterns toward a more plant-based eating style. The recommendations in the report had enormous economic implications, suggested major public policy changes, and challenged some deeply held philosophical and cultural beliefs.
It was in this climate during the early 1980s that the very influential Nurses’ Health Study at Harvard University2 was adopted to investigate the recommendations of this and similar reports.
Although the Nurses’ Health Study has yielded a variety of highly publicized diet and disease reports, [...]
Breast cancer is clearly a terrifying disease. Out of every nine women in America, at least one will fall victim to its toll. Despite massive research and immense funding, scientists are often at odds regarding its possible causes.
At the heart of the confusion and controversy is the role of a high-fat diet. On the one hand, extensive laboratory research and human epidemiological studies often link high-fat diets to higher rates of breast cancer. On the other hand, several prominent medical studies have shown little or no relationship between fat intake and breast cancer. Lacking conclusive evidence, most nutritional experts play it safe by suggesting that the most effective way to reduce breast cancer is to reduce overall fat intake.
What we have found from the China Project is that such advice is not sufficient. The fact that significantly lower breast cancer rates exist throughout China is not simply due to low-fat diets but also because these diets are largely plant-based.
Let’s look at the findings:
- Even though breast cancer is substantially lower in China, a broad 13-fold range can still be found between various areas of the country.
- Fat intake in rural China ranges between 6 and 24% of total calories. By contrast, this range soars to 25-45% of total calories in the U.S.
- Age at first menstruation (menarche) in China is typically 15-19 years, considerably later than the 10-14 years in the U.S.
- Blood levels of the female hormone estrogen are significantly lower among Chinese women than among U.S. women.
- As dietary fat declines from 24 to 6%, and these diets become richer in plant matter, breast cancer rates make a similar decline.
In our survey we found that girls who consumed diets that were limited in plant foods, yet were [...]