The Journal of the National Cancer Institute (JNCI) has published a paper that denies a major role to fruit and vegetable consumption in the prevention of cancer. Since this study contradicts many other studies, as well as a long-term US government recommendation ("5 per day"), it has gotten a lot of press. At this writing, there have been 520 news articles, almost all of them negative. "Simply eating your five a day will not protect you against cancer," is how the Independent (U.K.) phrased it.

However, there are several questions that need to be addressed about this study. Here are some initial thoughts. I hope to present some further thoughts after my visit with Prof. Colin Campbell this summer.

First, according to this European Prospective Investigation Into Cancer and Nutrition (EPIC) study, if the subjects had increased their fruit and vegetable intake by just 150 grams per day, they would have reduced their risk of getting cancer by 2.6 percent (men) and 2.3 percent (women). Now, 150 grams is the weight of one apple. In the United States in 2009 there were 766,130 cases of cancer in men and 713,220 cases in women, for a total of 1,479,350. Thus, by the study's own figures, one small apple or a handful of grapes could prevent 19,919 US cases of cancer in men plus 16,404 cases in women, for a total of 36,323 people. That's about the capacity of Fenway Park in Boston, where the Red Sox hold forth. So instead of minimizing the results (as virtually every media outlet chose to do) the authors of these articles could have put a positive spin on the EPIC findings. After all, is it a small thing to keep more than 36,000 Americans from getting cancer at such a minimal cost?

Looked at in another way, the patients in the study were divided up into five groups or "quintiles."

Quintile 1 consumed 0 to 226 grams per day (i.e. less than eight ounces maximum)
Quintile 2 consumed between 227-338 grams per day.
Quintile 3 consumed between 339-462 grams per day.
Quintile 4 consumed between 463-646 grams per day.
Quintile 5 consumed more than 647 grams per day (i.e., a minimum of 23 ounces)

The difference in the Hazard Ratio (i.e., the risk) of cancer between Quintile 1 and Quintile 5 was 11 percent. Thus, if everyone in the US adopted a diet in which they ate over a pound (23 ounces) of fruits and vegetables per day, the cancer incidence would drop from its present-day 1,479,350 for a savings of many thousands of cases of cancer.

The European Prospective Investigation Into Cancer and Nutrition (EPIC) encourages us to think internationally. The World Health Organization (WHO) has estimated that there are at least 12 million new cancers diagnosed worldwide (Science Digest 2008). According to the EPIC study, conversion to a moderately high fruit-and-vegetable diet could ideally save hundreds of thousands of people from getting cancer each year. This astonishing fact was hardly conveyed by the negative press reports on the EPIC study.

To be concluded, with references, next week

--Ralph W. Moss, Ph.D.

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