Mediterranean Diet Not Just for Your Heart

Karen Collins, MS, RD, CDN

American Institute for Cancer Research

            Most of us are familiar with the link between a Mediterranean-style diet and protection against heart disease. But several new studies present evidence that this plant-based diet – which features plenty of vegetables and limited meat, with olive oil the primary source of fat – also reduces cancer risk.  

The latest study to make headlines was published in July in the British Journal of Cancer. Researchers compiled information on over 25,000 Greek men and women and evaluated the relationship between adherence to a traditional Mediterranean Diet and cancer incidence.

Although none of the individual components of a Mediterranean diet were shown to significantly affect the participants’ cancer incidence, the dietary pattern as a whole proved promising. People who most closely conformed to the key dietary characteristics of a Mediterranean diet (ranking highest on at least two-thirds of the factors considered hallmarks of the diet) were 22 percent less likely to develop cancer.

            Among the key dietary characteristics included on the adherence scale were: above average consumption of vegetables, fruits and nuts, legumes, grains or fish; below average consumption of meat or dairy products; greater than average proportion of monounsaturated versus saturated fat consumption.

In addition, even those participants who did not closely adhere to the diet showed more protection from cancer the closer they came to the dietary goals. In other words, a few simple changes like adding more beans, or boosting vegetables and switching from butter to olive oil as the primary fat, could significantly change cancer risk.

In studies among the U.S. population, people who eat according to a more Mediterranean-type pattern have also shown lower cancer risk.   Research published in the Archives of Internal Medicine in 2007 revealed that men who most closely followed a Mediterranean diet showed 17 percent lower cancer mortality and women 12 percent lower, compared to those with the lowest Mediterranean diet adherence.  

A 2008 study that looked at diet patterns and breast cancer risk also showed that cancer incidence decreased when participants’ diets most closely resembled a Mediterranean pattern. According to the study authors, these women lowered their incidence of breast cancer by nearly a quarter compared to women whose diets were least like this pattern.

            But not all research supports this link. In fact, a study that was recently published in the American Journal of Clinical Nutrition found no connection between the Mediterranean-type diet and cancer.   One potential reason: Participants in this study who were labeled as part of the Mediterranean group ate less than half the vegetables and consumed less fruit, more meat and a higher percentage of saturated fat than the high adherence Mediterranean groups in the two aforementioned studies.

What’s the mechanism behind the purported protective effect of the diet? Experts suggest that increased antioxidant levels due to more vegetables, fruit and olive oil and less meat could contribute to both the reduction of heart disease and the lower cancer incidence.

            In addition, with its emphasis on low-calorie-dense foods like vegetables, fruit, legumes and grains, the Mediterranean diet could also support weight maintenance – a critical step to reduce risk of heart disease and several types of cancer. Be sure to note, however, that if thoughts of olive oil’s healthful qualities lead you to use excessive amounts or to overeat, that could lead to weight gain – which adds cancer risk.

September 1, 2008                                                    

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The American Institute for Cancer Research (AICR) is the cancer charity that fosters research on the relationship of nutrition, physical activity and weight management to cancer risk, interprets the scientific literature and educates the public about the results. It has contributed more than $86 million for innovative research conducted at universities, hospitals and research centers across the country. AICR has published two landmark reports that interpret the accumulated research in the field and is committed to a process of continuous review. AICR also provides a wide range of educational programs to help millions of Americans learn to make dietary changes for lower cancer risk. Its award-winning New American Plate program is presented in brochures, seminars and on its Web site, www.aicr.org. AICR is a member of the World Cancer Research Fund International.