Diets Promoted in the Media

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Q: I have been trying to follow the Eat Right for Your Blood Type diet and have been reading PH Miracle regarding acidity/alkalinity. Do either of these hold any credibility in your view?

Sharon, Bangor, Maine 

A: Your question brings up a very important issue for cancer survivors and the public at large: how do you sift through diets promoted in the media to figure out which have scientific merit and which are in fact distorted or misleading?

The old adage, "if it sounds too good to be true, it probably is," might be a good mindset to have when evaluating diets and supplements marketed towards cancer patients. There are over 10 million cancer survivors living in the U.S. In the current environment of an unregulated dietary supplement industry, companies can target sales messages that tap into the vulnerability of those affected by cancer and their loved ones. Buyer beware is a good strategy to keep in mind before beginning a supplement or diet regimen. We always encourage patients or their caregivers to speak with their nutritionist and/or physician to address any concerns about the merit or feasibility of following a "cancer-fighting" diet or supplement regimen.

Both of these diets you inquired about are examples of eating plans that boast exaggerated health claims. While there are certainly healthful foods included in these diets, there are also unnecessary recommendations to avoid certain foods and food groups. In fact, neither the Blood Type Diet nor the Alkaline Diet have scientific evidence to support the purported health benefits made by advocates of these plans. The Blood Type Diet and Acid/Alkaline Diet lack what we refer to as biologic plausibility. In other words, given the medical community's understanding of how the body works, these diets don't make sense. Without well designed, human research studies showing that these diets actually do what they say they can, qualified dietitians, nutritionists and other health care professionals can not recommend either of these diets to their patients.

For more information specifically on the Acid/Alkaline diet, please refer to an article published by one of our Dana-Farber nutritionists on the Intelihealth website: Alkaline Diets and Cancer: Fact or Fiction? 

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