Couple eating at breakfast table

There are thousands of phytochemicals that will never make it onto the side of a cereal box but may play a role in reducing the risk of chronic diseases—and those are just the ones we know about. Whole plant foods have consistently been found to be protective, so it’s reasonable for scientists to try to find the “magic bullet” active ingredient that can be sold in a pill, but “[p]ills or tablets simply cannot mimic this balanced natural combination of phytochemicals present in fruits and vegetables.” When isolated out, the compound may lose its activity or behave differently. The antioxidant and anticancer activities of plant foods are thought to derive from the “additive and synergistic effects of phytochemicals in fruits and vegetables,” meaning the whole may be greater than the sum of its parts. This helps explain why a pill can’t replace the complex combination of phytochemicals present in whole plant foods.

As T. Colin Campbell has pointed out, more than a hundred trials “overwhelmingly show no long-term benefit for vitamin supplements, along with worrisome findings that certain vitamins may even increase disease occurrence for diabetes, heart disease, and cancer.” Supplementation with fish oil, for example, appears useless or, even worse, “posing increased risk for diabetes,” yet the science doesn’t seem to matter. People continue to buy them.

“The public desire for quick fixes through pills…is overwhelming, especially when money can be made.”

Each plant has thousands of different phytochemicals, as well as entirely different phytonutrient profiles. So, there may be synergistic effects when eating different foods together, too. Eating beta-carotene in carrot form is more beneficial than in pill form. because of all the other compounds in the carrot that may synergize with the beta-carotene. Well, when we dip that carrot in hummus, we suddenly have the thousands of carrot compounds mixing with the thousands of chickpea compounds. So what happens if we mix different fruits with different vegetables or different beans?

As you can see in my video Food Synergy, combining foods across different categories increased the likelihood of synergy. For example, a study showed the antioxidant powers of raspberries and adzuki beans. If there were a strictly additive effect, the expected combined antioxidant power would simply be that of the raspberries plus that of the adzuki beans. However, the observed combined antioxidant power was actually greater than the sum of one plus the other.

What about cancer-fighting effects? The study was repeated, but, this time, different combinations of food were dripped on breast cancer cells growing in a petri dish. For some foods, the same synergistic effects were found. Grapes, for example, can suppress the growth of breast cancer cells about 30 percent, but onions worked even better, cutting breast cancer cell growth in half. One would assume that if we added half the grapes with half the onion, we’d get a result somewhere in the middle between the two. Instead, the researchers found that cancer cell growth was suppressed by up to 70 percent with that combination. The whole plus the whole was greater than the sum of the whole parts. Given these findings, did the researchers recommend people eat a variety of foods? Perhaps adding some raisins along with chopped red onions to our next salad? Where’s the money in that? No, the reason the researchers were investigating the different types of interactions was “to identify mixtures that hold synergistic interactions that can ultimately lead to the development of functional foods”—maybe something like grape-flavored Funyuns.

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NUTRITIONFACTS.ORG is a strictly non-commercial, science-based public service provided by Dr. Michael Greger, providing free updates on the latest in nutrition research via bite-sized videos. There are more than a thousand videos on nearly every aspect of healthy eating, with new videos and articles uploaded every day. NutritionFacts.org was launched with seed money and support by the Jesse & Julie Rasch Foundation. Incorporated as a 501c3 nonprofit charity, NutritionFacts.org now relies on individual donors to keep the site alive.

Dr. Greger is a physician, New York Times bestselling author, and internationally recognized speaker on nutrition, food safety, and public health issues. A founding member and Fellow of the American College of Lifestyle Medicine, Dr. Greger is licensed as a general practitioner specializing in clinical nutrition. Currently he proudly serves as the public health director at the Humane Society of the United States. Dr. Greger is a graduate of the Cornell University School of Agriculture and the Tufts University School of Medicine.

His latest book, How Not to Die, became an instant New York Times Best Seller. 100% of all proceeds he has ever received from his books, DVDs, and speaking engagements has always and will always be donated to charity. Dr. Greger receives no compensation for his work on NutritionFacts.org.

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