What's So Great About Phytochemicals?

The US Recommended Dietary Intake (DRI) for fruits and vegetables is 8 to 10 servings per day.  I know this sounds like a high hurdle but I cannot emphasize enough the health benefits to be gained by following this suggestion.  You would be hard-pressed to find a comparable health benefit from any single supplement.  Fruits and vegetables are loaded with plant-derived phytochemicals that give them flavor, a rainbow of colors and most importantly, resistance to disease.  Not only are the plants protected but so are you.  These phytochemicals, also called phytonutrients, share their immune-boosting and anti-inflammatory properties with every bite.  This is achieved through a number of bioactivities that include anti-oxidation, which protects DNA and other cell components from oxidative damage.  Other phytochemicals affect gene expression leading to the synthesis of health-promoting proteins while others function analogously to hormones.

As a Professor of Nutrition Sciences, two text books that I reply heavily on for current nutritional information are Nutrition Concepts and Controversies by Sizer and Whitney and Prescription for Nutritional Healing by Phyllis A. Balch.  Both books provide an in depth and well-balanced review of the roles played by Phytochemicals.  Among the most recognizable antioxidants are the carotenoids and flavonoids.  Carotenoids, which include beta-carotene, lycopene and lutein, can be found in deeply pigmented fruits and vegetables such as apricots, broccoli, carrots, sweet potatoes and tomatoes. Flavonoids are widespread in berries, vegetables, soybeans, whole wheat and other whole grains, wine and tea.  Wine and tea are also excellent sources of the antioxidants resveratrol and tannins.  Curcumin is an antioxidant and anti-inflammatory agent found in turmeric that may reduce blood clot formation and inhibit enzymes that activate carcinogens. 

Phytonutrients found in whole grains include alkylresorcinol, lignans and phytic acid, all of which reduce the risk of some cancers.  Lignans, found in flaxseed, contain phytoestrogen that blocks estrogen activity so reduces the risk of cancer of the breast, ovaries, colon and prostate.  Phytoestrogens, such as genistein, are found in soybeans and soy foods.  In cell-based studies genistein was shown to accelerate the growth of breast cancer cells at low doses and inhibit growth at high doses.  (Further details surrounding this controversy can be found at http://egglrock.blogspot.com/2014/10/are-you-afraid-of-soy.html).  Indoles and isothyiocyanates, found in cruciferous vegetables such as broccoli, brussel sprouts, cabbage, cauliflower, horseradish, mustard greens and kale, may trigger the production of enzymes that block DNA damage from carcinogens.  Other phytochemicals that have the capacity to neutralize carcinogens include monoterpenes found in citrus fruit peels and oils, and phenolic acids found in coffee beans, fruit, oats, potatoes and soy beans. Saponins found in alfalfa sprouts, green vegetables, potatoes and tomatoes are thought to prevent cancer by interfering with DNA replication.   As an added bonus, saponins also stimulate the immune response.  Capsaicin found in hot peppers is a phytonutrient that modulates blood clotting and pain perception.  Chives, garlic, leeks and onion contain a phytonutrient called allicin that functions as an antimicrobial agent and may also lower blood cholesterol.

As a pharmacologist I have spent decades searching for a magic (i.e. billion dollar) pill that would mimic these effects.  After spinning my wheels for so many years I have come to the conclusion that the health benefit of whole foods containing many thousands of these nutrients, simply cannot be duplicated with a single chemical compound formulated into a once-daily dose pill.  For those individuals who are reluctant to embrace fruits, vegetables and whole grains a product called Juice Plus+ may help to bridge this gap.  The Juice Plus+ company makes capsules and chewables from 30 whole fruits and vegetables.  Although the company certainly has its fair share of detractors the wealth of published data in peer-reviewed journal articles has conclusively demonstrated the product’s ability to positively affect biomarkers of human health.  Juice Plus+ is endorsed by a formidable number of physicians who clearly believe it is the next best thing to whole foods.  While the product cannot be used as a meal replacement it is a simple way to consume the best that phytonutrients have to offer.