plant-based diet have recently gained wider approval by mainstream medicine.
The American Heart Association and the American Diabetes Association have both recommended diets high in fruits and vegetables.
The latest American Cancer Society Guidelines, published in 2012, include "Eat a healthy diet, with an emphasis on plant foods," and "Eat at least 2½ cups of vegetables and fruits each day."1
The USDA also recommends increasing fruit and vegetable intake, as does the World Health Organization (WHO), which lists low fruit and vegetable intake among the top ten risk factors for premature death worldwide.
Why Are Plants Good For Us?For years, the benefits of plants were attributed to their abundant vitamins and minerals and/or their high fiber content. Although these factors cannot be overlooked, their polyphenol content may play a role as well.
Approximately 5,000 polyphenols have been identified, and like many vitamins, they act as antioxidants.2 The recommended dietary intake has been estimated at one gram per day.3
Their full range of benefits has yet to be defined, but they appear to be involved in cell signaling, regulating inflammation, gene regulation, and hormone balancing.
Plant Polyphenols: A Large, Healthy FamilyPolyphenols are classified as phenolic acids, flavonoids, stilbenes, and lignans. Flavonoids, which are the most familiar to us, are subdivided into flavonols, flavones, isoflavones, flavanones, anthocyanidins, and flavanols.
Flavonols consist of kaempferol, myricetin, and quercetin, compounds that occurs in apples and onions that have been the subject of recent research.
Flavones are comprised of luteolin and apigenin, and isoflavones, which occur in soy, consist of daidzein and genistein.
Flavonones include naringenin, eriodictyol and hesperetin. And flavanols, which consist of proanthocyanidins and catechins, have recently been in the spotlight due to their presence in red grapes and tea.4, 5, 6
Plant Polyphenols Prevent Chronic DiseasePolyphenols protect against a wide variety of diseases including heart disease, cancer, osteoporosis, diabetes, and neurodegenerative disease.3
Flavonoids may help protect against heart disease via their anti-inflammatory effect, as demonstrated by a reduction in C-reactive protein levels.7
They also support the production of nitric oxide, a gas that maintains blood vessel flexibility.
Plant Polyphenols Prevent CancerFlavonoid polyphenols reduce the risk of cancer through several mechanisms. They increase levels of detoxification enzymes, maintain normal cell cycle regulation, inhibit cellular proliferation, induce apoptosis, inhibit tumor invasion, and decrease inflammation.
Isoflavones, such as those found in soy, could help prevent cancers in another way: by blocking the effects of estrogen in sensitive tissues. Many breast cancers, for example, require estrogen to grow.
Isoflavones may also have pro-estrogenic effects in other areas, such as bone, where the hormone's effects are desirable.8, 9
Why Not Grow Your Own Plants?Polyphenols are just the latest positive aspect of a plant-based diet to come to light. It goes without saying that plant foods are colorful, delicious, and fun to prepare and grow.
Start with a few potted herbs in your kitchen window. If you are lucky enough to have a patio or balcony, an earth box is a great way to grow tomatoes, peppers, and other small vegetables.
If you have a yard, consider planting rows of vegetables or even fruit trees. Besides being good exercise, home gardening is a great way to ensure fresh produce is readily available.
- CA Cancer J Clin. 2012 Jan-Feb;62(1):30-67.
- Asian Pac J Cancer Prev. 2008 Apr-Jun;9(2):187-95.
- Am J Clin Nutr. 2005 Jan;81(1 Suppl):215S-217S.
- Am J Clin Nutr. 2004 May;79(5):727-47.
- Pharmacol Res. 2005 Sep;52(3):264-70.
- Obesity (Silver Spring). 2007 Jun;15(6):1473-83.
- Am J Clin Nutr. 2014 Mar;99(3):479-89.
- J Med Food. 2005 Winter;8(4):439-45.
- Int J Clin Exp Pathol. 2014; 7(4): 1687–1694.F
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