Polyphenols - Plant derived foods with secondary metabolites
Adequate Intake ?:
Phytochemicals that are present in the diet, and have been associated to health
benefits, include various groups of polyphenols (anthocyanins, proanthocyanidins, Isoflavones and resveratrol)
Plant derived foods such as fruits, nuts, vegetables, grains, legumes, spices, etc. exert some beneficial effects on human health, particularly on age-related diseases
Several health organizations around the world to recommend an increase in the intake of plant derived food
The capacity to reduce the risk of chronic diseases has been associated in part to non-nutrient secondary metabolites (phytochemicals) that have been shown to exert a wide range of biological activities
These metabolites have low potency as bioactive compounds when compared to pharmaceutical drugs, but since they are ingested regularly and in significant amounts as part of the diet, they may have a noticeable long-term physiological effect
Phytochemicals that are present in the diet, and have been associated to health benefits, include various groups of polyphenols (anthocyanins, proanthocyanidins, isoflavones and resveratrol)
Bioactivity has been associated with antioxidant properties which are involved in many of the chronic degenerative diseases (LDL oxidation in atheroma plaque development, DNA oxidation and cancer, oxidation and aging, inflammation, etc.)
In the past few years, many food bioactive constituents have been commercialized in the form of pharmaceutical products
These range of products cannot be truly classified as ‘food’ and a new hybrid term
between nutrients and pharmaceuticals, ‘nutraceuticals’, has been coined to designate them
Some of the most common phytochemicals found in the nutraceutical market are polyphenols such as anthocyanins, proanthocyanidins, isoflavones, resveratrol, etc
• What is the most convincing health benefit of proanthocyanidins?
reduction in blood pressure
• Are polyphenols well absorbed?
• What are the main health benefits of reseveratrol? How is resveratrol related aging? Does resveratrol supplementation work in humans?
Lower organisms turn on Sir2, results in humans aren't good, but can't do good studies.
• Why are isoflavones biologically active? What does the most current literature suggest about isoflavones and osteoporosis? Why might high isoflavone intakes be inappropriate for some?
History & Discovery:
Absorption and Storage:
Polyphenols and Cancer
Some polyphenols are considered cancer chemopreventive agents because they inhibit carcinogen activation, commonly catalyzed by cytochrome P450 enzymes, in vivo or in vitro
General inhibitors of cytochrome P450 enzymes are not useful, because they may affect their normal physiological functions such as in steroid metabolism
Many polyphenols are considered chemopreventive agents because they induce phase II enzymes. In theory, induction of phase II enzymes may facilitate the elimination of certain carcinogens or their reactive intermediates
Certain polyphenols inhibit arachidonic acid metabolism. Metabolism of arachidonic acid (and linoleic acid) leads to the production of many pro-inflammatory ormitogenic metabolites such as certain prostaglandins and reactive oxygen species
Isoflavones and lignans are phytoestrogens and have been demonstrated to modulate hormone-dependent carcinogenesis in animals