Phenols/polyphenols beneficial effects

Enrichment of processed food with plant material or plant extracts rich in polyphenols has two aspects in relation to human nutrition and human health. Food protected against oxidation has better keeping quality and will stay healthy longer since formation of toxic oxidation products, like cholesterol oxides, is being prevented (Britt et al., 1998). The other aspect is the beneficial effects of the intake of polyphenols on human health. Both of these aspects are, however, related to the availability of the phenolic substances. 

Polyphenols are ubiquitous in all plant organs where they are found as monomers or in polymerised forms (Schofield et al, 2001). In addition to the beneficial effect of poljq)henols, they also bind minerals and precipitate proteins and carbohydrates, in effect reducing the nutritive value of foods. Polyphenols have been classified for nutritional purposes into extractable and non-extractable types (Bravo, 1998). Extractable polyphenols are low-and intermediate-weight phenolics while non-extractable polyphenols have high molecular weight and are insoluble in normal solvents. 

The effects of wine and its polyphenol constituents on early indicators of coronary heart disease such as elevated levels of plasma lipids, platelets and serum antioxidant activity were discussed in a review by Cooper et al. (2004). This review also addressed whether the polyphenols or alcohol are responsible for the beneficial effects of wine on cardio-vascular health. The authors conclude that red wine polyphenols have little effect on plasma lipid concentrations, but that wine consumption reduces the susceptibility of low-density lipoprotein (LDL) cholesterol to oxidation and increase serum antioxidant capacity. These effects, however, do depend on the amount of wine that is consumed and the period of supplementation. It was suggested that specific polyphenols appear to have endothelium-dependent vaso-relaxing abilities. Red wine phenolics also have an inhibitory effect on platelet aggregation. Evidence suggests that alcohol has a positive synergistic effect with wine polyphenols on some atherosclerosis risk factors. Thus, evidence that wine drinking is beneficial for cardiac health appears positive. 

Since other dietary components affect absorption and excretion of deleterious compounds in foods, dietary protein, carbohydrate, fat, mineral, vitamin, or polyphenol content, as well as fiber, probably may influence the biological action of nutrients, antinutrients, and toxicants in foods. The paper by H. F, Stich and M. P. Rosen on antimutagenic and anticarcinogenic effects of naturally occurring phenolic compounds and that by T. K, Smith and M, S, Carson on the effect of diet on toxicosis of trichothecenes deserve special mention for pointing to promising future research directions on beneficial effects of diet on food safety. 

Overall, the research effort to identify health properties of the dried plum relies on two primary signatures for superfruit status—dietary fiber and mixed polyphenols. A Japanese research group has done much of the work on polyphenols, establishing a list of candidates for antioxidant or other cellular effects of prune compounds. Oligomeric proanthocyani-dins, chlorogenic acid, caffeoylquinic acid, various other phenolic acids, and lignans have exhibited antioxidant activity in test-tube studies. Each of these compounds is under research for potential beneficial roles supporting human health. 

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