Alcoholic Beverages as a Source of Estrogens

Alcoholic beverages contain not only alcohol but also numerous other substances (i.e., congeners) that may contribute to the beverages' physiological effects. Plants used to produce alcoholic beverages contain estrogenlike substances (i.e., phytoestrogens). Observations that men with alcoholic cirrhosis often show testicular failure and symptoms of feminization have suggested that alcoholic beverages may contain biologically active phytoestrogens as congeners. Biochemical analyses have identified several phytoestrogens in the congeners of bourbon, beer, and wine. Studies using subjects who produced no estrogen themselves (i.e., rats whose ovaries had been removed and postmenopausal women) demonstrated that phytoestrogens in alcoholic beverage congeners exerted estrogenlike effects in both animals and humans. Those effects were observed even at moderate drinking levels. KEY WORDS: alcoholic beverage; congener; estrogens; male; female; plant; alcoholic liver cirrhosis; testicular dysfunction; feminization; hypothesis testing; biochemical mechanism; animal model; ovary; moderate AOD use; prolactin; follicle stimulating hormone; luteinizing hormone; cholesterol; globulins; literature review The excessive consumption of alcoholic beverages is associated with numerous serious medical, social, and legal problems that exact a high human and economic price. Despite the monumental problems caused by alcohol abuse and dependence, however, the fact is that most people who drink consume moderate amounts of alcoholic beverages. Indeed, an additional direction for alcohol research has been generated by reports of the beneficial effect of moderate drinking on the risk of coronary heart disease (CHD) (Klatsky 1994). Thus, studies have found that compared with abstainers and heavier drinkers, moderate drinkers (i.e., women who consume up to one standard drink1 per day and men who consume up to two drinks per day) have a significantly reduced risk of CHD. This definition of moderate drinking also includes people who consume alcoholic beverages only occasionally and corresponds to the recommended limits for low-risk alcohol consumption (U.S. Department of Agriculture and U.S. Department of Health and Human Services 1995). When discussing the risks and benefits associated with alcoholic beverages, most people think in terms of the beverages' alcohol contents. Consequently, much of the research aimed at determining how alcoholic beverages affect the body has been conducted using alcohol solutions to approximate the effects of alcoholic beverages. Alcoholic beverages, however, contain numerous substances in addition to alcohol itself (i.e., congeners), which determine a beverage's taste, color, and aroma. Alcoholic beverages differ in both the composition and quantity of congeners. These variations result from the different methods and materials (e.g., grains, fruits, and hops) from which the beverages are produced. This article explores the hypothesis that congeners, particularly phytoestrogens, contribute to the effects of alcoholic beverages on the body. EVIDENCE OF THE ESTROGENIC ACTIVITY OF CONGENERS Researchers' interest in the congeners of alcoholic beverages first was spurred by various reports in the agricultural literature. For example, some studies reported that grazing animals feeding on particular forages and grasses showed evidence of impaired reproduction. Subsequently, using those forages, researchers isolated substances that exhibited estrogenlike activity and later identified them as estrogenlike substances of plant origin (i.e., nonsteroidal phytoestrogens) (see the following section). Finally, studies demonstrated that the phytoestrogens found in milled by-products and oils made from various grains, hops, corn, and rice exhibited biological activity both in experimental animals and in studies using cultured cells (see Gavaler et al. 1987a,b; 1995a,b; and references therein). Estrogens and Their Activities Estrogens are female sex hormones that are produced primarily in the ovaries. …