Alfalfa phytoestrogens

Hwang, J, Hodis, H and Sevanian, A (2001) Soy and alfalfa phytoestrogen extracts become potent low-density lipoprotein antioxidants in the presence of acerola cherry extract. J. Agric. Food Chem., 49, 308-314. 

An inverse correlation between thyroid cancer risk and phytoestrogens was recently proposed as a result of a multi-ethnic population-based case control study conducted in the San Francisco Bay Area (Hom-Ross et al., 2002). In this study, dietary habits and phytoestrogen consumption were assessed by a food-frequency questionnaire and by a nutrient database. The outcome of the study was that soy-based foods and alfalfa sprouts were associated with a reduction of thyroid cancer risk, whereas a Western diet did not influence cancer risk. No difference was observed between American and Asian women or between pre- and postmenopausal women. Furthermore, among the few compounds examined, the isoflavones genistein and daidzein and the lignan secoisolariciresinol were the phytoestrogens most frequently associated with risk reduction (Horn-Ross et al., 2002). 

The three main classes of phytoestrogens (and common food sources) are isoflavones (soybeans), lignans (cereals and oilseeds such as flaxseed), and coumestans (alfalfa sprouts). The biologic potency of phytoestrogens varies and is less than that of synthetic estrogen. 

Livestock ingestion of large quantities of phytoestrogens in certain clovers, alfalfas, and in moldy grains... 

There are considerable data on the chronic toxicity of NP in laboratory animals. The focus of these investigations has typically been evaluation of the potential reproductive and developmental effects of NP, due to its ability to modulate estrogen receptor-mediated responses. Many endpoints are not consistently observed across studies. Some of this variability may be due to differences in the conditions, design, and other test-specific variables of the toxicity tests. For example, since phytoestrogens are abundant in most laboratory animal feeds (such as found in soy and alfalfa) and are known to modulate estrogen receptor-mediated responses, phytoestrogens may be confounding factors as a result of the feed selection. 

Phytoestrogens (phytosterols)compounds with very mild hormonal activity, such as licorice, red clover, and alfalfa. 

Structures of phytoestrogens. These are diphenolic compounds found in plants, such as soybeans, sprouts of cloves, and alfalfa. 

Elakovich, S.D., and J.M. Hampton. 1984. Analysis of coumestrol, a phytoestrogen, in alfalfa tablets sold for human consumption. /. Agric. Food Chem. 32(1) 173-175. 

The three major chemical types of phytoestrogens that have been identified are flavones, isoflavones, and coumestans. The estrogenic potency of these com pounds is variable. The flavones are weak estrogens. The methoxyflavone, tricin, is a constituent of alfalfa and weakly estrogenic in the mouse. 

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