Fenugreek (Trigonella foenum-graecum) seeds contain mucilage, quercetin, luteolin, genistein, vitexintrigonelline, 4-hydroxyisoleucine, sotolon, diosgenin, luteolin, protodioscin and several other pharmacologically active saponins and isoflavones. Fenugreek has been used in a number of geographical regions worldwide as a galactogogue to increase milk supply and is included in numerous proprietary mixtures promoted to increase milk supply.[1-13] The galactogogue effect of fenugreek may be primarily psychological in humans;[14] however, animal studies indicate that fenugreek might work primarily by increasing insulin, prolactin and oxytocin secretion.[12,15] Evidence for a galactogogue effect is mostly anecdotal. A limited number of published studies of low to moderate quality have found mixed results for a galactogogue effect for fenugreek.[16-19] A meta-analysis of controlled studies found fenugreek to have a mild galactogogue effect and unknown safety profile.[13] In a US survey, of 122 mothers who used fenugreek as a galactogogue 43% thought it increased milk supply and 5% thought it decreased their milk supply.[20] Some evidence indicates that fenugreek might be more effective in the first few days postpartum than after 2 weeks postpartum.[21] Some of these studies used a multi-ingredient combination products in which fenugreek was only one component, so the results might be different from studies in which fenugreek was used alone. Galactogogues should never replace evaluation and counseling on modifiable factors that affect milk production.[22,23]
Fenugreek is "generally recognized as safe" (GRAS) as a flavoring by the U.S. Food and Drug Administration. Limited scientific data exist on the safety of fenugreek in nursing mothers or infants, although it has a long history of use as a food and medicine in India and China. When used as a medicinal, it is generally well tolerated in adults, but gastrointestinal side effects such as nausea, vomiting, diarrhea and flatulence may occur. Liver toxicity has been reported, both taken alone and in herbal combinations that included fenugreek.[24-27] Diarrhea and hepatomegaly occurred in a woman taking fennel, fenugreek, and goat's rue as galactogogues.[17] Another mother reported increased heart rate and breast congestion.[28] Allergic reactions, exacerbation of asthma, and a 14% decrease in serum potassium have been reported. One nursing mother developed toxic epidermal necrolysis thought to be caused by her intake of fenugreek as a galactogogue. Cross-reaction with chickpeas, peanuts, and other legumes is possible. Dosages typically used to increase milk supply are 1 to 6 grams daily; in dosages of about 25 grams or more daily, fenugreek may cause lowering of cholesterol and blood sugar. It can also interact with warfarin to cause bleeding. Caution should be used in giving high dosages to women with diabetes mellitus or those taking warfarin. In a survey of nursing mothers in the United States, 85 had used fenugreek as a galactogogue and 45% reported having experienced an adverse reaction from the supplement.[29] Perhaps its most unusual side effect is the imparting an odor of maple syrup to the urine, sweat, feces, and possibly breastmilk by the sotolon in fenugreek.[3,30-32]
Dietary supplements do not require extensive pre-marketing approval from the U.S. Food and Drug Administration. Manufacturers are responsible to ensure safety, but do not need to prove the safety and effectiveness of dietary supplements before they are marketed. Dietary supplements may contain multiple ingredients, and differences are often found between labeled and actual ingredients or their amounts. A manufacturer may contract with an independent organization to verify the quality of a product or its ingredients, but that does not certify the safety or effectiveness of a product. Because of the above issues, clinical testing results on one product may not be applicable to other products. More detailed information about dietary supplements is available elsewhere on the LactMed Web site.