The maca plant (Lepidium meyenii), native to the Andes of central Peru, has traditionally been used as a staple crop as one of the few plants that successfully grow in that harsh climate. But over the last decade, interest in maca has increased worldwide and it has been advertised as a superfood with the ability to balance hormones, improve concentration, enhance fertility, and increase energy and stamina. Maca is a cruciferous vegetable related to broccoli, cauliflower, turnip, and cabbage that is rich in protein and fiber as well as many essential amino acids. Maca boasts high amounts of vitamin C, iron, calcium, and copper, and various plant compounds believed to be the source of maca's beneficial effects on vigor. Maca's glucosinolates have an antibiotic-like effect and help ward off bacterial, viral, and fungal infection in the intestines. Maca's polyphenols are considered the source of improved digestion, brain function, and blood sugar levels, and offer protection against blood clots, heart disease, and certain cancers. The antifungal action of maca extract is thought to be related to the presence of imidazole alkaloids chemically similar to antifungal azoles. There are many studies assessing maca's medicinal benefits regarding sexual dysfunction regulation; neuroprotective effects; memory enhancement; and the root's antidepressant, antioxidant, anti-cancer, and anti-inflammatory properties. A 2012 review by Gonzales in Evidence Based Complementary Alternative Medicine assessed evidence from 75 clinical studies for the effectiveness of maca. The authors found that though further research is required, available data suggest that maca shows significant positive effects on fertility, mood, memory, osteoporosis, metabolism, and the treatment of some tumors. Most studies of maca focus on fertility and libido, and have shown there is some evidence that maca root affects men's fertility. A small number of studies have shown an improvement in some menopausal symptoms. A systematic review of randomized controlled trials published in Maturitas in 2011 found that maca eased menopausal symptoms including hot flashes and interrupted sleep. A highly cited 2006 clinical study by Meissner et al. in International Journal of Biomedical Science evaluated the therapeutic effects of maca as a non-hormonal alternative to hormone replacement therapy in perimenopausal women. Results revealed that in addition to reduction in body weight and blood pressure and an increase in serum high-density lipoprotein and iron, maca balanced levels of follicle-stimulating hormone, estradiol, prostaglandin, and adrenocorticotropic hormones. The researchers reported that maca significantly reduced frequency of hot flushes, incidence in night sweating, interrupted sleep pattern, anxiety, irritability, depression, and heart palpitations. Peruvians in the central Andes dry maca root and consume 20 g to 100 g maca powder daily in porridge or a sweet drink. Doses up to 3 g daily for up to 4 months have been found to be safe in clinical trials. Maca is generally sold as a powder, in capsules, or liquid extract, available from health food stores and online markets. The taste and aroma of maca is reminiscent of caramel or butterscotch. Maca is often included in smoothies, sprinkled on oatmeal, or included in no-bake desserts. In general, maca is considered safe and there is some evidence for beneficial pharmacological effects, but more studies presenting robust data are needed as the overall evidence is too limited to draw firm conclusions. There are no reports of adverse reactions after consuming maca. Maca has a high vitamin K content. Patients who take warfarin should be informed that more frequent INR monitoring may be required when taking maca.
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