Maca

Clinical summary

A nutritionally valuable native Peruvian plant that grows only in the harsh climate above 4,000 feet. Maca has been used traditionally to enhance fertility and sexual behavior in both men and women and to relieve menopausal symptoms. Maca has been purported to treat cancer and to improve stamina in cancer patients. Although animal studies show increased sexual function, few human trials have been performed. One human trial showed increased libido, while another showed improved sperm production and sperm motility. Both studies showed physiologic effects were not due to serum hormone levels. The hexanic extract of maca appears to be more effective at improving rat sexual performance than methanolic and chloroformic extracts. Studies have also shown increase in endurance in rats. Dried maca has been shown to have lower content of the suspected active metabolite than fresh maca. Maca is also available as a liquor, tonic and mayonnaise, although health benefit of these derivatives seems minimal. The therapeutic dose and toxicity of maca is unknown. No major adverse effects related to the consumption of maca have been reported

 Purported uses

• Cancer treatment
• Infertility
• Menopausal symptoms
• Sexual performance
• Strength and stamina

Mechanism of action

Maca root contains far greater amounts of glucosinolates than other members of the Brassicacae family, such as cabbage, cauliflower and broccoli. Fertility-enhancing properties of maca are thought to be due to aromatic isothiocyanates hydrolyzed from these glucosinolates. Furthermore, benzyl isothiocyanate has been reported to inhibit breast, stomach and liver cancer in rats. Aphrodisiacal properties are attributed to the prostaglandins, sterols and amides of polyunsaturated fatty acids. The most confounding question about maca’s effect is its ability to influence sexual performance without affecting serum hormone levels such as luteinizing hormone, follicle stimulating hormone, prolactin, testosterone and estradiol. It is therefore assumed that maca acts on the receptors for these hormones. Alkaloids purified from the maca root are thought to affect the hypothalamic-pituitary axis, explaining why maca can induce effects in both sexes.