Maca

Common names: Maca, black maca, red maca

Botanical names: Lepidium meyenii, Lepidium peruvianum

Parts used and where grown

Maca is a cruciferous vegetable in the mustard family, related to radishes and turnips. Used as food and medicine in the Andes Mountains of Peru, it is not known to occur naturally anywhere else in the world. The four major cultivars of maca are red, black, cream, and purple; none has been definitely proven to be medicinally superior to any other.

Maca has been used in connection with the following conditions (refer to the individual health concern for complete information):

Science Ratings

Health Concerns

Low libido

Male infertility

Stress

Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars

Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star

For a herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Maca root has been an important food for the native people in the Andes of Peru, including the Incas, for at least 2,000 years.¹ It is eaten baked, dried, mixed with milk, or in a variety of other forms and dishes. It is also traditionally believed to enhance strength, endurance, libido, and fertility.²

Active constituents

Maca contains substantial quantities of protein, fat, fibre, and minerals including iron, which also contribute to its nutritional value. It also contains glucosinolates,³ the strong-smelling compounds that are responsible for the pungent smell and taste of mustard family plants. Neither these nor any other constituents in maca have definitively been shown to contribute to its actions.

Preliminary studies have shown that maca can increase libido in healthy men.⁴ It does this without influencing levels of testosterone or any other sex hormones.⁵ Healthy men who take maca have also been shown to have increased semen volume, increased sperm counts, and enhanced sperm motility.⁶

Numerous animal studies show that maca extracts can increase sex drive and improve fertility.⁷ ⁸ ⁹ Other studies support that it can relieve the negative effects of stress reactions.¹⁰ The red cultivar, though not the black or cream, also reduced enlarged prostates in rats.¹¹

How much is usually taken?

The amount used successfully in studies so far has been 500 to 1,000 mg three times per day of dried root powder in capsules.¹²

Are there any side effects or interactions?

Glucosinolates can cause goitre (swollen thyroid gland with decreased activity) if taken in excess combined with a low-iodine diet. Though this is documented to occur with other glucosinolate-rich foods, it is not known if maca causes goitre.

At the time of writing, there were no well-known drug interactions with maca.

References
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1. Valentova K, Ulrichova J. Smallanthus sonchifolius and Lepidium meyenii - prospective Andean crops for the prevention of chronic diseases. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2003;147:119–30.

2. Smith E. Maca root: Modern rediscovery of an ancient Andean fertility food. J Amer Herbalists Guild 2003;4:15–21.

3. Piacente S, Carbone V, Plaza A, Zampelli A, Pizza C. Investigation of the tuber constituents of maca (Lepidium meyenii Walp.). J Agric Food Chem 2002;50:5621–5.

4. Gonzales GF, Cordova A, Vega K, et al. Effect of Lepidium meyenii (maca) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men. Andrologia 2002;34:367–72.

5. Gonzales GF, Cordova A, Vega K, et al. Effect of Lepidium meyenii (maca), a root with aphrodisiac and fertility-enhancing properties, on serum reproductive hormone levels in adult healthy men. J Endocrinol 2003;176:163–8.

6. Gonzales GF, Cordova A, Gonzales C, et al. Lepidium meyenii (maca) improved semen parameters in adult men. Asian J Androl 2001;3:301–3.

7. Cicero AF, Piacente S, Plaza A, et al. Hexanic maca extract improves rat sexual performance more effectively than methanolic and chloroformic maca extracts. Andrologia 2002;34:177–9.

8. Gonzales GF, Ruiz A, Gonzales C, et al. Effect of Lepidium meyenii (maca) roots on spermatogenesis of male rats. Asian J Androl 2001;3:231–3.

9. Ruiz-Luna AC, Salazar S, Aspajo NJ, et al. Lepidium meyenii (maca) increases litter size in normal adult female mice. Reprod Biol Endocrinol 2005;3:16.

10. Lopez-Fando A, Gomez-Serranillos MP, Iglesias I, et al. Lepidium peruvianum Chacon restores homeostasis impaired by restraint stress. Phytother Res 2004;18:471–4.

11. Gonzales GF, Miranda S, Nieto J, et al. Red maca (Lepidium meyenii) reduced prostate size in rats. Reprod Biol Endocrinol 2005;3:5.

12. Gonzales GF, Cordova A, Gonzales C, et al. Lepidium meyenii (maca) improved semen parameters in adult men. Asian J Androl 2001;3:301–3.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires March 2007.

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