Maca Root – Too Good To Be True?
Can an obscure Peruvian plant really improve fertility, sexual desire and increase endurance?
For about 2000 years inhabitants of the Junín plateau in the central Andean region of Peru have cultivated the biennial plant Lepidium meyenii. Maca is the root of this herbaceous crop, it is one of the few plants growing in the harsh conditions at altitudes between 4000 and 4500 metres. According to local belief Maca improves fertility. Apparently, Inca warriors would consume Maca root prior to battle to increase energy levels but were prohibited from further consumption after a successful conquest to avoid too much lusting after the local female populous. These days Maca is dried before being ground to powder and sold in health food shops either in capsules or in powdered form. It is increasingly used as a supplement to enhance fertility, libido and athletic performance. Maca has been shown to improve the sexual performance of rodents (note: if you do buy some make sure your house is rodent free!) Could it possibly do the same for us?
The Root of Fertility?
A significant factor in fertility is semen quality. In a small study from Peru 9 men were treated with 1500mg or 3000mg of Maca a day for 4 months. At both doses there was an improvement in several markers of semen quality including semen volume, total sperm count and motility. Interestingly, Maca did not significantly alter levels of hormones involved in sperm production. This suggests the mode of action may be to increase hormone sensitivity. An important caveat to note is this study did not demonstrate, or even attempt to demonstrate an effect on the most crucial outcome in fertility, a successful pregnancy. However, the results are encouraging.
Of course sexual desire is important factor not only in fertility but also in relationships. The same Peruvian researchers investigated the effect of different doses of Maca on fertility versus placebo. This trial was double-blinded and placebo-controlled, which is a reasonably rigorous study design. 57 healthy men took either a placebo, or Maca root at 1500mg or 3000mg per day. After 12 weeks 42% of men taking Maca root, at either dose, had an increase in sexual desire. By comparison none of the placebo group noticed any increase in sexual desire. Again no increase in testosterone levels was found. A caveat to this data is, though well designed, the trial only used men’s self-rating of desire levels.
The Root of Athletic Performance?
In 2009 researchers investigated whether a short period of Maca supplementation could affect sexual desire and performance in a 40km cycling time trial. This small pilot study included 8 men with an average age of 30 years. They were allocated either Maca (2000mg per day) or placebo for 2 weeks, followed by a one-week ‘wash-out’ period and then a further 2 weeks of supplementation with the alternative ‘supplement’. Interestingly, both placebo and Maca improved time trial performance, but only Maca did so to statistical significance from baseline. However, head to head comparison of placebo and Maca showed no statistically significant difference. Similar results for Maca were found for improved sexual desire. The small size of this study limited its power to demonstrate any effect versus placebo. So in this small trial Maca made cyclists faster and increased libido, but not substantially more than placebo.
The Root of All Evil?
As with all medicines, natural or otherwise, it is important to establish safety. None of the trials above have sought to do this for Maca. One study raised concerns that Maca contained a substance called MTCA that could cause dangerous cell mutations in the human body. Based on this the French Agency of Sanitary Security advised caution in Maca root consumption. Gastavo Gonzales, the Peruvian doctor who conducted two of the above studies on Maca root, disputes any safety concerns. He contests that MTCA has been found in fruit and fruit juices, and points to some of his own research suggesting Maca may have anti-cancer properties. Gonzales also suggests that the boiling of Maca to prepare it for supplements is likely to negate any potentially harmful effects. The University of Hertfordshire conducted a review by searching online fora for reports of side effects; they found people had noted symptoms including gastrointestinal symptoms, moodiness and insomnia. It is hard to determine how much weight to give this information.
So there is some limited evidence that Maca can improve sperm production, sexual desire and athletic performance. In the absence of any firm evidence to the contrary it also appears that Maca is safe for ingestion. This all bodes well for any MAMILs hoping to conceive and for any rampaging Inca warriors.
Dr Hugh Coyne
Private GP, Parsons Green