Acceptability, Safety, and Efficacy of Oral Administration of Extracts of Black or Red Maca (Lepidium meyenii) in Adult Human Subjects: A Randomized, Double-Blind, Placebo-Controlled Study

Abstract

The plant maca, grown at 4000 m altitude in the Peruvian Central Andes, contains hypocotyls that have been used as food and in traditional medicine for centuries. The aim of this research was to provide results on some health effects of oral administration of spray-dried extracts of black or red maca (Lepidium meyenii) in adult human subjects living at low (LA) and high altitude (HA). A total of 175 participants were given 3 g of either placebo, black, or red maca extract daily for 12 weeks. Primary outcomes were changes in sexual desire, mood, energy, health-related quality of life score (HRQL), and chronic mountain sickness (CMS) score, or in glycaemia, blood pressure, and hemoglobin levels. Secondary outcomes were acceptability and safety, assessed using the Likert test and side effect self-recording, respectively, and the effect of altitude. At low altitude, 32, 30, and 32 participants started the study receiving placebo, red maca, or black maca, respectively. At high altitudes, 33, 35, and 31 participants started the study receiving placebo, red maca, and black maca, respectively. Consumption of spray-dried extracts of red and black maca resulted in improvement in mood, energy, and health status, and reduced CMS score. Fatty acids and macamides were higher in spray-dried extracts of black maca than in red maca. GABA predominated in spray-dried extracts of red maca. Effects on mood, energy, and CMS score were better with red maca. Black maca and, in smaller proportions, red maca reduced hemoglobin levels only in highlanders with abnormally high hemoglobin levels; neither variety of maca reduced hemoglobin levels in lowlanders. Black maca reduced blood glucose levels. Both varieties produced similar responses in mood, and HRQL score. Maca extracts consumed at LA or HA had good acceptability and did not show serious adverse effects. In conclusion, maca extract consumption relative to the placebo improved quality of life parameters. Differences in the level of improvement between red and black maca are probably due to differences in the composition of these two plant varieties. Both maca extracts were well tolerated and safe.

Is the hype around the reproductive health claims of maca (Lepidium meyenii Walp.) justified?

“…It is possible that the perceived libido-enhancing of maca is due to its energising properties. The energising and antifatigue properties of maca have been investigated with promising results (Li et al, 2017, Gonzales-Arimborgo et al, 2016, Miao, 2015, Tang et al, 2017, Choi et al, 2012. Further investigation in this area is warranted.…”

“…In a small pilot study, dyadic sexual desire increased in cyclists after 14 days treatment at 2000mg/day of an aqueous maca extract (Stone et al, 2009).This may suggest that the aphrodisiac properties are found in the aqueous extract of maca, explaining why the effect was noticed much earlier than with gelatinised maca but the sample was also very small, which decreases accuracy of results. Another larger cohort study of 175 participants treated with 3g of spray-dried maca over a period of 12 weeks showed only a modest increase in sexual desire with red maca relative to placebo (Gonzales-Arimborgo et al, 2016; See Appendix 4)…”

Antioxidants in Maca (Lepidium meyenii) as a Supplement in Nutrition

“…People consuming regular maca have a lower interleukin-6 level and higher health scores than those not consume it [1]. Although macamides content is higher in black maca, red one enhanced the health score of human suffered from chronic mountain illness [55]. It has been shown in women that postmenopausal symptoms such as anxiety, depression and sexual dysfunction are reduced without being dependent on reproductive hormones [56,57].…”

“…By scavenging DPPH and peroxyl radicals, polysaccharides isolated from maca have protected human erythrocyte against hydrogen peroxide and inhibited the hemolysis [62]. Some studies suggested that maca consumption is well tolerated and has no adverse effect [55]. On the contrary, some studies have reported negative effects on blood pressure [57,63,64].…”

Aqueous extract of yellow maca (Lepidium meyenii ) improves sperm count in experimental animals but response depends on hypocotyl size, pH and routes of administration

“…Maca is used as food, and all studies with maca looking for biological activity have been performed through the oral route (Gasco, Aguilar, & Gonzales, ; Rubio et al., ; Yucra, Gasco, Rubio, Nieto, & Gonzales, ). This route in human has demonstrated to have high acceptability, it is safety and it has efficacy (Gonzales et al., ; Gonzalez‐Arimborgo, ). It is clear that in different investigations assessing products with systemic effects, the intraperitoneal route is preferred because it is an easy route of administration in experimental animals and this procedure avoids hepatic metabolism and a small amount of intraperitoneal injection may pass directly across the diaphragm and into the thoracic lymph (Abu‐Hijleh, Habbal, & Moqattash, ).…”