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. 2016 Aug 18;9(3):49.
doi: 10.3390/ph9030049.

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

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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

Carla Gonzales-Arimborgo et al. Pharmaceuticals (Basel). .
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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.

Keywords: Lepidium meyenii; adverse effects; black maca; botanicals; high altitude; human health; nutraceuticals; placebo; red maca; toxicity.

Conflict of interest statement

The present study received a grant from CONCYTEC/CIENCIACTIVA, Perú (N°010-2014-FONDECYT “CIENTIFICOS INC-CIRCULOS DE INVESTIGACION EN CIENCIA Y TECNOLOGIA” to the Research Circle in Plants with Effects on Health and a Grant from the “Canon, sobrecanon y Regalías mineras” of the Universidad Nacional Daniel Alcides Carrion, Pasco Peru. The funding sponsor did not participate in the design of the study; in the collection, analyses, or interpretation of data, in the writing of the manuscript, and in the decision to publish the manuscript. GF Gonzales is the manager of Cayenatur EIRL, a small, private enterprise producing nutraceuticals. The other authors have no conflict of interest.

Figures

Figure 1
Figure 1
Percentage of subjects perceiving an increase in sexual desire following a 12-week treatment with the placebo or a spray-dried extract of red or black maca at low (Upper) and high altitudes (Bottom). Bars are standard error. At LA, consumption of spray-dried extract of red maca increases the percentage of subjects with increased sexual desire over time (p = 0.0055). p > 0.05 between placebo and maca-treated groups. HA: p = 0.0027, p = 0.0000, and p = 0.0019 over time for treatments with placebo, red maca, and black maca, respectively. p = 0.03 (chi square = 6.96) at week 12 between treatment with spray-dried extract of red maca and placebo or spray-dried extract of black maca.
Figure 2
Figure 2
Percentage of subjects perceiving an increase in mood after treatment for 12 weeks with a placebo, spray-dried extract of red maca, and spray-dried extract of black maca. Percentage of subjects with a score for mood of 4–5 (in agreement or completely in agreement that consumption of the product increased their mood) at (Upper) low and (Bottom) high altitude. LA: p = 0.01; 0.01; 0.029; 0.0026 using chi square test at weeks 3, 4, 8, and 12 comparing treatment with placebo, spray-dried extract of red maca, and spray-dried extract of black maca. Placebo: p > 0.05 over time (weeks 1 to 12); red maca p = 0.0001 over time; black maca p > 0.05 over time (weeks 1 to 12). HA: p = 0.019; 0.04; and 0.05 using chi square test at weeks 1,2, and 12 comparing treatment with placebo, spray-dried extract of red maca and spray-dried extract of black maca. Placebo: p = 0.0001; red maca: p = 0.003; black maca: p = 0.0002 over time.
Figure 3
Figure 3
Percentage of subjects perceiving an increase in energy after treatment for 12 weeks with a placebo, red maca, or black maca at low (Upper) and high (Bottom) altitude. LA: p = 0.07; 0.02; 0.01; 0.003; 0.001 and <0.00001 using chi square test at weeks 1, 2, 3, 4, 8, and 12 comparing treatment with placebo, red maca, or black maca. Placebo group: p > 0.05 over time (weeks 1 to 12); red maca group: p = 0.0001 over time (weeks 1 to 12); black maca group: p > 0.05 over time (weeks 1 to 12). HA: p > 0.05 between placebo group and groups with red or black maca (chi square test at weeks 1, 2, 3, 4, 8 and 12). Placebo: p = 0.0001; red maca: p = 0.0001; black maca: p = 0.0001 over time (weeks 1 to 12).
Figure 4
Figure 4
Heath-Related Quality of Life Score (HRQL) in subjects receiving a 12-week treatment of a placebo, spray-dried extract of red maca, or spray-dried extract of black maca at low (Upper) or high altitude (Bottom). Data are mean ± standard error of the mean. Upper: LA: Placebo group: p > 0.05 with respect to time 0. Red maca group: p < 0.05 at week 8 and p < 0.01 at week 12 with respect to time 0 (one tail). Black maca group: p < 0.05 at week 4 with respect to time 0 and p < 0.01 at weeks 8 and 12 (one tail). p < 0.05 comparing red maca group with placebo group at eight and 12 weeks of treatment and p < 0.05 at week 4, and p < 0.01 at weeks 8 and 12, comparing the group treated with black maca with the group treated with a placebo; Bottom: HA: placebo group: p > 0.05 with respect to time 0. Red Maca group: p < 0.05 at week 8 and p < 0.01 at week 12 with respect to time 0. Black maca group: p < 0.01 at weeks 8 and 12 with respect to time 0. p < 0.05 black and red maca groups at weeks 8 and 12 with respect to the placebo group.
Figure 5
Figure 5
Delta of Qinghai score for Chronic Mountain Sickness (CMS) diagnosis in adult human subjects after a 12-week treatment with spray-dried extract of maca (red or black) or with a placebo at high altitude. Data are mean ± standard error of the mean. Placebo: p > 0.05 over time. Red maca: p < 0.05 at week 4 and p < 0.01 at weeks 8 and 12 with respect to values at time 0. Black maca: p < 0.05 at weeks 8 and 12 with respect to values at time 0. Red maca group: p < 0.05 at weeks 4 and 8 with respect to the placebo and p < 0.01 with respect to the placebo at week 12.
Figure 6
Figure 6
Flow diagram following the recruitment, enrollment, and number of subjects that finished treatment of the clinical trial at low altitude (A) and high altitude (B). Low altitude: Chi square: 0.11; p = 0.99 with respect to subjects who failed to complete the follow-up among different groups of treatment. High altitude: Chi square: 0.6; p = 0.99 with respect to subjects who failed to complete the follow-up among different treatment groups.
Figure 6
Figure 6
Flow diagram following the recruitment, enrollment, and number of subjects that finished treatment of the clinical trial at low altitude (A) and high altitude (B). Low altitude: Chi square: 0.11; p = 0.99 with respect to subjects who failed to complete the follow-up among different groups of treatment. High altitude: Chi square: 0.6; p = 0.99 with respect to subjects who failed to complete the follow-up among different treatment groups.

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References

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