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- Maca (Lepidium meyenii)
- Ethnobiology
- Ethnopharmacology
| Date:
03-15-2012 | HC# 111143-444
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Re: Review of Maca – a Promising Adaptogen
Gonzales
GF. Ethnobiology and ethnopharmacology of Lepidium
meyenii (maca), a plant from the Peruvian highlands. Evid Based Complement Alternat Med. 2012;2012:193496. doi:10.1155/2012/193496.
Maca
(Lepidium meyenii) grows in Peru at
elevations over 4000 m. It is used traditionally as food and to enhance
fertility in humans and animals. While there are related species in Europe and
North America, maca's habitat of intense cold, very intense sunlight, and
strong winds is unique. Cultivated in the Andes for 1500-2000 years,
consumption worldwide has risen dramatically since 2000 as maca's reputed
benefits have become widely known.
The
plant part used is the hypocotyl, maca's underground nutrient storage organ. A
fresh hypocotyl-root axis is about 10-14 cm long and 3-5 cm wide, shrinking as
it dries. Like many plants, maca from different producers (or different seasons,
microclimates, etc.) may vary significantly in chemical content. Dried maca has
about 10.2% protein, 59.0% carbohydrates, 2.2% lipids, and 8.5% fiber. It is
high in iron and calcium and has copper, zinc, and potassium. Hypocotyls vary
in color; 13 colors are known. Different colors indicate levels of unique secondary
metabolites, e.g., macaridine, macaene, macamides, and maca alkaloids. Sterol
and glucosinolate levels also vary with color.
Maca
is boiled in water or extracted in alcohol before consuming. One report of
(1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) in
maca suggested that it could be toxic, leading to a consumer alert from the
French Agency for Sanitary Security (AFSSAPS). However, MTCA occurs in many
foods in higher concentrations than in maca and has not resulted in reports of
toxicity. Maca is consumed from childhood in the Andes, usually as juice made
with several mixed colors of hypocotyls.
Maca's
effects on male and female reproductive capacity have been examined in vivo and
in human studies. While some found increased sexual behavior of male rodents
with maca administration, others did not. Maca increased sperm count and
motility in normal rats and those with several induced pathologies. Black maca,
and to a lesser extent yellow, were the most effective colors studied; red maca
was ineffective. In bulls, maca increased sperm quantity and quality. Healthy, human
males who used maca for four months had increased seminal volume, sperm count,
and sperm motility. A systematic review found four randomized clinical trials
(RCTs) assessing maca and human sexual function. Two found significant positive
effects, one in healthy, menopausal women and one in healthy, adult men. A
third, of healthy cyclists (gender unspecified), reported no effects; however,
data from the study show significantly improved self-rated desire compared to
baseline and to placebo. In a study not included in the systematic review
because no placebo effect was assessed, patients with selective serotonin
reuptake inhibitor-induced sexual dysfunction had significant improvement in
libido with maca. Another RCT assessed maca in mild erectile dysfunction and
found significant benefits in subjective perceptions of well-being. An
unpublished study in the author's laboratory found no effect on erection. In
female rodents and women, maca did not affect serum estradiol levels. An in
vitro assay found no proliferative effect on MCF-7 cells. In mice and trout,
maca improved embryo quality. The author's laboratory observed the most
improved mouse embryo quality with red maca. In guinea pigs and mice, the number
of offspring rose with maca. Red and black maca were protective of bone
architecture in ovariectomized rats, without estrogenic effects on uterine
weight.
Gonzales
reports for the first time a beneficial effect of maca in benign prostatic
hyperplasia (BPH). Red maca was more effective than yellow or black in
preventing prostatic hyperplasia (PH) induced by testosterone enanthate (TE) in
rodents. Different amounts of benzylglucosinolates in red maca extracts
produced dose-dependent effects on prostate weight, suggesting that these
compounds are responsible for the effect. Polyphenols in red maca may also contribute.
Red maca also reduced zinc levels in TE-induced PH, but not seminal vesicle
weight. Finasteride, BPH standard treatment, reduces prostate and seminal
vesicle weights but not zinc levels. Adding red maca might be beneficial. Maca's
mechanism of action is not known. Red maca did not affect serum hormone levels
in rodents or human males.
Although
no traditional descriptions have been found of maca's mental effects, children
are given maca in Peru to improve school performance. Black maca improved
memory and learning in memory-impaired mice; red and yellow maca did not. Maca
reduced depression and anxiety scores and was an energizer in healthy men,
compared with placebo. One RCT assessed effects of maca, alone or with other
supplements, in metabolic syndrome; results are not detailed. Another found
that gelatinized maca reduced systolic and diastolic blood pressure in healthy
men after 12 weeks. In another RCT, maca with cat's claw (Uncaria tomentosa) was compared with glucosamine sulfate in 95
patients with osteoarthritis. Both treatments significantly improved symptoms.
In a study of the health status of adults 35-75 years
old in the Peruvian central Andes, those who used maca were compared with
non-users. About 80% used maca; 85% of them for nutrition. Maca was associated
with higher health status scores, fewer fractured bones, lower signs of chronic
mountain sickness, lower body mass index, and lower systolic blood pressure.
Liver and kidney function, lipid profiles, and glycemic function of users did
not differ from non-users.
-Mariann
Garner-Wizard
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