Maca (Lepidium meyenii/peruvianum) is a turnip-like plant found high in the South American Andes mountains. It’s the highest altitude crop in the world, and is highly valued as a food and medicine both locally and world wide.
Indigenous cultures in the region have been found to have used maca as far back as 1600 BCE and have been cultivating maca for at least 2000 years.
It belongs to the Brassicaceae family of plants, which includes vegetables like mustard and cabbage.
Maca root is used as a food and medicine internationally for its effects on hormones, athletic performance, strength, sexual potency, libido, fertility and as a nutritive adaptogen. One of its common names is Peruvian ginseng due to its classification as a root, and broad range of adaptogenic actions.
Maca contains high amounts of various B vitamins, vitamin C, Vitamin D, vitamin E, minerals, and amino acids. In fact it contains high levels of 7 out of the 9 essential amino acids needed for life.
Maca’s benefits include aphrodisiac, antioxidant, adaptogenic, nutritive, lowers blood pressure, helps with menopausal symptoms, balances hormones, improves libido, and nutritive.
- Low sperm motility
- Altitude sickness
- Improving athletic performance
- Low libido
- Prostatic hyperplasia
- Low sperm count or motility
- Peruvian Ginseng
- Ayuk wilku
- Yellow, red, and black maca
Maca has been domesticated for about the last 2000 years by the Incas, and archaeologists have found primitive cultivars of the plant dating back as far as 1600 B.C (Taylor L. 2005).
The Andean Indigenous people’s live in a region virtually inhospitable to most plants, with hot direct sunlight, high winds, and freezing temperatures all in the same place, not to mention the rocky, nutrient deficient soil. Maca is one of the few edible plants growing in that region, so it has significant value on the cultures living there. Maca is often traded with cultures living at lower elevations for other staple foods like rice, corn, green vegetables, and beans (Taylor L. 2005).
Peruvians in particular have used Maca for thousands of years both as nutrition and medicine (Taylor L. 2005). The root is eaten here either fresh, or dried, and is often cooked in a similar fashion as sweet potatoes. The dried roots are instead boiled in water or milk to make a porridge (Taylor L. 2005), or juice (Gustavo F. Gonzales, 2012). Alcoholic drinks can be made and are referred to as Maca chica. Jams, puddings, and sodas can be made as well (Taylor L. 2005).
Maca has been used for centuries by various cultures in the Andes, including spanish conquistadors, as a fertility enhancing agent, in both humans and animals (Taylor L. 2005).
Today, Maca is still used in Peruvian medical systems to treat anemia, tuberculosis, menstrual disorders, menopause symptoms, stomach cancer, memory loss, reproductive disorders, and as an immunostimulant (Taylor L. 2005). Throughout America, The United States, Europe, and Australia, Maca has been growing in popularity for a wide range of illnesses, and as a general health promoting agent through various attributes. Some of these include: fertility enhancement, aphrodisiac effects, sports performance, hormone balancing, increased stamina, male impotence, promoting mental clarity, menstrual irregularities, blood glucose balancing, and chronic fatigue syndrome.
Maca is a perennial, growing in the high Andes mountains. Altitudes where this hardy plant is found ranges from (8000, to 14,500 feet). Maca is contained under the mustard family (Brassicaceae), and as such produces flowers typical to that family; small, self-fertile, off white flowers. Lepidium is one of the largest genera in the Brassicaceae family.
The hypocotyls (roots) are used nutritionally and medicinally, and resemble turnips in size and shape (in the same family). The root is cultivated in many South American countries, around the Andes mountains, particularly in the Carhuamayo, Junin, and Ondores in the Junin Plateau. The elevation of the mountains is necessary for the quality cultivation of this tuberous root vegetable. Typically, cultivators grow Maca as if it were an annual, even though technically it is a perennial. It takes roughly 7-9 months to produce roots ready for harvest.
Taylor L. (2005) suggests in her book that although most Maca is listed as Lepidium meyenii, in fact, most Maca is a different species (L. Peruvianum). This was backed up when a study done investigating the similarities of the two species, found that the Maca cultivated in the Peruvian Andes was indeed L. peruvianum (H. O. Meissner et al., 2015). This same study also confirmed that although many sources will refer to L. Meyenii, and L. peruvianum as synonymous, they are in fact dissimilar. This brings questions as to which species of “Maca” has actually been used in many of the scientific literature simply referring to its common name as “cultivated Peruvian Maca”.
Cultivation of this herb has grown substantially in recent years. Less than 50 hectares of land were devoted to the cultivation of this plant back in 1994, just 5 years later it was reported that 1200 hectares of land were in use for Maca production (Taylor L. 2005). In fact, the exportation of maca from Peru has increased from 1,415,000 USD in 2001 to USD 6,170,000 USD in 2010 (Gustavo F. Gonzales 2012).
The taste of Maca can be compared to that of butterscotch, with different varieties producing slightly different tastes and colours, but most producing a slightly tangy, sweet flavour.
13 varieties of maca have been described ranging in color (and thus common name) from white, red, yellow, and black, with yellow being the most frequent (J. Rubio et al., 2006). Of the varieties, slight differences in biological properties have been reported.
Black maca has presented the greatest effect on spermatogenesis (gustavo F. Gonzales, 2012), and latent learning, though did not have as strong an effect on prostate reduction as compared to other varieties (J. Rubio et al., 2006). Black maca has also been reported to have positive effects on sperm motility (Gustavo F. Gonzales 2012).
Red maca was shown to have the strongest effect on prostate size (J. Rubio et al., 2006), but little effect on sperm motility (Gustavo F. Gonzales, 2012).
Yellow maca was noted to have a positive effect on sperm counts in rats, as well as improved sperm motility (Gustavo F. Gonzales, 2012), and a medium effect on prostatic-hyperplasia (Gustavo F. Gonzales, 2012). All three varieties (yellow, black and red) were noted to have the same effect on depression in mice (J. Rubio et al., 2006).
Habitat, Ecology, Description:
Maca is found in the central Peruvian Andes (G. F. Gonzales et al., 2014), usually about 3500 meters or more above sea level. There seems to be much debate over what altitude is preferred by this plant, some sources listing an exclusive altitude between 4000 meters, and 4500 meters above sea level (G. F. Gonzales 2012), others listing that it grows between 8000 and 12000 feet (~2500 – 3600 meters) (Taylor L. 2005). Whatever the case, it is apparent that maca needs the high altitude in order to thrive. With this comes, searing hot sun at times, freezing cold weather at others, high winds, and often periods of intense dryness.
Harvesting, Collection, Preparation:
Maca (of all varieties), is generally found in dried, powdered form, due to its ease of use, and long shelf life. The hypocotyls of Peruvian Andes maca, range in size greatly, and fall into a range from about 7g to 24g of dried hypocotyls each (Gustavo F. Gonzales, 2012). Fresh roots contain about 80% water, and look about the size of turnip.
Gustavo F. Gonzales (2012) makes note that the boiling or otherwise heating of maca roots changes the metabolite levels. He reports that the aqueous extract of maca effective if it has been boiled, and suggests that the boiled aqueous extract, has similar effect as hydroalcoholic extract of Lepidium spp.
Maca contains glucosinolates, which are sensitive to heat. On the other hand, sulforaphane in maca is actually increased if undergone heating. Other metabolites influenced by heat include antioxidants (found to increase with heat in tomatoes), and Vitamin C (heat sensitive) (Gustavo F. Gonzales, 2012).
Other factors to note when preparing maca for medicinal purposes, is to consider the variety. Red maca is best for prostate hyperplasia with yellow a good second choice, and black for increasing fertility, with yellow following behind as a good second choice for this a well. All three work close to the same on depression. Since yellow maca is by far the most common on the market today, it can be suggested that yellow maca is a good choice for most medicinal uses of maca.
Nutritionally, Maca has the highest nutritional value out of any food crop grown in the Peruvian Andes. It is rich in sugar, protein, starches, and essential nutrients (most notably iron and iodine) (Taylor L. 2005).
Taylor L. (2005) suggests the main plant chemicals include alkaloids, amino acids, beta-ecdysone, calcium, carbohydrates, fatty acids, glucosinolates, iron, magnesium, p-methoxybenzyl isothiocyanate, phosphorous, potassium, protein, saponins, sitosterols, stigmasterol, tannins, vitamin B1, vitamin B2, vitamin B12, vitamin C, vitamin E, and zinc.
A more complete description of the composition of dry maca provided by Gustavo F. Gonzales (2012) shows 10.2% proteins, 59% carbohydrates, 2.2% lipids, and 8.5% of fibre. Maca also contains free fatty acids including linoleic, palmitic, and oleic acids. Saturated fatty acids represent 40.1% compared to unsaturated fatty acids which are 52.7%. Maca contains amino acids (mg/g protein) leucine (91.0mg), arginine (99.4mg), phenylalanine (55.3mg), lysine (54.3mg), glycine (68.30mg), alanine (63.1mg), valine (79.3mg), isoleucine (47.4mg), glutamic acid (156.5mg), serine (50.4 mg), and aspartic acid (91.7 mg). Other amino acids present but in less proportion are histidine (21.9 mg), threonine (33.1 mg), tyrosine (30.6 mg), methionine (28.0 mg), hydroxyproline (26 mg), proline (0.5 mg), and sarcosine (0.70mg). Minerals include iron (16.6 mg/100 g dry matter), calcium (150 mg/100 g dry matter), copper (5.9 mg/100 g dry matter), zinc (3.8 mg/100 g dry matter), and potassium (2050 mg/100 g dry matter) among others (Gustavo F. Gonzales, 2012). Secondary metabolites include macaridine, macaene, macamides (Gustavo F. Gonzales, 2012).
Pharmacology and medical Research:
The term “adaptogen” refers to plants or other substances that augment non-specific resistance in the body, and help the body to adapt to various situations. Therefore protecting it from stressful events and factors. (F.R Mendes et al., 2007). Therefore, it could be argued that maca may fall under the classification of an adaptogenic botanical based on the following effects: supportive effect of the HP axis (H. O. Meissner et al, 2006), antioxidant (Gustavo F. Gonzales, 2012), fertility enhancing effects (Gustavo F. Gonzales, 2012), and Neuroprotective effects (Gustavo F. Gonzales, 2012). The effects maca appears to produce on the HP axis, in turn improves the function of endocrine glands throughout the body, provide a nonspecific effect on vitality, and adaptability in the body through various organ systems. These effects can be noted in macas antidiabetic, neuroprotective, antidepressant, anti stress, fertility enhancing, aphrodisiac, antihypertensive, and menopausal supportive effects. All of these pathologies are corrected by improving normal functioning of the body, rather than through stimulation of processes in a single direction. The author notes that he has not found evidence of bidirectional action in maca, however he has noticed the effects are normalizing in almost all aspects of the effects produced. A few exceptions include maca inhibitory effects on angiotensin I-converting enzyme (Gustavo F. Gonzales, 2012), more research is needed in this area to determine how far this inhibition will go.
The very low toxicity noted in maca, is another important factor to consider in classifying this substance as an adaptogen.
At this time, the author suggests Lepidium meyenni, and L. peruvianum should be considered and researched further as an adaptogenic botanical.
A study done comparing the effectiveness in three varieties of Maca (yellow, red, black), found that all three had a similar effect on depression in mice (J. Rubio et al., 2006).
Maca was shown to significantly inhibit angiotensin I-converting enzyme (ace) in vitro (Gustavo F. Gonzales, 2012). This enzyme, as well as potassium, which is contained in fairly high amounts, are both relevant in the pathophysiology of hypertension, thus maca may produce antihypertensive effects.
Extracts of both red maca, and black maca have both shown protective effects in the bones of ovariectomized rats, while appearing not to affect estrogen levels (Gustavo F. Gonzales, 2012), providing some evidence that maca has anti-osteoporosis effects in postmenopausal mammals.
Black maca has been reported to provide support in memory impairment, through its antioxidant, and Ache inhibitory effects (Gustavo F. Gonzales, 2012).
It has been reported by various studies that red maca has the greatest effect on prostatic-hyperplasia (J. Rubio et al., 2006) (Gustavo F. Gonzales), with yellow maca offering intermediate support for the condition.
The constituents to be held responsible for these effects are under debate however, with some researchers suggesting benzyl glucosinolates, and others suggesting polyphenols (Gustavo F. Gonzales, 2012).
With treatment of red maca on TE-treated rats, effects were reversed, reducing prostate weight and zinc levels, however no change was observed on seminal vesicle weight which is another organ dependent on androgen (Gustavo F. Gonzales, 2012). These results offer more indication that macas effects on the sexual organs are not through androgen receptors.
N. S. Chauhan et al., (2014) reports that the improved sexual desire in both males, and females is not related to changes in pituitary, or gonadal hormones. They note that Maca does not activate androgen receptors, and conversely may in fact block androgen receptors instead.
This evidence was contradicted by other research investigating macas effects on hormones in relation to menopausal symptoms, these researchers suggested the effects produced were a result of HP axis related activity from the alkaloids contained within maca, which in turn improve function of the adrenals and thus, androgen production (H. O. Meissner et al., 2006).
The conflicting evidence, may be a result from the design of the studies.
Despite various companies, and websites advertising as such, maca does not affect serum testosterone, or intratesticular testosterone (Gustavo F. Gonzales, 2012), or other pituitary, and gonadal hormones, and in fact does not appear to function through stimulation of the androgen receptors (N. S. Chauhan et al., 2014), though this evidence is conflicting, and is suggested to affect these receptors as a secondary process from improvement of the HP axis instead (H. O. Meissner et al., 2006), possibly through normalizing effects rather than stimulation.
Gustavo F. Gonzales (2012) reports that “scientific evidences suggest that maca may be an energizer” (page 6).
The fertility enhancing effects of Maca were reported back in 1961, and since then has been the subject of much research looking closer at these effects. (Taylor L. 2005) (Gustavo F. Gonzales, 2012).
Taylor L. (2005), warns that many of the research conducted on Maca, has been funded by 2 main marketers of Maca products in the United States. She also warns of studies conducted that measure libido enhancement, as this is a very subjective measurement, and should not be taken as hard scientific evidence.
Taylor L. (2005) suggests that the fertility, and libido enhancing properties of Maca, may simply be a result of Macas high protein, and vital nutrient profile. Dried Maca root contains roughly 10% protein, derived from amino acids, these amino acids are necessary for many cellular functions within the body, including sexual processes (Taylor L. 2005). She refers to the neurotransmitters dopamine, and noradrenaline which both play a major role in sexual arousal, and physical performance during sex. These neurotransmitters require phenylalanine, tyrosine, and histadine, all of which are contained within Maca root.
Arginine is another amino acid with strong connections to fertility, especially in males. There are multiple libido enhancement supplements on the market that contain arginine for this reason (Taylor L. 2005). N. S. Chauhan et al. (2014) reports improvement of larganine-nitric oxide activity from Maca use, and relates this to a decrease in ejaculation latency in mice.
Histidine is another amino acid contained in Maca root that plays an important role in sexual function specifically for men. The body uses histidine to produce histamine, which is then used in the corpus cavernosum to produce ejaculation (Taylor L. 2005). Maca therefore may be useful in treating fertility problems relating to aorgasmia, due to its histidine content.
A study done investigating the effects of various plant medicines on sexual performance and virility, suggests the mechanism of action of L. meyenii on virility, lies in its action on spermatogenesis, and decreases in latent period of erection and ejaculation. This effect was noted to be much more significant in mice with less sexual experience, or mice with ED, and disappeared over chronic use (N. S. Chauhan et al., 2014).This suggests a normalizing, over stimulating effect, which is parallel to the thoughts suggested by Taylor L. (2005) placing responsibility on Maca’s nutritional profile for its effects on sexual performance and virility. Gustavo F. Gonzales (2012) reports that maca has been found to increase sperm count in both normal rats, as well as rats with pathological conditions produced from exposure to high altitude, lead acetate, and malathion. He also notes yellow maca, and black maca, had a positive effect on sperm motility, but no effects were noted in this area from red maca.
Both histidine, and arginine also offer vasodilation effects within the body (Taylor L. 2005), which in turn increase blood flow to the sex organs in both males, and females.
According to Gustavo F. Gonzales (2012), macaenes and macamides have been reported to have probable responsibility as well with the improved sexual behaviour noted with maca, however more research in this area is needed.
Taylor L. (2005), related macas hormone balancing effects back to its amino acid content as follows; although hormones are very chemically diverse, they are constructed simply from amino acids, and cholesterol. If the body is given the building blocks more readily, it is much easier to produce these hormones when they are needed.
It has been reported that Maca does not activate androgen receptors (N. S. Chauhan et al., 2014), however in ovariectomized rats, treatment with an ethanol extract over the course of 28 weeks was shown to produce support for postmenopausal symptoms related to hormones (Yongzhong Zhang et al., 2014). This conflicting evidence suggests hormonal effects are likely due to nutritional, or other means, rather than direct stimulation of androgen ergic system, or that the different durations of the two tests may have influenced the differenc in results.
Other research, such as that of H. O. Meissner et al, (2006), suggests that the hormone balancing effects maca has is through HP axis support, which in turn improves functions of the endocrine glands throughout the body.
The author suggests a combination between improvement of the HP axis function through alkaloids present within the plant, as well as an increase in amino acid, and cholesterol content needed to produce various neurotransmitters throughout the body. If this were the case, it would explain maca’s adaptogenic effects, thyroid supportive effects, antidepressant effects, stress supportive effects, menopausal supportive effects, antidiabetic effects, and neuroprotective effects.
Yongzhong Zhang et al., (2014) conducted a study investigating the effects of Lepidium meyenii on the hormonal levels in ovariectomized rats. This study concluded that ” Long-term Maca supply modulates endocrine hormone balance in OVX rats, especially it decreases enhanced FSH levels. It is proposed that Maca may become a potential choice for postmenopausal women”. Researchers refer to a previous study done by another group over the span of 6 weeks that noted no change in hormonal levels. They postulate that the longer duration of the experiment (28 weeks) that they conducted may have been responsible for the conflicting results. They determine that the mechanism in which Maca is affecting hormone levels in ovariectomized rats is unknown during the time this study was conducted. H. O. Meissner et al, (2006) suggests this action is through support of the HP axis.
Gustavo F. Gonzales (2012) reports that “Black maca seems to improve experimental memory impairment induced by ovariectomy, orchidectomy, scopolamine, and alcohol due in part to by its antioxidant and Ache inhibitory activities” (Page 4).
Other aspects that may provide neuroprotection, may be result from the support maca alkaloids are suggested to have (H. O. Meissner et al, 2006).
H. O. Meissner et al, (2006) suggests that maca alkaloids act upon the hypothalamus pituitary axis, as this explains why its effects on endocrine glands are not limited to the ovaries or the testes, but instead on adrenals, , thyroid, and pancreas as well as all endocrine glands throughout the body.This is the suggested mechanism of action by these researchers for balancing female hormones post menopause (via ovariectomized mice).
If this is the case, the author suggests that improved thyroid health would most likely only be noticed in thyroid deficient people caused by low TSH rather than with a problem from the thyroid function itself. In other words, it appears maca does not “stimulate” the thyroid, but rather improves HP axis function, and thus thyroid function. Maca seems to be more adaptogenic in endocrine function than it is a stimulant for thyroid, or metabolic functions.
Toxicity and Contraindications:
Histidine may cause issues with allergies through histamine response.
It has been reported that maca contains MTCA, which has been suggested to be toxic, however this chemical is a natural component in many plants, including oranges, grapefruits, fermented garlic, and several other plants with which consumption is not associated with toxicity (Gustavo F. Gonzales, 2012). Maca should not be considered toxic for this reason. Population studies have been conducted on maca as well, resulting in no toxicological indications from prolonged use of high dosages of maca as nutritional agent (Gustavo F. gonzales, 2012).
No hepatotoxic effects, or general toxic effects, including in embryo development in mice, have been found associated with maca and maca extract (Gustavo F. Gonzales, 2012).