One of the amazing phenomena in nature is the adaptation of a plant or animal to its environment. As it relates to medicinal effects of a plant, the composition of active compounds can be greatly influenced by geography, altitude, climate and other factors. These stressors will often lead to the formation of protective factors within the plant to help it survive. Often, these compounds also exert significant effects in improving human health.

A great example of this environmental influence leading to different expression of chemical composition within the plant is Peruvian Maca (Lepidium meyenii). This fascinating member of the cabbage family is a close relative of the turnip, but lumping it in with common cruciferous vegetables is almost a disservice to its health benefits even with other members of the cabbage family having their own list of health improving actions. The point being is that Maca is special and is worthy of the reverence associated with it.

A Maca Primer

Maca is native to the northern Puna region of Peru and Bolivia where the elevation is typically 11,000 to 14,000 feet - just above the tree line, but below the permanent snow cap. Maca is the highest elevation food crop in the world. However, the Puna area is a very difficult environment for crops beyond its elevation. At any time of the year, temperatures can range from below freezing to 60° F. Even when the area experiences drought in terms of precipitation, humidity remains fairly high. As a result, frosts are frequent including during the growing season. Here is the bottom line point, all of these environmental stressors result in the unique chemical composition of Peruvian Maca.

Maca is a small plant that grows to about six inches tall and across. Its turnip-shaped root ranges roughly 1 inch to 3 inches in diameter at harvest. It is this root that has been treasured for thousands of years for to its ability to increase energy, stamina and fertility. For the people of the Puna, it is still a valuable food.

Maca is pungent, that is a polite word to describe a strong, bitter taste. But, it also has a sweetness to it as well. It is an interesting and unusual flavor, and there is a variance with the taste due to changes in growing conditions. There are also different forms of Maca that also vary in their chemical composition and applications. The roots grow in 3 basic color groups:

• Yellow Maca makes up about 60% of all Maca roots harvested in Peru. It is the most commonly used and the most researched of all Maca products. It works to boost energy, enhance concentration and balance hormones.  
• Red Maca comprises about 25% of the annual harvest and is the sweetest tasting of all Maca powders. Studies have shown it to have the highest phytochemical levels of all Maca colors. It is regarded as the most effective type for women due to its hormone balancing effects as well as action on bone health.
• Black Maca is the rarest of all Maca colors, making up around 15% of the annual harvest.  Studies have shown black Maca to be the most effective for men, especially for muscle building, endurance, mental focus, and libido.

The Nutritional and Phytochemistry of Maca

Dried powdered maca is nutrient dense, especially in minerals like calcium, magnesium, zinc, and potassium. It also contains approximately 13-16% protein and is rich in essential amino acids. It is also rich in fiber (8.5%), carbohydrates (59%), and free fatty acids (2.2%). Despite its excellent nutritional profile, even more exciting are the phytochemicals of Maca. There are many unique compounds, but first it is important to point out that members of the cruciferous vegetable family are all known to contain compounds known as glucosinolates. These compounds are the valuable anti-cancer agents in kale, cabbage, broccoli, etc. that also influence hormonal metabolism in positive ways. The glucosinolates in Maca are unique with the benzyl glucosinolates and glucotropaeolin being especially important to its action.

Maca also contains some unique alkaloids collectively referred to as macamides and include macaridine and macaene. Alkaloids are generally fast acting compounds. These alkaloids of maca exert their action on central control mechanism in the hypothalamus, pituitary, adrenals, and other endocrine organs. Much of the adaptogenic effect of Maca are likely due to these valuable compounds.

Anthocyanidins and other flavonoids best known from berries are responsible for the pigmentation of black and red maca. These pigments also contribute to some of the health benefits, especially antioxidant activity.

Maca also contains alkamides. These compounds are best known as the tongue tingling components of Echinacea.

Lastly, Maca contains a number of sterols including brassicasterol, beta-sitosterol, campesterol, and stigmasterol.

When I look at the chemical composition of Maca, I can definitely understand why it is such a unique tasting food, but I also can see how subtle variations in the ratios of these active components in the different Maca color types as well as the gelatinized extract could yield different effects.  

Commercial Maca Preparations

Peruvian maca powder is prepared from roots that are harvested, sun-dried, cleaned and ground into a fine powder. During this process the roots are never heated above 45 C (115 F) thereby preserving the maximum amount of nutrients, enzymes, and beneficial glucosinolates.

In preparing gelatinized maca powder, the sun-dried roots are first boiled and then pressurized in order to remove all starch content. It takes 4 kg of maca powder to produce 1 kg of gelatinized maca extract (a 4:1 ratio). Heating the maca destroys the enzymes and alters some of the glucosinolates, but it does concentrate many of the active compounds as well as make them easier to digest. For example, heating increases the formation of sulforaphane, a derivative of Maca glucosinolates and best-known as a component in broccoli sprouts.

Health Benefits of Maca

Maca is a food. And, as such there is evidence to support its health promoting effects. Since it is consumed by Peruvians native to the central Andes in the naturally dried form and in amounts >20 g per day there is a historical study population to look to for safety and effects of Maca. One study, in particular, is worth mentioning. The study, based on a survey, assessed maca consumption, sociodemographic aspects, health status, and fractures in men and women aged 35–75 years old in this population. What the results indicated was that Maca consumption was associated with significantly higher scores in health status. It was also associated with lower rate of fractures, and lower scores of signs and symptoms of chronic mountain sickness. In addition, maca consumption was associated with lower body mass index and blood pressure.

Another study showed similar results on health scores, but showed Maca consumption was associated with lower levels of interleukin-6 (IL-6), an important marker for inflammation and oxidative damage. High serum IL-6 levels have been associated with aging, obesity, increased incidence of cardiovascular disease, cognitive impairment, and a shorter life expectancy. Higher IL-6 levels are also associated with living at higher altitudes. Hence, it appears that nature provided an answer to the those living in the high altitudes of the Andes.

Maca and Sexual Function

One of maca’s most renowned benefits is the enhancement of sexual desire and function for both men and women. Clinical trials confirm these properties, including maca’s benefits in erectile function. In men, Maca does not appear to directly affect the level of testosterone, but rather acts on the entire endocrine system to reduce the harmful effects of stress while improving mood, energy, and endurance. Women also respond well to Maca. For example, in one small randomized, double-blind, placebo-controlled, crossover trial in postmenopausal women, maca was shown to reduce anxiety and depression, and lower measures of sexual dysfunction.

The reality is that sexual dysfunction is highly prevalent in modern society worldwide affecting 20–30% of men and 40–45% of women. Most sexual dysfunction is related to reduced sexual desire in both females and males and erectile dysfunction (ED) in men. Since Maca impacts and improves both major causes of sexual dysfunction it is little wonder that this application has probably become the reason why most men and women are looking to add Maca into their diet.

Maca as an Adaptogen

Maca bears all of the criteria to meet being classified as an “adaptogen.” That is probably why it is mistakenly referred to as Peruvian ginseng by some marketers. Maca is not in the ginseng family, but does possess ginseng-like adaptogenic activity. Adaptogens historically been used to:

• Restore vitality in debilitated and feeble individuals
• Increase feelings of energy
• Improve mental and physical performance
• Prevent the negative effects of stress and enhance the body’s response to stress

One of the consistent findings in the human clinical data is that Maca boost mood scores, reduces feeling of stress and anxiety, and increases perceived energy levels.  

Maca and Blood Pressure

One of the findings in the study mentioned above in Peruvian Andeans was a blood pressure lowering effect with Maca. One double-blind study in healthy men did show that gelatinized maca reduced systolic and diastolic blood pressure after 12 weeks of use. Another study in postmenopausal women also showed a blood pressure lowering effect with regular Maca powder.

Practical Recommendations

The standard dose for dried powdered Maca or gelatinized Maca is typically 1,500-3,000 mg once or twice per day. Higher dosages may be required for more therapeutic effects, but for a general health boost a daily dosage of 1.5-6 g is appropriate.

Keep in mind that there are individualized responses to Maca, just like any food. If you are smaller, you might want to start at the lower end of the dosage range. If you are larger, the higher range.

Maca is generally very well-tolerated. If it does cause some gastrointestinal irritation, consider the gelatinized form.