Maca (Lepidium meyenii) is a Peruvian plant of the Brassica (mustard) family which grows exclusively in the central Andes at high altitudes, a habitat of intense cold and sunlight, and strong winds. Cultivated for more than 2000 years, Maca root, the edible part of the plant, is traditionally used as a food and in traditional folk medicine to enhance sexual function, fertility, energy, alertness, mental concentration, mood and physical immunity. Yet, only a limited number of its purported benefits have been supported in scientific studies. These include its nutritional content and its energizing, antioxidant, fertility-enhancing and cognitive-supporting properties.
Dried Maca (unprocessed) is a very nutrient-dense food, made up of approximately 10% protein, 60% carbohydrates, 8.5% fibre and 2% fat. It contains almost all of the essential amino acids needed by humans, as well as a number of micronutrients, including iron, calcium, copper, zinc and potassium. (Nutrient levels vary depending on the type of Maca and how it is processed.) It is also considered to have adaptogenic qualities due to its demonstrated ability to help the body adapt to a number of stressors.
Thirteen main types of maca have been described that can be characterized by the color of their roots, being the edible portion of the plant. Recent studies have demonstrated that different types of Maca (according to its color - black, red or yellow) have somewhat different properties and health benefits. (1, 2, 3)
In both animal and cell models, Maca has been shown to be a source of antioxidants, compounds which play a vital, health-protecting role in human life. Antioxidants have been shown to help protect against various metabolic diseases, heart disease, brain disorders and age-related syndromes, as they help the body combat cellular damage caused by free radicals (reactive chemicals containing oxygen). In these studies, Maca was shown to not only increase levels of important antioxidants including superoxide dismutase and glutathione, but it also significantly decreased cholesterol levels and also exhibited cellular neurobiological protection. (1, 2, 3)
While further research is needed to better understand how the antioxidants in Maca impact human health, these findings suggest promise for Maca’s protective role against chronic human diseases characterized by oxidative damage.
Maca is traditionally used by Adean Indians for its supposed ability to improve energy, and was used as a tonic for Inca warriors to increase their energy and vitality. However, there is only a limited body of research supporting these claims.
Supplementation with Maca extract for 2 weeks was found to significantly improve performance time in a 40 km cycling race. In another study of human subjects placed in two areas (the Peruvian highlands, close to where Maca is cultivated and where consumption is traditional, and at the lowland coast where Maca consumption is less common), supplementation with both red and black maca resulted in improvement in mood and energy (and even more so with red Maca, which has a higher concentration of GABA (Gamma-Aminobutyric Acid), a neurotransmitter that researchers suspect may boost mood or have a calming, relaxing effect on the nervous system).
In a number of animal model forced swim oxidative stress tests, three forms of Maca (yellow, fermented and gelatinized and extracted) were found to increase endurance, demonstrating its ability to improve physical stamina and preserve energy and thought to play an adaptogen-like role. (1, 2, 3, 4) (Interestingly, a study on pre-menopausal women similarly found that gelatinized Maca exhibited distinctive functions peculiar to adaptogens, suppressing stress hormone output and generally balancing hormone levels.)
No traditional use records of Maca’s effect on cognitive function have been found. Natives in the central Peruvian Andes claim that the use of Maca in children improves school performance, although they do not know which variety of Maca best impacts learning and memory.
Experimental studies in animal models suggest that Maca does in fact improve learning and memory. Three varieties have been studied (black, red, and yellow), and black Maca was the only variety to show significant biological effects. Maca was found to improve induced memory impairment and to decrease brain markers of oxidative stress, in both cases reflecting effects on the brain tied to Maca’s antioxidant capacity. (1, 2, 3)