Moringa frequently asked questions

The moringa tree Moringa oleifera is increasingly being studied for numerous properties of applied interest. In the course of work on these properties, many questions arise from both scientists and potential consumers. Here I address some of the most common such questions. I explain that moringa's correct scientific name is Moringa oleifera Lam., and that Moringa pterygosperma is not a synonym but an illegitimate name. The wild range of Moringa oleifera is unknown but it might be native of lowland northwestern India. It is cultivated in all tropical countries, but it is probably best to avoid saying that it is "naturalized" because some uses of this word imply that the plant has become invasive. There are thirteen described species in the genus Moringa, but additional new species probably await description, especially in northeast Africa. Traditionally, leaves of Moringa oleifera, M. concanensis, and M. stenopetala are eaten, and the tubers of young M. peregrina are sometimes eaten roasted. All other species have local medicinal uses. Current commercial use so far emphasizes M. oleifera dried leaf meal in capsules, often touting protein content. Simple calculations show that capsules have negligible protein nutritional value. Such use in pill form rather than as a food leads to the frequent question of whether moringa has "side effects". A review of studies shows that moringa has low levels of trypsin inhibitors, tannins, saponins, and lectins, meaning that there is no reason to expect that normal levels of consumption would lead to discomfort from these compounds. Nearly 40% of moringa calcium may be present in the form of oxalates, but current data suggest that these are insoluble, excreted, and do not contribute to the formation of kidney stones. Goitrogenic glucosinolates are probably absent, and if present are probably in very low concentrations. Moringa might have abortifacient potential, especially in concentrates. Given its usefulness and relative lack of antinutritional factors, there is global interest in growing moringa, so I examine its climate preferences. Moringa oleifera is a plant of the lowland dry tropics, growing best in places where annual low temperatures do not dip below 15 degrees C, rainfall is less than 1500 mm and distributed in one or two rainy seasons, and below 500 m a.s.l. I conclude by underscoring the need for studies of all of these aspects across the entire diversity within M. oleifera and across the genus.