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American Journal of Cardiology. 96:1034-1035, 2005.Nuts Are Also a Rich Source of Magnesium for Life's Sake
Bushman of the Kalahari
In the report by Nash and Westpfal, I found it somewhat disappointing that the rich source of magnesium (Mg) in nuts  was not mentioned. The authors apparently do not appreciate that the cardiovascular advantages provided by nuts (i.e., the favorable effect on lipids, endothelial function, insulin sensitivity, and anti-inflammatory and anticlotting effects) are all provided by Mg,[2,3] Early human survival must have been dependent on great endurance capacity, as exemplified by the Bushmen of the Kalahari Desert, who have the capability of chasing an antelope for up to 2 days until the animal drops from exhaustion,
However, it is even more astonishing that the Bushmen can accomplish this feat without a drop of water (Hitchcock R, personal communication), despite the enhanced potential for a heat-induced Mg ion deficit and the potential for vasoconstrictor-induced endothelial dysfunction. Mg is a calcium blocker and antioxidant,  and it is stored in the bones, skeletal muscles, and soft tissues. The !Kung Bushmen of Botswana are almost entirely dependent on hunting and gathering. However, in addition to prey, what other sources of Mg exist for these extraordinary populations? Mongongo nuts, because of their reliability and abundance, provide about l/2 of their vegetable diet by weight. The average daily consumption of about 300 of these nuts provides > 1,200 calories and > 50 g of protein (the caloric equivalent of >2 lb of cooked rice and protein equivalent of about 14 oz of lean beef). Finally, these nuts are drought resistant and can be harvested for up to I year after falling to the ground. 
William J. Rowe, MD
18 May 2005
1) Nash S, Westpfal M. Cardiovascular benefits of nuts. Am J Cardiol 2005;95:963-965.
2) Seelig M. Cardiovascular consequences of magnesium deficiency and loss: pathogenesis, prevalence and manifestations-magnesium and chloride loss in refractory potassium repletion. Am J Cardio/ 1989;63 (suppl):4G - 21G.
3) Maier J, Malpuech-Brugere C, Zimowska W, Rayssiguier Y , Mazur A. Low magnesium promotes endothelial celJ dysfunction :implications for atherosclerosis, inflammation and thrombosis. Biochim Biophys Acta 2004; 1689: 13-21.
4) Rowe W. Endurance exercise and injury to the heart. Guest Editorial. Sports Med ]993;]6: 73-79.
5) Lee RB. What hunters do for a living, or how to make out on scarce resources. In: Lee RB, De Vore I, eds. Man the Hunter. New York: Aldine De Gruyter, 1968:30-48.