Milkfat and processed milk
That cardiovascular lesions are not induced by the fat of whole milk, but may be caused by the lack of accompanying nutrients in processed milk products gains support from a number of controlled rat experiments. S. Dreizen and his coworkers (J. Nutr., 74:75, 1961) have shown that rats restricted to a diet of nonfat dry cow's milk induced atherosclerosis of the aorta and its major branches, together with a syndrome of accompanying afflictions in 50 percent of the animals.
Other investigators have demonstrated that rats reared on an exclusive whole milk diet supplemented with iron, iodine, manganese, and copper do not develop cardiovascular lesions (Kemmerer, A. R. et al. Am. J. Physiol., 102:319, 1932; McCay, C. M., et al. J. Gerontol., 7:61, 1952). This, incidentally, would would be in agreement with those epidemiological studies of the African herdsmen tribes -- the Masai, Somalis, and Samburus -- who live almost exclusively on a milk-meat diet.
In one other experiment, Dreizen and his colleagues conducted a series of studies with ten groups of rats on different kinds of milk diets (J. Atheroscler. Res., 6:537, 1966). The results of these tests disclosed that rats reared on a diet of dry whole cow's milk (without supplements) developed overt atherosclerosis in 30 percent of the animals, while 40 percent succumbed to vascular lesions on a diet of nonfat dry milk. However, the investigators found that complete protection was afforded virtually all the animals against cardiovascular complications on diets of (1) reliquified whole milk; (2) dry whole milk supplemented with iron, copper, manganese, and iodine; (3) reliquified whole milk plus the trace elements; and (4) reliquified nonfat dry milk plus 3.6 percent sweet cream and the trace elements. These investigators assert that "a diet of nonfat dry milk, 3.5 percent butter, and the trace minerals gave almost complete protection, slight arteriosclerotic damage being found on histologic examination in only one of the thirty animals." They noted that neither the inception or prevention of atherosclerosis was related to cholesterol levels, nor, for that matter, to calcium or phosphorous levels.
These data suggest that adequate whole milk, including the butterfat, and essential trace minerals actually protect against cardiovascular damage. This, we have noted, concurs with other findings (Lowenstein, 1964; Mann, 1964; Shaper, Am. Heart J., 63:437, 1962) of the African tribes who live on a diet of raw whole cow's and goat's milk, a 60 to 65 percent butterfat diet, yet are virtually free of coronary heart disease. According to Dreizen and his colleagues, not only was the saturated butterfat of whole milk not to blame, but its inclusion in the diet was vital to the health of the cardiovascular system. It was the lack of adequate nutrients in a diet totally free of fat that caused medical atherosclerosis and renal damage. Butterfat, itself, appears to protect against atherosclerosis! More material on this subject will be presented later.
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