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Holick, M. F., MacLaughlin, J. A. & Doppelt, S. H. (1981) Factors that influence the cutaneous photosynthesis of previtamin D3. Science 211:590-593 When human skin was exposed to simulated solar ultraviolet radiation, epidermal 7-dehydrocholesterol was converted to previtamin D3. During prolonged exposure to simulated solar ultraviolet radiation, the synthesis of previtamin D3 reached a plateau at about 10 to 15 percent of the original 7-dehydrocholesterol content, and previtamin D3 was photoisomerized to two biologically inert isomers, lumisterol3 and tachysterol3. Increases either in skin melanin concentration or in latitude necessitated increases in the exposure time to simulated solar ultraviolet radiation required to maximize the formation, but not the total content, of previtamin D3. In order of importance, the significant determinants limiting the cutaneous production of previtamin D3 are (i) photochemical regulation, (ii) pigmentation, and (iii) latitude.

Cholesterol, coconuts, and diet on Polynesian atolls: a natural experiment: the Pukapuka and Tokelau island studies. Prior IA, Davidson F, Salmond CE, Czochanska Z. Am J Clin Nutr. 1981 Aug;34(8):1552-61. PMID: 7270479 Two populations of Polynesians living on atolls near the equator provide an opportunity to investigate the relative effects of saturated fat and dietary cholesterol in determining serum cholesterol levels. The habitual diets of the toll dwellers from both Pukapuka and Tokelau are high in saturated fat but low in dietary cholesterol and sucrose. Coconut is the chief source of energy for both groups. Tokelauans obtain a much higher percentage of energy from coconut than the Pukapukans, 63% compared with 34%, so their intake of saturated fat is higher. The serum cholesterol levels are 35 to 40 mg higher in Tokelauans than in Pukapukans. These major differences in serum cholesterol levels are considered to be due to the higher saturated fat intake of the Tokelauans. Analysis of a variety of food samples, and human fat biopsies show a high lauric (12:0) and myristic (14:0) content. Vascular disease is uncommon in both populations and there is no evidence of the high saturated fat intake having a harmful effect in these populations.

Since it was first approved for use in food products by the FDA back in 1981, aspartame has been a very controversial substance. Everyone from the American Cancer Society to Gizmodo has written about this artificial sweetener. Because aspartame is found in everything from yogurt to diet soda to gum, it's important to understand why this substance has such a controversial reputation.

Active specific immunotherapy with supportive measures in the treatment of advanced palliatively nephrectomised renal adenocarcinoma. A controlled clinical study. Tykkä H. Scand J Urol Nephrol Suppl. 1981;63:1-107. PMID: 6184775

The most common imbalance in the acid-base balance in the industrialized countries is mild chronic metabolic acidosis caused by the diet rich in the animal protein. Proteins are metabolized to organic acids. The typical American diet produces after metabolism approximately 100 meq of acid every day (Barzel 1995). This kind of a diet has been proved to cause aciduria and calciuria as a consequence of acidosis and thus a loss of total calcium of the body (Breslau et al. 1988, Schuette et al. 1980, Licata et al. 1981). Cola drinks that contain phosphoric acid are another acidosis-inducing ingredient of diet, especially among young people (Barzel 1995).

Acid-base balance has an effect on bone turnover, especially on the rates of bone resorption and calcium mobilization. Bone mineral participates in the defense against acid-base disturbances, especially against metabolic acidosis (Lemann et al. 1966, Green & Kleeman 1991). The role of the bone mineral is important in the acid-base disorders, as no appreciable change in the intestinal calcium absorption occurs (Bichara et al. 1990). In the mammalian body, mainly three hormones regulate the calcium metabolism and the bone turnover. 1,25-dihydroxycholecalciferol (vitamin D derivative) increases calcium absorption from the intestine and, indirectly, from bone. Parathyroid hormone mobilizes calcium from the bone and increases the urinary phosphate excretion. Calcitonin inhibits bone resorption (Ganong 1981). Used as drugs, these hormones are also capable of inducing acid-base disorders. Calcitonin administration (Escanero et al. 1991) and vitamin D excess (Bichara et al. 1990) have been reported to cause metabolic alkalosis.