Sex- and age-related differences in dietary and blood chemistry factors were investigated in subjects adhering to their usual lifestyles. Diet records were examined daily and blood chemistry profiles were monitored five times during the 1-yr study. As expected, high-density lipoprotein cholesterol was significantly higher in women than in men. Values of creatine phosphokinase, aspartic aminotransferase, alanine aminotransferase, glucose, triglycerides, urea nitrogen, uric acid, and total bilirubin were higher in men than in women. Glucose was lower while high-density lipoprotein cholesterol, albumin, and total protein were higher in the younger women than in older women. Alcohol consumption by men correlated positively with aspartic aminotransferase and alanine aminotransferase but not with high-density lipoprotein cholesterol. Alcohol consumption by women did correlate positively with high-density lipoprotein cholesterol but not with the aminotransferase enzymes. Correlations between serum high-density lipoprotein cholesterol and vitamin C intake were positive and significant in women. In men, high levels of high-density lipoprotein cholesterol seems to be associated with very high vitamin C intakes, but no associations were apparent at normal levels of these parameters. Serum cholesterol did not correlate significantly with dietary cholesterol, saturated fat, linoleic acid, or P/S in men or women.

A statistically significant inverse association was generally found between plasma total lipid, cholesterol, or phospholipid and biotin status of 300-day-old male inbred BHE (IN-BHE) rats. Plasma, liver, and carcass lipid of both sexes generally had a significant direct association with liver lactate dehydrogenase activity; an inverse association in males resulted with improved biotin status. Elevated plasma lactate indicative of anaerobic glycolysis was found. It is proposed that an increased reductive environment – a consequence of accumulated NADH – could account for enhanced triglyceride synthesis and that this effect could explain the obesity in the IN-BHE rats. After the injection of 300 µg of biotin, plasma levels of lactate and pyruvate fell in male rats, indicating a stimulatory effect of biotin upon the oxidative pathways in these animals.

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