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SummaryThe effects of different levels of vitamin E on SMSG and lacrimal gland lipids were studied in rats. Feeding of purified diets containing 0, 250, or 2500 IU vitamin E/kg of diet was initiated during gestation and continued throughout lactation and then to the pups until 1 month after weaning. SMSG and lacrimal glands were extracted for lipids and the effects of vitamin E on lipid and fatty acid composition were examined. Total lipid content was not affected by different levels of vitamin E. Total lipid phosphorus was, however, decreased with an increase in dietary vitamin E. Vitamin E content of the SMSG and lacrimal glands was increased by severalfold depending upon the level of dietary vitamin E. The fatty acid composition of total lipids, neutral lipids, and phospholipids showed that the levels of C20:3 ω9 were reduced and those of C20:3 ω6 were increased as the dietary levels of vitamin E were increased. This resulted in a decrease in the ratio of C20:3 ω9 to C20:3 ω6.

EFA deficiency was created in young weanling rats by feeding for 16 weeks purified diets containing 0% fat or 7% hydrogenated coconut oil (HCO). Control rats were fed similar diets which contained 7% corn oil or 5% HCO + 2% corn oil. Submandibular salivary gland (SMSG) lipids were extracted and analyzed for the concentrations of the free fatty acids (FFA), triglycerides (TG), total lipid P and the proportions of various phospholipids. In EFA-deficient SMSG, the concentrations of FFA and TG fractions were lower compared to those of the controls. Total lipid P was either unaffected or slightly increased; the proportion of phospholipids was not changed. Possible reasons for these changes in SMSG lipids are discussed.

The fatty acid composition of rat molars and incisors was essentially the same whether starch or sucrose was the dietary carbohydrate. A slight increase in palmitic acid and decrease in unsaturated fatty acids was noted in the rats fed starch as compared with those fed sucrose.

Weanling rats were maintained on a cariogenic diet for three or six weeks. Two control groups were given this diet ad libitum; the food intake of two other groups was restricted. The restricted groups gained less weight and developed less dental caries. Phospholipids and free fatty acids were the main lipid fractions in molars and incisors. Food restriction altered the amounts of these two fractions in the teeth.

Caries incidence was generally lower in rats fed a cariogenic diet that contained four different oils and fats at a 9% level than in those fed a diet with a 3% level of the same oil or fat. The amount of linoleic acid in pooled samples of dentin and enamel extracted from the molars and incisors was related to the amount of linoleic acid in the diet.