Effect of a long-term change from a mixed to a lactovegetarian diet on human saliva.

The effects of this long-term dietary change on secretion rate, buffer capacity, concentration of sodium and potassium and amylase activity of stimulated parotid and whole saliva was studied in 20 healthy, normal-weight, non-smoking omnivores. Salivary counts of mutans streptococci and lactobacilli were also made. Dietary surveys were carried out and saliva samples collected before (baseline) and 3, 6 and 12 months after the dietary change as well as 3 yr after the end of the lactovegetarian diet period. The dietary data showed an increase in the consumption of fruits, vegetables and dairy products and a decrease in meat, fish, eggs, sweets and biscuits. These changes led to an increased intake of carbohydrates, fibre and water. After 12 months on the vegetarian diet, the secretion rate, buffer capacity and sodium concentration of whole saliva and the secretion rate of parotid saliva had increased significantly. At the 3-yr follow-up, the buffer capacity and sodium concentration were still elevated, while the secretion rate had almost returned to the baseline values. The potassium content of whole saliva showed a tendency to increase during the vegetarian diet period, but had decreased again at the 3-yr follow-up.