Seasonal fluctuations of the vitamin A and C content of Palestinian milks

Abstract

1. The vitamin A and vitamin C contents of Palestinian fresh milk from three different sources were determined at regular intervals during the period February 1938 to March 1939. Between October 1938 and March 1939, these contents were also determined in Jerusalem pasteurized milk.2. The carotene and vitamin A content of Palestinian milk corresponds to that of American and European stable milk. This is due to insufficiency of green fodder in the diet of Palestinian cattle.3. Emek milk from the Valley of Jezreel contains more carotene and vitamin A than does the Kiryath Anavim milk from a hill district, owing to the better supply of green fodder in the valley. Milk from a Jerusalem dairy contains less carotene and vitamin A than does the milk from the nearby Kiryath Anavim settlement.4. All the milks examined show seasonal fluctuations in the carotene and vitamin A content. These variations are in direct relation to the supply of green fodder. The secretion of carotene begins to increase in January to April, according to the source of the milk, and begins to fall in August.5. The average percentage of carotene to the total vitamin A substances (carotene and vitamin A) ranges between 38 and 50. The ratio carotene to total vitamin A varies seasonally and otherwise in accordance with the total vitamin A in the milk.6. The vitamin C content of Palestinian milk lies in the same range as that of European and American milks.7. All milks examined contained considerably more vitamin C during the second than during the first half of the year with a peak in June and July. This increase does not seem to bear any relation to feeding practice.8. The losses of vitamin A and vitamin C found in pasteurized milk correspond with those given by European and American authors.9. Transportation of milk over long distances may cause almost complete loss of vitamin C.