Vitamin D is the collective name for a group of closely related lipids. Its main biologic function is to maintain serum calcium and phosphorus concentrations within the normal range by enhancing the efficiency of the small intestine to absorb these minerals from the diet. In addition, it has potent anti-proliferative, pro-differentiative and immuno-modulatory functions and plays important roles in promoting oral health and preventing colon cancer. The main portion of vitamin D3 derives from the conversion of 7-dehydrocholesterol upon exposure to ultraviolet rays. Vitamin D naturally present in the diet in larger quantities is cholecalciferol (vitamin D3) contained in foods such as oily fish. Smaller quantities of vitamin D3 occur in meat, eggs, milk and dairy products. In many countries milk is fortified, mainly by adding vitamin D3. Most of the milk sold at retail in the United States is fortified, while the fortification is less common in Europe. We used a commercially available ELISA method for the determination of vitamin D in milk. 55 individual samples of unfortified cow's milk from different herds were analyzed as well as 10 different types of milk for human consumption on the market. The enzyme immunoassay method used was confirmed as a useful tool to measure the vitamin D in the milk as it greatly reduces the time required to perform the conventional HPLC analysis. An interesting variation was found among individuals that may be associated with management factors and specific genetic effects. In this regard an interesting relationship was highlighted between vitamin D content and the genetic polymorphism of ?-lactoglobulin, the main milk whey protein involved in the transport of small hydrophobic molecules such as retinol and vitamin D. The relatively high content of vitamin D in the sam- ples analyzed justifies the limited use of the fortification of milk in our country and suggests an opportunity to improve the con- tent of vitamin D naturally present in milk. This result could be obtained either by acting on the herd management or evaluating the possibility to select individuals genetically predisposed to produce milk with a higher vitamin D content.
Natural variation of vitamin D in cow's milk
S Chessa;
2013
Abstract
Vitamin D is the collective name for a group of closely related lipids. Its main biologic function is to maintain serum calcium and phosphorus concentrations within the normal range by enhancing the efficiency of the small intestine to absorb these minerals from the diet. In addition, it has potent anti-proliferative, pro-differentiative and immuno-modulatory functions and plays important roles in promoting oral health and preventing colon cancer. The main portion of vitamin D3 derives from the conversion of 7-dehydrocholesterol upon exposure to ultraviolet rays. Vitamin D naturally present in the diet in larger quantities is cholecalciferol (vitamin D3) contained in foods such as oily fish. Smaller quantities of vitamin D3 occur in meat, eggs, milk and dairy products. In many countries milk is fortified, mainly by adding vitamin D3. Most of the milk sold at retail in the United States is fortified, while the fortification is less common in Europe. We used a commercially available ELISA method for the determination of vitamin D in milk. 55 individual samples of unfortified cow's milk from different herds were analyzed as well as 10 different types of milk for human consumption on the market. The enzyme immunoassay method used was confirmed as a useful tool to measure the vitamin D in the milk as it greatly reduces the time required to perform the conventional HPLC analysis. An interesting variation was found among individuals that may be associated with management factors and specific genetic effects. In this regard an interesting relationship was highlighted between vitamin D content and the genetic polymorphism of ?-lactoglobulin, the main milk whey protein involved in the transport of small hydrophobic molecules such as retinol and vitamin D. The relatively high content of vitamin D in the sam- ples analyzed justifies the limited use of the fortification of milk in our country and suggests an opportunity to improve the con- tent of vitamin D naturally present in milk. This result could be obtained either by acting on the herd management or evaluating the possibility to select individuals genetically predisposed to produce milk with a higher vitamin D content.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
