Does milk contain vitamin d
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Vitamin D Content in Milk: An Overview
Vitamin D in Cow's Milk
Cow's milk naturally contains vitamin D, although the levels can vary significantly. Research indicates that milk from cows fed normal levels of vitamin D contains approximately 40 IU per liter of vitamin D activity. This includes various vitamin D compounds such as cholecalciferol (vitamin D3) and 25-hydroxycholecalciferol, which together account for the biological activity observed in milk. However, increasing the dietary vitamin D intake of cows only slightly increases the vitamin D content in their milk.
Fortification of Milk with Vitamin D
To combat deficiencies and prevent diseases like rickets, milk is often fortified with vitamin D. Fortified milk can significantly improve vitamin D status in individuals. For instance, a study on postmenopausal women showed that daily intake of milk enriched with calcium and vitamin D led to a significant increase in serum vitamin D levels and bone mineral density. Similarly, vitamin D-fortified milk has been shown to improve vitamin D status in various population groups, including children and adults .
Vitamin D in Human Milk
Human milk also contains vitamin D, though in varying amounts. Studies have found that human milk contains between 40 to 50 IU per liter of vitamin D activity, primarily from vitamins D2, D3, and 25-hydroxyvitamin D3 . These compounds account for more than 90% of the total vitamin D activity in human milk.
Issues with Vitamin D Fortification
While fortification is beneficial, it must be carefully monitored. There have been instances of both underfortification and overfortification. For example, a study found that many milk samples contained less than the amount of vitamin D stated on the label, while some contained significantly more, leading to potential health risks . Excessive fortification can lead to hypervitaminosis D, as seen in cases where individuals consumed milk with excessively high levels of vitamin D.
Conclusion
Milk, both cow's and human, contains vitamin D, though the levels can vary. Fortification of milk with vitamin D is a common practice to ensure adequate intake and prevent deficiencies. However, the fortification process must be carefully monitored to avoid health risks associated with incorrect vitamin D levels. Overall, fortified milk is a valuable source of vitamin D and contributes significantly to improving vitamin D status in various populations.
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