- Vitamin D and Intestinal Calcium Absorption
- The Role of Calcium and Vitamin D in Bone Health
- Calcium/Vitamin D
- Get the Facts on Calcium and Vitamin D
Vitamin D and Intestinal Calcium Absorption
Boosting Vitamin D May Not Protect Bonesand shop n save ofallon mo how to remove yahoo powered
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium , magnesium , and phosphate , and multiple other biological effects. The major natural source of the vitamin is synthesis of cholecalciferol in the skin from cholesterol through a chemical reaction that is dependent on sun exposure specifically UVB radiation. Vitamin D from the diet, or from skin synthesis, is biologically inactive. A protein enzyme must hydroxylate it to convert it to the active form. This is done in the liver and in the kidneys. As vitamin D can be synthesized in adequate amounts by most mammals exposed to sufficient sunlight, it is not an essential dietary factor, and so not technically a vitamin. Cholecalciferol is converted in the liver to calcifediol hydroxycholecalciferol ; ergocalciferol is converted to hydroxyergocalciferol.
Vitamin D is often recommended for use with calcium supplements to increase absorption.
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Have a question? Ask ODS: ods. Vitamin D is a fat-soluble vitamin that is naturally present in very few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis. Vitamin D obtained from sun exposure, food, and supplements is biologically inert and must undergo two hydroxylations in the body for activation. The first occurs in the liver and converts vitamin D to hydroxyvitamin D [25 OH D], also known as calcidiol. The second occurs primarily in the kidney and forms the physiologically active 1,dihydroxyvitamin D [1,25 OH 2 D], also known as calcitriol [ 1 ].
The Role of Calcium and Vitamin D in Bone Health
New Recommendations for Calcium and Vitamin D Intake
The information included here will help you learn all about calcium and vitamin D — the two most important nutrients for bone health. Calcium is a mineral that is necessary for life. In addition to building bones and keeping them healthy, calcium enables our blood to clot, our muscles to contract, and our heart to beat. Every day, we lose calcium through our skin, nails, hair, sweat, urine and feces. Our bodies cannot produce its own calcium.
The principal function of vitamin D in calcium homeostasis is to increase calcium absorption from the intestine. Calcium is absorbed by both an active transcellular pathway, which is energy dependent, and by a passive paracellular pathway through tight junctions. This article reviews recent studies that have challenged the traditional model of vitamin D mediated transcellular calcium absorption and the crucial role of specific calcium transport proteins in intestinal calcium absorption. There is also increasing evidence that 1,25 OH 2 D 3 can enhance paracellular calcium diffusion. The influence of estrogen, prolactin, glucocorticoids and aging on intestinal calcium absorption and the role of the distal intestine in vitamin D mediated intestinal calcium absorption are also discussed. Studies in vitamin D receptor VDR null mice have indicated that the principal function of vitamin D in mineral homeostasis is to increase calcium absorption from the intestine Li et al.
Recent media reports and studies have left many confused about calcium supplements and their effect on the heart. While some studies have suggested a possible link between calcium supplements and heart-related problems, substantial evidence supports that taking the recommended amount of calcium supplements poses no risk to the heart., You probably already understand that calcium is good for your bones and helps ward off osteoporosis.
Get the Facts on Calcium and Vitamin D