Vitamin D
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Vitamin D is becoming an increasingly important player in a healthful diet. Over the past 10 years, a spate of research has linked it to an impressive and diverse array of potential benefits. In addition to vitamin D’s well-known function of increasing calcium absorption and thereby helping encourage healthy bone growth, it has shown promise in helping to prevent certain cancers, heart disease, diabetes, and osteoarthritis. 1
The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. It promotes bone mineralization in concert with a number of other vitamins, minerals, and hormones. Without vitamin D, bones can become thin, brittle, soft, or misshapen. Vitamin D prevents rickets in children and osteomalacia in adults — skeletal diseases that result in defects that weaken bones. 2
Understand the role of vitamin D. Although most people are familiar with calcium�s role in bone health, it is important to know that vitamin D is responsible for helping your body absorb and effectively utilize calcium. Unfortunately, research shows that over 70 percent of women ages 51-70 and nearly 90 percent of women over 70 are not getting an adequate intake of vitamin D from food and supplements. Low levels of vitamin D are associated with reduced calcium absorption, bone loss and increased risk of fracture. 3
The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. Recently, research also suggests vitamin D may provide protection from osteoporosis, hypertension (high blood pressure), cancer, and several autoimmune diseases. 4
Vitamin D helps the heart: A study published last month in the journal Circulation looked at the impact of vitamin D blood levels on heart health in people with high blood pressure. Participants in the study with low vitamin D levels were twice as likely to have angina, a heart attack, heart failure or a stroke as those with normal vitamin D levels. 5
Vitamin D is unique in many ways. At the time of its discovery in 1919, vitamins A, B, and C were already identified; D was the next letter in line, so that was the name given to the compound. However, vitamin D behaves like a hormone in the body, relaying chemical messages — something no other vitamin does. For example, vitamin D signals the intestines to absorb calcium from foods and to regulate its uptake by bone cells. 6
Vitamin D is found in some foods, especially milk and fortified cereals, and is made by the body after exposure to sunlight. It is necessary for bone health, and some studies suggest that it may protect women from developing breast cancer in the first place. 7
Maintenance of serum calcium levels within a narrow range is vital for normal functioning of the nervous system, as well as for bone growth and maintenance of bone density. Vitamin D is essential for the efficient utilization of calcium by the body (1). The parathyroid glands sense serum calcium levels and secrete parathyroid hormone (PTH) if calcium levels drop too low (diagram). 8
A: It may be enough sunlight exposure in some parts of the country throughout the year, but sunlight exposure is difficult to measure. Factors such as the amount of pigment in your baby�s skin and skin exposure affect how much vitamin D is produced by your body from sunlight. In the more northern parts of the country during the winter, the amount of sunlight is not enough for any baby. Exposing infants and children�s skin to sunlight has been shown to increase the risk for skin cancer later in life. Sunscreens should be used on all children when in sunlight but it prevents vitamin D formation in the skin. 9
This does not mean that vitamin D is having a protective effect itself, although this is one hypothesis. It is also possible that higher vitamin D levels may be a marker of other health practices, e.g., eating a healthier diet or engaging in more physical activity � which could be related to sun exposure, though not necessarily, researchers said. 10
The Institute of Medicine, a group that uses scientific research to formulate public health policies, currently recommends an Adequate Intake, or AI, rather than a specific daily amount of vitamin D. The AI for vitamin D is 200 International Units for adults under age 50, 400 IU for those 51 to 70, and 600 IU for those age 71 and above. As new studies continue to showcase vitamin D’s potential benefits, more scientists are calling for increased recommendations. Some suggest as much as 10,000 IU –currently the tolerable upper intake daily. 11
Intrigued by the concept, Harvard epidemiologist Edward Giovannucci in the mid-1990s began examining data from a continuing study of 33,000 female nurses who submitted blood samples in 1989 and another following 18,000 male health workers who gave blood samples in 1993. He had to wait a while for data to roll in. But in 2004 he found that the nurses with the highest initial vitamin D levels had a 47% lower risk of colon cancer over the next decade; in 2007 his researchers reported that the male health workers with the best D levels had a 54% lower colon cancer risk. 12
Numerous effects of vitamin D on bone have been demonstrated. In cell cultures, vitamin D stimulates differentiation of osteoclasts. However, studies of humans and animals with vitamin D deficiency or mutations in the vitamin D receptor suggest that these effects are perhaps not of major physiologic importance, and that the crutial effect of vitamin D on bone is to provide the proper balance of calcium and phosphorus to support mineralization. 13
A 40-year review of research found that a daily dose of vitamin D could halve the risk of breast and bowel cancer, two of the biggest cancer killers. Scientists from the University of San Diego reviewed 63 scientific papers published since the 1960s and concluded that there was a need for “public health action” to boost vitamin D levels. Vitamin D deficiency “may account for several thousand premature deaths from colon, breast, ovarian and other cancers annually,” they wrote in the American Journal of Public Health. 14
Vitamin D deficiency: The classical manifestations of vitamin D deficiency is rickets, which is seen in children and results in bony deformaties including bowed long bones. Deficiency in adults leads to the disease osteomalacia. Both rickets and osteomalacia reflect impaired mineralization of newly synthesized bone matrix, and usually result from a combination of inadequate exposure to sunlight and decreased dietary intake of vitamin D. 15
References
The Panacea offers these health-extracts to help people investigate health-related subjects in greater depth using the references given in each paragraph. Kindly note that these are current extracts from the web, meant for research, and that these are not meant to be medical advise. For all your health-related needs you must consult trained and licensed personnel.
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