Vitamin D is a group of fat-soluble molecules known as secosteroids. Vitamin D itself is a fat-soluble vitamin that is not available in many foods. However, photochemically, it is produced when ultraviolet rays from sunlight strike the skin and trigger Vitamin D synthesis. Vitamin D externally, though, is biologically inert in the human body, and "must undergo two hydroxylations in the body. The first occurs in the liver and converts Vitamin D to 25-hydroxyvitamin D The second occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin d (VanDen Berg 1997, S76). Although called a vitamin, Vitamin D is not actually an essential dietary vitamin because it can be synthesized in more than adequate amounts from sunlight. Typically, an organic chemical, or group of chemicals, is known as a vitamin when it must be obtained through diet or other means, and cannot be synthesized through bodily processes. Vitamin D has many uses in the human body. It is an essential element in promoting calcium from the gut and product enough serum calcium and phosphate to allow for the bone structure to remain solid, new bone cells to build, and the regeneration of bone from bruising, breaks, or even aging. Without Vitamin D, bones become thin, brittle, misshapen and unable to hold the body. As the body ages, Vitamin D helps prevent osteoporosis, which is why many aging individuals need calcium supplementation (Madrid, 2009). Vitamin D has other roles within the human health sector -- it helps modulate the relationship between nerves and muscles, reduce inflammation, and improve immune function (Eads 1994). New research also shows that exposure to sunlight and the resulting Vitamin D and calcium production keeps periodontal issues healthy. Many periodontal diseases are inflammatory processes in which there is an overreaction to bacteria in the mouth that damages the bone. Enough sunlight -- enough production of Vitamin D and calcium actually may prevent this from happening (Dryden, 2005).

Vitamin D and the Body- In the past two decades, a number of robust studies have shown that Vitamin D has even more of an integral effect upon the human body. We now know that the substance is critical from the enzymatic level to helping keep the neurotransmitters healthy, and even more, the link between adequate Vitamin D and the human immune system. We now know that low levels of Vitamin D in geriatric patients may have an effect in premature aging and increased mortality; and this effect is proportional to ethnicity. Vitamin D has been shown, of course, to be critical in the formation and growth of healthy bone tissue in children and adolescents, but what is not as widely known is that these effects continue even through menopause, and Vitamin D is critical for both men and women throughout their adult life cycle- regardless of their milk intake. Moderate to high doses of Vitamin D have, on occasion, been shown to decrease risks for cardiovascular disease, depending on the other variables in question. Low levels of Vitamin D are associated, though, with multiple scholeoris. Supplementation with Vitamin D may have a protective effect, but studies suggest that keeping Vitamin D levels more optimal can decrease the chance of the onset of the disease. Additionally, low Vitamin D levels are often associated with some cancers, and supplementation is helpful in all but prostate cancer (Feldman, et.al., eds. 2005).

Serum concentration of 25 (OH) D. is one of the best indicators of Vitamin D status. This measurement reflects Vitamin D produced from food and supplements, and serves as a biomarker of the effects of Vitamin D, but not the amount of Vitamin D stored in the body's fat cells. Circulating Vitamin-D tests, though, are not accurate because they have a half-life of but 15 hours and only decrease if there is a severe or chronic deficiency. The recommended amounts of Vitamin D vary by age, and are really more of a minimum requirement to prevent deficiency:

0-12 months = 400IU

1-13 years = 600 IU

14-70 years = 600 IU

>70 = 800 IU

Pregnant or lactating women, add 600 IU per day (Vitamin D, 2012).

Vitamin D Deficiencies -- For children, an inadequate supply of vitamin D comes from deficiencies that result in impaired bone mineralization and bone softening. Rickets, for instance, is a childhood disease characterized by an impairment of growth of the long bones, primarily caused by a lack of Vitamin D and the resultant inability to use calcium and phosphorous to develop bone health. Rickets does not typically appear in...

Rickets as a disease was described as early as 1650 and the determination of dietary causes confirmed during World War I. It is possible, however, to have dietary rickets even in areas with strong sunlight -- particularly when there is a lack of animal protein in the diet.
In young infants in poorer countries, breast milk is low in Vitamin D and the combination of social customs and climate prevent adequate exposure to sunlight. For instance, in countries like Nigeria and Bangladesh, Rickets most often occurs among toddlers and children who have limited access to dairy products and who primarily exist on a cereal-based diet. Likewise, Rickets was endemic in some of the 19th century immigrant populations in the United States, but with the increased consumption of milk after World War II and so many foods being enriched with Vitamin D, it is rare to find rickets in the American population.

Osteomalacia is an adult disease, characterized by bone thinning and muscle weakness. The condition has a basis in the body's inability to retain and use Vitamin D, but research has yet to find a correlation between musculoskeletal pain and the lowered amounts of Vitamin D among sufferers.

Nutritional Supplementation of Vitamin D- Because the issue of skin pigment, clothing, and exposure to sun can be so variable, it is important to note the potential for nutritional supplementation of Vitamin D However, very few foods contain enough Vitamin D to be usable to the human body. The best sources are fatty fish (salmon, tuna and fish liver oils), small amounts are found in beef liver, cheese and egg yolks. In the United States, though, almost all the milk supply is fortified with 100 IU/cup of Vitamin D and infant formulas in both the United States and Canada are mandated to be fortified with 40-100 IU in the United States and 40-80 IU/Kcal in Canada (Vitamin D).

Vitamin D and Pregnancy/Lactation -- Pregnant women should have above average intake of Vitamin D during gestation, which will contribute to positive immune effects. Ironically, though, 40-80% of pregnant women have some sort of a Vitamin D deficiency. This data is alarming since it shows that this deficiency also may contribute to modifying factors of risks of a number of chronic diseases. The research, in fact, shows that it is vital that the pregnant mother have enough Vitamin D throughout the pregnancy so that the tissues can "remember" the levels necessary for optimum metabolic effects and work towards using those levels (Kaludjerovic and Vieth, 2010).

Once the baby is born, the amount of usable Vitamin D in the mother's diet is even more critical. Vitamin D in mother's milk reflects the Vitamin D status of the mother and thus, if the mother is at risk for lower Vitamin D serum levels, the child is then at risk for rickets, failure to thrive, diabetes, and other immune related diseases. Particularly during pregnancy, the mother's immune system can benefit from Vitamin D supplementation, dosage depending on climate, weight, and overall health. Globally, over 1 million deaths occur in infants in developing countries because of inadequate or less than optimal nutritional uptake in breast milk. While the standard viewpoint is that breast milk is best, the baby's "perfect food," the simple fact is that if the mother has an inadequate supply of Vitamin D in her tissues, she is not able to pass on the optimal benefit of a complete nutritional product to the baby. The Vitamin D stores of the newborn depend 100% on the mother, and bone mass and other immune related issues are in direct relation to the mother's capacity to store Vitamin D "It the mother is Vitamin-D deficient, the infant will be deficient because of decrease maternal fetal transfer" (Balasurbramanian and Ganesh, 2008).

Vitamin D Deficiency -- Prevention in Infants -- From a global perspective, many medical researchers believe that children six months to five years should be given Vitamin D supplements, particularly during the winter months. Additional research shows that dark-skinned people who now live in temperate climates have overall lower Vitamin D levels, to the point that they are less efficient at actually making Vitamin D because the increased melanin in their skin hinders adequate Vitamin D synthesis. This is particularly important for pregnant women who are darker skinned, because they are then unable to pass on the needed Vitamin D to the fetus, sometimes causing a deficiency at birth. The American Academy of…