In this blog post, we discuss what vitamin D does for our health and why it's so important.It's so important because there's a high chance you're lacking adequate levels of it.DID YOU KNOW: Over 40 percent of Americans are deficient in vitamin D. Let's bring it back with some history first.The Discovery of Vitamin DVitamin D’s existence was first considered in 1840 when a Polish physician discovered that the incidence of rickets (a skeletal disorder) had a much higher occurrence rate in children living in the industrial center of Warsaw versus those living in the countryside.He concluded that the relative difference in the prevalence of rickets was due to sun exposure. His hypothesis was not well received and largely ignored by mainstream medicine.In 1980, Sir Edward Mellanby discovered that beagles housed exclusively indoors and fed a diet of oatmeal developed rickets which, with the addition of cod liver oil, could be treated successfully. Further tests and experimentation followed, and vitamin D was discovered.The Different Forms of Vitamin DVitamin D comes in a variety of different forms. The most important for humans are vitamin D2 and vitamin D3.D2 is synthesized by plants. D3 is synthesized by the skin when it is exposed to ultraviolet B (UVB) rays (in real person speak: the sun gods).Vitamin D is not actually a vitamin, but rather a prohormone. When our body is exposed to, or receives, vitamin D, it activates the vitamins in the liver and kidneys. This activation process (known as vitamin synthesis) turns the vitamin D into a hormone (or activated vitamin D).Vitamin D is not actually a vitamin, but rather a prohormone. We can access vitamin D via sun exposure, a limited number of foods, and supplements.Health Benefits of Adequate Vitamin D Levels in the BodySo why do we need Vitamin D?Vitamin D is linked to numerous health benefits due to its ability to influence genetic expression. The following is a list of vitamin D’s proposed health benefits.Promotes Healthy BonesVitamin D stimulates the absorption of calcium and phosphorus into the body, both of which are essential for maintaining bone health.A vitamin D deficiency in a child may manifest as rickets, and in an adult as osteomalacia (softening of the bones) or osteoporosis.Vitamin D May Help with Weight LossTrying to stack the weight loss cards in your favor? You want vitamin D in your corner.Getting adequate amounts of vitamin D has been linked to the ability to lose more weight.In a study by the University of Cambridge, subjects who took calcium and vitamin D supplements daily lost more weight than those who took a placebo pill.The research suggested that the extra calcium and vitamin D worked as appetite suppressants.In a Journal of Women’s Health Study, women with insufficient vitamin D levels were more susceptible to weight gain than those with adequate amounts.Associated with Lower Cancer RatesEarly stage epidemiologic research suggests that the incidence of, and death rates for, certain cancers are lower among individuals living in southern latitudes, where levels of sunlight exposure are higher. Researchers think that the variation in vitamin D levels might explain the discrepancy.Vitamin D regulates cell growth and cell-to-cell communication. Some studies have suggested that the hormonally active form of vitamin D may slow or even reduce cancer progression by promoting cellular differentiation, decreasing cancer cell growth, stimulating cell death, and preventing angiogenesis or new blood vessel formation.D for DepressionThe sun — and the resultant vitamin D — have legitimate feel-good superpowers. So much so that adequate levels of vitamin D are linked to warding off depression and regulating mood.In a Journal of Internal Medicine study, research showed that people with depression who received vitamin D supplements experienced an improvement in their symptoms.Immune System BoostVitamin D regulates the expression of genes that influence the immune system. This means that Vitamin D assists the body to attack and destroy bacteria, viruses, and infections, including the common cold and flu.In one study, children given 1,200 international units of vitamin D per day for 4 months during the winter had a reduced risk of contracting the influenza A infection by over 40 percent.May Lowers Risk of DiabetesVitamin D may help to reduce the risk of insulin resistance by improving the body’s sensitivity to insulin (the hormone responsible for regulating blood sugar levels). Insulin resistance is usually a precursor to type 2 diabetes. Vitamin D has been linked to glucose metabolism.One study found that participants with low vitamin D levels were more likely to develop type 2 diabetes, pre-diabetes, or metabolic syndrome, regardless of their weight.In obese and lean participants alike, it was found that those with a metabolic disorder had lower levels of vitamin D, and those without metabolic disorders had higher levels of vitamin D. These findings indicated that “vitamin D is associated more closely with glucose metabolism than obesity.” Interested in learning more about the sunshine vitamin?Check out our other vitamin D posts on the symptoms of vitamin D deficiency or different sources of vitamin D to learn more!