9 Vital Functions Of Vitamin D

Vitamin D, which is technically a hormone rather than a vitamin, is a crucial nutrient. Unfortunately, many Americans – even those who eat a good diet – are vitamin D deficient.

Typically, we get a vitamin D boost from the sun, but because we are wearing more sunscreen and spending more time INSIDE our levels are falling, putting us at greater health risks. In fact, there is research linking vitamin D deficiency to over 200 diseases.

Although most people think of vitamin D as just the “sunshine vitamin”, they often do not fully understand the significant ways that vitamin D affects your brain, body and overall health. Here are just a few:


Vitamin D receptors are found all over the body, including the immune cells. Research has clearly shown that vitamin D deficiency is part of the seasonal nature of cold and flu outbreaks – less sunlight means less vitamin D, which leads to lower immunity and more illness.


It’s well-documented that vitamin D is essential for the proper absorption of calcium, and it’s been shown to greatly reduce fracture risk in two ways. First, it helps with the formation of stronger bones; second, Vitamin D helps improve balance and prevent falls by enhancing muscle contraction.


One of the byproducts of vitamin D’s breakdown, called 1,25(OH)2D, enters muscle cells and affects the nucleus. Once there, the vitamin D metabolite enhances the cell’s contraction ability. Since muscles work by contraction and relaxation, a muscle’s ability to contract is essential to its strength and response to outside forces. Vitamin D, then, makes muscles stronger in a very direct way.


As many studies indicate, vitamin D plays a role in keeping our lungs healthy due to vitamin D possessing a range of anti-inflammatory properties – with greater concentrations of vitamin D resulting in greater lung health benefits.


Research has demonstrated an inverse relationship between vitamin D levels in the blood and high blood pressure (HBP or hypertension). In other words, the lower the vitamin D, the higher the blood pressure. The excess strain and resulting damage from high blood pressure causes the coronary arteries serving the heart to slowly narrow and harden, greatly increasing the risk of a heart attack.


Because vitamin D is a fat-soluble vitamin, it helps to regulate kidney function and plays a very beneficial role in treating kidney disease.


When it comes to being happy, the scientific evidence is clear. The lower your vitamin D levels, the more likely you are to feel blue rather than happy. Low levels of vitamin D have long been associated with a higher incidence of depression. Interestingly, when vitamin D3 supplements were compared to anti-depressants in a 2014 study, the positive effect of vitamin D3 on mood was comparable to the effects of the anti-depressants.

Weight Loss

When you don’t have enough vitamin D, you feel hungry all the time, no matter how much you eat. That is because low levels of vitamin D interfere with the effectiveness of leptin, the appetite hormone that tells you when you are full. When vitamin D is replenished and back to normal levels, leptin’s actions are restored, thus creating feelings of satiety and aiding in weight loss.

Cognitive Function

In the past few years, many studies have linked shortage of vitamin D with cognitive impairment in older men and women. Research has demonstrated that vitamin D has a variety of neuroprotective roles, including helping to rid the brain of beta-amyloid, an abnormal protein that is believed to be a major cause of Alzheimer’s disease. Additionally, an international study (the largest to date) shows that seniors with very low levels of vitamin D are at twice the risk of Alzheimer’s disease.

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Donna Wasson

The article was very informative yet it failed to tell how to test yourself for Vitamin D levels and to give the recommended daily dose to achieve these health benefits.


Test is done through blood work. Your PCP-Primary Care Physician is able to work such test and subsequent dosage that would replenish any Vit D deficiency.


*order such test (not “work such test”), Sorry for the typo.


I would like to add that it is often assumed that tiredness and exhaustion are a symptom of aging, however, it might well be a serious vitamin D deficiency. Constant fatigue usually occurs due to lack of phosphorus and calcium being absorbed into the system,which in turn can trigger joing and bone pain in elderly.