How vitamin D might save your life

If your childhood was anything like mine, you may have found yourself being fed multi-vitamin tablets or the dreaded spoon of cod liver oil by well-meaning adults. We all know that vitamins are beneficial, but there is growing evidence to suggest that vitamin D may be even more important than we have been led to believe. The vitamin may even provide protection against cancer, heart disease, and even sleep disorders.

In the past, vitamin D deficiency was marked by an increased risk of fractures, rickets, and osteoporosis. This is because vitamin D’s main function is to aid in the uptake of small molecules like calcium, magnesium, and phosphates from the intestines. Calcium uptake is particularly important for maintaining bone density.

A recent study has determined that higher vitamin D concentrations are associated with a lower risk of cancer in Japanese populations. It has been found that vitamin D reduces cell proliferation and differentiation in malignant cells. Other studies have found an association between vitamin D levels and a reduced risk of coronary heart disease. Even more studies link vitamin D deficiency with fatigue. Given how such diseases plague our societies, why do so  many of us not get our daily allowance of vitamin D?

It has much to do with how we obtain – or don’t obtain – our vitamins. Vitamin D is made up of couple vitamers (forms): D2 and D3. D2 is formed in yeasts and fungi when hit by ultraviolet light. D3 is an animal-based source and formed from cholesterol when sunlight hits the skin. D3 formation in our skin is a delicate balance between the levels of the pigment melanin – the main determinant of skin colour – and the intensity of sunlight. A higher concentration of melanin is associated with a darker skin colour and protects well against UV ray damage. However, it also means that the conversion of cholesterol to vitamin D is slowed.

Evolutionarily speaking, this makes sense, as we can observe a decrease in skin pigmentation with increasing latitude and decreasing sunlight intensity. As sunlight intensity decreases, less melanin is required to protect against UV rays and to make use of the limited light to synthesise vitamin D. A notable exception to this pattern is the Inuit of Northern Canada. Due to their high latitude, one would expect them to have a pale skin colour, yet their fish heavy diet provides them with all the vitamin D they require. Therefore, their skin has not reduced in pigment concentrations.

Although our skin does a good job of synthesising this necessary molecule, during months where there is limited sunlight, it simply isn’t enough. Current guidelines suggest a daily intake of 10 micrograms of vitamin D, which would likely require some supplementation in the form of vitamin tablets or diet changes. It must be stressed that vitamin D overdose is possible via supplements; however, it seems our parents were onto something with the cod-liver oil after all.

Image credit: stevepb via pixabay

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  1. Marc Sorenson
    Mar 28, 2018 - 06:24 PM

    Vitamin D is wonderful, and the most natural way to acquire it is sun exposure. 20 minutes of full-body sun exposure at midday can stimulate the skin to produce 20,000 IU. However, sun exposure produces other vital photoproducts such as serotonin, endorphin, nitric oxide and BDNF. Here are some facts about the positive effects of sun exposure that you man not have known:
    •Women who actively seek the sun have half the risk of death compared with those who avoid the sun.
    •A Spanish study shows that women who seek the sun have one-eleventh the hip-fracture risk as those who avoid sun.
    •Men who work outdoors have half the risk of melanoma as those who work indoors.
    •Women who avoid the sun have 10-times the risk of breast cancer as those who embrace the sun.
    •Women who sunbathe regularly have half the risk of death during a 20-year period compared to those who stay indoors.
    •Sun exposure increases nitric oxide production, which leads to a decrease in heart disease risk.
    •Sun exposure dramatically improves mood through the production of serotonin and endorphin.
    Sun exposure increases the production of BDNF, essential to a properly functioning nervous system.
    For more information: Sunlight Institute website:


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