Vitamin D is commonly known as the “sunshine” vitamin as our bodies can produce it from cholesterol when our skin is exposed to sunlight. Between 50-90% of our vitamin D is absorbed through the skin via sunlight [J Mak, An Evidence-Based Review of Efficacy and Safety of Dietary, Natural Supplements and Sunlight in Vitamin D Deficiency, IntechOpen, 2019]. Even though vitamin D can also be found in certain foods, our main source comes from the production in the skin after sunlight exposure.
Vitamin D plays essential roles in the body. Since it improves our capacity to absorb calcium and phosphorus, it helps maintain bones, teeth, cartilage and muscles healthy. Vitamin D also plays a crucial function in helping our immune system work properly. For example, it stimulates the proliferation of immune cells and regulates the synthesis of a protein that kills pathogens, including viruses and bacteria.
Vitamin D deficiency is common and can lead to a loss of bone density, which can contribute to osteoporosis and fractures (broken bones). In children, it can cause rickets, a rare disease that causes the bones to become soft and bend. That being said, excessive amounts of vitamin D from supplements can lead to nausea, muscle weakness, neuropsychiatric disturbances, pain, loss of appetite, dehydration, excessive thirst, kidney stones, stomach pain, constipation and diarrhea. In extreme cases, an excess of vitamin D can cause renal failure, calcification of soft tissues throughout the body (including in coronary vessels and heart valves) and cardiac arrhythmia.
Few foods are naturally rich in vitamin D. Vitamin D-rich foods include fatty fish (such as trout, salmon, herring, mackerel, sardine) and fish liver oils. Smaller amounts are found in organ meat (e.g. beef liver), mushrooms (e.g. maitake, chanterelle, morel), egg yolks and fortified foods (such as fortified milk).
Athletes have higher needs in vitamin D than sedentary people. Research suggests that low vitamin D levels increases the risk for stress fractures, acute illness, and suboptimal muscle function. Not only does vitamin D aid in the regulation of electrolyte metabolism, but it is required for hormone synthesis and for the maintenance of skeletal muscle health.
In conclusion, our vitamin D levels impact many aspects of our mental and physical health. In order to make sure that your vitamin D levels are balanced and steady, make sure to test your levels and to evaluate how you can make the right changes to rebalance your body and mind.