Around the world, an estimated 7% of the population has severe vitamin D deficiency. In addition, approximately 33% have insufficient vitamin D levels. The body naturally produces vitamin D3 when the skin is exposed to sunshine (i.e. ultraviolet rays). Insufficient sunlight exposure can create a need to obtain adequate vitamin D in other ways. Given that only small amounts of vitamin D can be obtained from food, a supplement can offer one way to address insufficient vitamin D.
Studies are finding a relationship between insufficient vitamin D and many illnesses. It is unclear whether this lack of vitamin D results in the development of illness, or whether having an illness leads to a greater lack of vitamin D. For example, having a chronic illness can restrict outdoor activities, resulting in less time spent in the sun. The lack of sunlight exposure could result in insufficient levels of vitamin D. Other factors that can affect vitamin D levels include health behaviours (such as eating habits or drug and alcohol consumption), being overweight, or having a chronic disease that reduces the ability to absorb vitamin D from food through the intestine.
In addition, clinical trials providing supplementation to adults with insufficient levels of vitamin D (but at levels greater than 50 nmol/l) cannot provide conclusive evidence that vitamin D supplements improve chronic illnesses such as cancer, heart disease, type 2 diabetes, or poor bone density. This suggests that taking a vitamin D supplement will not give you a better prognosis. Therefore, it is important to be clear about the reasons why you may take a vitamin D supplement.
Firstly, anyone with a severe deficiency in vitamin D (serum 25 OHD) should be treated. Severe deficiency in vitamin D levels is a serious health concern that should be promptly addressed. Vitamin D plays a significant role in our immunity. There are vitamin D receptors located on the body’s immunity cells, and the body relies on vitamin D to activate the production of antimicrobial protein. These proteins act as the first line of defense in the body’s immune system. Provided that sufficient vitamin D levels are maintained over time, vitamin D provides an anti-inflammatory effect.
A number of studies have looked at the potential benefit of vitamin D supplementation to reduce the severity of respiratory illnesses such as Covid-19. At present the results remain inconclusive. However, one consistent finding is that people with insufficient levels of vitamin D who consistently take supplementation (in daily or weekly doses) can strengthen their immunity against getting an acute infection such as Covid-19. This is possible because vitamin D reduces the replication rates of the virus. However, if they do become ill, taking a vitamin D supplement will not necessarily reduce the severity of that illness.
Vitamin D plays an important role in processing calcium, which is essential in maintaining bone health. When there is a vitamin D deficiency, the body cannot effectively metabolise calcium, which can result in bone disease or dysfunction. Vitamin D supplements combined with calcium supplements is proven to treat rickets caused by poor nutrition.
Taking a combination of vitamin D and calcium supplements can reduce the risk of falls or broken bones for older adults with a pre-existing deficiency in vitamin D and/or calcium.
Multiple sclerosis is a chronic degenerative neurological disease. There is a greater risk of developing multiple sclerosis in cases of a genetic deficiency in vitamin D (serum 25 OHD). Although there is no known cure, study findings suggest that vitamin D supplements help to manage multiple sclerosis by correcting a vitamin D deficiency related to genes.
There is scientific evidence to suggest that vitamin D supplements can lower the risk of developing pre-eclampsia or gestational diabetes for women with high-risk pregnancies. High-risk pregnancies can be caused by factors such as prior history of pre-eclampsia during a pregnancy, pre-existing high blood pressure or renal disease, or having a higher weight.
If you fall into one of the above categories, the first step is determining whether you have a vitamin D deficiency. Talk to your healthcare professional about testing for vitamin D deficiency or insufficiency and whether a vitamin D3 supplement may provide additional nutritional support.
