Why it's important to supplement with vitamin D in the winter

Rickets was historically referred to as the "English disease", and for good reason: the UK still has the lowest vitamin D status in Europe. The British Medical Journal reports that between 53.7 and 90.9% of the British population have insufficient levels of vitamin D. In severe cases, vitamin D deficiency can cause muscle weakness, impaired physical function, low testosterone, depression and the aforementioned bone deformities.

Touted as a "biomarker of a healthy lifestyle",  vitamin D status reflects an active outdoor way of life. Following exposure to the sun, the skin produces 90% of our vitamin D. However, from October to March, the sun's strength is inadequate at all European cities north of Madrid.

Vitamin D levels vary throughout the year, corresponding with the angle of the sun, the extent of cloud cover and the amount of skin exposure. Coupled with the trend towards decreased time outdoors in the general population, many otherwise healthy men are now at risk of vitamin D deficiency. Consuming sufficient vitamin D via the diet is challenging as only limited foods have significant levels of vitamin D. Thus, supplementation with a product like Son's "Immune Health Supplement" is recommended. 

A study at Liverpool Football Club reported that vitamin D levels plummeted by up to 71% from August to December. Sixty-five per cent of the team reached an "unacceptable" level of vitamin D deficiency, interpreted by the researchers as "harmful to various aspects of health and athletic performance". 

There are vitamin D receptors in almost all immune cells. Vitamin D deficiency is a "seasonal stimulus" for flu. Bouts of flu begin to increase from September and peak in January. This coincides with when vitamin D levels are at their lowest. Men who exercise are at further risk of respiratory infections during periods of increased training volume, especially when combined with episodes of stress and sleep deprivation. 

There is conflicting advice from the Institute of Medicine and the Endocrine Society, with the latter recommending supplementing significantly more. Regardless, suggested doses of vitamin D3 will also vary according to skin tone and lifestyle. Vitamin D is a fat-soluble vitamin (structurally, it's more similar to a hormone), so whilst the optimal dose can be debated, absorption is 32% greater following a high-fat meal. 

Backed by the Institute of Medicine recommendations, Son’s Immune Health Supplement contains 1,000 IU of vitamin D3, combined with ten additional evidence-based ingredients to support optimal immune function.

All of our blog articles are reviewed by our Medical Director before publication.