Vitamin D supplementation supports immunity,  prevents asthma and influenza

A recent Cochrane review showed that low blood levels of vitamin D (the ‘sunshine vitamin’) have been linked to an increased risk of asthma attacks in children and adults with asthma. Asthma sufferers given vitamin D experienced fewer asthma attacks that needed treatment with oral steroids. Vitamin D supplementation reduced the risk of attending hospital with an acute asthma attack from 6 per 100 to around 3 per 100. Researchers concluded that Vitamin D supplementation is likely to offer protection against severe asthma attacks. As usual, further trials focusing on children and people who experience frequent severe asthma attacks have been deemed necessary before definitive clinical recommendations can be made. However, given that vitamin D is an essential vitamin that’s often in short supply for many people, that surely is indication enough.

There is much data showing that vitamin D is an important component in the prevention of influenza (Schwalfenberg, 2015) and upper respiratory tract infections (Yamshchikov et al, 2009) and in reducing risk of ARDS (the main cause of mortality in Covid-19 infection)

Food sources - Oily fish (salmon, mackerel, trout, herrings, sardines, anchovies), mushrooms, eggs and meat are rich in D, as well as fortified foods.

Vitamin D and magnesium are essential for the proper absorption of calcium, explaining vitamin D’s important role in bone health. However, no dietary source for "The Sunshine Vitamin" even comes close to vitamin D levels made naturally from the sun's rays.