Vitamin D is called the Sunshine Vitamin. A fat-soluble vitamin called so because it takes the sun’s rays (UVB rays between 11 am to 3 pm) hitting our skin to get the process of manufacturing this vitamin in our body started. There are no food sources for this vitamin.
In a study I conducted in 325 pregnant women and their newborns during my Endocrinology training at the municipal-run Nair Hospital at Mumbai Central – 80% of women and 70% of their newborns had low Vitamin D levels. What was glaring was that many of these women were from poor socioeconomic strata who sold vegetables and fruits on the streets and had a lot of sun exposure. They still had low Vitamin D levels. The pollution levels can explain this – highly polluted air scatters UVB rays and prevents them from reaching us. So, sun exposure alone cannot guarantee good Vitamin D levels.
Vitamin D regulates the absorption of calcium into our bodies for bone health and keeps our muscles strong. Effects of Vitamin D deficiency – People with low Vitamin D levels are prone to bone pains, muscle pain and weakness, increased risk of falls and fractures. A level between 30 – 100 ng /ml is considered normal. This can often be achieved by supplementation only.
There are a lot of misconceptions about this vitamin.
The ultraviolet B rays crucial for Vit D to be generated reach the earth between 11 am to 3 pm (maximum 12-2 pm), so early morning rays won’t help.
Unfortunately, other factors besides the duration of sun exposure can cause Vitamin D deficiency. India has one of the highest pollution levels. The vital UVB rays are scattered in the atmosphere and do not reach our skin in sufficient quantity. So, despite sun exposure, Vitamin D levels can be low. Many other factors like the season, angle of the sun with the earth, and the colour of our skin also impact UVB.
As I explained previously, there is no Vit D food source, and we are almost exclusively dependent on sunlight which is often not effective due to pollution. That is why, as long as we take a maintenance dose of Vit D (60,000 units monthly = 2000 units daily) is sufficient to maintain Vit D levels in the normal range ( 30 – 100 ng/ml). People often take the weekly dose appropriately but skip the monthly doses in fear of side effects.
Also, a monthly dose of Vit D is cheaper than a blood test for Vit D.
Though Vit D can enhance innate immunity, there is no definitive proof ( only observational studies) to reduce COVID infection risk. However, due to misinformation, many patients have taken large doses of Vit D and ended up with toxic levels of Vit D.