Across race, country, culture, social strata, age, sex, BMI and religion one thing is very common and that is vitamin D deficiency. It’s close to 80-90 percent insufficient across populations. Currently, routine testing for Vitamin D is not recommended even in developed nations as the cost of testing is very expensive compared to the treatment.
Vitamin D is not available in milk (even breast milk) unless fortified. Due to some misinterpretation Vitamin D fortification was stopped in Europe 40 years back (they mistook Edwards syndrome for Vitamin D toxicity due to fortification forcing the federal government to ban it across Europe).
Vitamin D fortification in milk and edible oil was approved both by FDA and the Indian government. A study in JAMA (Journal of American medical association) by Jia Guo Zhoa showed no difference in reduction in a fracture in patients taking Vitamin D and others taking none. That triggered huge controversy, but now it’s proved that this particular study didn’t take adequate vitamin D dosage (they supplemented with a mere 400 IU/day).
11 am to 2 pm is the best time for getting Vitamin D, as the UV-B is at its best. 10 am till 3 pm is also a good time. Early morning walks in the sun is very good for your health but it doesn’t suffice your Vitamin D requirement. Not only bones but muscles, heart, brain, teeth, nerves and pancreas (to produce insulin and prevent diabetes) need Vitamin D.
Recent studies report a lower incidence of breast and other cancer in women taking Vitamin D supplements. Traditionally family physicians in the US ask the parents if they notice sweating over the forehead in the night. That seems to be a classical and first sign of deficiency.
Bone pain, fatigue and growth pains in children are classic symptoms of this disease.
Sunscreen with more than SPF 30 blocks all the UV-B required to synthesize Vitamin D.
Macrophages (cells that fight infection) also need Vitamin D, so when adequate it prevents flu, cold, asthma (this was an interesting observation made with the incidence of these diseases more during winter when the sun in very little in the northern hemisphere).
The best source of Vitamin D for vegetarians is sun-dried mushrooms and for non-vegetarians is oily fish (salmon and mackerel). Pollution and low altitude both have a negative effect in Vitamin D synthesis through sunlight. Bathing after the sun exposure doesn’t wash off the synthesized vitamin. Blood levels 30-100IU is normal, anything above 150 is toxic, which is unlikely with sunlight and very rarely with supplements.
Earlier it was recommended to take Vitamin D in empty stomach and with fatty foods, but currently, there is no such recommendation. Anytime is fine. Fracture, bone deformities, diabetes, multiple sclerosis, both rheumatoid and osteoarthritis, CCA, hypertension, peripheral vascular disease, schizophrenia, dementia and depression have all been associated with vitamin D deficiency.
Overexposure to sunlight to synthesize Vitamin D in countries like Australia and New Zealand have reported a higher incidence of squamous cell carcinoma and malignant melanoma.
Dr Shriram Krishnamoorthy is an Associate Consultant, Orthopaedics, Fortis Malar Hospital, Chennai