Kent, Inner Mongolia and Calgary of course! It also happens to be the point at which, heading northwards in the winter months, no Vitamin D is produced from sunlight when it hits our skin.
In my profession there is 'debate', even disagreement, about the use of food supplements yet we have been advocating them for decades — without much thought about the 'evidence'. So up North (even further than 51 degrees) in Scotland the decision to provide free vitamin supplements for all mothers-to-be is a curiosity. It includes Folic Acid (reduce risk of neural tube defects like spina bifida), Vitamin C (no evidence of benefit says NICE) and Vitamin D (no clear evidence of benefit). Nor for iron by the way. If we were following best 'evidence' well-nourished ladies have no need for supplementation. Promoting a healthy diet (but supplementing with folic acid) seems sensible. BUT it is official policy — also to give vitamins to infants and children. Actually, Vitamins A, B1, B2, B3, B6 and D2. I have come round to the idea of targeted food supplements not only because the principle is consistent with public policy but because maybe there is indeed nutrient deficiency in our modern diet. Maybe there should be less 'debate' and more effort in producing regulated food supplements so we know what we are swallowing.
Personal view: Dr Rob Lawson