Breast milk would be perfect for babies if we lived like our distant ancestors in central Africa where the sun shines brightly almost everyday and we wore only light clothing or perhaps nothing at all. As it is breast milk of women in Britain and most of Europe contains very little vitamin D and not enough to keep babies in optimum health.
The sun is not strong enough in northern Europe to make any vitamin D for half the year and our cloudy climate means that even in summer we often get little vitamin D from one week to the next. So some 80% of the population have sub-optimal vitamin D levels of the sunshine vitamin in winter and even in summer some 50% are sub-optimal.
Doctors and nutritionists in the UK have a traditional dislike of food supplements. They argue that most people can get all the nutrients they need from a varied and balanced diet. Vitamin D is the one exception. Unless you are an Eskimo eating fish two or three times a day it is impossible to get more than about 10% of the vitamin D needed for optimum health, from food.
Vitamin D is popularly called the sunshine vitamin and the sun is our natural source. Unfortunately for years health messages have been about the danger of being exposed to sun and retreating into the shade and covering up with clothing. Anyone following the old Cancer Research UK advice is risking vitamin D deficiency and making themselves ill.
CR UK advice has now changed but relatively few people are aware that we can now sunbathe sensibly and recharge our Vitamin D without being scared by threats of skin cancer.
But we still have a problem with Big Derma, capable of being rather sinister when it comes to persuasion. In order to get vitamin D from sunshine it is necessary to avoid wearing suncream except when you want to stay in the sun for a long time. When it comes to sun exposure little and often is best, and the more skin that is exposed the greater the chance of making enough vitamin D before burning. To get optimum vitamin D take care to avoid putting on suncream unless you need to in order to stop burning.
Even so it is difficult for anyone in the UK to get enough sun and enough vitamin D in our climate. So, as the Chief Medical Officers advise in their recent letter to health professionals, breast fed babies should be given a vitamin D supplement to prevent vitamin D deficiency. The CMOs suggest 10 micrograms a day for mothers but this is not enough to put vitamin D into their milk in any substantial amount and the US Institute of Medicine says that up to 4000 IUs a day is safe.