Researchers analysing the long-running Nurses Health Study, in looking for the effect of vitamin D intake during adolescence on the incidence of MS, have come up with an important finding.

Their study was to some extent confounded by the fact that in the US, cow's milk is fortified with vitamin D, and so possible beneficial effects of adolescent vitamin D intake through dairy products might be counteracted by harmful effects of milk on MS development. The authors were aware of this, and so looked at milk consumption as well as vitamin D intake.

The finding of note in this study was that nurses who consumed three or more servings of whole milk a day in adolescence were 47% more likely (p=0.04) to develop MS in later life than those who did not. While the authors point out that this needs to be replicated in further studies, it fits well with previous epidemiological and laboratory research of the harmful effects of cow's milk. It is particularly relevant for parents wishing to minimise the risk of MS in their offspring. 

Dietary intake of vitamin D during adolescence and risk.pdf