Most vulnerable are pregnant and breastfeeding women, the under fives, the over 65s, those with darker skin and those who don’t get much sunshine. For them, a daily 10 microgram (µg) supplement is advised to avoid rickets in children, which has re-emerged recently, and osteomalacia, a related complaint, in adults.
Brief but regular sunshine exposure provides vitamin D via skin synthesis. But many of us are not benefiting because of sunscreen use or because we don’t get outside enough.
Despite fortification of margarine and spreads with vitamin D, intakes from these and other dietary sources average 3.1µg/day and 2.6µg/day respectively in UK men and women. This is well short of the 5–10µg/day supplement recommended for at-risk adults across Europe. The impact of the recent addition of vitamin D to some breakfast cereals has yet to be reflected in dietary survey data.
In the US and Ireland, milk is fortified with vitamin D. A review of policy is underway, reporting to UK government in 2014. Time will tell whether more extensive fortification of food supply is recommended.
Professor Judy Buttriss is director general of the British Nutrition Foundation and has been awarded Fellowship of the Association of Nutrition.