Vitamin D - a crucial vitamin for pregnant and breastfeeding women Sep 2010
Vitamin D - a crucial vitamin for pregnant and breastfeeding women
Vitamin D is an essential nutrient at all ages, particularly for pregnant and breast feeding mothers. Recent evidence confirms concerns about adequate levels of vitamin D in UK in these groups of the population. A recent report in the British Journal of Nutrition from a team at the UK’s Institute of Child Health has suggested that there is a ‘strong case’ for supplementation of the diet during pregnancy with vitamin D. (1)
Vitamin D is essential for the absorption of calcium in the body. Without it, insufficient calcium is absorbed which has a negative impact on bone health. A deficiency of vitamin D manifests as rickets. Vitamin D can be manufactured in the body by the action of sunlight on the skin. It is also found in some foods including oily fish and eggs, Margarine, some breakfast cereals and powdered milk are fortified with vitamin D.
Low levels of Vitamin D
There is concern that climatic and cultural influences in the UK mean that the exposure of the skin to adequate amounts of sunlight can be limited and production of vitamin D in the skin is suggested to be marginal for some sub groups of the population. The production of vitamin D in the skin is dependent on exposure to sunlight for a period of time during the day. This exposure can be reduced or stopped by the use of sun block, clothes that cover the skin or during winter months. Pregnant women on low incomes are entitled to a range of nutrients, including vitamin D, as part of the Healthy Start Scheme.
Recommendations for vitamin D intakes
The UK’s Department of Health recommend that pregnant women should have 10 micrograms of vitamin D per day, a level that the researchers suggest exceeds that available from diet and that manufactured in the skin, hence their recommendation the supplements could be beneficial for pregnant women. The UK’s National Institute of Health and Clinical Excellence (NICE), however, did not endorse vitamin D supplementation in its review of Maternal and Child Nutrition (3) but stated that ‘all women should be informed about the importance for their own and their baby’s health of maintaining adequate vitamin D stores during pregnancy and whilst breastfeeding’ and that ‘in order to achieve this women may choose to take 400IU/day as in the Healthy Start Multivitamin Supplement’.
The Scientific Advisory Committee on Nutrition in their review of vitamin D (4) stated:
‘In most instances, these intakes cannot be met from the diet and at the present time can only be guaranteed by supplementation. A recommendation of 10µg (400 IU) a day has been made for pregnant and lactating women and for people over the age of 65 years. Although this has been in place for sometime, there is concern that it is overlooked or not implemented by health professionals and he general public.’
Concerns about low levels of vitamin D
The researchers stated that evidence showed that a proactive approach to supplements coincided with a much lower incidence of deficiency linked diseases such as infantile hypocalcaemia [also known as William's syndrome, which affects development], and rickets [which weakens bones].
Women are more likely to be vitamin D deficient than men, and a previous study found one in four pregnant mothers has been found to be vitamin D deficient during winter and spring. Whilst women from some ethnic minorities are recognised to be at greater risk because their darker skin means they do not absorb as much sunlight, there are also concerns about levels of vitamin D in the wider population.
Conclusion
Clearly there is some confusion regarding the recommendation for supplementation of diets of pregnant women with vitamin D. Health professionals who are key to the dissemination of health and dietary advice to pregnant and breastfeeding mothers are best placed to evaluate individuals’ situations and requirements and advise appropriately. Further research in this area will support and develop knowledge and help to ensure that clear advice is available to pregnant and breastfeeding mothers.
References
1 Hypponen E, Boucher B ‘Avoidance of vitamin D deficiency in pregnancy in the United Kingdom: the case for a unified approach in National policy’ British Journal of Nutrition 2010 (http://journals.cambridge.org/action/displayFulltext?type=1&pdftype=1&fid=7829174&jid=BJN&volumeId=-1&issueId=-1&aid=7829172)
2 Department of Health (2010) ‘Vitamin D an essential nutrient for all…’
http://www.dh.gov.uk/prod_consum_dh/groups/dh_digitalassets/documents/digitalasset/dh_111302.pdf
3 NICE (2008) ‘Guidance for midwives, health visitors, pharmacists and other primary care services to improve the nutrition of pregnant and breastfeeding mothers and children in low income households.’
http://guidance.nice.org.uk/PH11
4 Scientific Advisory Committee on Nutrition (2007) Update on Vitamin D – position statement by the Scientific Advisory Committee on Nutrition
http://www.sacn.gov.uk/pdfs/sacn_position_vitamin_d_2007_05_07.pdf)