Child nutrition expert Judy More looks at the call for vitamin D supplementation for everyone
In July 2016, Public Health England (PHE) adopted the recommendations on vitamin D supplementation made by the Scientific Advisory Committee on Nutrition (SACN), which had reviewed the evidence and the prevalence of vitamin D deficiency among the population in the UK.
SACN developed recommended dietary intakes – Reference Nutrient Intakes (RNI’s) – for those over four years of age and safe intakes for children under four years, to ensure that the UK population has enough vitamin D to protect musculoskeletal health all year round.
The previous advice from 1991 only set recommended dietary intakes for the at-risk groups – pregnant and breastfeeding mothers, infants from six months, one-four year olds, those over 64 years of age,1 and those whose exposure to sunlight is limited by institutional or indoor living, or covering the skin when outside.2
The new policy and recommendations can be found at PHE website: https://www.gov.uk/government/publications/sacn-vitamin-d-and-health-report
Why did policy change?
The previous policy set by the Committee on Medical Aspects of Food and Nutrition in 1991 considered that sufficient vitamin D was synthesised in the skin when it is exposed to sunlight, and therefore dietary intakes of vitamin D were not necessary for most of the UK population between the ages of 4 and 64 years.1
However, the results from the latest National Diet and Nutrition Survey (NDNS)3 show that low serum levels of vitamin D are found in significant numbers of all population groups in the UK: in winter 30-40% of all age groups in the general population are classed as vitamin D deficient. Even towards the end of summer 8% of adults and 13% adolescents remain deficient.4 SACN therefore set new recommendations for dietary intakes:
- RNI of 10μg/day for those four years and above
- A safe intake of 10μg/day for children aged one-four
- A safe intake of 8.5-10μg/day for infant 0-12months.5
The RNI and safe intakes include intake from all dietary sources i.e.:
- Natural food sources – oily fish, red meat, eggs
- Fortified foods – fat spreads, some brands of breakfast cereals and yogurts, formula milks for infants
There is considerable variation in exposure to sunlight and the ability to synthesise vitamin D from sunlight and SACN decided that a dietary intake of 10μg/day would keep even those less proficient at synthesising vitamin D above the level of deficiency.
The latest NDNS also shows that most of the population consume less than 3μg vitamin D per day from food.4 To increase this up to 10μg through food would require a serving of oily fish each day, which would be expensive and is not recommended due to the toxin levels in oily fish. A dietary supplement is therefore necessary to attain the new RNI for vitamin D.
Vitamin D deficiency
Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal mineralisation of bone and teeth and to prevent hypocalcaemic tetany. It is also needed for bone growth and bone remodelling.6 Without sufficient vitamin D, bones can become thin, brittle or misshapen. Clinical manifestations are:
- Hypocalcaemic seizures due to low blood calcium levels – seen in young infants as a result of maternal vitamin D deficiency during pregnancy
- Rickets in growing children
- Osteomalacia in adults
- Osteoporosis in older adults.
Other roles of vitamin D are less well defined but epidemiological evidence strongly suggests it plays a role in growth, muscle strength, prevention of falls in the elderly and in decreasing the risk of cardiovascular disease, inflammatory and autoimmune diseases, some cancers and other chronic diseases such as:
- Type 1 and 2 diabetes
- Upper respiratory tract infections and wheeze including asthma
- Infectious diseases
- Multiple sclerosis.
Low vitamin D levels are also associated with severe pre-eclampsia in pregnant women.7,8
Which supplements to recommend?
The two main forms of vitamin D are:
- Vitamin D3 (cholecalciferol) produced by dermal synthesis and provided by the few foods and most vitamin supplements
- Vitamin D2 (ergocalciferol) provided by some supplements and found in small amounts in mushrooms Both forms are metabolised in the same way, but the 25 hydroxyvitamin D3 has a longer half-life than 25 hydroxyvitamin D2. Supplements of vitamin D3 are considered more beneficial than supplements of vitamin D2.
Healthy Start supplements
English CCGs and local authorities and Scottish health boards are required to provide them free of charge to the beneficiaries of the Healthy Start scheme and sell them at a fixed price to other clients. Unfortunately, availability of these supplements varies.
Over the counter supplements
Patients should be advised to buy vitamin D3 supplements from brands sold in pharmacies, such as Baby D, Boots, Colief, HealthAid and Vitabiotics, as these have reliable quality control standards. Most multi-vitamin supplements sold in the UK include vitamin D along with other vitamins, but content varies and may not meet the recommendation.
The BNF lists licensed brands for prevention.
1. Department of Health (1991) Dietary Reference Values for Food Energy and Nutrients for the United Kingdom The Stationery Office, London
2. Department of Health (1998) Nutrition and Bone Health: with particular reference to calcium and vitamin D The Stationery Office, London
3. Public Health England and Food Standards Agency (2014) National Diet and Nutrition Survey: results from Years 1 to 4 (combined) of the rolling programme for 2008 and 2009 to 2011 and 2012 https://www.gov.uk/government/statistics/national-diet-and-nutrition-survey-results-fromyears-1-to-4-combined-of-the-rolling-programme-for-2008-and-2009-to-2011-and-2012
4. Public Health England and Food Standards Agency (2014) National Diet and Nutrition Survey: results from Years 1 to 4 (combined) of the rolling programme for 2008 and 2009 to 2011 and 2012 https://www.gov.uk/government/statistics/national-diet-and-nutrition-survey-results-fromyears-1-to-4-combined-of-the-rolling-programme-for-2008-and-2009-to-2011-and-2012
5. Scientific Advisory Committee on Nutrition (2016) SACN Vitamin D and Health report Available at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/537616/SACN_Vitamin_D_and_Health_report.pdf
6. Holick MF. J Investig Med. 2011;59(6):872-80
7. Dror DK. Curr Opin Obstet Gynecol. 2011 Dec;23(6):422-6
8. Bodnar LM, Catov JM, Hyagriv NS, et al. J Clin Endocrinol Metab 2007;92:3517e22
Declaration of Interest
Judy More works freelance and is a member on the Colief Expert Panel