Public Health England (PHE) is advising today (21st July 2016) that 10 micrograms of vitamin D are needed daily to help keep healthy bones, teeth and muscles.
This advice is based on the recommendations of the Scientific Advisory Committee on Nutrition (SACN) following its review of the evidence on vitamin D and health.
Vitamin D is made in the skin by the action of sunlight and this is the main source of vitamin D for most people. SACN could not say how much vitamin D is made in the skin through exposure to sunlight, so it is therefore recommending a daily dietary intake of 10 micrograms. PHE advises that in spring and summer, the majority of the population get enough vitamin D through sunlight on the skin and a healthy, balanced diet. During autumn and winter, everyone will need to rely on dietary sources of vitamin D. Since it is difficult for people to meet the 10 microgram recommendation from consuming foods naturally containing or fortified with vitamin D, people should consider taking a daily supplement containing 10 micrograms of vitamin D in autumn and winter.
People whose skin has little or no exposure to the sun, like those in institutions such as care homes, or who always cover their skin when outside, risk vitamin D deficiency and need to take a supplement throughout the year.
Vitamin D regulates the amount of calcium and phosphate in the body, both needed for healthy bones, teeth and muscles. It is found naturally in a small number of foods including oily fish, red meat, liver and egg yolks and in fortified food like breakfast cereals and fat spreads.
Background
The latest data from the PHE National Diet and Nutrition Survey (2008 to 2012) shows that 23% of adults aged 19 to 64 years, 21% of adults aged 65 years and above and 22% of children aged 11 to 18 years have low levels of vitamin D in their blood. This is not the same as having a deficiency, where you would be unwell, but rather means that you are at greater risk of developing a deficiency. If a person is deficient of vitamin D they will be clinically unwell and will need to be treated by a doctor.PHE recommends against people using sunbeds because extreme short-term use could cause severe burning and long-term damage to the skin, with a possible increased risk of developing skin cancer.
SACN reviewed the evidence on vitamin D and health outcomes. In addition to musculoskeletal health, SACN reviewed the relationship between vitamin D and non-musculoskeletal health outcomes including cancer, Type 1 diabetes, multiple sclerosis and heart disease but found insufficient evidence to draw any firm conclusions.
The recommendations refer to average intake over a period of time, such as one
week, and take account of day-to-day variations in vitamin D intake. Vitamin D plays an important role in the regulation of calcium and phosphate in the body. It is therefore essential for bone health. Without adequate vitamin D, bones can become thin, brittle and mis-shapen. In extreme cases this can lead to rickets in children, a condition involving a softening of the bones that can lead to fractures and deformity. In adults softening of the bones is called osteomalacia, and may cause pain and muscle weakness.
From the full report:
S.25 Mean dietary intakes of vitamin D from all sources (including supplements) were: 2-4 µg/d (80-160 IU/d) for ages 1.5-64y; 5 µg/d (200 IU/d) for adults aged = 65y.
S.28 For all age groups in the UK, mean plasma 25(OH)D concentration was lowest in winter and highest in summer. Around 30-40% of the population had a plasma 25(OH)D concentration < 25 nmol/L in winter compared to 2-13% in the summer. A large proportion of some population groups did not achieve a plasma/serum 25(OH)D concentration = 25 nmol/L in summer (17% of adults in Scotland; 16% of adults in London; 53% of women of South Asian ethnic origin in Southern England; and 29% of pregnant women in NW London).
Metabolism S.5 Vitamin D is converted to its active metabolite, 1,25-dihydroxyvitamin D (1,25(OH)2D), in two hydroxylation steps. The first hydroxylation is in the liver, where vitamin D is converted to 25- hydroxyvitamin D (25(OH)D), which is the major circulating metabolite of vitamin D and is widely used as a biomarker of vitamin D status; the second hydroxylation is in the kidney where 25(OH)D is converted to 1,25(OH)2D.
The proportion of the population (by age) with a plasma 25(OH)D concentration < 25 nmol/L was: 2-8%, 5m-3y; 12-16%, 4-10y; 20-24%, 11-18y; 22-24%, 19-64y; 17-24%, = 65y and above.
S.7 At latitudes below 37 degrees North, UVB radiation is sufficient for year round vitamin D synthesis. At higher latitude, vitamin D is not synthesised during the winter months. In the UK, sunlight-induced vitamin D synthesis is only effective between late March/early April and September and not from October onwards throughout the winter months.
Sources
NHS Choices - report on what the papers say
PHE advice is detailed on NHS choices. (but was this page really updated on 18/02/2015?)
PHE advice is detailed on NHS choices. (but was this page really updated on 18/02/2015?)
SACN’s Vitamin D and Health report (300 pages) published 21 July 2016 (pdf)
which highlights the report’s main findings and recommendations.
View documents related to the consultation on the draft report.These documents include a substantial number of consultation comments received by SACN, as well as SACN’s response to these comments.
Above report edited by crabsallover from: https://www.gov.uk/government/news/phe-publishes-new-advice-on-vitamin-d
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