Ten or 15 minutes of sun a few times a week is normally all you need, but because our exposure to sunlight during a good old Irish summer is more than likely very limited, it is important to be aware of dietary sources to ensure you are getting adequate intakes of vitamin D.
Vitamin D plays an essential role in the absorption and use of calcium and phosphorus, so it is crucial for the formation and health of bones, teeth and cartilage. Without sufficient vitamin D bones can become thin, brittle, or misshapen. Prolonged vitamin D deficiency can cause rickets in children and osteomalacia (softening of the bones) in adults. More marginal vitamin D deficiency is likely to be a significant contributing factor to osteoporosis risk.
A good dietary intake of calcium and vitamin D can help protect against osteoporosis. Intakes of vitamin D may also be linked to the reduced risk of several diseases including psoriasis, diabetes and some types of cancer. It can do more than just protect the bone. Vitamin D is important for muscle strength and may play a role in helping to prevent rheumatoid arthritis.
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| What is the recommended daily allowance? |
In Ireland and the UK, the recommended daily allowance (RDA) for vitamin D is 0-10µg/ day depending on how much sunlight you obtain. For those aged over 51 years the RDA is 10µg/ day.
The absorption of vitamin D from sunlight can vary at different times of the day and year. Very little, if any, vitamin D is absorbed through sunlight from October to end of March due to Ireland's northerly latitude.
During the summer months we absorb vitamin D from the sun especially between the hours of 11am and 3pm. Therefore we need to take extra care in wintertime to ensure we are getting enough vitamin D from food.
Sunscreen can also reduce vitamin D absorption from the sun as ultraviolet rays are prevented from penetrating the skin. With both our climate and safe sun protection practices possible factors in affecting our vitamin D status, a good dietary intake, supplements and food fortification are important to help prevent low vitamin D status.
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| Good dietary sources of vitamin D |
Who should take vitamin D supplements?
A report recently published by the Food Safety Authority of Ireland (FSAI) recommended the implementation of vitamin D supplementation in all infants aged 0-12 months given the re-emergence of rickets in infants in Ireland. Other countries at a similar latitude to Ireland have identified this problem and do have a vitamin D supplementation policy in place. Good sources for babies include Abidec if solely breast fed, infant formula and follow on milks.
Elderly people who do not get sufficient skin exposure to sun along with a poor dietary intake, those who cover themselves for religious or cultural reasons, those with malabsorption conditions and those with kidney disease are particularly at risk of being deficient in vitamin D.
Also certain medications may interfere with the body's conversion of vitamin D. Therefore the elderly and people who are confined to indoors may also benefit from a vitamin D supplement.
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