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18th Nov 2016

The Truth About How Much Vitamin D We Need In Our Diets

Amanda Cassidy

We chatted to the leading expert on vitamin D, Dr Michael Holick, when he visited Ireland recently and got the lowdown on myth versus reality when it comes to our ‘sunshine’ health. 

Recently, the Food Safety Authority of Ireland has weighed in on the subject after over 20 cases of rickets in toddlers were reported in Irish hospitals in just four years. This condition is caused by a lack of vitamin D and was thought to have been eradicated due to better nutrition. It is believed that poor dietary habits could also have contributed to the problem.

1.Why is it important that we get vitamin D?

It is essential for good health in our bones and teeth as it helps the body absorb more calcium from food to help develop normal and strong bones. It is not just important for children; while bone growth is greatest during childhood and teenage years, adults continue to lay down bone up until they are 30 years old. In middle age, we gradually begin to lose our bone mass, but calcium and vitamin D are still vital to maintaining healthy bones. This wonder vitamin also helps to regulate cell division, normal muscle function and supports the function of the immune system.

2. Do we get enough Vitamin D in Ireland?

Sunshine does help our bodies produce vitamin D, but because of our geographical location we don’t tend to get the enough sunlight to produce the vitamin D we need. In fact, we don’t get any vitamin D from the sun between October and April. I recommend a dose of one thousand international units a day of vitamin D for both infants and adults — unless they’re getting plenty of safe sun exposure. (International Units are a standard used by the scientific community to measure the amount of fat-soluble vitamins such as A, D and E in a capsule or tablet. You can find this information on the back of a particular box of a supplement or under the dietary information on food packaging)

3. Does suncream stop us getting enough? 

A sunscreen SPF of 30 and up does reduce your ability to make vitamin D from the sun by 98 per cent. While it is important to protect our skin from any harmful sun damage, sensible sun exposure is ok. For example, 10-15 minutes of sun exposure is ok, as long as the skin doesn’t redden. This would be considered a safe level of exposure to the arms and legs, however never expose your face without sunscreen.

4. What are some other ways of getting our vitamin D?

Obviously, we get it from sunshine, but you can also get Vitamin D from cod liver oil, oily fish such as mackerel and salmon, eggs, supplements or other fortified foods such as Supermilk. Other sources include sun-dried mushrooms.

5.  What about infants?

The HSE recommends vitamin D supplements for babies in Ireland. All infants, whether breastfed or formula fed, should receive a daily supplement of 5 micrograms of vitamin D drops. These are available from most pharmacies.

Dr Michael Hollick is an American endocrinologist who specialises in the field of vitamin D. His work has been the basis for diagnostic tests and therapies for vitamin D-related illnesses. He is a professor of medicine at the Bostin University Medical Centre and author of The Vitamin D Solution: A 3-Step Strategy to Cure Our Most Common Health Problems.