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Do I need to supplement vitamin D this winter?

October 28, 2022 by Heather

Vitamin D is one of the nutrients we get asked about the most. But how important is it for our health?  How do we know if we have enough or need to boost our levels?  And can we do that with food? Find out more below.

What does vitamin D do for us?

Lots!  Vitamin D rose to prominence during the pandemic due to the huge amount of evidence on it’s role in immune health and Covid recovery, severity and even prevention, although more research is needed.  But we have known for a long time that having enough is vital to maintain healthy bones. This is a challenge for the 50% of us women over the age of 50 in Ireland at risk of an osteoporosis-related fracture, due to it’s role in the absorption of calcium.  It also plays an important role in heart health, diabetes prevention, joint and skin health, risk of some forms of cancer including breast and colorectal cancer and indeed all immune health issues, especially auto immune disease like coeliac disease and rheumatoid arthritis.  Almost every cell in our body has receptors for vitamin D. This is why it is important for so many different aspects of health.

How do I know if I have enough?

Unfortunately, we know that a large proportion of Irish people do not have optimal levels of vitamin D, especially during the winter.  A study based on Irish GP results published last year showed that 40% of us had insufficient levels of vitamin D, rising to 50% over the winter.

It is difficult to know whether you have enough without testing as unlike other essential nutrients like iron.  There are no obvious signs of vitamin D deficiency.  Levels can be measured in a simple blood test. In some cases, especially where you have a history of osteoporosis or autoimmune disease, your GP may be able to do this. There are also several labs offering at home blood tests that can be useful, including Lets Get Checked and Gastrolife.

It is worth checking your levels, particularly if you have an underlying condition or lifestyle factor that increases your risk of deficiency. This includes an immune issue, osteopenia or osteoporosis, gastrointestinal disease, long covid, history of an eating disorder or gastric band surgery.  People with darker skin need more sunshine to make vitamin D, so are at higher risk for deficiency, as are people who wear total skin covering. The elderly are also at higher risk of deficiency as they may spend more time indoors.

What about kids?

Vitamin D deficiency is a significant issue for babies and children in Ireland. Like the elderly, they are also an at-risk group in need to supplementation.  The bone disease rickets, caused by vitamin D deficiency and thought to be eradicated 60 years ago has re-emerged as a health issue here and in other countries with similar latitudes like Canada.  If mums have low vitamin D levels when pregnant, it is very likely that their babies will be born with insufficient levels.  Some formulas are fortified, so supplementing additional vitamin D is especially important for breastfed babies.

Current HSE recommendation is to supplement vitamin D for all babies and children under the age of 4 from Halloween to St Patrick’s Day.  We recommend that older children also supplement (your need for this nutrient does not magically stop at the age of 4!)  and also recommend that pregnant mums check their levels or at least ensure that they are getting some in their pregnancy multivitamin.

Can I boost levels through food?

The best source of vitamin D is the sun, as it is made by the action of sunshine on our skin. And given Ireland’s northerly latitude, our sun is only strong enough between April and September to produce vitamin D.  We need at least 15 minutes of safe sun exposure daily during this time to build up our stores. This is why so many more of us become deficient over the winter. This is the very time our immune systems might need more support.   Even during the summer, many people wear sunscreen to protect from skin cancer.  This can reduce vitamin D production by up to 90%.  And as we get older, we cannot make vitamin D as easily.

There are small amounts of vitamin D is some foods including oily fish (aim to eat twice per week), liver, eggs and dairy products.  Vegetarians and vegans may be more likely to have low levels.  Some foods like milk, plant-based milk and breakfast cereals are fortified with vitamin D.  Food does not usually provide enough to even maintain levels and certainly not enough to correct a deficiency.

How else can I increase my levels?

Short of a sun holiday, the best way to top up your levels is with a supplement.  But it can be a minefield as there are so many options available. In clinic we prefer to use D3 in liquid form as it is very well absorbed and brings up levels promptly for most people.  However, like vitamin D levels, uptake varies hugely from person to person.  Many multivitamins contain it although you need to check the form and amount.  We recommend speaking to your local health food store or pharmacist for advice.  Or of course getting in touch with us 🙂

How much do I need?

How much you need to supplement, if at all, will depend on your own levels.  And bear in mind if testing that this time of year, after the summer, your levels are likely to be at their highest and will fall over the winter.  An award-winning Irish study published in the Irish Medical Journal last year highlighted the need for supplementation for much of the population to protect against Covid 19.  It is now a government recommendation that anyone over the age of 65 takes a vitamin D supplement.

Recommendations on optimal levels vary considerably.  However, vitamin D levels below 50 nmol/L are classed as insufficient and present a risk for bone health.  Optimal levels are between 80 and 120 nmol/L.

If you are not in a position to get your levels checked, 2000iu is a reasonable daily amount to take. However, if your levels are low, you may need more.  As vitamin D is fat soluble, meaning it can be stored in the body, it is possible to overdo supplementation.  In very rare cases this can lead to kidney issues.

If you would like to check your levels of key nutrients including omega 3, zinc, selenium, magnesium, vitamin D, vitamin A and other antioxidants, get in touch to find out more about our Functional Nutritional Profile.

Filed Under: Blog, bones, Healthy Eating, Vitamins

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