Get the low-down on Vitamin D, why you need to get your level checked and why it's more important than ever to have it working for you! Looking at the rate of Vitamin D deficiency in Australia and worldwide, the stats are concerning. By making a few simple tweaks in lifestyle, food and supplementation, you can start reaping more benefits of this nutrient and hormone.
A quick look at Vitamin D:
Though it’s labelled a vitamin, Vitamin D acts like a steroid hormone, controlling the amount of calcium and phosphate in your body. What does this mean for you? It means it’s is a crucial element to your overall health, having critical effects on the immune system and especially the health of bones, muscles and teeth.
An increasing amount of data also shows Vitamin D extends way beyond just healthy bones. Low levels of Vitamin D is implicated in an increased risk of pneumonia and upper respiratory viral infections - something especially important to note in the current world's events.
The relationship between Vitamin D and serotonin synthesis has also been studied; feeling moody and tired? You might need a dose of sunshine! If you want to keep looking and feeling young too, you'll want to make sure your Vitamin D levels are optimised - participants in a large epidemiological study found that those who supplemented with Vitamin D regularly had longer telomeres (they protect your DNA from damage) than those who didn’t. Vitamin D may also provide improved muscle strength for athletes, though more testing is needed.
Vitamin D in humans is mainly sourced as vitamin D3 (cholecalciferol), which is formed through the action of ultraviolet B (UVB) radiation on the skin. In other words, when you get a healthy amount of sun exposure, you get Vitamin D3. (this is why it’s called the ‘Sunshine vitamin’). When researching supplementation, you may see both Vitamin D2 and Vitamin D3 referenced and wonder what the difference is – an easy way to separate the both is Vitamin D2 is plant-based, whereas Vitamin D3 is animal-based.
Are you Vitamin D deficient?
According to statistics, approximately 1 in 4 Australian adults have varying degrees of deficiency. Levels lower than 50 nmol/L considered suboptimal and thus, deficient. In summer it should be higher, naturally due to more sun exposure (60-70 nmol/L). By booking in a blood test at your local GP, you’ll be able to see where you’re at. Even if you’re not completely deficient, you can still be considered ‘insufficient’.
The challenge with Vitamin D deficiency is it can have no clear symptoms, and therefore might not be suspected as a cause for some medical issues. Severe forms of vitamin D deficiency present as rickets or osteocalcin, but this is uncommon. Many symptoms can be made worse by a lack of Vitamin D (low mood or feeling generally 'off' for example), the best option is to get a blood test done to ascertain whether the levels are where they should be.
You are more likely to be Vitamin D deficient if you...
- Have darker skin (especially if living where there is little sun): With changes in technology and the crisscrossing of cultures all over the world, you now may be living in an area and climate completely different to your ancestors. As a person with dark skin, you have higher levels of melanin, which filters UVB and reduces the absorption of Vitamin D into the skin. This simply means you may need to spend extra time outdoors, increase your Vitamin D levels through diet and supplementation.
- Are obese or overweight: Unfortunately, this type of Vitamin D insufficiency may be related to its decreased bioavailability (ability to be absorbed) due to it being deposited in body fat. If it is trapped in body fat stores, then there is less circulating the blood. There is still much study being done in the connection between body fat and Vitamin D, including whether low Vitamin D leads to higher body fat, and whether Vitamin D supplementation can assist body fat loss.
- Are always indoors or avoiding sun exposure: This goes without saying – no sun, no sunshine vitamin! You may be wondering, does wearing sunscreen impact on my Vitamin D levels? Though there is conflicting information out there, an international expert panel in 2017 concluded that sunscreen use does not interfere with Vitamin D. This appears to be supported by an Australian study which suggested that regular sunscreen use did not interfere! So keep being sun smart and slip slop slap. Getting the balance between adequate sun exposure and sun protection is key, and something that seems to elude many of us.
- If you are over 70 years old: If you’re a senior, you’re at higher risk of Vitamin D deficiency and its associated risks, especially musculoskeletal health and preventing the dangers of falls and fractures. You will be more at risk of lack of intestinal absorption of Vitamin D and also the reduced synthesis from the sun. Vitamin D supplementation may be necessary in this case.
Can you get Vitamin D just from food sources?
Certain foods do contain some Vitamin D, but sadly you won’t be able to meet your daily requirements. Fatty fish, cheese, liver, egg yolks, foods fortified with Vitamin D are commonly cited as sources of Vitamin D, though food sources make up only 5-10% of our requirements. Plant oils have also been considered as an option for improving Vitamin D levels; a study using UVB-treated wheat germ oil observed an improvement in the mice studied, but could not reach the same level as D3 supplementation. Overall, the scientific consensus is choosing Vitamin D3 over D2.
What's the best dose for Vitamin D?
Sun exposure is the most important aspect of Vitamin D synthesis. The challenge with Vitamin D recommendations when it comes to sun exposure is that it varies depending on the time of year, location, climate and general environment. A general suggestion is approximately 10-15 minutes of sunlight per day, with higher needs in the winter. Always check the recommendations for your local area, the UV radiation levels and take into consideration your Vitamin D status.
Aside from getting enough sun and choosing Vitamin D foods, supplementation is an excellent option that has much academic study in support of it. For those with mild Vitamin D deficiency, Australian guidelines recommend 1000-2000IU of Vitamin D3 supplementation. With greater levels of deficiency, greater amounts are required. There is evidence that 4,000-5000 IUs may be an optimal amount, however, as always, work together with your medical practitioner to determine what is right for you.
Studies have found toxicity with only larger doses of Vitamin D, at over 10,000 IU/day. Being a fat-soluble vitamin, it’s best to have your supplement with meals, particularly high-fat foods. If you have it with a fat-free meal, you’ll still absorb some of it, though it won’t be to the optimal amount.
Final thoughts:If there's a vitamin to be prioritising, it's Vitamin D. Understand your risk factors and make sure you get to know this powerful health promoter. Get some sunshine, make healthy eating important (including the Vitamin D sources mentioned), and supplement where there are gaps. There's a huge variety of supplements containing Vitamin D, some fortified with other ingredients, so always read the label and when in need, consult a professional to make sure it's right for you.
by Paula Vargas Duran
*Disclaimer: Always talk to your healthcare professional before taking any medication. Vitamins and minerals are not a sole source of nutrition.
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