What's the Deal with Vitamin D?

Should you take a supplement?

Studies have shown that around one third of Australia’s population is Vitamin D deficient, and around 75% of us have suboptimal levels, with current consensus that levels be above 50nmol/L.

Vitamin D plays many important roles in the body, the most well-known is supporting strong bones but it also influences the immune system, has a role in cell growth as well as heart health.

We can get Vitamin D in three ways:  through food, sunlight and by taking a supplement. However, with only low levels of vitamin D found in food (sources include fatty fish, liver and eggs) and the challenge to balance time in the sun with UV exposure, can mean we are not able to get enough Vitamin D through sun and food alone.

So, when would you need to take a supplement?

Factors that might put you at risk for a vitamin D deficiency include:

• Limited Sun Exposure:  Not getting enough sun exposure can occur for many reasons, like wearing concealed clothing for cultural or religious reasons, working mainly indoors and even where you live. It is safe to get sun exposure through winter without sun protection measures when the UV index is under 3. However even vitamin D deficient adults require protection when the UV index is 3 or over.
• Older age: As we age we have a reduced capacity to make vitamin D in our skin and are also more likely to stay indoors.  Vitamin D deficiency ranges between 20%-100% in elderly, with institutionalized adults who are not supplemented being at the highest risk.
• Infants who are exclusively breast fed: - Babies who are only breast fed with a mother who has a low vitamin d levels, together with a darker skin tone and little sun exposure are at a high risk of vitamin D deficiency.  Most infant formula has added Vitamin D; hence bottle-fed infants are at a lower risk.
• Obesity. Individuals with a higher percentage of body fat tend to store vitamin D made by skin, in fatty tissue, resulting in less being available to the body. Vitamin D from food and supplements appears is more readily available to the body and hence is more effectively used.
• Darker skin. Darker skin contains more melanin, which acts as a natural sunscreen and can reduce the production of vitamin D in the skin. People with a dark complexion synthesize less vitamin D on exposure to sunlight than those with light-coloured skin. 
• Certain Medicines. Medications such as cholesterol-lowering drugs, drugs for preventing epilepsy and some can diuretics reduce absorption of vitamin D from the intestines.
• Inflammatory Bowel Disease. Disorders such as celiac disease and Crohn's disease involve a reduced ability to absorb dietary fat, and that can lead to less vitamin D being absorbed. Individuals that have had sections of bowel removed are at an even greater risk of deficiency.

If you're worried about not getting enough vitamin D, ask your healthcare provider if you should be tested for a deficiency or if you need to take a vitamin D supplement.