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What’s the deal with Vitamin D?

What’s the deal with Vitamin D?

Here in New Zealand, we love the sun – in fact, we live for it! So what’s all this talk about vitamin D deficiencies? Naturopath Annaliese Jones sheds some light on the magic of the sunshine vitamin and how to make sure you’re getting your fix without the risk.

Important for healthy bones, good mood and much more, vitamin D is known as the sunshine vitamin – but despite all the sunshine we get in New Zealand over the summer months, it seems many of us just aren’t getting enough of it.

We drive to work, sit in an office and drive home again in the evening. And unfortunately we can’t make up for all that indoor living with a weekend trip to the beach, covered in hats and sunblock. It’s no wonder around one in three New Zealanders have less than the recommended level of vitamin D.

For many of those with a deficiency, the symptoms may be hard to pinpoint, or there could be no symptoms present at all. Some may feel tired, with subtle aches and pains, others can experience bone pain (particularly in the ribs or shins) or muscle weakness, which can present as heaviness in the legs or difficulty climbing stairs. We’ve had sun avoidance drilled into us from an early age, and there’s no denying that staying protected from the sun during certain times of the day is crucial for reducing the risk of skin cancers, but in order to keep our vitamin D levels healthy, we need to be exposing our skin to the sun without sunscreen to stimulate vitamin D synthesis.

The way we make vitamin D from sunlight almost seems like magic, but there’s some beautiful science behind it. When UVB sun rays stimulate cholesterol in our skin it is converted into vitamin D3, the precursor to active vitamin D. This then travels to the liver where it is converted into 25-hydroxyvitamin D (this is the form of vitamin D that is measured if you have your blood levels tested). Finally, the molecule is transported to the kidneys where it’s converted to its active form – vitamin D. The active vitamin D then travels through the body, taking up crucial roles in all areas of health, in particular the immune system, bone health, hormone imbalances and cancer risk.

What are the benefits of vitamin D?

Vitamin D was discovered in the 1920s while researching the painful childhood bone disease rickets. The fortification of foods with vitamin D eradicated most cases but it was just the start of our understanding about the link between bone health and vitamin D levels. Since then we’ve learned that vitamin D plays the main role in regulating calcium and phosphate absorption from the intestine. Lack of vitamin D can reduce our absorption from 40 percent to 10 percent, leading to poor calcium stores and an increased risk of fractures and osteoporosis.

Vitamin D deficiency and its relationship to prostate, colon and breast cancer have all been researched. Cancer is a very complex disease and much more research is needed, but there does appear to be a benefit in having healthy levels of vitamin D as a preventative measure. Optimal vitamin D levels have been shown to reduce the incidence and severity of colds and flus while also playing a role in managing autoimmune diseases such as Crohn’s, psoriasis and Hashimoto’s.

How do you find out if you’re deficient?

You can self–refer for a vitamin D test. It costs around $50 and is a simple blood draw; just call your local blood-testing lab to arrange one. It’s best to consult a professional once you have your results. As a general guide, organisations such as Osteoporosis Australia recommend your levels should be no lower than 50 nmol/L (nanomoles per litre) at the end of winter. D-test.co.nz is an online test which gauges whether you may have contributing factors which could indicate a vitamin D deficiency.

How do you get vitamin D form the sun safely?

Although Osteoporosis New Zealand doesn’t disclose its recommendation for optimum vitamin D levels, they do recommend sun exposure at certain times of the day to keep your vitamin D levels healthy:

September-April

  • 5-15 minutes before 10am or after 4pm with your arms and hands exposed.

May-August

  • A brisk walk or outdoor activity around the middle of the day with arms, face and hands exposed.

It’s really important that you use sun protection (sunscreen, hat, sleeves and sunglasses) outside these times. You must also consider your own medical history or family history of skin cancers, and other pertinent information like what medications you’re taking, as some make us more sun sensitive.

If you’re very dark-skinned, live in the South Island, are pregnant, elderly or obese your need for vitamin D may be increased. Sometimes, being kissed by the sun may not be enough and supplementation may be appropriate. If you do end up supplementing, it’s important to check your levels periodically so you don’t overdo it.

Can I get vitamin D from food?

Diet alone is not enough to provide sufficient levels of vitamin D, as 80 percent of our vitamin D comes from the sun’s UVB rays. However, consuming oily fish such as sardines, salmon and mackerel will provide some, as will eggs and liver (go on!). Eating vitamin- and antioxidant-rich colourful fruit and vegetables can also help to protect skin from the damaging effects of UV radiation.

How do supplements help?

Vitamin D supplements come in liquid, tablet and capsule form. Liquid forms can be more readily available to the body compared to capsules or tablets, but it all comes down to personal preference. Be sure to consult a healthcare professional to determine the correct dosage for you.

Annaliese Jones

Annaliese JonesAnnaliese is NADIA's resident wellness expert.

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