Body & Fitness

Let the sun shine in

It seems the sun’s not all bad, after all. We need its rays to make vitamin D.

If you’re staying in the shade or slathering yourself in sunscreen this summer, you’re reducing your chances of getting potentially fatal skin cancer. However, you may also be increasing your chances of getting other types of illnesses. While overexposure to UV radiation may cause skin cancer, the sun also has some health benefits. The trouble is, how do you reap those benefits without risking skin cancer?

Why do we need the sun?

our body makes vitamin D from the sun’s rays. This important nutrient is also found naturally in some foods, including fatty fish, egg yolk, butter, full-fat milk and meat (especially liver). But it’s difficult to get enough vitamin D for our needs from food alone – the sun is a much better source. In some countries, it’s compulsory for certain foods to be fortified with vitamin D, but it is voluntary here and only a few products have vitamin D added. Vitamin D is also available as a supplement.

Why is vitamin D important?

It’s vital for strong bones – a shortage can lead to illnesses like rickets and osteoporosis. Some medical experts believe a lack of vitamin D may also play a part in a variety of other conditions. These include:

  • Diabetes (both type 1 and type 2)

  • Heart disease, stroke and high blood pressure

  • Gum disease

  • Autoimmune illnesses like rheumatoid arthritis and multiple sclerosis

  • Some types of cancers, especially colon cancer

  • Depression

  • Chronic muscle and bone pain

  • Pre-eclampsia (a pregnancy complication)

Do Kiwis have enough vitamin D?

Generally, no. Studies show our levels are low. In one survey, nearly 50% of adults tested were found to have insufficient levels while 3% were totally deficient. Low vitamin D levels were highest among Pacific Islanders. People with darker skin need more sun exposure to make vitamin D than fair-skinned people.The disease rickets, which causes bone deformities in children, is making a comeback in this country, says Professor Scragg, particularly among children of Pacific Island descent.

Professor Scragg says it does appear that people’s efforts to avoid getting skin cancer – our most common cancer, which kills around 300 Kiwis a year – may be a factor contributing to our low levels of vitamin D. Sunscreen stops our skin from making vitamin D. Vitamin D levels are lower in winter than summer because the UV rays are too weak to make it, especially in the south of New Zealand.

How do you know if you’ve got a vitamin deficiency?

often you don’t. Symptoms can include general aches and pains, plus an increased risk of catching an infectious disease, but these could also be due to other causes. Breaking bones easily may be one sign. If your doctor suspects you have low vitamin D levels, they can order a blood test. People more likely to have lower levels of vitamin D include the elderly, those with darker skin, those who live in the south of the country and people who cover their bodies for cultural or religious reasons.

So can we ignore the sun-smart message about protecting our skin from the sun?

No, absolutely not. It is there for a reason. Trying to boost your vitamin D must never be an excuse to overdo unprotected sun exposure. You need to find a balance between getting enough sun to maintain vitamin D levels but not so much that you risk getting skin cancer. That’s easier said than done, especially as “safe” amounts vary between individuals. Your age, the colour of your skin and where you live in New Zealand can make a difference to how much exposure you should get.

What should I do?

Concerned organisations, including the Cancer Society of New Zealand and the New Zealand Dermatological Society, have joined forces with a variety of experts, including Professor Scragg, to release a position statement called The Risks and Benefits of Sun Exposure in New Zealand. In it, they say:

  • Always avoid getting sunburned. Protect yourself against the sun’s rays between 11am and 4pm from September to the end of March.
  • During summer you should be able to get enough vitamin D by doing everyday outdoor activities outside those peak times. People with fair skin who burn easily should only need to expose their face, hands and arms for a few minutes, while people who tan more easily or have darker skin may need longer.
  • To get enough vitamin D without getting burnt, you should expose larger areas of skin for shorter periods of time, rather than smaller areas for longer.
  • People with a greater chance of vitamin D deficiency and those who have a high risk of getting skin cancer should talk to their doctor about taking supplements.

The statement adds that more research is needed before advice can be given on the specific amount of sun exposure needed to make enough vitamin D and at the same time avoid sunburn. This may be because some experts say the UV wavelengths needed to produce vitamin D are roughly the same as those that can cause skin damage and cancer.

Professor Scragg says while we may find we have to go out unprotected in peak times to get the vitamin D we need, the key is to not get burnt. “You should base the amount of time you spend in the sun on previous experience of how long it takes you to get burnt and cover up before you start to burn.”Supplements appear to be as effective as the sun, says Professor Scragg, but the sun is cheaper and easier to get.

  • To read the full report Risk and Benefits of Sun Exposure in New Zealand, visit www.sunsmart.org.nz

Senior supplement

The importance of vitamin D has been recognised by ACC, who are supporting a programme to give supplements to elderly people in rest homes.The programme came about after research showed that vitamin D supplements increase muscle strength, balance and flexibility and may therefore reduce the number of falls suffered by elderly folk in rest homes by 25% – that’s an estimated 5000 falls a year.People who live in residential care may have a vitamin D deficiency because they don’t get outside in the sun very often. It’s also harder for older folk to make vitamin D from the sun because of age-related changes to their bodies, such as having thinner skin.

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