Vitamin D Deficiency in Australia and NZ

We get Vitamin D from the exposure of our skin to sunshine. We do not get significant levels from food unless we are including cod-liver oil as a food item. Oily fish is not a reliable source of Vitamin D.
It appears that Vitamin D levels have slumped in Australia and New Zealand. Both countries have been very active in promoting the “don’t burn in the sun” message, which is good, especailly for the young. But this campaign may have been at the expense, in some cases, of healthy levels of sun exposure.
Vitamin D deficiency and insufficiency (which means lower than optimal, but not actually deficient) are common even in some of Australiaʼs sunnier spots. For example one study I read about reported Southeast Queensland as having 40.5% of the population deficient in vitamin D in winter and spring. Interestingly Geelong, Victoria, was 37.4%. Tasmania was an alarming 67%.
What are the problems associated with low vitamin D? Many people are aware that vitamin D is very important for the absorption of calcium and that deficiency can lead to thin bones (osteoporosis) or soft bones (rickets). Low vitamin D also leads to muscle weakness and an associated increase in the risk of falling over. Muscle weakness, falls and weak bones are not a good combination.
Recent research has been highlighting the fact that low Vitamin D levels can impact on many other areas of our health. It appears to increase the risk of cancer of the stomach, colon, liver, pancreas, lung, breast, prostate, bladder and kidney. It also appears to increase the risk of heart disease, high blood pressure, auto-immune diseases and type II diabetes.
So what can we do in winter time to get enough vitamin D? Our options are really limited to three things: sunshine, special saunas that use ultraviolet B radiation and oral supplements of D3. If you live in a cold place it is not really wise to try sunbathing in winter time as it is easy to catch a chill. One enthusiastic sunbather I talked with ended up in hospital with pneumonia – definitely something to be avoided. You could head to a more tropical zone for a sun-bathing holiday. Or you could buy an expensive sauna. But the most economical method for most of us is a supplement. I take 25mcg (1000iu) of vitamin D at bedtime. I would recommend this dose for most adults during non-daylight-saving time. By the way, if you have trouble sleeping, Vitamin D might be the answer. It improves sleep in most people when taken last thing at night.
Can you overdose with Vitamin D? Yes, but adults have to take quite a lot: 2,500 – 3,750 micrograms (100,000 – 150,000 IU) per day can be toxic to many people. Symptoms include diarrhoea, vomiting, headache and muscle weakness.
What is Vitamin D3 made from? I am informed that most D3 in Australia is manufactured by shining UV light onto cholesterol collected from sheepʼs wool.
What is the minimum sun exposure needed to prevent bad vitamin D deficiency. In caucasions (white skin) it is about three hours of full sun exposure to the face and lower arms per week. For olive-skinned folk it is probably about 4 hours per week and for really dark skinned people it will be even more.
Finally, if you are serious about preventing skin cancer you need to pay as much attention to having a healthy diet as you to avoiding burning in the sun. So eat a diet high in antioxidants and low in junk food and animal fat and when the weather is favourable, get your dose of sunshine.
Dr David Bird MBCHB, Dip Clinical Nutrition, FRACGP, FACNEM. Lifestyle Consultant, Highwood Health Retreat. References available on request. www.highwoodhealth.org