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Ask a Scientist -- Dr. Robert Scragg

Questions and Answers with Dr. Robert Scragg, MD, PhD
Professor of Epidemiology
Head of the Section of Epidemiology & Biostatistics
University of Auckland, New Zealand

This newsletter profiled our 60% lower rate of Diabetes. Our latest paper, just published with YOUR Data, shows a full 60% lower rate of incidence of type 2 diabetes with our median serum level of 41 ng/ml vs.the NHANES median of 22 ng/ml.  

Vitamin D and Grey Hair

Q: I am 68, taking 15k, and have noticed my hair has pretty much stopped greying and in several areas it seems to be growing in now in non-gray hairs. Is this a natural occurrence for folks taking higher doses (proper doses) of Vitamin D3?

A: I am not aware of any research on whether vitamin D prevents or reverses the greying of hair with age. Your observation is very interesting. But it would need to be confirmed by a double-blind randomized controlled trial of vitamin D supplementation before we could be certain that vitamin D has this effect. If it did, I am sure there would be plenty of takers to get this benefit!  

Vitamin D in New Zealand

Q: How is it that people living in New Zealand, where there is plenty of sunshine, need to take a Vit D3 supplement? Are their levels generally too low and if so why is this? I live in the UK and can understand the need as we have so little sunshine available.

A: Surprisingly, vitamin D levels, as measured by the main blood marker (25-hydroxyvitamin D), are lower in New Zealand than in the USA. There are three possible reasons for this.

1)  Very few foods are fortified with vitamin D in New Zealand, in contrast with the US where many foods are.

2)  The availability of ‘over the counter’ vitamin D supplements from chemists and pharmacists is much lower than in the US. For example, in new Zealand vitamin D supplements are mainly taken in multivitamin tablets, at very low doses. There is a mega-dose vitamin D3 tablet of 50,000 IU, but this is only available through a prescription from a registered medical practitioner.

3)  New Zealand, along with Australia, has a very strong public health policy against mid-day sun exposure, because of our high rates of melanoma and other skin cancers, compared with the US. Mid-day is the best time to boost vitamin D levels from sun exposure. But the current policy in New Zealand is to avoid sin exposure between about 10am to 4pm (particularly in summer).