Vitamin D, known as the sunshine vitamin, may stave off diabetes as it It significantly improved the action of insulin, according to new research.according to new research.
The nutrient boosts glucose metabolism – which is impaired in sufferers.
A study suggests high doses of the supplements slow the condition in newly diagnosed patients and may even keep it at bay.
It significantly improved the action of insulin, the hormone that controls blood sugar, in the muscle tissue of participants after six months.
Lead author Dr Claudia Gagnon, of Laval University in Quebec, said: “The reason we saw improvements in glucose metabolism following vitamin D supplementation in those at high risk of diabetes, or with newly diagnosed diabetes, while other studies failed to demonstrate an effect in people with long-standing type 2 diabetes is unclear.
“This could be due to the fact that improvements in metabolic function are harder to detect in those with longer-term disease or that a longer treatment time is needed to see the benefits.”
Her team examined the effect of vitamin D on 96 patients with either type 2 diabetes – the form linked to obesity – or pre-diabetes.
This is where glucose levels are higher than normal – which can lead to the full-blown disorder.
Markers of insulin function and glucose metabolism were measured before and after six months of high-dose vitamin D supplementation – about five times the recommended amount.
Half of the middle aged participants, mainly in their 50s and 60s, were assigned to 5,000IU of vitamin D daily and the others a placebo.
The recommended amount for people in Canada is a maximum 1,000IU – four times lower than guidelines for people in Britain.
Less than half (46%) of participants were determined to have low vitamin D levels at the start. But supplementation with vitamin D was highly effective.
One in five Brits have insufficient levels of vitamin D. More than four million people in the UK have diabetes, mostly the type 2 form caused by unhealthy lifestyles.
Boosting levels with a daily supplement has been shown to cut the risk of dying from cancer by 13 per cent.
Vitamin D is made by the body when exposed to sunshine but modern lifestyles mean many spend more time indoors.
The study published in the European Journal of Endocrinology says high-dose supplementation can improve glucose metabolism to help prevent the development and progression of diabetes.
This is the process by which simple sugars found in many foods are processed and used to produce energy.
Type 2 diabetes is an increasingly prevalent disease that places a huge burden on patients and society.
It can lead to serious health problems including nerve damage, blindness and kidney failure.
People at high risk of developing type 2 diabetes can be identified by several risk factors including obesity or a family history of the disease.
Low vitamin D levels have previously been linked to the disease. But some studies have reported no improvement in metabolic function.
However, these often had a low number of participants or included individuals with normal vitamin D levels at the start who were metabolically healthy, or who had long-standing type 2 diabetes.
Whether vitamin D supplementation has any beneficial effect in patients with prediabetes or with newly diagnosed diabetes, especially in those who have low vitamin D levels, remains uncertain.
Dr Gagnon suggests future studies should evaluate whether there are individual clinical or genetic factors that affect how different people respond to vitamin D supplementation and if the positive effect on metabolism is maintained in the longer term.
She added: “Type 2 diabetes and pre-diabetes are a growing public health concern and although our results are promising, further studies are required to confirm our findings, to identify whether some people may benefit more from this intervention, and to evaluate the safety of high-dose vitamin D supplementation in the long term.
“Until then I would suggest that current vitamin D supplementation recommendations be followed.”