Previously in this blog I have covered some of the evidence linking vitamin D with positive health outcomes, including a reduced risk of cardiovascular disease and several forms of cancer. Vitamin D has also been linked with diabetes, in that some studies have found those with higher levels of vitamin D to be a reduced risk of this condition. There has also been a little evidence that supplementation with vitamin D and/or calcium may have some benefit in terms of blood sugar control. There’s a hint, therefore, that higher intakes of these nutrients might reduce the risk of type 2 diabetes.
Recently, a study was published which assessed the impact of giving nutrient fortified yoghurt to individuals with type 2 diabetes. 90 individuals were treated with one of the following each day:
- 500 mls of plain yoghurt
- 500 mls of plain yoghurt containing 1000 IU of vitamin D and 300 mg of calcium
- 500 mls plain yoghurt containing 1000 IU of vitamin D and 500 mg of calcium
A range of body and biochemical measurements were assessed at the beginning and end of the study.
At the beginning of the study, about three-quarters of the study participants were deemed to be ‘insufficient’ in vitamin D (vitamin D3 level 27.5 – >50.0 nmol/l = 11.0-20.0 ng/ml). About 40 per cent were deemed to have severe deficiency (<27.5 nmol/l = 11.0 ng/ml). At the end of the study, vitamin D levels had risen significantly in groups 2. and 3. Relative rise was about 75 per cent in both groups, which corresponded to an absolute rise of 30-35 nmol/l (12.0-14.0 ng/ml).
Those in groups 2. and 3. saw significant reductions in:
- Weight
- Body mass index
- Waist circumference
- Fasting blood sugar (glucose) level
- HbA1c level (gives a guide to blood sugar levels over the preceding 2-3 months)
As well as improvement in markers of insulin sensitivity (to an extent comparable to treatment with the diabetes drug metformin).
The authors of this study conclude that vitamin D fortified yoghurt (with or without additional calcium) helped blood sugar control in type 2 diabetics probably through direct effects on insulin sensitivity and indirectly also through improvements in weight.
One interest thing to note about this study was just how effective vitamin D-supplemented yoghurt was in raising vitamin D levels. Vitamin D is fat-soluble, and it’s just possible, I suppose, that the fat in the yoghurt enhanced the absorption and ‘bioavailability’ of the vitamin D.
References:
1. Nikooyeh B, Daily consumption of vitamin D- or vitamin D + calcium-fortified yogurt drink improved glycemic control in patients with type 2 diabetes: a randomized clinical trial.
Neyestani TR, Farvid M, Alavi-Majd H, Houshiarrad A, Kalayi A, Shariatzadeh N, Gharavi A, Heravifard S, Tayebinejad N, Salekzamani S, Zahedirad M. Am J Clin Nutr. 2011 Feb 2. [Epub ahead of print]
Very interesting. As Vitamin D is fat-soluble, and there is an obsession in this country to reduce our fat intake (or even eliminate it altogether), there must be a lot of people with a severe Vitamin D deficiency. It is so wrong that I find it hard to buy full fat yoghurt at my local supermarket.
Just out of interest, was the supplementation D3 or D2?
Frederica
Good question. The answer is D3
Oral D3 requires dietary fat to be effective. Skin-derived D3 doesn’t. See Vitamins D and K as Pleiotropic Nutrients.
If the study(ies) you refer to sit with a general sense that Vitamin D deficiency is not uncommon amongst people of ‘western’ populations and that said deficiency links to conditions including insulin resistance and/or metabolic syndrome then it reminded me of a similar suggestion that another vitamin deficiency, Vitamin C, could also be responsible for ill health. In 1992 Rath and Pauling presented an argument that cardiovascular disease (CVD) could be attributable to ascorbate (Vitamin C) deficiency. Does their paper still sit well with more recent literature?
It is reflection of our times that reduced fat products seem to out-number full fat products, as Carol says, on the supermarket shelves. We’re converts in our household, only full fat and unsweetened yoghurt finds its way into our trolley (cart).
Just as an aside is it worth bearing in mind that the presence in the diet of ‘the wrong sort of fats’ may also be a factor that could be promotional of insulin resistance? Here a study found Omega-3 and omega-6 polyunsaturated fatty acids had opposing effects on insulin resistance.EPA was associated with better glucose balance, while omega-6 polyunsaturated fatty acids were associated with elevated insulin resistance. For two years I’ve chosen my fats more carefully, marg is ‘out’ and butter is ‘in’, and products containing veg oils are avoided too. I haven’t suffered the muscle lethargy or ‘dull’ mind that were symptoms that often accompanied my type-2 diabetes. I don’t miss them – meaning the marg and the symptoms!
I have tried adding vitamin D3 to full fat yogurt but my blood sugars were not reduced. This is possibly due to milk increasing my blood sugar levels when added to porridge for example. So far D3 taken with water has not had any effect.
Ray Fiveash, diabetics should avoid eating porridge. It raises blood sugar very quickly. i have type 1 diabetes (20 year veteran!) and used to wonder why after eating such a healthy food as porridge my blood sugar was so high so quickly. Later found out it’s not good for diabetics, which is strange as it’s supposedly low GI.
Plus type 2 diabetes is reversible. research it, there’s no magic cure just the right amount of excecise diet control, it’s do-able. go to mercola.co m and search ‘reverse diabetes’, it is an excellent website.