Low vitamin D levels linked with raised risk of metabolic syndrome

Vitamin D used to be a nutrient that was believed to be important for bone health and little else. But in recent years, it has grown to be associated with an increasing number of conditions including cardiovascular disease, cancer, multiple sclerosis, improved mood and enhanced immunity. New research suggests that another condition that might be influenced by vitamin D is metabolic syndrome. This condition, characterised by a range of potential issues including excess weight around the midriff, high blood pressure, raised blood sugar and raised levels of blood fats known as triglycerides. Metabolic syndrome is a precursor of type 2 diabetes, and is also associated with an increased risk of cardiovascular disease.

The research in question assessed the relationship between vitamin D levels and metabolic syndrome in Chinese adults aged 50-70. Compared to those with the highest levels of vitamin D, those with the lowest levels were found to be at a 52 per cent increased risk of metabolic syndrome. Also, lower levels of vitamin D were found to be associated with higher insulin levels, higher measures of insulin resistance, and higher levels of HbA1c (a measure of blood sugar levels over the preceding 2-3 months). All of these things taken together would suggest higher levels of vitamin D is associated with improved blood sugar and insulin regulation and a reduced risk of type 2 diabetes.

Another thing that was interesting about this study was just how prevalent suboptimal levels of vitamin D were in this population. Individuals were adjudged to be vitamin D insufficient or deficient if their vitamin D levels were 50-<75 and <50 mmol/L respectively (20-<30 and and <30 ng/ml). Prevalence of insufficiency and deficiency was about 70 and 25 per cent respectively.

This study is epidemiological in nature and cannot be used to conclude that vitamin D protects against metabolic syndrome and associated issues. However, it does, yet again, link higher vitamin D levels with distinct benefits for health.

As an addendum, I’d like to add that I was particularly interested in this study because I have quite a strong family history of type 2 diabetes. And, I recently had my vitamin D levels checked for the first time too. I had these assesedat the end of our winter in the UK because I wanted to check my levels at their likely low point in the year. Having said this, I think I get a LOT of sunshine exposure throughout the year one way or another and have not used sunscreen for about 20 years. My levels came back at a crashingly low 15 ng/ml, which puts me in the firmly vitamin D deficient category. It was a bit of a shock, I can tell you. I am currently supplementing with vitamin D (3000 IU per day, currently) and plan to re-check my levels at the end of the summer. I’m hoping to have at least doubled my vitamin D levels by then.


Lu L, et al. Plasma 25-hydroxyvitamin D Concentration and Metabolic Syndrome among Middle-aged and Elderly Chinese. Diabetes Care Epub ahead of print publication on 14th April 2009 DOI: 10.2337/dc09-0209

18 Responses to Low vitamin D levels linked with raised risk of metabolic syndrome

  1. Chris 14 May 2009 at 9:37 am #

    I think Michael van Straten is an advocate of Vitamin D. I’ve been thumbing the pages of ‘The Omega 3 Cookbook and Michael cautions that Vitamin D may be deficient in a Vegetarian Diet. He quotes oily fish as the richest dietary source and of course says Vit D can be synthesised in the body by the interaction of ultra-violet light upon the skin. “.. unfortunately, in the UK the necessary wave-lengths are only present during the summer months – if we’re lucky.” Very clearly explained , Michael.

    On page 28 Michael touches upon the topic of type 2 diabetes in children arising from:- (he says)
    “* 20% of children are now clinically obese
    * the vast majority do not come near to the optimum amount of EFAs.
    * the vast majority consume far too much omega 6.”

    Van Straten cites several chronic conditions which can be successfully treated, naturepathically, with omega 3 and although he does not specifically include type 2 diabetes it is noted that Barry Sears, author of books in the ‘Zone’ series presses home the importance of omega 3 EFAs to healthy metabolism. Omega 3 fats are building blocks to compounds with important metabolic regulatory function, – ‘Eiconosoids’ – says he.

    Oily fish are abundant in omega 3 because they graze upon zooplankton found generally in cold waters. The zooplankton are the abundant origin of omega 3. Both the ability of the human body to synthesize Vitamin D and the dietary availability of omega 3 and Vitamin D in oily fish, have a relationship to lattitude. Dietary availability may increase as the potential to synthesise from UV decreases.

    Perhaps in part, both Vit D and omega 3 are synergistic or compesatory?

    I live in Manchester and am type 2 diabetic. For both those reasons, John, I’m going to follow your lead and supplement my Vit ;D.

  2. Anna Salvesen 14 May 2009 at 1:53 pm #

    I’m not surprised at all by your very low Vitamin D status. Nearly everyone I know who is tested (any location in the US or UK) and not supplementing with what is typically considered to be very high doses (1000iU D3 per EACH 25 pounds of body weight), is either low in the reference range or deficient. I think you’ll need a higher dose, actually, if you want to get your level consistently above 50ng/mL.

    I weigh 125 pounds and taking 2-3000iU only raised my 25 (OH)D to 44 ng/mL in late fall – it had dropped at next summer’s end when I tried to use only spring and summer sun exposure w/o D3 supplementation. I’m sure age has something to do with it, as well as the amount of time I spend indoors. At 46 yo, I can’t keep my 25 (OH)D above 40 ng/mL with prudent, regular sun exposure alone, even in living in So California and spending 2 weeks in Italy last summer! I now take 5000iU D3 per day, my husband takes 8000iU and our son takes 3000iU during the school year (1/3 to 1/2 that dose in the summer for our son). We test twice a year now (late winter, late summer) and keep our level at 60-80ng/mL with that dosing rate.

    That dose rate has worked well for my dad in upstate NY, too. He’s the only one of my family in NYS who wasn’t severely deficient (he’s also the oldest and healthiest).

  3. Mike 15 May 2009 at 9:15 am #

    A fews years from now everyone will be discussing their vitamin D levels rather than cholesterol levels. Here is a site with some good summaries of the data. http://www.vitaminD3UK.com

  4. Expat 15 May 2009 at 9:00 pm #

    I’m not sure the flesh of oily fish has that much vitamin D in it?
    Now cod-liver oil is a different matter. It was a well used remedy in the UK in years past, and regularly given to children to promote health. Perhaps this is no longer the case? Just goes to show, the parents of fifty+ years ago had more common sense than we realised.

  5. Mike 16 May 2009 at 4:58 pm #

    Worth taking a look at http://www.vitaminD3UK.com they have an offer to supply their customers children free of charge with vitamin D.

  6. Trinkwasser 16 May 2009 at 5:29 pm #

    Katharine Morrison


    one of the few other low carb doctors in the UK has reported finding clinical rickets in Scotland, and I have read another doctor finding the same in Manchester.

    Something seems to be eating our vitamin D!

    Maybe the low fat diet has some responsibility as it is fat soluble, maybe it’s the imbalance of Omega 6 vs Omega 3 or the lack of sat fats, or statins or some other factor are interfering with its processing. Or all of the above and other factors.

  7. Mike 16 May 2009 at 8:23 pm #

    Its simply lack of sunshine and our lifestyle that keeps us indoors. Did you see the publication this week showing higher cancer rates in US cities compared to rural areas. Again I bet that is just due to lower vitamin D levels

  8. Margaret Wilde 16 May 2009 at 11:01 pm #

    See the World Action on Salt and Health (WASH) website, which has this amazing quotation:

    “It was calculated that a modest reduction in salt intake from 10g to 5g would have the same effect on hip bone density as an increase in calcium intake of 1000mg, a difficult amount to achieve without resorting to supplements.”

    And this:

    “Diuretics, through a reduction in extra cellular volume, reduce calcium excretion leading to a positive calcium balance, increase bone density and reduce bone fractures.”

    So salt intake can reduce calcium levels and bone density. I believe that salt intake/salt sensitivity/sodium retention/fluid retention also reduces vitamin D levels.

  9. Alexandra 17 May 2009 at 2:13 pm #

    The Salt issue is an interesting one. I believe there is processed salt that’s not beneficial like the comments above reveal; and organic salt or salt taken with enough water…that is beneficial…see http://www.watercure.com and http://www.watercure2.org/.

    Thanks for the links about D3 as well, very grateful.

  10. m. cawdery 17 May 2009 at 11:55 pm #

    Vitamin D (calciferol/calcitrol) is produced in the body. It is derived from cholesterol! When on statins calciferol is also depleted as collateral damage along with CoQ10 (ubiquinone), the dolichols, steroid and hormones and selenoproteins. For a full review of the adverse effects of statins and their metabolic explanation Google “Graveline” or go to http://www.spacedoc.net . In general the elderly have low Vit D.

  11. m. cawdery 18 May 2009 at 12:02 am #

    A number of studies have shown that reduced salt intake from 9g to 4g resulted in a reduction of 2mmHg in systolic BP. The US NIH “Womens Health Initiative” (48,000+ women over 8+ years and costing $415 million) which included reduced salt resulted in NO BENEFITS. On the other hand a baby food maker in the US reduced salt to very low in baby food. Result babies DIED. Beware of too low salt intake particularly in the heat.

  12. Mike 19 May 2009 at 9:15 am #

    today there was a press release from http://www.vitaminD3UK.com offering their Scottish customers free vitamin D for their children. If you look at their web site the offer is good for everyone but they are focusing on Scotland

  13. Chris 20 May 2009 at 12:22 am #

    Mike, the link and those pages seem interesting, thanks. Interesting that they attribute a role to cholesterol as being the compound that is converted by the action of UV exposure into Vit D. It has me wondering that if a person is subject to Vit D deficiency then the bodies’ physiological response might be to raise cholesterol levels in order to maximise Vit D synthesis when conditions (ie. UV levels) permit. If that is true then it might be expected that Vit D supplementation might register when a persons lipid profiles are checked? Anyone know?

    Dr Briffa, are you able to clarify the units, please? The comment refers to IU whereas my pot of multivitamins attributes the unit of ug (micrograms) to the Vit D component.

  14. Dave 20 May 2009 at 2:05 am #

    Wow! A level of 15! In my opinion you need 6,000u, not 3,000.

  15. Dr John Briffa 20 May 2009 at 3:33 pm #


    “Dr Briffa, are you able to clarify the units, please? The comment refers to IU whereas my pot of multivitamins attributes the unit of ug (micrograms) to the Vit D component.’

    1 microgram = 40 IU

  16. Mike 21 May 2009 at 4:57 am #

    Amazing folk still talk about getting enought vitamin D from diet alone. It is impossible to do so. Also as we get older ie over 45 we become very poor at making vitamin D even in the presence of strong sunlight. Once over that age really the only way to keep your levels up is to supplement. Take a look at http://www.vitaminD3world.com all the data is there. The site also offers a good newsletter

  17. jean 21 May 2011 at 4:23 pm #

    I have just been been told that i am low in my vitamin D, BUT HAVE HA LOST OVER A STONE IN WEIGHT, would this be a part of the problem ?


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