Taking vitamin D may assist fat loss and reduce risk of chronic disease

There is a ton of research which links higher levels of vitamin D (and/or increased sun exposure) with reduced risk of a range of conditions including diabetes, multiple sclerosis, several forms of cancer and heart disease. These studies are voluminous, and tend to be quite consistent, but they still can’t tell us for sure that vitamin D has genuine disease-protective properties.

We get more insight in this regard from clinical studies in which individuals are, say, treated with vitamin D and their outcomes compared to a group treated with placebo. Recently a study was published on-line which did just this, and it turned up at least some interesting results, I think [1].

The study in question involved treating overweight and obese Iranian women with 1000 IU of vitamin D3 (cholecalciferol) for a period of 12 weeks. A number of different parameters were measured, including:

  • HDL-cholesterol levels – higher HDL levels are associated with reduced risk of heart disease
  • Apolipoprotein A-1 (ApoA-1) levels – ApoA1 is a component of HDL-cholesterol, and is associated with a reduced risk of heart disease
  • LDL-cholesterol:Apoliprotein B100 (ApoB-100) ratio – this ratio is a marker for the size and density of LDL-cholesterol particles. Lower ratios correspond with larger, less dense LDL-cholesterol, which appear to be harmless in comparison to so-called ‘small, dense’ LDL-cholesterol
  • Fat mass

Compared to the group taking a placebo, those taking vitamin D saw:

  • Significant increase in HDL levels
  • Significant increase in ApoA-1 levels
  • Significant decrease in LDL-cholesterol: ApoB-100 ratio

All of which point to a reduced risk of cardiovascular disease over time. In addition though, the vitamin D-treated group saw a reduction in their fat mass of 2.7 kg on average (compared to the placebo group’s average loss of less than ½ kg).

This study provides at least some evidence which supports the idea that vitamin D has a ‘causal’ link with cardiovascular disease and other chronic conditions.

My personal aim is to keep my vitamin D levels at around 50-60 ng/ml (125-160 nmol/l). I get as much summer sun-exposure as I possibly can (without burning), but also supplement with vitamin D3. One thing I’ve realised is that to optimise my vitamin D levels I’m needing to take much higher doses of vitamin D than the usually recommend daily intake of 400 IU. Typically, I require several thousand IUs per day to do this.

How do you know if you’ve got enough vitamin D on board? The only sure way to know is to test.


1. Vafa M, et al. Vitamin D3 and the risk of CVD in overweight and obese women: a randomised controlled trial. British Journal of Nutrition Published online: 09 February 2012


24 Responses to Taking vitamin D may assist fat loss and reduce risk of chronic disease

  1. snowmoonelk 17 February 2012 at 4:55 pm #

    Can one overdose on Vit D?

  2. Dr John Briffa 17 February 2012 at 5:08 pm #


    Technically, the answer to your question is ‘yes’. However, I have to tell you I’ve seen many people take dosages of 5,000-10,000 IU daily and not run into problems here. To be sure (and safe) though, it’s important to keep and eye of levels through testing.

  3. Sue Bedford 17 February 2012 at 5:21 pm #

    I took high dose vitamin D3 for several months then asked my GP for a 25 Hydroxy Vitamin D test. She said that the surgery had been sent a letter from the local hospital stating that they must stop doing this test unless a patient was suspected of calcium deficiency – how ridiculous! I had the test done privately which thankfully showed I was in the optimum range. Three of my clients, who took no Vitamin D, also had the test privately and all of them came up as severely deficient. I find it incredible that GPs cannot offer this test to their clients as a matter of routine, or maybe it’s just my area that has this policy.

  4. roger 17 February 2012 at 5:47 pm #

    I find it interesting that where there’s a shortage of Vitamin D, the liver produces more cholesterol, which is needed for proper absorption, to grab whatever Vitamin D IS available. That being so, it seems unsurprising to me that increasing vitamin D levels reduces cholesterol.

  5. Agate Karevoll 17 February 2012 at 6:22 pm #

    A recent large 5-year study found that noone was overdosing on less than 35000 IU. Also interesting to me is another study finding that 90% of Hashimoto’s autoimmune sufferers have a genetic defect which makes it difficult to absorb D3. We need to keep levels at the top of 95% reference interval.

  6. ValerieH 17 February 2012 at 8:02 pm #

    I have run across a few articles recently about vitamin K in relation to calcium and vitamin D. It seems vitamins can’t really be isolated. Nutrient dense foods contain the nutrition in the right combination for health.

  7. DanC 17 February 2012 at 8:09 pm #

    Dr Briffa – Congrats for publishing something positive about supplementation. The American Medical-Pharmaceutical Complex now hate you.

  8. Jules 17 February 2012 at 9:25 pm #

    I have Crohns and generally have Vit D levels at the ‘low end of normal’ – 45nmol/L. I find it difficult to get anyone to discuss reasonable levels of supplements as they seem more interested in the prescription drugs. I currently take Vit D 1000iu / 25 mcg daily plus other supplements. I also find it difficult to request a blood test from my GP; the York Test does not take blood if you are on immunosuppressants and I am on Azathioprine 125 mg daily, any ideas?

  9. Joe Wrigley 17 February 2012 at 11:19 pm #

    Do you have any recommendations for getting a vitamin D test done? What is the position of most GP practices, are they driven by the PCT? What about private testing, any experiences with that?

  10. sweetpotato 17 February 2012 at 11:51 pm #

    I am taking vitamin D3 drops along with my husband. It is made from sheeps lanolin and olive oil is added. You have to be VERY careful with dropper since one dropper can hold like 80k units! We don’t get much sun in the winter in Pacific NW in the winter. We were taking two drops or 4K units a day. After about 5 weeks we ended up with migraines big time and disorientation which we never get and we stopped taking the vitamin D. We have begun taking it again but only at one drop of 2K a day and that seems to work better. I would say it all depends on your genetics and what you eat and testing to see how YOU do on vitamin D. Tests here are quite pricey at around 80.00 for just a vitamin D test so it’s not something most people will want to do each month. They need to make a less expensive test and something over the counter too.

  11. Steve 18 February 2012 at 12:57 am #

    You can get a National Health vitamin d lab test for £20:

  12. Dr John Briffa 18 February 2012 at 1:19 am #


    Thanks for this link. Didn’t know about this service. Looks great!

  13. kem 18 February 2012 at 2:08 am #

    I took a course of cholicalciferol strong at the beginninh of last winter (June) which was 10k IU/day for 7 days and 10k IU on the first of the next three months. Not a shiffle when I expect to have two rounds of a cold.

  14. Kevin 18 February 2012 at 2:37 am #

    I started to become insomniac last year after several months of taking 2000IU of vitamin D3 every day. Lack of sleep – waking up at 4am every night- was driving me nuts. Then I read about how high doses of synthetic vitamin D3 can cause can cause magnesium deficency. Stopped the vitamin D, started taking magnesium, and normal sleep was immediately restored. I became very wary of Vit D supplementation as a result of this experience. I have only recently started taking it again, but in a natural form – Green Pastures Cod Liver Oil – with no ill effects. I am continuing to take magnesium though, and would recommend that everybody who is following Dr Briffa’s advice to knock back loads of vitamin D also considers their manesium status – taking a lot of Vit D may also mean you will require more magnesium.

  15. Megan 18 February 2012 at 3:07 am #

    I have been supplementing with D3 for several years and have been free of any cold/infection for as long. I have also cut out grains, all sugars and stuck to a pretty high protein meat/fish and vegetable diet with nuts, plenty of fats (olive oil, butter, goose fat, coconut), full fat dairy and lots of free range eggs. I am never hungry and find it easy not to yield to temptation. Happily, I have lost a stone on this “dangerous”, saturated fatty, eggy fare and have never felt better or more energetic. How can denatured diet food, watery milk and vile marg ever be fit for human consumption?

  16. frances 18 February 2012 at 1:44 pm #

    I have been taking 5000-10000 iu a day for about 2/3 years now, and am tested 6 monthly by the Vit D action grass roots project. Being someone who cycles everywhere, eats loads of oily fish etc etc, I was surprised at the start to have a very low level of Vit D. Now I have got it up to 55. I have had no problems taking it at this level and in fact sleep better these days than before (although I think it is important to take Vit D in the morning). I also try to get bits of body out into the sun whenever possible, even in the winter, to get as much of the natural stuff as possible, and have stopped using sun tan lotions. I certainly seem to be and feel healthier these days.

  17. Donald 19 February 2012 at 5:08 pm #

    Our practice has been using this web site: http://vitamindtest.org.uk/ to obtain accurate D3 levels for patients who may have deficiency. Its easy to use an inexpensive. Most GP’s don’t agree to accepting the cost, even with diabetic, depressed or borderline osteoporotic/osteopenic cases.

    Patients who pay for the test are sent a print out sheet that suggests they are within normal limits if their blood levels are on or above 50 mmol/L, which may be low for some individuals. Providing patients are aware of the essentials of biological individuality and the complexity of the testing process, then I think regular blood testing can be extremely helpful.

    It helps patients get educated in taking charge of their health. Good post Dr Briffa.

  18. anthony Kerstein 19 February 2012 at 7:26 pm #

    I take Holland & Barrets’ own label cod liver oil which has three times the ‘recommended’ dose of vitamin D. Is this enough and would this be regarded as supplementation?

  19. jake3_14 19 February 2012 at 9:47 pm #

    Another commenter mentioned this in passing, but getting the *right* type of Vit. D. test is essential for determining one’s Vit. D status. In the states, this test is known as a 1,25OHD test. This is not the default test given for Vit. D status; one must request it specifically.

  20. Robin Dowswell 20 February 2012 at 6:46 pm #

    You are right that it is important to get the correct test done, but I think you’ve identified the wrong one. The correct one, that is the same as what the NHS offer for £20 here in the UK is the 25OHD test, also known by the name calcidiol. 1,25OHD is calcitriol, which does not give as good an indication of vitamin D status. My website: http://www.drdobbin.co.uk/vitamin-d-new-supervitamin has more about this.

  21. Sue 20 February 2012 at 6:46 pm #

    The 1,25 OHD test is not the best test for vitamin D. It must be the 25 Hydroxy Vitamin D test. See Dr Mercola’s article at http://articles.mercola.com/sites/articles/archive/2002/02/23/vitamin-d-deficiency-part-one.aspx

  22. Ted Hutchinson 11 March 2012 at 9:03 pm #

    The £20 UK 25(OH)D Vitamin D test mentioned above from CITYASSAYS.org.uk is at an introductory price. This is due to rise to £25 in APRIL.
    As Dr Briffa says, it’s important to keep and eye of levels through testing, so it may be worth stocking up with a few spare test kits now at the lower price so you are able to test twice yearly at the current price. This will show how current supplement level affects your status + (hopefully) the effect of summer sunshine so you are better able to work out how much is required to keep 25(OH)D between 50~60ng/ml through the winter.
    The best before date on my pack was 10-2015, so going out of date should not be a problem.

  23. Stephen Corson RPh 25 June 2012 at 2:37 am #

    I have seen real results from this study…Well done


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