Low vitamin D levels linked to metabolic syndrome
By Stephen Daniells, 04-Aug-2009

Increasing blood levels of vitamin D are linked to a lower prevalence of the metabolic syndrome, as well as improved ‘good’ cholesterol levels, says a new study.

According to findings published in the Journal of Clinical Lipidology, the lowest levels of the sunshine vitamin were associated with a 31 per cent prevalence of metabolic syndrome, compared to only 10 per cent for people wit the highest average levels.

The researchers noted that the results do not prove that low vitamin D levels contributes or causes metabolic syndrome, and called for more studies to “assess whether increasing vitamin D intake will improve the metabolic cardiovascular risk factor profile”.

“Although previous surveys have also reported associations between low 25(OH)D concentration and metabolic syndrome components, to our knowledge, the present investigation is the first to report this finding in a sample with a high prevalence of vitamin D dietary supplement users in which frequencies of vitamin D insufficiency and deficiency were low,” wrote the researchers, led by Kevin Maki from Illinois-based Provident Clinical Research

Metabolic syndrome (MetS) is a condition characterised by central obesity, hypertension, and disturbed glucose and insulin metabolism. The syndrome has been linked to increased risks of both type-2 diabetes and cardiovascular disease (CVD).

Study details

The researchers analysed vitamin D levels in the blood of 257 men and women aged over 18. Dietary and supplementary intakes were assessed using a food frequency and dietary supplement questionnaires, said the researchers.

Their results showed that vitamin D blood levels were associated with HDL cholesterol levels.

“The most notable finding from the present study was the strong relationship between serum concentrations of 25(OH)D and HDL-C concentrations,” wrote the researchers.

“Each 10 ng/mL increment in 25(OH)D was associated with an increase of 3.8 to 4.2 mg/dL in HDL-C [...] This is of considerable potential importance given that each 1 mg/dL increment in HDL-C is associated with a 4 to 6 per cent reduction in coronary heart disease (CHD) risk.”

They also observed inverse associations between vitamin D levels and triglyceride levels, body mass index, and waist circumference, meaning that higher vitamin D levels were associated with lower values for these measurables.

Explanation

“A potential explanation for our observation of an inverse association between 25(OH)D and indicators of adiposity (waist and body mass index) may be that vitamin D is fat soluble and is therefore easily sequestered in adipose tissue,” wrote the researchers.

“Thus, there is a greater storage capacity for vitamin D in overweight and obese individuals, which may result in a reduced circulating concentration of 25(OH)D.

“As a result, in order to maintain a given circulating 25(OH)D concentration, overweight and obese individuals may have to consume higher quantities of vitamin D than would be the case for normal weight populations,” they said.

Source: Journal of Clinical Lipidology
Published online ahead of print, doi: 10.1016/j.jacl.2009.07.003
“Serum 25-Hydroxyvitamin D is Independently Associated with High Density Lipoprotein Cholesterol and the Metabolic Syndrome in Men and Women”
Authors: K.C. Maki, M.R. Rubin, L.G. Wong, J.F. McManus, C.D. Jensen, J.W. Marshall, A. Lawless

Thanks nice article.

Mmmm, must get some vitamin D suppliments!

Living in Newcastle UK it would be well to
to ensure your status has reached between 50~60ng/mL 125~150nmol/l.

after you have been taking an
EFFECTIVE amount of Cholecalciferol for 3months.
$5 discount code ~~~~~~.
While at the end of this lousy summer 5000iu/daily may just about be sufficient if you also get as much sunshine as is available, however you may need to use up to 1000iu for each 25lbs you weigh plus 100iu/d for each extra 2.5lbs.

A more formal abstract with some more detail is at http://www.sciencedirect.com/scienc...1f584e13b9af54d

A good study and let's hope the call "for more studies to “assess whether increasing vitamin D intake will improve the metabolic cardiovascular risk factor profile” will be answered.


However I'm puzzled by one detail.
<<
“A potential explanation for our observation of an inverse association between 25(OH)D and indicators of adiposity (waist and body mass index) may be that vitamin D is fat soluble and is therefore easily sequestered in adipose tissue,” wrote the researchers.

“Thus, there is a greater storage capacity for vitamin D in overweight and obese individuals, which may result in a reduced circulating concentration of 25(OH)D.

“As a result, in order to maintain a given circulating 25(OH)D concentration, overweight and obese individuals may have to consume higher quantities of vitamin D than would be the case for normal weight populations,” they said. >>

The researchers were measuring Blood serum levels of D and their correlation with risk factors. They were also measuring (or estimating) Vit D intake. Presumably they had the data to plot intake against blood serum levels, but this link is not documented in the study as reported. Even though they speculate on it's significance.
So they could make a start on answering their own question with data already present.
Nevertheless, I can only agree with the call to do a good study (presumably an "intervention" study) to assess all three sides of this triangle, ( D Intake vs Blood serum D vs "Bad Things Happening") This would be a relatively cheap study to do given the long half life and safety of Vit D. One pill a week would be all that was required.

Further along this speculative road, if the D was going into fat tissue it would be expected to eventually reach a steady state, as long as fat levels were not increasing, or the D was not being destroyed within the fat tissue. So the buffering effect of extra fat would be a feature only of the start up phase of higher D intake. Any intervention study should investigate if such buffering exists and plot it's magnitude.
Here's hoping.

The trouble is that it's almost impossible to assess intake from sun exposure particularly from a questionaire. There are so many factors to account for (age, skin colour, amount of skin exposed, time of day) that it's simply unrealistic.

Only if it were an amount that guaranteed the recipient attained and maintained a 25(OH)D level around 55ng 135nmol/l.
Only when you have the thyroid working at it's optimum level will the metabolic rate be properly regulated.

But that would depend on intake. Remember the half life of D3 is just 3 weeks and there are dietary factors such as fibre intake that further reduce that half life.
If you are not getting sufficient to meet your daily needs and some of what you are getting is being locked up in fat cells only to deteriorate over time without being of any use to the body it's going to be like trying to fill a bath with the plug out.

Let's remember that vitamin D is a fat soluble vitamin. So absorption of vitamin D requires sufficient fat in the diet. Let's also remember that cholesterol in the skin aids the conversion of sunlight into vitamin D. Could the low fat diet and the cholesterol lowering mania of the statinators and mainstream medicine be playing a role? You betcha!

It is also interesting that adequate vitamin D is correlated with high HDL and low triglycerides, exactly the profile conferred by a low carbohydrate diet. Hmmm. . .

My Mom always had us take D with fat right then. Usually a spoonful of peanut butter.

Dr Art Ayers Cooling Inflammation has some interesting observations on why we may not be getting all the Vitamin D3 we used to from exposure to sunshine

We know there is huge difference in the vitamin d response to sunlight and we also know some people still have low vitamin d levels despite abundant sun exposure.

In the same way we know that consuming large amounts (anything greater than 4% of calories) of omega 6 increases the potential for skin cancer, it may be that one of the mechanisms by which this occurs is increased pro inflammatory cytokine production on the skin in those with high omega 6 low omega 3, status.

I had been thinking that people with high inflammatory status actually used up their vitamin d3 faster than people with low inflammatory status but it's very likely that Dr Ayers is right as well, skin with the potential for high inflammatory cytokine production is less able to convert cholesterol to vitamin d3 given UVB exposure.