A great many factors influence body weight, most of them well known to us: but could a specific nutritional deficiency be hampering your efforts to stay in shape?
Vitamin D deficiency has an array of troubling symptoms, and according to a number of studies, we can add weight gain to the lengthy list.
So what’s the link here, and are there genuine grounds for adding vitamin D to your diet as a means of keeping the weight off? Read on to find out.
Vitamin D and Metabolism
Vitamin D is perhaps best known for its immune-enhancing properties, which is why we are often advised to consume supplements during winter.
Produced by the body when exposed to direct sunlight, vitamin D actually has a vast range of functions, helping us utilise and maintain healthy calcium levels, protecting our bones, teeth and muscles, and also helping with cell division.
While vitamin D is absolutely critical for calcium metabolism, its role in metabolism as a whole is not yet fully understood.
However, studies have frequently exposed a link between vitamin D deficiency and obesity. Whether low vitamin D is caused by a higher body mass index, or the other way around, is sadly still in the realm of speculation.
Certainly it is possible that, since many overweight individuals tend to cover up, they are laying the foundations for a deficiency. Sunlight is, after all, our best source of the nutrient.
In 2017, researchers in Valencia learned that during spring and summer months the body can manufacture 1,000 IU of vitamin D in just ten minutes. And that’s with 25% of the body exposed!
Another factor which must be considered is that larger people require a higher dosage of vitamin D to avoid deficiency.
Because it is a hormone rather than a regular vitamin, there is an interplay between vitamin D and other hormones/neurotransmitters within the body. Some people have theorised that the interaction of vitamin D and testosterone has an effect on body fat, since higher levels of vitamin D appear to correlate with increased levels of testosterone.
More testosterone, meanwhile, increases metabolic rate and prevents new fat cell creation.
And let’s not forget that fat cells themselves contain vitamin D receptors. Perhaps this is why higher levels of belly fat correlate with lower vitamin D levels among obese individuals.
Setting aside the fact that overweight people tend to have lower vitamin D levels, let’s look at the link between low vitamin D and weight gain.
Low Vitamin D and Weight Gain: Clinical Studies
Much of the attention paid to this topic stems from a 2012 study of 4,600 women aged 65 and over.
Published in the Journal of Women’s Health, researchers discovered that vitamin D-deficient females were more likely to gain weight than their non-deficient counterparts.
Although the study received plenty of press, it should be noted that the weight gain was minor. Like, really minor: specifically a two-pound weight gain over five years.
While it probably won’t compel you to add vitamin D to your diet, there must be some association here – particularly given the number of subjects in the trial.
Clearly many will be thinking that, if indeed low vitamin D and weight gain are linked, high vitamin D and weight loss must – in some way – also be linked. And there is some evidence to suggest just that.
In one study, obese college students were instructed to follow a calorie-restricted diet over 12 weeks, after which alterations in weight, visceral fat mass and visceral fat area were recorded. The caveat? Half of the students received daily calcium (600mg) and vitamin D3 (125 IU) supplements while half did not.
After three months, there was no difference in weight change between the two groups. Interestingly, however, those given supplements enjoyed “significantly greater decreases in visceral fat mass and fat area.”
It should be noted that 125 IU is a very low dosage. The highly respected Vitamin D Council believes most people need about 5,000 IU per day to achieve a healthy status.
Another randomised study conducted over 16 weeks found that the same calcium-and-vitamin-D protocol, albeit in higher doses (1050mg and 300 IU, respectively), correlated with a clear reduction in “visceral adiposity” compared with the placebo group.
The reason researchers included calcium was quite simple: just as low vitamin D intake appears to correlate with obesity/weight gain, so too does calcium.
To quote from a 2013 review which appeared in the journal Nutrients, “the overall impression is that vitamin D with or without calcium appears not to have a definite effect on weight, but may affect fat mass and distribution.”
High Vitamin D and Weight Gain
“Hold on… what?!”
Yes, there is some evidence to suggest that high-dose vitamin D supplements actually help with weight gain.
In a 2018 study led by the University of the Punjab and Queen Margaret University, mega-dose supplements helped malnourished children gain weight and develop language/motor skills.
The children received two doses of 200,000 IU – and the weight gain after 8 weeks was, on average, an extra 0.26 kg compared to the placebo control group.
In other words, you are unlikely to accidentally gain weight from vitamin D unless you are taking stupendous dosages.
Everyone should make an effort to maintain sufficient blood levels of vitamin D. Fat loss is just one potential benefit, but there are far more important reasons.
For example, did you know that higher circulating vitamin D concentrations are associated with a lower risk of colorectal cancer?
Maintaining healthy vitamin D levels may also forestall the onset of inflammatory diseases such as rheumatoid arthritis.
Because food sources of vitamin D are limited, the best way of increasing your intake is by exposing your skin to the sun. Since that’s not always possible throughout the year, and since it also entails the risk of sun damage if you stay out too long, using a dietary supplement is advised.
While the former is available in two dosages – 5,000 IU and 1,000 IU – the latter contains 4,000 IU per tablet.
The sublingual option is perhaps best for those with absorption problems, since the micro tablets dissolve under the tongue and quickly enter the bloodstream.
Covering your bases from a nutritional standpoint is a no-brainer. With vitamin D you’ll protect your bones, brain and immune system – and you just might keep those fatty deposits to a minimum!