One of the most replicated findings in vitamin D research is that the higher your vitamin D, the less you weigh; the lower your vitamin D, the more you weigh. Conventional wisdom says that fat-soluble vitamins, like D, dissolve themselves in fat and disappear from the blood.
Another explanation is even simpler: if you dissolve a teaspoon of sugar in a glass of water, it will be sweeter than if you dissolve it in a quart of water. That is, anything (vitamin D) dissolved in a limited mass (fat) will be more concentrated.
But what about the possibility of vitamin D playing a causative role, not just an associative role, in obesity and body mass? That is, to a limited extent, does vitamin D act like a diet pill? Last week, Dr. Selehpour of the Tehran University of Medical Sciences found some interesting results in her randomized controlled trial.
Salehpour A, Shidfar F, Hosseinpanah F, Vafa M, Razaghi M, Hoshiarrad A, Gohari M. Vitamin D3 and the risk of CVD in overweight and obese women: a randomised controlled trial. Br J Nutr. 2012 Feb 9:1-8. [Epub ahead of print]
In this RCT of 77 overweight women, they gave half a small dose of vitamin D (1,000 IU/day), and half a placebo. In just 12 weeks, the vitamin D group had lost five more pounds than the control group. They also found improved scores in lipoprotein/cholesterol ratios for better heart health in the vitamin D group verses the placebo. Which brings some readers to a question: “If I want to diet, how much vitamin D should I take?”
First, 5,000 IU/day is for otherwise healthy adults weighing average adult weight (125-200 pounds). If you’re above this weight, however, 32 IU per pound per day is a good rule of thumb (as reported in the “Body weight and vitamin D blood levels” blog above. This means that a 300lb person would need 10,000 IU/day, though it wouldn’t surprise me if they needed more. Only way to know is to test blood levels. As your weight decreases, it is important to reduce your dose.
I doubt vitamin D is a classic diet pill. It may work by increasing your activity as your “get up and go” is back. Just lying on the sofa popping vitamin D pills will get you nowhere, however. Follow that urge to take the walk, clean out the garage, and take that weekend trip.