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.
References:
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
