A new trial from the Women’s Health Initiative has found that vitamin D and calcium supplementation helps improve cholesterol levels in older women.
Cholesterol levels in your blood can be predictors of cardiovascular risk. Specifically, high levels of low-density lipoprotein (LDL) cholesterol, high levels of triglycerides (TG), and low levels of high-density lipoprotein (HDL) cholesterol may increase your risk of cardiovascular disease.
Vitamin D may play a role in cardiovascular health in a variety of different ways, such as helping to regulate blood pressure and reduce inflammation. As for cholesterol, research on vitamin D’s effect on cholesterol levels have been scarce and inconsistent.
Recently researchers, publishing their results in the journal Menopause, looked at how vitamin D and calcium supplementation might effect LDL, TG, and HDL levels using data from the Women’s Health Initiative. The Women’s Health Initiative was a large randomized controlled trial that examined the effects of 400 IU/day of vitamin D and 1,000 mg/day of calcium supplementation on a variety of health markers among women aged 50 to 79 years old.
For the current study, the research team analyzed data of 576 women, 291 of which received the vitamin D and calcium and 285 of which received a placebo. The researchers looked at vitamin D levels and measurements of the lipid markers both before and after 2 years of supplementation.
Here’s what the researchers found:
- In the vitamin D and calcium group, vitamin D levels increased from an average 20.1 ng/ml to 24.3 ng/ml.
- Compared to the placebo group, the women in the vitamin D and calcium group saw a decrease of 4.46 mg/dL in LDL levels.
- In the vitamin D and calcium group, a 38% increase in vitamin D levels led to a 1.28 mg/dL decrease in LDL levels.
- Higher vitamin D levels were associated with higher HDL levels and lower TG levels. The lower TG levels were only observed once the women had reached a vitamin D level above 15 ng/ml.
The researchers concluded,
“Oral [vitamin D and calcium] (1,000 mg of elemental calcium combined with 400 IU of vitamin D3 daily) results in a significantly increased concentration of 25(OH)D3 and decreased LDL-C levels. We also demonstrated that higher serum concentrations of 25(OH)D3 are significantly associated with improvement in all three lipid parameters tested (HDL-C, LDL-C, and TG).”
During the Women’s Health Initiative, the women were allowed to take their own vitamin D supplements in addition to the 400 IU, meaning that we cannot know for sure the exact dose that caused these effects. Additionally, the researchers state that their small study population may limit their results.
These results suggest a possible role for vitamin D in cholesterol. Future trials should look at larger, controlled doses of vitamin D to see if it leads to a greater effect. We have had a few trials now that are either small populations, for small lengths of time or using small doses, which may explain previous inconsistent research.
Schnatz, P. F. et al. Calcium/vitamin D supplementation, serum 25-hydroxyvitamin D concentrations, and cholesterol profiles in the Women’s Health Initiative calcium/vitamin D randomized trial. Menopause: The Journal of The North American Menopause Society, 2014.