Good news for sun worshippers and anyone concerned about their blood pressure: a powerful new genetic analysis has found a causal link between higher vitamin D levels and lower blood pressure.

Many previous studies have reported an “association” between vitamin D deficiency and high blood pressure, but it is much more difficult to show that low vitamin D “causes” high blood pressure in large groups of people. Although this has already been proven in animal experiments, human clinical studies are riddled with inconsistencies and variability—one major limitation is that they usually measure vitamin D levels directly from blood samples, and these measurements are sensitive to factors like lifestyle and time of year. But an international team of researchers believes that they have overcome this problem by looking at differences in our genetic code—called variants—that can cause slight changes in the performance of the proteins they produce.

Just as your apple pie recipe might call for more sugar, and turn out sweeter than mine, your genetic recipe for certain proteins might cause you to naturally have more vitamin D. The researchers developed a method to estimate a person’s tendency for higher vitamin D levels based on their genetic sequences, and then analyzed genetic data and blood pressure levels from over 100,000 people on three continents. They found a strong association between higher estimated vitamin D and decreased risk of hypertension and, more importantly, they’ve provided evidence of a clear cause-and-effect relationship. Vitamin D deficiency (like high blood pressure) is all too common in developed nations. While sunshine is the best source of vitamin D, special lamps and dietary supplements can also provide it.

(Source: Lancet Diabetes & Endocrinology, Early Online Publication, 26 June 2014, doi:10.1016/S2213-8587(14)70113-5[link].)