11/15/2025
Important research specifying “optimal” blood levels for vitamin D3 supplementation to lower heart disease risk- greater than 40-80 ng/ml (which for most participants meant taking 5000 IU or more daily). This closely follows my recommendations (50-80 ng/ml) for patients, which can also lower the risk of MS and breast cancer. I start patients at 5000 IU in the winter and check after a month or so to make sure they are achieving an optimal level. Be aware that some local labs use 50 ng/ml as an upper limit of the reference range. This is insufficient and an old reference range. Current reference ranges have an upper limit of 80 to 100. We use Quest, which has the updated ranges. So if your doctor tells you you’re getting too much vitamin D because your levels are over 50, please share this research with them. If you’re an adult in Maine and you’re not supplementing vitamin D3, I guarantee you are at a suboptimal level. Of the thousands of vitamin D tests I have run on patients, I find the only individuals who have optimal levels who are not taking supplements are the children in the summertime. Get your D3 tested!
Research Highlights: Adults with heart disease prescribed vitamin D in doses tailored to reach blood levels considered optimal for heart health (>40-80 ng/mL) had a reduced risk of heart attack by more than half (52%) compared to those who did not...