High blood pressure often affects older and obese people; vitamin D supplements may help lower it.

A new study has found that taking 600 international units (IU) of vitamin D per day—the amount typically recommended for adults—lowers blood pressure in older adults, especially those who are obese.

Experts caution that exceeding the recommended intake, even below the safe upper limit (UL), does not necessarily translate to additional benefits.

Supplementation Reduced Blood Pressure

The study, published Tuesday in the Journal of the Endocrine Society, involved 221 older obese adults who received vitamin D supplements at either 600 IU per day or 3,750 IU per day over one year. Currently, the Institute of Medicine (IOM) recommends a daily intake of 600 IU.

Partcipants’ overall systolic blood pressure decreased by 3.5 mm Hg after one year, and diastolic blood pressure decreased by 2.5 mm Hg after one year.

Those who took higher doses of 3,750 IU daily had a slightly higher decrease of 4.2 mm Hg for systolic blood pressure. In comparison, those who took the lower 600 IU per day generally reported a reduction of 2.8 mm Hg after one year.

The authors concluded that the differences between the high- and low-dose vitamin D groups were not statistically significant.

People with a higher body mass index (BMI) of over 30 saw more significant reductions in blood pressure, especially in the high-dose group. People who took blood pressure medication with their vitamin D also observed substantial decreases in their overall blood pressure.

All participants also received daily supplements that included 1,000 milligrams of calcium.

No Significant Benefits From Higher Doses

The study’s findings showed that regular supplementation resulted in a decrease in blood pressure among participants. However, a comparison of the two dosage groups found that higher dosages of vitamin D did not provide further health benefits.

“More vitamin D is not better in terms of blood pressure,” study author Dr. Ghada El-Hajj Fuleihan from the American University of Beirut Medical Center told The Epoch Times in an email. “Indeed, 3,750 IU/day does not lower blood pressure more than 600 IU/day, which is the Institute of Medicine recommended dose.”

These results “need to be validated in a trial with blood pressure as the primary outcome,” she added.

The research team considered the UL for vitamin D intake established by the IOM (4,000 IU daily) when selecting doses for participants. “3,750 IU/day is below the IOM UL, and was specifically selected to be so,” Fuleihan wrote.

The higher dose is unlikely to cause harmful health effects, she added. “None of our patients had signs or symptoms of vitamin D intoxication,” she noted. Symptoms of vitamin D intoxication include nausea, vomiting, and kidney stones.

Fuleihan emphasized that the decision to supplement vitamin D should ultimately be made in consultation with a patient’s primary health care provider.