Study: Taking Higher Doses of Vitamin D Does Not Affect Cancer, CVD Risk

Taking a higher dose of vitamin D than recommended for 5 years does not affect total mortality or the incidence of cancer or cardiovascular disease (CVD) in older men and women, results of a study by the University of Easter Finland show.

Low levels of vitamin D have been linked to an increased risk of many chronic diseases, as well as premature death. However, it cannot be directly deducted from observational studies whether the use of vitamin D supplementation reduces the risk of death or disease.

The Finnish Vitamin D Trial (FIND) was conducted at the University of Eastern Finland between 2021 and 2018 and aimed to examine the effects of a higher-than-recommended dose of vitamin D on the risk of developing diseases.

The FIND trial included 2495 individuals, men who were aged 60 years or older and women aged 65 years or older, who were randomized for 5 years to either the placebo group or the groups that received either 40 or 80 micrograms (1600 or 3200 IU, respectively) of vitamin D3 per day.

None of the individuals had cancer or CVD at the start of the trial and were allowed to use their own vitamin D supplement of up to 20 micrograms (800 IU) per day, which was the recommended intake for this age group at the time when the trial started.

Research forms used at the beginning of and during the trial to collect comprehensive information from the study participants on the incidence of and lifestyle, nutrition, and risk factors for the diseases.

The information on the incidence of diseases and on deaths was also obtained from national health registers, and about one-fifth of the randomly selected participants underwent more detailed examination and provided blood samples.

During the 5 years of the trial, 119 individuals developed CVD, 129 individuals received a cancer diagnosis, and 19 died.

There was no statistically significant difference in the number of events between each group. The vitamin D doses proved to be safe, as there were no differences in adverse reactions between the groups.

In the sub-sample examined, the mean blood vitamin D (calcidiol) concentration was 75 nmol/L (30 ng/mL) as baseline. After about 1 year, the mean calcidiol concentration was 100 nmol/L (40 ng/mL) in the group taking 40 micrograms of vitamin D per day and 120 nmol/L (48 ng/mL) in the group taking 80 micrograms per day.

There was no significant change in calcidiol concentrations in the placebo group. Just 9% of individuals had low vitamin D levels at baseline, which is less than 50 nmol/L (20 ng/mL).

The findings of the trial were also well in line with similar studies’ results that showed that taking a higher dose of vitamin D than recommended for many years does not have a significant effect on the risk of developing CVD or cancer if the body’s vitamin D status is already adequate.

The study results do not support the use of large vitamin D doses for the prevention of cancer or CVD but do support seeking the recommended intake.

In addition to these findings, investigators will provide reports on the other effects of vitamin D supplementation on falls and fractures, infections, mood changes, pain conditions, type 2 diabetes, and other outcomes.

Reference

Taking high-dose vitamin D supplements for five years did not affect the incidence of cardiovascular disease or cancer. EurekAlert. News release. January 5, 2022. Accessed January 6, 2022. https://www.eurekalert.org/news-releases/939321