Vitamin D3 and Omega-3 supplementation fails to improve cardiac function: VITAL trial

United states: A study published in the Journal of the American Heart Association, JAHA, has concluded that in adults aged ≥50 years, there is no significant effect of vitamin D3 and Omega-3 fatty acids supplementation on cardiac structure and function after two years.

Activated vitamin exerts antihypertrophic effects directly and causes regression of LV hypertrophy with improvement in systolic and diastolic LV function, as mentioned in animal studies. Human data remain limited, and no larger trials have been performed. So this study examined the effect of vitamin D supplementation and whether it can improve cardiac structure and function or not in a large randomized trial. A team of researchers conducted the study, and the lead researcher was Dr. Alvin Chandra from the Department of Internal Medicine at UT Southwestern Medical Centre.

The VITAL (Vitamin D and OmegA‐3 Trial), a nationwide trial, evaluated the results of vitamin D3 and n−3 fatty acids on cardiovascular and cancer risk. The present study was a substudy of VITAL.

The key points of the study are:

• Change in LV mass was the primary endpoint detected in the study.

• A total of 1025 participants were enrolled in this study.

• The median age was 64 years, including 52 % of men.

• 43% of participants had a history of hypertension.

• The participants underwent echocardiography at baseline and two years.

• The Median 25‐hydroxyvitamin D level at baseline was 28.0 ng/mL.

• 79 % of participants (395 in treatment, 411 in placebo) returned for follow‐up, and their echocardiograms were analyzed.

• The two echocardiograms had a median interval of 734 days.

• No significant changes in interventricular septal thickness and posterior and relative wall thickness were recorded in the study.

• A smaller increase in LV end‐diastolic diameter was reported in participants randomized to vitamin D compared with placebo (P=0.035).

• 25‐hydroxyvitamin D level measured in the Vitamin D and placebo group was 39.0 ng/mL vs. 29.0 ng/mL.

• A slight difference in body mass index, 26.0 kg/m2 versus 27.0 kg/m2, was reported.

• There was no significant difference in LV mass change between t vitamin D and placebo arms after two years. (P=0.32).

• There was no significant difference between changes in systolic and diastolic LV function.

• No changes in cardiac structure and function were recorded between the n−3 fatty acids and placebo arms.

The research explained the background of the study "Vitamin D supplementation had been tied to regression of left ventricular (LV) hypertrophy in animal models, and it also improves LV function. Human studies are scarce in this context, so we examined whether vitamin D supplementation can improve cardiac structure and function in a large randomized trial in midlife/older individuals aged ≥50 years."

The study showed that the supplementation of vitamin D3 or n−3 fatty acids in adults aged ≥50 years without a history of cardiovascular disease has no effects, after two years, on cardiac structure and function.

The researchers explained that regular vitamin D3 or n−3 fatty acid supplementation is not an indication for preventing adverse cardiac remodeling, as described in the study.

They wrote "We determined the vitamin D3 dose (2000 IU/d) based on data from observational studies, while the n−3 fatty acids dosage (1 g/d) was based on AHA guidelines. Our findings do not support vitamin D3 or n−3 fatty acids supplementation in preventing LVH or other abnormalities for cardiac structure and function ."

The researcher mentioned the strengths of their study as the large sample size, the higher retention rate, the high mean rate of medication adherence, and the imaging protocol.

They highlighted, "Our findings are consistent with the ancillary study of VITAL, VITAL‐HF (Vitamin D and Omega‐3 Trial‐Heart Failure), according to which vitamin D or omega‐3 fatty acids supplementation does not significantly reduce the rate of first heart failure hospitalization." They wrote, "Our study echoes the results from the main VITAL study."

Further reading:

Impact of Vitamin D3 Versus Placebo on Cardiac Structure and Function: A Randomized Clinical Trial. Alvin Chandra et al.Journal of the American Heart Association. 2022;11:e025008