According to the World Health Organization (WHO), cardiovascular disease is currently the leading cause of death around the world.
Past research shows there are several healthy lifestyle choices people can make to help lower their cardiovascular disease risk, such as following a heart-healthy diet.
When it comes to what we eat, previous studies have examined how certain vitamins and minerals — such as vitamin C, vitamin E, vitamin D, and B vitamins like vitamin B12 — might impact heart disease risk.
“Vitamins play essential roles in many processes that help maintain cardiovascular health, including the normal functioning of blood vessels and the regulation of certain metabolic pathways,” Ameer Awashra, MD, a medical doctor in the Department of Medicine at An-Najah National University in Nablus, Palestine, told Medical News Today.
“Studying these relationships is important because nutritional deficiencies are potentially preventable and treatable. However, we also need to understand whether correcting these deficiencies actually reduces the risk of heart attacks, strokes, and other cardiovascular complications,” Awashra noted.
He is the first author of a new review published in Nutrition Journal, which found that, while vitamin B12 may have certain effects on heart health, taking a supplement does not consistently prevent major cardiovascular events.
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However, researchers did find the strongest evidence of a potential clinical benefit of vitamin B12 supplementation in stroke prevention.
For this review, the researchers looked at past research involving vitamin B12 and cardiovascular health.
“We focused on vitamin B12 because of its essential role in homocysteine metabolism and other processes involved in maintaining vascular health,” Awashra said.
“Previous observational studies have linked low vitamin B12 levels with an increased risk of cardiovascular disease. However, clinical trials investigating vitamin B12-containing supplementation have not consistently demonstrated that correcting these abnormalities prevents cardiovascular events.”
– Ameer Awashra, MD
“This difference between what we observe in laboratory measurements and what we see in actual patient outcomes caught our attention,” he continued. “We wanted to examine the available evidence more closely, understand why these findings sometimes disagree, and identify which patients might benefit most from vitamin B12 assessment and supplementation.”
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The review concluded that, while vitamin B12 has several effects on heart health, taking it as a supplement didn’t always lead to widespread clinical benefits and didn’t consistently prevent major heart disease events.
“I believe this is one of the most important messages of our review: improving a laboratory measurement does not necessarily translate into better clinical outcomes,” Awashra explained. “For example, vitamin B12-containing supplementation can reduce homocysteine levels, which have been associated with cardiovascular risk.”
“However, large randomized trials have generally failed to demonstrate consistent reductions in heart attacks or cardiovascular deaths,” he cautioned. “This tells us that cardiovascular disease is complex and cannot necessarily be prevented by correcting a single nutritional or metabolic factor.”
“The practical implication is that vitamin B12 supplementation remains important for individuals with a confirmed deficiency, but current evidence does not support routinely taking additional vitamin B12 solely to prevent cardiovascular disease,” Awashra added.
Scientists did discover that the strongest clinical benefit of vitamin B12 supplement on cardiovascular health may be in stroke prevention.
“This finding suggests that the potential cardiovascular benefits of B-vitamin supplementation may depend on a person’s underlying nutritional status and the environment in which they live,” Awashra said.
“Studies have shown a more noticeable reduction in stroke risk in populations where folic acid fortification is not mandatory, possibly because individuals in these regions are more likely to have lower baseline folate levels,” he added.
“Importantly, most of these studies evaluated combinations of B vitamins, particularly folic acid, vitamin B12, and vitamin B6,” Awashra told us.
“Therefore,“ he continued, “we cannot conclude that vitamin B12 alone is responsible for the observed reduction in stroke risk. The significance is that nutritional interventions may be more effective when directed toward populations with specific nutritional needs rather than being recommended universally.”
MNT had the opportunity to speak with Cheng-Han Chen, MD, a board-certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, about this review.
Chen, who was not involved in this review, said it is not entirely clear why vitamin B12 supplementation might be associated with a lower risk of stroke, but not a lower risk of heart disease.
One possible explanation, he said, is that these conditions develop through different, although sometimes overlapping, biological mechanisms.
“Vitamin B12 helps regulate homocysteine, an amino acid that, at elevated levels, has been associated with vascular problems,” Chen explained.
“However, lowering homocysteine does not necessarily reduce the risk of all cardiovascular events equally. More research is needed to determine whether B12 has a meaningful protective effect against stroke in certain populations and why that effect may not extend to other forms of cardiovascular disease,” he pointed out.
MNT also spoke with Monique Richard, MS, RDN, a registered dietitian nutritionist and owner of Nutrition-In-Sight, who likewise was not involved in this review.
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Richard said these findings are a good reminder of why we need to look beyond associations and understand what the research actually tells us.
“Vitamin B12 is essential for neurological function, healthy red blood cell formation, DNA synthesis, and the metabolism of homocysteine, an amino acid associated with cardiovascular risk. It makes biological sense that B12 deficiency could have implications for vascular health, but that does not necessarily mean supplementing everyone will prevent heart disease.”
– Monique Richard, MS, RDN
However, “a supplement is only one part of the equation,” she pointed out. “We need to consider the person, the reason for supplementation, the form and dose, consistency of use, and whether the intervention addresses the underlying issue.“
“Correcting a deficiency is important, but we should not promise cardiovascular protection that clinical trials have not consistently demonstrated,” Richard advised.
