According to the analysis, vitamin D supplements successfully cut the risk of death from cancer, while supplementation with omega-3 fatty acids significantly reduced the odds of heart attacks.
As it turns out, these results back up the findings of an earlier study published in the New England Journal of Medicine (NEJM).
The NEJM study, which followed nearly 26,000 individuals for about five years, found that vitamin D supplementation successfully reduced cancer-related deaths by 25 percent, while omega-3 fatty acids in the form of fish oil supplements decreased the occurrence of heart attacks by up to 28 percent. (Related: More than just brain food: High DHA fish oils found to boost your immunity.)
“It does appear that these dietary supplements have benefits: for vitamin D, reducing cancer deaths; and for omega-3s, reducing heart attacks,” lead author JoAnn Manson said.
As detailed in the NEJM, Manson and her colleagues had one surprising finding: fish oil supplementation was more beneficial to people who did not regularly eat fish. The researchers noted a 19 percent reduction in major cardiovascular events and a 40 percent reduction in heart attacks in the said group.
“We found it surprising with the omega-3s that there was such a strong signal for heart attack reduction, and the results varied so much with fish consumption,” Manson said, adding that people who ate two servings of fish per week will not likely see any benefit from omega-3 supplementation.
Because of this, Manson said, additional research must be undertaken to determine the individuals who would benefit the most from supplementation with either vitamin D or omega-3 fatty acids, as well as the two supplements’ potential risks toward different subgroups of people.
One such subgroup was African-Americans, whom Manson described as having the most dramatic results in lowering heart attack risk after taking omega-3 supplements.
According to Manson, they had a 77 percent lower incidence of heart attack than the control group of individuals not taking any supplements.
However, Manson notes that more research is needed, adding that if other studies can show that African Americans can indeed benefit from omega-3 supplements, this approach may be a potential way to help reduce heart attacks in this population.
“It may be a way to reduce health disparities [in terms of this endpoint], as far as cardiovascular disease is concerned,” Manson said.
According to the Heart Foundation, African Americans experience high death rates due to heart disease compared with whites and other ethnic groups, with about 48 percent of African American women and 44 percent of African American men having some form of heart disease.
Despite its benefits, however, the National Cancer Institute warns that people should avoid excessive intake of vitamin D as it can increase the body’s calcium levels. This, the researchers said, can lead to conditions such as calcinosis or the development of calcium salt deposits in the kidneys, heart, and lungs and hypercalcemia or high blood levels of calcium
“In general vitamin D or fish oil is not too harmful,” Benjamin Hirsh, the director of preventive cardiology at Northwell Health's Sandra Atlas Bass Heart Hospital in Manhasset, New York, said, adding that omega-3 supplements may improve heart health, especially among African Americans.
“For African Americans who are healthy overall, increasing omega-3 supplement intake may be worthwhile and protective. There’s no harm and possibly some great benefit,” Hirsh said.
Hirsh noted that when talking about what steps to take to help reduce unwanted health outcomes, it is important to focus on the steps that have already been proved to make a big difference.
“Before people get hung up on taking supplements as a way to demonstrate that they are doing well, they really have to just focus on lifestyle improvements, such as exercising regularly and eating healthy. Otherwise, they’re missing the big picture,” Hirsh said.
Meanwhile, Manson and the rest of her research team expect to continue with a longer-term follow-up of their study population. According to Manson, doing so will allow them to look further into genetic factors and biomarkers that might predict health outcomes. This, Manson said, could enable them to identify individuals who are likely to benefit from supplements.
You can read more articles about how to keep your heart healthy at Heart.news.