Many people routinely take nutritional supplements such as vitamin D and fish oil to avoid major killers such as cancer and heart disease.
But the record about the possible benefits of the supplement was mixed.
Current government-sponsored research provides the most convincing evidence for the use of supplements. And the results published in the two papers are mostly disappointing.
Dr. Lawrence Fine, director of clinical application and prevention at the National Heart, Lung, and Blood Institute, part of the National Institutes of Health, said: "Both clinical trials were negative.
"Overall, fish oil or vitamin D did not really lower heart disease or cancer rates," Fine says.
The results were published at the American Heart Association Scientific Sessions in Chicago and published online at the New England Journal of Medicine. Paper focused on vitamin D supplementation and paper focused on fish oil.
The study involved 26,000 healthy adults aged 50 or older who had no history of cancer or heart disease participating in the Vital research project. 20% of the participants were African-American.
Some of the participants consumed 1 gram of fish oil containing omega-3 fatty acids and 2,000 units of vitamin D daily. Others consumed the same dose of vitamin D and placebo, while others consumed the same amount of fish oil and placebo. The last group took two placebo. For more than five years, researchers have found no overall benefit.
Although the overall outcome is disappointing, it seems to be beneficial to heart attack, which is one aspect of heart disease and fish oil.
Secondary analysis showed that taking fish oil reduced the risk of heart attack by 28%. This is a "statistically significant outcome," says Dr. JoAnn Manson, director of preventive medicine at the Boston Brigham Women's Hospital. She led the study.
The people most likely to benefit were those who did not consume a lot of food on a daily basis and African Americans.
In this study, African Americans had a 77% lower risk of heart attack compared with placebo, "a dramatic decline," Manson says. More research is needed to confirm this study, but it has been reasonable for African Americans to talk with healthcare providers about whether they are candidates for taking fish oil supplements.
In an article in the New England Journal of Medicine, author John F. Keaney and Dr. Clifford J. Rosen pointed out that some analysis of the study A person who raises heart attacks and does not eat a lot of fish as a positive result for African Americans should be interpreted with caution.
There were no serious side effects such as bleeding, hypertension, and gastrointestinal symptoms.
Manson and her colleagues plan to further analyze their data and find possible links between vitamin D and fish oil and cognitive function, autoimmune diseases, respiratory infections and depression. Previous studies suggest that supplements may help in this condition.
Meanwhile, NIH official Lawrence Fine tells us not to discard fish oil and vitamin D.
"If either omega-3 or vitamin D is currently being considered for supplementation, then talking to your doctor or health care provider is the next step," Fine says.
Fine and Manson emphasized that vitamin D and omega-3 fatty acids found in fish oil are important nutrients, but emphasized that the best way to achieve this is as part of a balanced diet. It also includes eating fish with fats such as sardines, tuna, salmon and vitamin D fortified cereal, milk and orange juice.
Another study published at the same meeting investigated whether substances derived from ingredients of fish oil, known as icosapent ethyl, could already reduce adverse events among people with cardiovascular risk factors such as atherosclerosis, diabetes or known hyperlipemia As triglycerides.
Overall, the study found a 25% reduction in risk for patients taking the extract. These patients were less likely to be hospitalized for heart disease, death, heart attack or stroke, or surgery for chest pain, angioplasty, stenting, or bypass surgery.
"We have reported a significant reduction in risk," says Dr. Deepak Bhatt, a research associate and a cardiologist at Brigham and Women's Hospital.
The study was also a randomized clinical trial and traced participants for an average of 5 years. Volunteers brought the icosapent ethyl sold under the brand name Bascepa and was developed by Amarin Corporation to support Bhatt's research.
This product can only be prescribed to patients with high triglycerides. However, the company is expected to apply for FDA approval within the next year to expand treatment to include all high-risk cardiovascular patients. [Copyright 2018 NPR]