A very large 5-year trial of 26,000 by The North American Menopause Society (NAMS) is examining whether fish oil and vitamin D can effectively prevent cancer or cardiovascular disease. The VITamin D and OmegA-3 Trial (VITAL) shows promising signals for some outcomes:
Fish Oil - Omega-3 fatty acids
Small, but non-significant, reduction in cardiovascular
Significant reductions in heart attacks
Vitamin D
No reduction on cardiovascular or cancer
Statistically significant reduction in total cancer mortality for trial participants 2+ years