For example, one recent review of 63 randomized, placebo-controlled clinical trials of dietary supplements in Western adults found that in 45 of them no benefits were found, 10 showed a trend toward harm and 2 showed a trend toward benefit, while 4 reported actual harm, and 2 both harms and benefits; only vitamin D and omega 3 fatty acids had strong enough benefits and lack of harm to suggest possible efficacy [ 3 ].
1
—
—