(HealthDay News) – Nearly 40% of adults in the United States take dietary supplements such as fish oil, and most report that they would not stop taking them even if they were shown to be ineffective, according to a research letter published online Nov. 19 in the Archives of Internal Medicine.

Robert J. Blendon, ScD, from the Harvard School of Public Health in Boston, and colleagues surveyed 1,579 adults in the United States by telephone regarding whether they take dietary supplements other than vitamins or minerals (such as echinacea, ginseng, probiotics, or amino acids), for what purposes, and why.

The researchers found that 37.8% reported taking dietary supplements. The most common was fish oil or other omega-3 supplements, taken by 23.9%. The most common reasons were “to feel better” (41%), “to improve overall energy levels” (40.8%), and “to boost immune system” (35.9%). Having access to supplements was reported as important in 82.3% of users. Only 25.4% of supplement users said that they would stop taking them if public health authorities said they were ineffective.

“Practicing physicians should be aware that substantial numbers of persons take supplements to treat potentially serious health conditions, and many of them may not share this information with their physicians,” Blendon and colleagues write.

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