Fish oil (omega-3 PUFA) preparations are today extremely popular and amongst the best-researched dietary supplement. During the 1970s, two Danish scientists, Bang and Dyerberg, remarked that Greenland Eskimos had a baffling lower prevalence of coronary artery disease than mainland Danes. They also noted that their diet contained large amounts of seal and whale blubber and suggested that this ‘Eskimo-diet’ was a key factor in the lower prevalence. Subsequently, a flurry of research stared to investigate the phenomenon, and it was shown that the ‘Eskimo-diet’ contained unusually high concentrations of omega-3 polyunsaturated fatty acids from fish oils (seals and whales feed predominantly on fish).
Initial research also demonstrated that the regular consumption of fish oil has a multitude of cardiovascular and anti-inflammatory effects. This led to the promotion of fish oil supplements for a wide range of conditions. Meanwhile, many of these encouraging findings have been overturned by more rigorous studies, and the enthusiasm for fish oil supplements has somewhat waned. But now, a new paper has come out with surprising findings.
The objective of this meta-analysis was to evaluate the association of anxiety symptoms with omega-3 PUFA treatment compared with controls in varied populations.
A search was performed of clinical trials assessing the anxiolytic effect of omega-3 PUFAs in humans, in either placebo-controlled or non–placebo-controlled designs. Of 104 selected articles, 19 entered the final data extraction stage. Two authors independently extracted the data according to a predetermined list of interests. A random-effects model meta-analysis was performed. Changes in the severity of anxiety symptoms after omega-3 PUFA treatment served as the main endpoint.
In total, 1203 participants with omega-3 PUFA treatment and 1037 participants without omega-3 PUFA treatment showed an association between clinical anxiety symptoms among participants with omega-3 PUFA treatment compared with control arms. Subgroup analysis showed that the association of treatment with reduced anxiety symptoms was significantly greater in subgroups with specific clinical diagnoses than in subgroups without clinical conditions. The anxiolytic effect of omega-3 PUFAs was significantly better than that of controls only in subgroups with a higher dosage (at least 2000 mg/d) and not in subgroups with a lower dosage (<2000 mg/d).
The authors concluded that this review indicates that omega-3 PUFAs might help to reduce the symptoms of clinical anxiety. Further well-designed studies are needed in populations in whom anxiety is the main symptom.
I think this is a fine meta-analysis reporting clear results. I doubt that this paper truly falls under the umbrella of alternative medicine, but fish oil is a popular food supplement and should be mentioned on this blog. Of course, the average effect size is modest, but the findings are nevertheless intriguing.