The base trial and the secondary analysis were both the work of a group of researchers based in Australia and New Zealand. The research was published recently in the journal Prostaglandins, Leukotrienes and Essential Fatty Acids.
Result found in data from insulin resistance trial
The researchers analyzed data from a trial that was aimed at seeing if a high DHA fish oil supplementation regimen for 12 weeks could lower insulin resistance. That trial, which was published in August in teh same journal, found that the supplement reduced insulin resistance in the 36-person treatment arm of the study. The study cohort ranged in age from about 38 years told to about 63 years old and ranged from moderately overweight to significantly obese. In this larger study the researchers did not observe any sex dependent effects.
When combing through the data and looking just at the men, though, the researchers did notice an effect. The fish oil intervention significantly raised testosterone levels in the treatment group as opposed to placebo.
The test material was a fish oil supplement supplied by Norwegian omega-3s firm Epax. It contained 430 mg of DHA and 60 mg of EPA per gram of fish oil. Epax has long been known for being able offer custom fish oil formulations with EPA and DHA concentrations ranging from 50 mg/g up to 800 mg/g. The researchers administered 2 grams of fish oil capsules as an intervention, so each subject received 860 of DHA and 120 of EPA every day for 12 weeks. The placebo was 2 grams of corn oil in capsules.
“In conclusion, compared to placebo, intervention with DHA-enriched fish oil was associated with an increase in testosterone concentrations in overweight and obese males. Changes to testosterone in males were closely associated with reductions in n-6PUFAs DGLA and AA in erythrocyte membranes,” the authors concluded.
The researchers noted that as a limitation that this was a secondary analysis. The original study was not specifically weighted in a statistical sense to look at the testosterone endpoint.
GOED: Result lines up with other research
Harry Rice, PhD, chief science officer of the Global Organization for EPA and DHA Omega-3s (GOED), said the result is an interesting one. And the fact that it corroborates other research bolsters confidence in the result.
“The results from this secondary analysis are intriguing, not just because there appears to be an effect of DHA-rich fish oil on levels of testosterone, but because of the potential to use DHA in the treatment of men with mild hypogonadism. In August, a review addressing the potential metabolic benefits of O-3s for hypogonadism was published in Nutrients and that review provides me additional confidence in the present results. At the very least, the present results should be considered hypothesis generating for the design of future research, which of course is needed,” he said.
Sources: Prostaglandins, Leukotrienes and Essential Fatty Acids
2020 Nov 12;163:102204. doi: 10.1016/j.plefa.2020.102204. Online ahead of print
Dietary supplementation with docosahexaenoic acid rich fish oil increases circulating levels of testosterone in overweight and obese men
Authors: Abbott KA, et al.
Prostaglandins, Leukotrienes and Essential Fatty Acids
2020 Aug;159:102154. doi: 10.1016/j.plefa.2020.102154. Epub 2020 Jun 13
DHA-enriched fish oil reduces insulin resistance in overweight and obese adults
Authors: Abbott KA