Daily ETA Intake Associated With Lower Psoriasis Risk

A close-up of bad psoriasis on a person’s arm
The relationship between daily dietary eicosatetraenoic acid (ETA) and psoriasis is investigated in a study of the general American population.

Daily dietary intake of eicosatetraenoic acid (ETA) may lower the risk for psoriasis in a dose-dependent manner, according to findings from a cross-sectional study published in Clinical, Cosmetic and Investigational Dermatology.

Investigators utilized data from the National Health and Nutrition Examination Survey (NHANES) 2003-2006 and 2009-2014, calculating daily dietary n3 polyunsaturated fatty acids (PUFA) amounts in participants’ diets based on 24-hour dietary recall interviews, conducted twice. Dietary n3 PUFAs included ETA, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) obtained from daily foods and not supplements.

Investigators defined psoriasis by participants’ responses to the question, “Have you ever been told by a doctor or other health care professional that you have psoriasis?” Multivariable logistic regression analysis, trend tests, subgroup analysis, and interaction tests were used to evaluate the associations of ETA, EPA, and DHA with psoriasis risk.

Of 15,733 participants included in the study, 414 had psoriasis and 15,319 were control participants. The mean age in the psoriasis group was 41.72 and 38.20 years in the control group (P <.001), and about 46% of both groups were men. Participants in the psoriasis group had a higher average BMI (P =.001) and were more likely to be veterans (P =.001) and smokers (P <.001) compared with the control group.

The average doses of daily dietary ETA, EPA and DHA for 95% percentile participants in the study were 0.16 g, 0.18 g and 0.30 g, respectively. The multivariate-adjusted model only showed a significant association between ETA and lowered psoriasis risk, not EPA or DHA. The odds ratio of psoriasis was 0.30 (95% CI, 0.12-0.88; P =.019) for ETA, 1.92 (95% CI, 0.78-4.74; P =.158) for EPA, and 1.28 (95% CI, 0.72-2.27; P =.408) for DHA.

Trend tests showed a dose-effect relationship between daily dietary ETA intake and psoriasis, with the risk for psoriasis decreasing linearly as the amount of daily ETA intake increased. This association was stable in different subgroup analyses.

The study was limited by obtaining data via dietary recall interviews and self-reported psoriasis diagnosis, which are not very accurate methods.

Based on their findings, the study authors recommended an ETA supplement for patients with psoriasis or predisposed to psoriasis. Since the daily doses of EPA and DHA in this study were “far below that in previous studies,” they suggested that “EPA and DHA may need higher doses or intravenous injections to reduce the risk and inflammation of psoriasis.”


Zhan J, Tang X, Wang F, Han J. Association between daily dietary eicosatetraenoic acid intake and the lower risk of psoriasis in American adults. Clin Cosmet Investig Dermatol. Published online October 23, 2021. doi:10.2147/CCID.S333288