Vanke School of Public Health, Tsinghua University
Objectives: High-fat diet was considered a risk factor for male pattern hair loss (MPHL). However, n-3 fatty acids (FAs) were demonstrated to have anti-oxidative stress and anti-inflammatory effects, which might potentially improve hair loss. On the contrary, the animal model indicated a contradictory result that n-3 can induce MPHL in mice. To our knowledge, there is no population-based study to explore the association of diet n-3 or n-6 intake with hair loss.
Methods: We included 15,813 men from UK Biobank, aged 40–70 y, and established a logistic regression model to examine the association of MPHL improvement during the initial visit and second repeat assessment of MPHL with diet n-3 and n-6. We calculated baseline and average n-3 FAs, n-6 FAs and n-3/n-6 intake based on 24-hour dietary recall and divided them into quartiles. MPHL status was assessed by self-reported visual extent of baldness, and classified into four patterns based on four pictograms with severity increasing from 1 to 4. MPHL improvement means the bald pattern in the second visit is lower than the first. We adjusted the model for demographic, behavioral, mental and genetic factors and intakes of energy and total fat. Moreover, restricted cubic spline regression (RCS) was also applied. Stratified analysis was further conducted by rs6152 genotype, which is highly indicative of the ability to develop MPHL.
Results: There were 14,791 men who did not improve and 1,022 men who improved during follow-up. Fully adjusted logistic regression analysis revealed that the middle quartile (Q2, Q3) of baseline n-3 intake had higher non-improvement risk (OR=1.2, 95%CI:1.00,1.44; OR=1.32, 95%CI:1.07,1.61) than the lowest quartile (Q1). The results of the average n-3 intake were similar. The baseline Q3 of n-3/n6 had an OR of 1.26 (95%CI:1.05,1.51) compared to Q1, but no significant association was found for n-6. The RCS analysis showed an inverted U-shaped curve. Stratified analysis by rs6152 genotypes showed a similar trend.
Conclusions: Our population-based study first revealed that n-3 fatty acids may be not beneficial for improving hair loss in middle-aged or elderly men and suggest a potentially harmful effect. As a condition that significantly impacts physical and emotional health, the role and mechanism of n-3 in MPHL needs further exploration.
