Hypersensitivity to dietary fatty acids in women with restrictive anorexia nervosa: A pilot psychophysical study across chain length and saturation.

Individuals with anorexia nervosa (AN) consistently show lower fat intake and preference than healthy controls. Whether this avoidance is accompanied by altered orogustatory detection of dietary fatty acids (FAs) across chemical classes is unknown. In this pilot study, we measured psychophysical detection thresholds for lauric (C12:0, saturated), oleic (C18:1, monounsaturated), and linoleic (C18:2, polyunsaturated) acids in 50 healthy controls (76% female) and seven women with restrictive AN (rAN) using a forced choice ascending procedure (0.001-100 mM). rAN participants were reassessed at days 66 and 99 of treatment. We replicated the bimodal distribution of linoleic acid thresholds in controls (Hartigan's D= 0.102, p < .001), with a 53% taster proportion consistent with prior work. Women with rAN detected all three FAs at substantially lower concentrations than female controls (all pFDR ≤ .019; rank-biserial r range -.534 to -.835), with no detectable FA-type-specific modulation. Treatment effects could not be reliably estimated due to attrition. Although the small clinical sample limits mechanistic inference, the absence of FA-type specificity is compatible with, but does not establish, generalised orogustatory sensitisation, which may represent a clinically relevant dimension of fat aversion in rAN.