Effects of diacylglycerol-enriched alpha-linolenic acid oil on skin properties in mild skin discomfort: a randomized, double-blind, placebo-controlled study

Skin barrier function impairment and inflammation promote allergen invasion through the skin, leading to sensitization and exacerbation of allergic diseases. Intake of linseed oil, an oil rich in alpha-linolenic acid (ALA), suppresses inflammation and allergic symptoms. To our knowledge, the effects of diacylglycerol-enriched ALA (ALA-DAG) oil intake on skin properties and allergic symptoms have not been evaluated. We performed a double-blind, randomized, placebo-controlled, parallel-group study of 60 individuals aged 20-59 years with mild skin discomfort, including dryness, itching, and redness, to investigate the effects of ALA-DAG intake on skin and allergic symptoms. Participants were divided into two groups treated with either 2.5 g/day of ALA-DAG or placebo oil for 8 weeks. The skin properties were measured at baseline and at 8 weeks. Allergic symptoms were measured at 4 and 8 weeks. Compared with placebo oil intake, ALA-DAG intake increased skin hydration in the cheek, reduced nasal congestion and nose itchiness, and decreased mite-specific immunoglobulin E in the blood. Subgroup analysis showed that participants who were positive for mite allergen sensitization had reduced facial redness after ingesting ALA-DAG. These findings suggest that ALA-DAG intake improves skin properties and alleviates allergic symptoms.