Evidence for an interaction between linoleic acid intake and skin barrier properties in healthy dogs - a pilot study

Dogs suffer from skin associated issues with a disproportionate frequency, with consequent interest in providing nutrition to optimize their skin's natural defences. Linoleic acid (LA) is known as an essential nutrient in dogs and plays a critical part in the lipid component of skin barrier formation. Minimum requirements have been defined, primarily based on eliminating signs of deficiencies such as dry, flaky skin and inflammation. Zn has been shown as an important nutrient for maintaining epidermal health. This pilot study investigated whether there are skin barrier benefits from feeding both linoleic acid and Zn at levels significantly in excess of published minimum requirements. Eight Labrador retrievers were fed a diet containing 3.8 g/Mcal LA, 21 mg/Mcal Zn for 12 weeks to establish baseline conditions for all dogs (basal diet). After this period, for a further 12 weeks, the dogs were switched onto a diet containing 7.9 g/Mcal LA and 50 mg/Mcal Zn (test diet). Transepidermal water loss (TEWL measurements) were used as a measure of skin quality and integrity and were taken at the end of the initial feeding period, and at 6 and 12 weeks of the test feeding period. TEWL was reduced by 8.11 g/m2/h (P < 0.001) six weeks after instigation of the test diet, and by 7.52 g/m2/h (P < 0.005) at 12 weeks, compared to the levels (14.73 g/m2/h) at the end of the basal feeding trial period. The results showed evidence of improved barrier properties as TEWL when feeding higher levels of LA and Zn for six and 12 weeks.