Fatty acid composition of normal and atrophied heel fat pad.

Capillary gas-liquid chromatography was used to analyze the fatty acid composition of normal heel fat pads from subjects without systemic disease (N = 8) and atrophied heels from patients with diabetic peripheral neuropathy (N = 4), rheumatoid arthritis (N = 1), peripheral vascular disease (N = 1), and hereditary sensory neuropathy (N = 1). In the normal subjects, the fatty acid composition of subcutaneous abdominal fat was also obtained for comparison. Three saturated fatty acids (myristate, palmitate, and stearate) and four unsaturated fatty acids (palmitoleate, oleate, vaccenate, and linoleate) comprised over 90% of the total fatty acid composition. Higher percentages of unsaturated fatty acids and lower percentages of saturated fatty acids were found in the normal heel fat pads when compared to subcutaneous abdominal fat. The increase in the ratio of unsaturated fatty acids to saturated fatty acids (4.4 versus 2.5, P < .01) may decrease triglyceride viscosity and enhance the biomechanical efficiency of the heel fat pad. Though the number of patients is small, no statistically significant compositional differences were noted between the heel fat from normal subjects and from subjects with peripheral neuropathies, rheumatoid arthritis, or peripheral vascular disease. However, the heel fatty acid composition of the one subject with a hereditary sensory neuropathy was less unsaturated and more saturated than normal with a ratio of unsaturates to saturates similar to that of the abdomen (2.8).