Adipose tissue fatty acids and size and number of fat cells from birth to 9 years of age—A cross-sectional study in 96 boys

We studied interrelations between the size and number of fat cells and the composition of fatty acids in 96 boys from birth to 9 years of age. The size of fat cells increased during the first months of life and decreased over the second 6 months, in parallel with the tissue fat concentration and the skinfold thickness of subcutaneous fat. From the end of the first year of life, the size of the fat cell increased slowly. The number of fat cells did not begin to increase until the end of the first year of life, maintaining a continuous increase until 9 years of age. During the first years of life, important changes occurred in the concentration of adipose tissue fatty acids. Palmitic acid had the greatest concentration in adipose tissue at the moment of birth and then decreased, becoming stabilized from the age of 2 or 3 years. The concentrations of lauric, myristic, and myristoleic acids followed a course similar to that of adipocyte growth, probably reflecting changes in the accumulation of fat by the adipocyte. At the moment of birth, the concentrations of linoleic acid (C18:2), an essential fatty acid not synthesized by the organism, were low, increasing from the very first months of life. This increase correlated with the increase in fat cell size and number. These interrelations between the size and number of fat cells and the composition of adipose tissue fatty acids suggest the important role dietary fat can play in the childhood endowment of adipocytes.