Correlation between essential fatty acids and parameters of bone formation and degradation

There are two types of essential fatty acids (EFAs), the n-6 derived from linoleic acid (LA) and the n-3, derived from alpha-linolenic acid (ALA). Most of the functions of the EFAs require the conversion of LA and ALA to their metabolites including, gammalinolenic (GLA), dihomogammalinolenic (DGLA), arachidonic (AA) (n-6) and eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids (n-3). Supplementing specific GLA:EPA ratios has effects on bone formation and degradation. A study was designed to investigate the effect of various dietary ratios of n-6:n-3 on calcium homeostasis. Female Sprague Dawley rats were ovariectomised (OVX) at age =11 weeks, and were supplemented from age 12 weeks for six weeks with different ratios (9:1; 3:1; 1:3; 1:9) of GLA:EPA. Bone parameters and red blood cell (RBC) fatty acid profiles were measured at age=18 weeks. RBC GLA and DGLA increased in groups 9:1 and 3:1(p<0.05). EPA and DGLA increased in 1:3 and 1:9 while AA decreased (p<0.05). Correlations were calculated between bone calcium, deoxypyridinoline (Dpyd) and specific fatty acids. DGLA was positively correlated with femur calcium and negatively with Dpyd excretion while DHA and EPA were correlated with femur calcium.