Lowered omega 3 polyunsaturated fatty acids in serum phospholipids and cholesteryl esters of depressed patients

Depression is associated with a lowered degree of esterification of serum c holesterol, an increased C20:4 omega 6/C20:5 omega 3 ratio and decreases in omega 3 fractions in fatty acids (FAs) or in the red blood cell membrane. The aims of the present study were to examine: (i) serum phospholipid and c holesteryl ester compositions of individual saturated fatty acids (SFAs), m onounsaturated FAs (MUFAs) and polyunsaturated FAs (PUFAs) in major depress ed patients vs. healthy volunteers; (ii) the relationships between the abov e FAs and lowered serum zinc (Zn), a marker of the inflammatory response in depression; and (iii) the effects of subchronic treatment with antidepress ants on FAs in depression. The composition of the FAs was determined by mea ns of thin layer chromatography in conjunction with gas chromatography. Lip id concentrations were assayed by enzymatic colorimetric methods. The oxida tive potential index (OPI) of FAs was computed in 34 major depressed inpati ents and 14 normal volunteers. Major depression was associated with: increa sed MUFA and C22:5 omega 3 proportions and increased C20:4 omega 6/C20:5 om ega 3 and C22:5 omega 6/C22:6 omega 3 ratios; lower C22:4 omega 6, C20:5 om ega 3 and C22:5 omega 3 fractions in phospholipids; lower C18:3 omega 3, C2 0:5 omega 3 and total (Sigma)omega 3 FAs, and higher C20:4 omega 6/C20:5 om ega 3 and Sigma omega 6/Sigma omega 3 ratios in cholesteryl esters; lower s erum concentrations of phospholipids and cholesteryl esters; and a decrease d OPI. In depression, there were significant and positive correlations betw een serum Zn and C20:5 omega 3 and C22:6 omega 3 fractions in phospholipids ; and significant inverse correlations between serum Zn and the Sigma omega 6/Sigma omega 3, C20:4 omega 6/C20:5 omega 3, and C22:5 omega 6/C22:6 omeg a 3 ratios in phospholipids. There was no significant effect of antidepress ive treatment on any of the FAs. The results show that, in major depression , there is a deficiency of omega 3 PUFAs and a compensatory increase in MUF As and C22:5 omega 6 in phospholipids. The results suggest that: (i) there is an abnormal metabolism of omega 3 PUFAs in depression; (ii) the FA alter ations in depression are related to the inflammatory response in that illne ss; and (iii) the disorders may persist despite successful antidepressant t reatment. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.