Fatty acid composition of subcutaneous adipose tissue and gastric mucosa: is there a relation with gastric ulceration?

BACKGROUND: Both in vitro and epidemiological studies indicate that dietary polyunsaturated fatty acids may play a protective role against peptic ulcer in humans. Adipose tissue fatty acid composition is thought to reflect dietary fatty acid intake. The aim of the present study is to investigate adipose and gastric mucosa fatty acid levels in relation to gastric ulceration status. METHODS: Fifty two adult outpatients undergoing upper gastrointestinal tract endoscopy participated in the study. Adipose tissue samples were taken from the abdomen and buttock during the endoscopy procedure and samples from gastric tissue were taken from a subsample of 30 subjects. The presence of Helicobacter pylori was determined using the CLO test. Capillary gas chromatography was used for the extraction of 36 and 42 adipose tissue and gastric mucosa lipids respectively. RESULTS: The monounsaturated fatty acids (MUFAs) C18:1n-12c, C16:1n-5, C16:4n-1 and the polyunsaturated fatty acids (PUFAs) C16:3n-4, C20:3n-3, C20:4n-6, C21:5n-3 and C18:2n-9c,12t of the gastric mucosa were present in higher proportions in ulcer negative patients. These unsaturated fatty acids, however, each contributed less than 1% on average to total fatty acid content. In addition, higher average levels of eicosapentaenoic acid (EPA) C20:5n-3 and docosahexaenoic acid (DHA) C22:6n-3 were detected in abdominal and buttock samples in CLO negative controls, compared to CLO positive controls. Adipose tissue and gastric mucosa n-6 and trans fatty acid levels were positively linearly correlated (r = 0.37 and 0.41 for n-6 and trans fatty acids respectively). CONCLUSION: Certain minor MUFAs and PUFAs of the gastric mucosa appear to be present in higher proportions in ulcer negative patients. Overall, the findings provide only weak evidence of an association between the gastric mucosal fatty acids and the presence of gastric ulceration. The higher average levels of EPA and DHA in abdominal and buttock adipose tissue in CLO negative controls could be an indicator that dietary FAs inhibit Helicobacter pylori growth. Larger studies are necessary to provide evidence of a biologically relevant effect.

Lack of an association of depression with n-3 polyunsaturated fatty acids in adipose tissue and serum phospholipids in healthy adults.

Studies have shown that depression relates to biomarkers of both short-term and long-term polyunsaturated fatty acid intake. However, it is not known which of these two biomarkers is more closely related to depression. The aim of this study was to examine the relationship of depression with both adipose tissue and serum phospholipid polyunsaturated fatty acids and to assess the importance of each of these two biomarkers in relating to depression. This is a cross-sectional study of healthy adults from the island of Crete. Subjects were examined by the Preventive Medicine and Nutrition Clinic of the University of Crete. Subjects were 394 healthy adults (175 males, 219 females) aged 18-60. The sample consisted of farmers from a number of rural communities of Crete. Fatty acids were determined by gas chromatography in adipose tissue and serum phospholipids. Information about depression was obtained through the Beck Depression Inventory (BDI) and Zung Self-rating Depression Scale (ZSRDS). Adipose tissue alpha-linolenic acid (ALA) (C18:3n-3) was inversely correlated to BDI (r=-0.17, p<0.02). Multiple linear regression analysis taking into account the possible confounding effect of age, gender, body mass index (BMI), smoking and educational level did not confirm this association. The other polyunsaturated fatty acids in adipose tissue were not related to depression. Serum phospholipid polyunsaturated fatty acids did not correlate with depression. This study did not show that the polyunsaturated fatty acids in the adipose tissue are better predictors of depression than those in serum phospholipids.

Depression and serum adiponectin and adipose omega-3 and omega-6 fatty acids in adolescents.

The purpose of the present study was to investigate for a possible relationship between depression and serum adiponectin and adipose tissue omega-3 and omega-6 PUFA. The sample consisted of 90 healthy adolescent volunteers from the island of Crete. There were 54 girls and 36 boys, aged 13 to 18. The mean age was 15.2 years. Subjects were examined by the Preventive Medicine and Nutrition Clinic of the University of Crete. Depression was assessed through the use of the Beck Depression Inventory (BDI) and the Center for Epidemiologic Studies Depression Scale (CES-D). Fatty acids were determined by gas chromatography in adipose tissue. CES-D correlated with dihomo-gamma linolenic acid (DGLA). Multiple linear regression analyses showed that BDI was negatively associated with eicosapentaenoic acid (EPA), while CES-D was positively associated with DGLA in adipose tissue. Serum adiponectin was not significantly associated with depression. The negative relationship between adipose EPA and depression in adolescents, is in line with findings of previous studies involving adult and elderly subjects, demonstrating negative relations between depression and adipose omega-3 PUFA. This is the first literature report of a relationship between depression and an individual omega-3 fatty acid in adolescents. The inverse relationship between adipose EPA and depression indicates that a low long-term dietary intake of EPA is associated with an increased risk for depression in adolescents.

Depression and adipose polyunsaturated fatty acids in an adolescent group.

The purpose of the present study was to investigate the relation between adipose tissue polyunsaturated fatty acids, an index of long-term or habitual fatty acid dietary intake and depression. The sample consisted of 90 adolescents from the island of Crete. There were 54 girls and 36 boys, aged 13-18. The mean age was 15.2 years. Subjects were examined by the Preventive Medicine and Nutrition Clinic of the University of Crete. Depression was assessed through the use of the Beck Depression Inventory (BDI) and the Center for Epidemiologic Studies Depression Scale (CES-D). Unlike other studies, there were no significant relations between adipose tissue n-3 or n-6 polyunsaturated fatty acids and depression. BDI correlated positively with adipose tissue C20:3n-6/C18:3n-6 ratio, while CES-D correlated positively with adipose tissue (C20:3n-6+C22:5n-3)/(C18:3n-6+C20:5n-3) ratio. Depressed subjects (BDI>16, CES-D>16) had significantly elevated adipose tissue C20:3n-6/C18:3n-6 and (C20:3n-6+C22:5n-3)/(C18:3n-6+C20:5n-3) ratios, than non-depressed subjects. The observed positive relation between depression and the particular fatty acid ratios, in the present study, appears to indicate increasing activity of elongases, the enzymes responsible for elongating polyunsaturated fatty acids into their longer-chain derivatives, with increasing depression. This is the first literature report of a possible relation between elongases and depression. The observed relation may stem from a possible over-expression of the HELO1 (ELOVL5) gene, the gene encoding a protein responsible for elongating long-chain polyunsaturated fatty acids, in the adipose tissue of depressed adolescents.

Depression and adipose polyunsaturated fatty acids in the survivors of the Seven Countries Study population of Crete.

The purpose of the present study was to investigate the relation between adipose tissue polyunsaturated fatty acids, an index of long-term or habitual fatty acid dietary intake and depression. The sample consisted of 150 elderly males from the island of Crete. The subjects were survivors of the Greek Seven Countries Study group. The mean age was 84 years. The number of subjects with complete data on all variables studied was 63. Subjects were examined by the Preventive Medicine and Nutrition Clinic of the University of Crete. Depression was assessed through the use of the short form of the Geriatric Depression Scale (GDS-15). Depression correlated negatively with adipose tissue alpha-linolenic acid (C18:3n-3). Depressed subjects had significantly reduced (-10.5%) adipose tissue C18:3n-3 levels than non-depressed subjects. The observed negative relation between adipose tissue C18:3n-3 and depression, in the present study, appears to indicate increasing long-term dietary C18:3n-3 intakes with decreasing depression. This agrees with findings of other studies indicating an inverse relation between depression and consumption of fish and n-3 polyunsaturated fatty acids. This is the first literature report of a relation between adipose tissue C18:3n-3 and depression. Furthermore, this is the first report of a relation between adipose PUFA and depression in an elderly sample. Depression has been reported to be associated with elevated cytokines, such as, IL-1, IL-2, IL-6, INF-gamma and INF-alpha. Fish oil and omega-3 fatty acids, on the other hand, have been reported to inhibit cytokine production. The observed negative relation between adipose C18:3n-3 and depression, therefore, may stem from the inhibiting effect of C18:3n-3 or its long-chain metabolites on cytokine synthesis.