Dietary omega-3 fatty acids and depression in a community sample

To evaluate the association between omega-3 polyunsaturated essential fatty acids and depression, data regarding prevalence rates of self-reported depression and median daily dietary intakes of these fatty acids were obtained from an age-stratified, population-based sample of women (n = 755; 23-97 year) in the Barwon Statistical Division of south-eastern Australia. A self-report questionnaire based on Diagnostic and Statistical Manual-IV criteria was utilised to determine 12-month prevalence rates of depression in this sample, and data from biennial food frequency questionnaires examining seafood and fish oil consumption over a 6-year period were examined. Differences in median dietary intakes of omega-3 fatty acids between the depressed and nondepressed cohorts were analysed and results were adjusted for age, weight and smoking status. No significant differences in median intakes were identified between the two groups of women (median, interquartile range; depressed = 0.09g/day, 0.04-0.18 versus nondepressed = 0.11 g/day, 0.05-0.22, p = 0.3), although overall average intakes of omega-3 fatty acids were lower than recommended and rates of depression within this sample higher than expected, based on previous data. Further research that takes into account ratios of omega-6 to omega-3 polyunsaturated essential fatty acids, as well as other dietary sources of omega-3 fatty acids, is warranted.     

Dietary intake of long-chain omega-3 polyunsaturated fatty acids: contribution of meat sources

OBJECTIVE: We examined the relative contributions of meat and fish to the dietary intakes of long-chain omega-3 polyunsaturated fatty acids (LCn3PUFAs). METHODS: A database detailing 4550 foods and 4298 recipes recorded in the 1995 Australian National Nutrition Survey (NNS95) was updated with new fatty acid compositional data then used to determine intakes from 24-h dietary recalls of 13858 individuals. This approach was validated with food frequency questionnaires from 8321 of these individuals. RESULTS: Fatty acid intakes were comparable to our previous estimates from NNS95 except for LCn3PUFAs, which were considerably higher. Mean intakes in adults estimated from the 24-h recalls were 75, 71, and 100 mg/d for eicosapentaenoic acid, docosapentaenoic acid (DPA), and docosahexaenoic acid, respectively, giving a total of 246 mg/d. This is 30% greater than our previously published estimate of LCn3PUFA intake, the difference being attributable to inaccuracies in pre-existing data on the fatty acid composition of certain foods, particularly the DPA content of meats. We estimate that 43% of the LCn3PUFAs consumed by adults in the NNS95 survey originated from meat, poultry, and game compared with 48% from fish and seafood. Steak and kidney pies and other meat-containing cereal-based products accounted for an additional 4%. Beef and lamb contributed 28% of the total LCn3PUFA intake, whereas pork and poultry contributed 4% and 10%, respectively. Food frequency questionnaires produced similar results. CONCLUSION: Meat is a major source of LCn3PUFA, particularly DPA, for most Australians. When DPA is included in the definition of LCn3PUFAs, almost half the average adult intake of LCn3PUFA appears to originate from meat sources.     

Dietary fatty acids and the aging brain

Aging contributes to physiological decline and vulnerability to disease. In the brain, even with minimal neuronal loss, aging increases oxidative damage, inflammation, demyelination, impaired processing, and metabolic deficits, particularly during pathological brain aging. In this review, the possible role of docosahexaenoic acid (DHA) in the prevention of age-related disruption of brain function is discussed. High-fat diabetogenic diets, cholesterol, and the omega-6 fatty acid arachidonate and its prostaglandin metabolites have all been implicated in promoting the pathogenesis of Alzheimer's disease. Evidence presented here shows DHA acts to oppose this, exerting a plethora of pleiotropic activities to protect against the pathogenesis of Alzheimer's disease.     

Dietary effect of omega-3 type polyunsaturated fatty acids on serum and liver lipid levels in rats

The dietary effect of omega-3 type highly polyunsaturated fatty acid concentrate (PUFA mix) was investigated on cholesterol and triglyceride levels in the serum and liver, and high density lipoprotein cholesterol (HDL-cholesterol) levels in the serum. The PUFA mix prepared from squid liver oil contained about 75% of total omega-3 type fatty acids. In rats fed the normal diet to which 3% PUFA mix was added, the levels of triglyceride, total cholesterol and phospholipid in the serum markedly decreased as compared to rats fed a 3% methyl-oleate diet. However, lipid peroxide values in the liver and serum increased in rats fed PUFA mix-diets. In the hypercholesterolemic rats, a 5% PUFA mix-diet caused growth retardation and a corresponding reduction in food intake. Lipid peroxide in the liver and serum were more elevated in rats fed diets containing 1, 3 and 5% PUFA mix than in rats fed diets containing 5% oleate or 5% linoleate. In all the rats on PUFA mix-diets, there were depression of serum total cholesterol and elevation of serum HDL-cholesterol. The ratio of HDL-cholesterol to total cholesterol increased in proportion to the amounts of dietary PUFA mix. Total cholesterol level in the liver was depressed after PUFA mix feeding.     

Effects of dietary omega-3 polyunsaturated Fatty acids on the skeletal-muscle blood-flow response to exercise in rats

The polyunsaturated fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) affect vascular relaxation and involve factors (e.g., nitric oxide) that contribute to exercise-induced increases in skeletal-muscle blood flow (Q). The authors investigated whether DHA and EPA supplementation augments skeletal-muscle Q and vascular conductance (VC) and attenuates renal and splanchnic Q and VC in exercising rats. Rats were fed a diet of 5% lipids by weight, of which 20% was DHA and 30% EPA (PUFA group, n = 9), or 5% safflower oil (SO group, n = 8) for 6 wk. Heart rate (HR), blood pressure (MAP), and hind-limb, renal, and splanchnic Q were measured at rest and during moderate treadmill running. MAP, HR, and renal and splanchnic Q and VC were similar between the 2 groups at rest and during exercise. In the PUFA group, Q (158 ± 27 vs. 128 ± 28 ml × min?1 × 100 g?1) and VC (1.16 ± 0.21 vs. 0.92 ± 0.23 ml × min?1 × 100 g?1 × mm Hg?1) were greater in the exercising hind-limb muscle. Q and VC were also higher in 8 of 28 and 11 of 28 muscles and muscle parts, respectively. These increases were positively correlated to the percent sum of Types I and IIa fibers. Results suggest that DHA+EPA (a) enhances Q and VC in active skeletal muscle (especially Type I and IIa fibers) and that the increase in Q is due to an increase in cardiac output secondary to increases in VC and (b) has no apparent influence on vasoconstriction in renal and splanchnic tissue.     

Nutritional intervention with omega-3 Fatty acids in a case of malignant fibrous histiocytoma of the lungs

We present a case of a 78-yr-old man with malignant fibrous histiocytoma with multiple lesions in both lungs. Following diagnosis, he declined conventional chemotherapy and elected nutritional intervention by increasing intake of omega-3 fatty acids and lowering intake of omega-6 fatty acids. We estimated that he consumed 15 g of the long-chain omega-3 fatty acids eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) per day, and the ratio of linoleic acid/long-chain omega-3 fatty acids in his diet was 0.81. Serial computed tomography scans and pulmonary x-rays revealed remarkably a slow and steady decrease in the size and number of bilateral nodules. He has no apparent side effects from consuming large quantities of fish and algae oils rich in DHA and EPA and he remains asymptomatic.     

Dietary omega-3-polyunsaturated fatty acids prevent the development of metastases of colon carcinoma in rat liver

Background Fish oil consisting of omega-3 polyunsaturated fatty acids (PUFA) seems to reduce the incidence of colon cancer. The effect of PUFAs on metastasis of colon carcinoma is still unclear. Aim The study was designed to examine the effects of a diet rich in omega-3-PUFAs on a model of colorectal metastasis. Methods Thirthy animals (WAG/Rij) were randomly assigned to receive an omega-3 diet or a control diet to evaluate their effect on tumor growth. The target male rats (WAG/Rij) were fed a diet containing 15% omega-3-fatty acids three days before and 28 days after intervention and the control rats received 15% coconut oil at the same time points. CC 531 cells, a moderately differentiated colon adenocarcinoma, were injected into the spleen of each rat. After 28 days of diet, animals were sacrificed. The tumor growth was evaluated macroscopically and microscopically in liver tissue. The tissue was examined after immunostaining and the use of monoclonal antibodies. Results PUFAs decreased the index of tumor load from 1.54 in the controls to 0.79 in the treatment group (P = 0.036). While 69.2% of the control animals were tumor positive, only 21.4% of the target animals showed tumor after omega-3-fatty acid (P < 0.05). Conclusion We could show that omega-3-fatty acids may decrease malignant metastatic tumor growth in the liver.     

Dietary intake of folate, other B vitamins, and omega-3 polyunsaturated fatty acids in relation to depressive symptoms in Japanese adults

OBJECTIVE: Although a favorable effect of dietary folate and omega-3 polyunsaturated fatty acids (PUFAs) on depression is suggested from epidemiologic studies in Western countries, evidence from non-Western populations is lacking. We examined cross-sectional associations between the intake of folate, other B vitamins, and omega-3 PUFAs and depressive symptoms in Japanese adults. METHODS: Subjects were 309 Japanese men and 208 Japanese women 21-67 y of age. Dietary intake was assessed with a validated, brief, self-administered diet history questionnaire. Depressive symptoms were defined as present when subjects had a Center for Epidemiologic Studies Depression scale score > or =16. Adjustment was made for age, body mass index, work place, marital status, occupational physical activity, leisure-time physical activity, current smoking, current alcohol drinking, and job stress score. RESULTS: The prevalences of depressive symptoms were 36% for men and 37% for women. Folate intake showed a statistically significant, inverse, and linear association with depressive symptoms in men but not in women. The multivariate odds ratios (95% confidence intervals) for depressive symptoms for men in the first, second, third, and fourth quartiles of folate intake were 1.00 (reference), 0.78 (0.38-1.63), 0.57 (0.27-1.18), and 0.50 (0.23-1.06), respectively (P for trend = 0.045). No statistically significant linear association was observed for the intake of riboflavin, pyridoxine, cobalamin, total omega-3 PUFAs, alpha-linolenic acid, eicosapentaenoic acid, or docosahexaenoic acid in either sex. CONCLUSION: Higher dietary intake of folate was associated with a lower prevalence of depressive symptoms in Japanese men but not women.     

Acne vulgaris,mental health and omega-3 fatty acids: a report of cases

Acne vulgaris is a common skin condition, one that is associated with significant psychological disability. The psychological impairments in acne include higher rates of depression, anxiety, anger and suicidal thoughts. Despite a paucity of clinical research, patients with skin conditions and/or mental health disorders are frequent consumers of dietary supplements. An overlap may exist between nutrients that potentially have both anti-acne and mood regulating properties; examples include omega-3 fatty acids from fish oil, chromium, zinc and selenium. Here we report on five cases of acne treated with eicosapentaenoic acid and antioxidant nutrients. Self-administration of these nutrients may have improved inflammatory acne lesions and global aspects of well-being; the observations suggest a need for controlled trials.     

Dietary omega-3 fatty acids differentially influence ova release and ovarian cyclooxygenase-1 and cyclooxygenase-2 expression in rats

Ovulation is a prostaglandin (PG)-dependent process. Although n-3 polyunsaturated fatty acids (PUFA) and conjugated linoleic acid (CLA) have differing effects in the body, both reduce PG synthesis. We hypothesized that dietary n-3 fatty acids and CLA would differentially alter ovarian PG profiles through reductions in expression of enzymes involved in PG biosynthesis resulting in enhanced ovulation. Our objectives were to determine how dietary stearidonic acid and eicosapentaenoic acid (EPA) at 0.3 g/100 g diet and mixed isomers of CLA at 0.7 g/100 g diet, human achievable levels with daily consumption of fish or beef and dairy products, respectively, would influence ovulation and ovarian cyclooxygenase-1 (COX-1) and COX-2 expression in ovulation-induced rats. After 27 days on diet and ovulation induction, ovaries were isolated and analyzed from 22 pups per diet. Eicosapentaenoic acid ingestion reduced ova release by 16% while increasing PGE₂ and PGF_2α release without altering COX-1 or COX-2 expression. Conversely, ovarian COX-1 expression was increased 135% with stearidonic acid ingestion associated with increased PGF_2α without altering PGE₂ or ova release. Conjugated linoleic acid ingestion reduced COX-2 expression to 65% of that in rats consuming control and EPA diets; however, without affecting ovulation or PGs. Although it is generally believed that the COX-2 is the primary COX involved in ovulation, these results demonstrated that the n-3 PUFA differently affect ovarian COX-1 expression and that this effect differs from CLA, which reduced COX-2 expression. Further, although ovarian PGF_2α is the primary PG altered by dietary n-3 PUFA, n-3 PUFA differentially influence ovarian PG biosynthesis and can decrease ova release, possibly induced through constitutive COX-1 enzyme expression.