Background: Research suggests that a low omega-3 index may contribute to the low heart rate variability and the increased risk of cardiovascular morbidity and mortality in bipolar disorders. However, so far, no intervention trial with EPA and DHA has been conducted in bipolar patients attempting to increase their heart rate variability. - Methods: 119 patients with bipolar disorder according to DSM-IV were screened, with 55 euthymic bipolar patients—owing to inclusion criteria (e.g. low omega-3 index (< 6%), SDNN < 60 ms.)—being enrolled in a randomized, double-blind, 12-week parallel study design with omega-3 fatty acids (4 capsules of 530 mg EPA, 150 mg DHA) or corn oil as a placebo, in addition to usual treatment. Heart rate variability as well as the omega-3 index were measured at baseline and at the endpoint of the study. - Results: A total of 42 patients (omega-3: n = 23, corn oil: n = 19) successfully completed the study after 12 weeks. There was a significant increase in the omega-3 index (value at endpoint minus value at baseline) in the omega-3 group compared to the corn oil group (p < 0.0001). However, there was no significant difference in the change of the SDNN (value at endpoint minus value at baseline) between the treatment groups (p = 0.22). In addition, no correlation between changes in SDNN and change in the omega-3 index could be detected in the omega-3 group (correlation coefficient = 0.02, p = 0.94) or the corn oil group (correlation coefficient = − 0.11, p = 0.91). Similarly, no significant differences between corn oil and omega-3 group regarding the change of LF (p = 0.19), HF (p = 0.34) and LF/HF ratio (p = 0.84) could be demonstrated. - Conclusions: In our randomized, controlled intervention trial in euthymic bipolar patients with a low omega-3 index and reduced heart rate variability no significant effect of omega-3 fatty acids on SDNN or frequency-domain measures HF, LF and LF/HF ratio could be detected. Possible reasons include, among others, the effect of psychotropic medication present in our trial and/or the genetics of bipolar disorder itself. Further research is needed to test these hypotheses.

Salmon is a good source of long chain (LC) omega 3 fatty acids and selenium; these are well recognised for their health benefits. Recommendations for LC omega 3 fatty acid intakes presume equivalence between fish and fish oil. The aim of this research was to compare the effects of consuming salmon with salmon oil capsules on LC omega 3 fatty acid and selenium status. Forty four healthy subjects were randomly assigned to consume either two servings of 120 g farmed New Zealand King (FNZK) salmon/week or 2, 4 or 6 capsules of salmon oil/day for 8 weeks. Fasting blood samples, anthropometric measures, food consumption habits information and blood pressure (BP) measurements were obtained at the study commencement and ending. Each subject’s intake of LC omega 3 fatty acids and selenium was determined by analysing the fatty acid and selenium content of duplicate portions of cooked salmon and capsules. The amount of salmon consumed was then calculated by subtracting unconsumed amounts of salmon and then calculating the intake of LC omega 3 fatty acids as grams of LC omega 3 fatty acids consumed per day. Percentage of compliance to capsule intake, based on counts of unconsumed capsules, was calculated to determine the amount of LC omega 3 fatty acids consumed per day from capsules. Change in red blood cells (RBC) LC omega 3 fatty acid levels from equivalent amounts of LC omega 3 fatty acids consumed from capsules and salmon were compared using linear regression analysis predictive models fitted to the capsule data. Omega 3 index was calculated. LC omega 3 fatty acid intakes from salmon and 2, 4 and 6 capsules were 0.82, 0.24, 0.47 and 0.68 g/day, respectively. Equal amounts of LC omega 3 fatty acids consumed from salmon and capsules resulted in similar increases in RBC LC omega 3 fatty acids and omega 3 index (RBC eicosapentaenoic acid (EPA): 0.80 [0.58 – 1.02] vs. 1.00 [0.71 – 1.27] %; RBC docosahexaenoic acid (DHA): 0.93 [0.58 – 1.29] vs. 0.99 [0.68 – 1.31] %; omega 3 index: 1.92 [1.46 – 2.38] vs. 2.25 [1.65 – 2.83] %). The capsules did not contain selenium, but the salmon provided 6.84 µg selenium/day. Plasma selenium concentrations increased significantly in the salmon group compared to the capsule

Salmon is a good source of long chain (LC) omega 3 fatty acids and selenium; these are well recognised for their health benefits. Recommendations for LC omega 3 fatty acid intakes presume equivalence between fish and fish oil. The aim of this research was to compare the effects of consuming salmon with salmon oil capsules on LC omega 3 fatty acid and selenium status. Forty four healthy subjects were randomly assigned to consume either two servings of 120 g farmed New Zealand King (FNZK) salmon/week or 2, 4 or 6 capsules of salmon oil/day for 8 weeks. Fasting blood samples, anthropometric measures, food consumption habits information and blood pressure (BP) measurements were obtained at the study commencement and ending. Each subject’s intake of LC omega 3 fatty acids and selenium was determined by analysing the fatty acid and selenium content of duplicate portions of cooked salmon and capsules. The amount of salmon consumed was then calculated by subtracting unconsumed amounts of salmon and then calculating the intake of LC omega 3 fatty acids as grams of LC omega 3 fatty acids consumed per day. Percentage of compliance to capsule intake, based on counts of unconsumed capsules, was calculated to determine the amount of LC omega 3 fatty acids consumed per day from capsules. Change in red blood cells (RBC) LC omega 3 fatty acid levels from equivalent amounts of LC omega 3 fatty acids consumed from capsules and salmon were compared using linear regression analysis predictive models fitted to the capsule data. Omega 3 index was calculated. LC omega 3 fatty acid intakes from salmon and 2, 4 and 6 capsules were 0.82, 0.24, 0.47 and 0.68 g/day, respectively. Equal amounts of LC omega 3 fatty acids consumed from salmon and capsules resulted in similar increases in RBC LC omega 3 fatty acids and omega 3 index (RBC eicosapentaenoic acid (EPA): 0.80 [0.58 – 1.02] vs. 1.00 [0.71 – 1.27] %; RBC docosahexaenoic acid (DHA): 0.93 [0.58 – 1.29] vs. 0.99 [0.68 – 1.31] %; omega 3 index: 1.92 [1.46 – 2.38] vs. 2.25 [1.65 – 2.83] %). The capsules did not contain selenium, but the salmon provided 6.84 µg selenium/day. Plasma selenium concentrations increased significantly in the salmon group compared to the capsule

Salmon is a good source of long chain (LC) omega 3 fatty acids and selenium; these are well recognised for their health benefits. Recommendations for LC omega 3 fatty acid intakes presume equivalence between fish and fish oil. The aim of this research was to compare the effects of consuming salmon with salmon oil capsules on LC omega 3 fatty acid and selenium status. Forty four healthy subjects were randomly assigned to consume either two servings of 120 g farmed New Zealand King (FNZK) salmon/week or 2, 4 or 6 capsules of salmon oil/day for 8 weeks. Fasting blood samples, anthropometric measures, food consumption habits information and blood pressure (BP) measurements were obtained at the study commencement and ending. Each subject’s intake of LC omega 3 fatty acids and selenium was determined by analysing the fatty acid and selenium content of duplicate portions of cooked salmon and capsules. The amount of salmon consumed was then calculated by subtracting unconsumed amounts of salmon and then calculating the intake of LC omega 3 fatty acids as grams of LC omega 3 fatty acids consumed per day. Percentage of compliance to capsule intake, based on counts of unconsumed capsules, was calculated to determine the amount of LC omega 3 fatty acids consumed per day from capsules. Change in red blood cells (RBC) LC omega 3 fatty acid levels from equivalent amounts of LC omega 3 fatty acids consumed from capsules and salmon were compared using linear regression analysis predictive models fitted to the capsule data. Omega 3 index was calculated. LC omega 3 fatty acid intakes from salmon and 2, 4 and 6 capsules were 0.82, 0.24, 0.47 and 0.68 g/day, respectively. Equal amounts of LC omega 3 fatty acids consumed from salmon and capsules resulted in similar increases in RBC LC omega 3 fatty acids and omega 3 index (RBC eicosapentaenoic acid (EPA): 0.80 [0.58 – 1.02] vs. 1.00 [0.71 – 1.27] %; RBC docosahexaenoic acid (DHA): 0.93 [0.58 – 1.29] vs. 0.99 [0.68 – 1.31] %; omega 3 index: 1.92 [1.46 – 2.38] vs. 2.25 [1.65 – 2.83] %). The capsules did not contain selenium, but the salmon provided 6.84 µg selenium/day. Plasma selenium concentrations increased significantly in the salmon group compared to the capsule