Fish oil consumption associated with fewer vascular diabetes complications, study finds
Researchers studied 20,338 patients with diabetes from the U.K. Biobank, assessing habitual fish oil use by asking at baseline about supplement use and micro- and macrovascular complications by reviewing hospital inpatient records.
Taking fish oil supplements and having higher omega-3 polyunsaturated fatty acid (n-3 PUFA) levels were associated with lower risks of macrovascular and microvascular complications among patients with type 2 diabetes, a study found.
Researchers studied 20,338 patients with diabetes from the U.K. Biobank, assessing habitual fish oil use by asking at baseline about supplement use and diabetic complications by reviewing hospital inpatient records. Results were published by the Journal of Clinical Endocrinology & Metabolism on July 12.
Fish oil users were older and more likely to be female, White, and physically active. They drank alcohol more frequently and were more likely to take aspirin, vitamins, minerals, and other dietary supplements. They were less likely to currently smoke or to have obesity. Fish oil users had more hyperlipidemia and hypertension but lower HbA1c levels. They had a healthier diet, based on the markers of eating more fish, fresh vegetables, and fruits and less processed meat.
During 13.2 years of follow-up, 5,396 people developed macrovascular complications and 4,868 people developed microvascular complications. After multivariable adjustment, patients taking fish oil had lower risk of composite macrovascular complications (hazard ratio [HR], 0.90; 95% CI, 0.85 to 0.97), coronary heart disease (HR, 0.91; 95% CI, 0.84 to 0.98), peripheral artery disease (HR, 0.72; 95% CI, 0.61 to 0.83), composite microvascular complications (HR, 0.89; 95% CI, 0.83 to 0.95), diabetic kidney disease (HR, 0.87; 95% CI, 0.79 to 0.95), and diabetic retinopathy (HR, 0.88; 95% CI, 0.80 to 0.97).
Higher plasma n-3 PUFA levels, especially docosahexaenoic acid (DHA), were associated with lower risks of macrovascular and microvascular complications. For the patients with the highest levels of DHA versus the lowest (by quartile), the HRs were 0.68 (95% CI, 0.57 to 0.81) for composite macrovascular complications, 0.63 (95% CI, 0.51 to 0.77) for heart disease, and 0.59 (95% CI, 0.38 to 0.91) for diabetic neuropathy.
According to the study authors, biomarkers including lipid profile and inflammatory markers collectively explained 54.4% and 63.1% of associations of plasma DHA with risks of composite macrovascular complications and heart disease.
Evidence from previous research on this question has been limited and inconsistent, the study authors noted, with doses varying among studies. While more research is needed into the dose and ratio of components of fish oil, “in this prospective study of individuals with type 2 diabetes, habitual use of fish oil and higher plasma n-3 PUFA levels, especially DHA, were associated with lower risks of both macrovascular and microvascular complications,” they said.