RSS Feeds
Effects of n-3 Polyunsaturated Fatty Acids on Glucose Homeostasis and Blood Pressure in Essential Hypertension
A Randomized, Controlled Trial
- Ingrid Toft, MD;
- Kaare H. Bonaa, MD, PhD;
- Ole C. Ingebretsen, MD, PhD;
- Arne Nordoy, MD, PhD; and
- Trond Jenssen, MD, PhD
- From the University of Tromso and Tromso University Hospital, Tromso, Norway. Acknowledgments: The authors thank the staff of the General Clinical Research Centre and thank Jorunn Ekrem, Angstromse Lund Bendiksen, Gro Bolstad, and Hege Iversen for technical assistance. Grant Support: In part by the Norwegian Diabetes Association, Nordic Research Funding, and the Research Council of Norway. Pronova Biocare provided the test medication. Requests for Reprints: Ingrid Toft, MD, Department of Internal Medicine, Tromso University Hospital, N-9038 Tromso, Norway. Current Author Addresses: Drs. Toft, Nordoy, and Jenssen: Department of Internal Medicine, Tromso University Hospital, N-9038 Tromso, Norway. Dr. Bonaa: Institute of Community Medicine, University of Tromso, N-9037 Tromso, Norway. Dr. Ingebretsen: Department of Clinical Chemistry, Tromso University Hospital, N-9038 Tromso, Norway.
Abstract
Objective: To determine whether dietary supplementation with fish oil adversely affects glycemic control in patients with hypertension.
Design: Randomized, double-blind, placebo-controlled study.
Patients: 78 persons with untreated hypertension recruited from a population survey.
Intervention: Participants were randomly assigned to receive eicosapentaenoic and docosahexaenoic acids, 4 g/d, or corn oil placebo, 4 g/d, for 16 weeks.
Measurements: An oral glucose tolerance test; assessments of insulin release, glucose disposal, and insulin sensitivity done using the hyperglycemic clamp technique to keep plasma glucose levels at 10 mmol/L for 180 minutes; assessment of insulin sensitivity done using a euglycemic hyperinsulinemic clamp technique (infusing insulin and glucose to keep plasma glucose levels at 5 mmol/L); assessments of lipid levels and blood pressure. Measurements were done before and after intervention.
Results: Changes in integrated glucose and insulin response after the oral glucose challenge did not differ between the fish oil and corn oil groups after intervention (−0.6 ± 0.7 compared with −1.0 ± 0.6 mmol/L [P > 0.3] for integrated glucose and 143 ± 76 compared with 169 ± 84 pmol/L [P > 0.3] for insulin response). Changes in first-phase insulin release (34 ± 72 pmol/L in the fish oil group compared with 191 ± 112 pmol/L in the corn oil group [P > 0.3]), second-phase insulin release (179 ± 66 pmol/L compared with 257 ± 122 pmol/L [P > 0.3]), and insulin sensitivity index (−0.03 ± 0.01 compared with −0.01 ± 0.01 [µmol/kg · min ÷ pmol/L]; P > 0.3) were also similar in both groups after treatment. Fish oil lowered systolic blood pressure by 3.8 mm Hg more than control (P = 0.04) and lowered diastolic blood pressure by 2.0 mm Hg more than control (P = 0.10). After fish oil treatment, triglyceride levels decreased by 0.28 ± 0.08 mmol/L more than control (P = 0.01), and very-low-density lipoprotein cholesterol levels decreased by 0.13 ± 0.04 mmol/L more than control (P = 0.01).
Conclusion: Fish oil, in doses that reduce blood pressure and lipid levels in hypertensive persons, does not adversely affect glucose metabolism.
- Copyright ©2004 by the American College of Physicians
Related Clinical Content
