ACP Journal Club. Review: omega-3 polyunsaturated fatty acid supplements do not reduce major cardiovascular events in adults

White fish reduces cardiovascular risk factors in patients with metabolic syndrome: the WISH-CARE study, a multicenter randomized clinical trial

BACKGROUND AND AIMS

Reduction of cardiovascular risk with high consumption of fish in diet is still a matter of debate, and concerns about heavy metal contamination have limited consumption of oily fish. We aimed to evaluate the effect of regular ingestion of white fish on cardiovascular risk factors in patients with metabolic syndrome.

METHODS AND RESULTS

Multicenter randomized crossover clinical trial including 273 individuals with metabolic syndrome. An 8-week only-one dietary intervention: 100 g/d of white fish (Namibia hake) with advice on a healthy diet, compared with no fish or seafood with advice on a healthy diet. Outcomes were lipid profile, individual components of the metabolic syndrome, serum insulin concentrations, homeostasis model of insulin resistance, serum C-reactive protein and serum fatty acid levels. We found a significant lowering effect of the intervention with white fish on waist circumference (P < 0.001) and diastolic blood pressure (P = 0.014). A significant lowering effect was also shown after the dietary intervention with fish on serum LDL concentrations (P = 0.048), whereas no significant effects were found on serum HDL or triglyceride concentrations. A significant rise (P < 0.001) in serum EPA and DHA fatty acids was observed following white fish consumption. Overall adherence to the intervention was good and no adverse events were found.

CONCLUSION

In individuals with metabolic syndrome, regular consumption of hake reduces LDL cholesterol concentrations, waist circumference and blood pressure components of the metabolic syndrome.

CLINICAL TRIAL REGISTRY

White Fish for Cardiovascular Risk Factors in Patients with Metabolic Syndrome Study, Registered under ClinicalTrials.gov Identifier: NCT01758601.

Effects of long-term administration of saturated and n-3 fatty acid-rich diets on lipid utilisation and oxidative stress in rat liver and muscle tissues

The incidence of metabolic syndrome components including obesity, lipid deregulation, insulin resistance (IR) and non-alcoholic fatty liver disease is increasing rapidly in wealthy societies. The present study was designed to determine the effect of different nutritional lipid patterns (quantity and quality) on lipid utilisation and oxidative stress in the liver and muscle of rats in an integrated fashion. A total of forty-eight Wistar male rats were fed for 12 weeks with a mixed, lard or fish-oil diet, containing either 50 or 300 g lipid/kg. Rats developed liver steatosis associated with moderate liver injury when fed the 30 % lipid diets, in spite of the absence of overt obesity or IR, except when fed the lard 30 % lipid diet. The intake of the 30 % lipid diets decreased hepatic lipogenesis and mitochondriogenesis and increased lipid peroxidation and protein oxidation. Surprisingly, muscle lipid content was not modified whatever the administered diet. The intake of the 30 % lipid diets increased the muscle protein expression of fatty acid (FA) translocase/cluster of differentiation 36 (FAT/CD36), PPARγ co-activator 1α (PGC-1α) and muscle carnitine palmitoyltransferase 1 (m-CPT1), reflecting increased FA transport in the muscle associated with increased oxidative metabolism. The lard 30 % lipid diet led to IR without modifying the muscle lipid content. The fish-oil 30 % lipid diet failed to prevent the development of hepatic steatosis and made the tissues more prone to oxidation. Overall, the present study suggests that the FA composition of muscle is more important than lipid accumulation itself in the modulation of insulin sensitivity, and indicates that precaution should be taken when advising an unphysiologically high (pharmacological) supplementation with long-chain n-3 PUFA.