People who eat lean fish once a week or more have reduced odds of having the metabolic syndrome. The increase in metabolic risk over the next 13 years is also reduced, according to the PhD thesis of Christine Tørris.
MAIN RESULTS:
- Lean fish consumption is associated with beneficial changes in development of the metabolic syndrome and its components, whereas consumption of fatty fish is not.
- Lean fish seems to be driving the association between increased fish consumption and reduced odds of having the metabolic syndrome also in cross sectional studies.
THESIS DEFENCE:
Thesis: Lean fish consumption is associated with decreased risk of metabolic syndrome – Results from a large population-based study
Candidate: Christine Tørris
Time: August 23, 2017 at 12:15
Place: Domus Academia, University of Oslo: Gamle festsal
Link to university website (in Norwegian)
SUMMARY:
About one fourth of the adult Norwegian population have the metabolic syndrome, characterized by central obesity, high blood pressure, high blood glucose and an adverse lipid profile. Persons with the metabolic syndrome have significantly increased risk of cardiovascular disease.
(1) In a review of the existing literature on the subject, Tørris and co-workers found that four out of seven studies show inverse associations between fish consumption and the metabolic syndrome. Three of the studies found such an association among men, whereas only one found a link between increased fish consumption and less metabolic syndrome in women. Several of the studies lacked controlling for potential confounders.
(2/3) Both of the two cross sectional studies in the thesis show reduced odds of having the metabolic syndrome among fish-eaters in the general population, also after adjustment for potential confounders. The first study only finds this association in individuals between 60 and 70 years old who eat fish at least once a week, whereas the link is found in men and women of all ages in the second study. However, further analyses of both studies show that only lean fish consumption is associated with less metabolic syndrome, whereas no such association was found for fatty fish.
Also, in both studies a higher intake of both fatty fish and lean fish is generally associated with lower triglyceride levels and higher levels of HDL cholesterol. The first study includes almost 24 000 subjects from the fourth wave of the Tromsø study (1994–1995). The other includes almost 13 000 participants from Tromsø 6 (2007–2008). About 90 % of the participants reported to eat fish at least once a week.
(4) Participants in Tromsø 4 who ate lean fish at least once a week had a less unfavorable change in metabolic risk factors over the next 13 years than participants who ate lean fish less frequently. After adjustment for potential confounders, the changes in total metabolic risk and lipid profile were still less pronounced among the fish-eaters. Surprisingly, the opposite was found for people who ate fatty fish at least once a week: The increase in metabolic risk over time seemed to be higher than for people who did not eat fatty fish regularly.
This longitudinal study contains data on more than 10 000 individuals who participated in both Tromsø 4 and 6.
REFERENCES:
(1) Tørris, C., Molin, M., & Småstuen, M. C. (2014). Fish consumption and its possible preventive role on the development and prevalence of metabolic syndrome-a systematic review. Diabetology & metabolic syndrome, 6(1), 112.
(2) Tørris, C., Molin, M., & Småstuen, M. C. (2016). Associations between fish consumption and metabolic syndrome. A large cross-sectional study from the Norwegian Tromsø Study: Tromsø 4. Diabetology & metabolic syndrome, 8(1), 1.
(3) Tørris, C., Molin, M., & Småstuen, M. C. (2016). Lean fish consumption is associated with lower risk of metabolic syndrome: a Norwegian cross sectional study. BMC public health, 16(1), 1.
(4) Tørris, C., Molin, M., & Småstuen, M. C. (2017). Lean Fish Consumption Is Associated with Beneficial Changes in the Metabolic Syndrome Components: A 13-Year Follow-Up Study from the Norwegian Tromsø Study. Nutrients, 9(3), 247.
