SENDAI, JAPAN. An elevated C-reactive protein (CRP) level is a strong risk factor for cardiovascular disease, thought to indicate low-grade inflammation and contribute to plaque in the blood vessels. Previous studies suggest that a greater intake of fish is linked to healthy CRP levels.
A recent study investigated this link among the Japanese, who have a higher overall intake of marine products and lower mean CRP concentrations than Western populations. A team from Tohoku University surveyed 401 men and 570 women aged 70 years and older living in Tsurugaya, Japan. Fish intake was measured by questionnaire and CRP concentrations by testing blood plasma samples. Mean daily EPA and DHA intake was 1.38 grams in men and 1.17 grams in women. Analysis showed that increasing intakes of overall n-3 fatty acids were significantly linked to a reduction in risk of elevated CRP, defined as 1.0 mg/L (0.1 mg/dL) serum or more. Individuals in the top quarter for total n-3 FA intake (ALA, EPA and DHA) had a 56 per cent lower incidence of elevated CRP than those in the bottom quarter. Those in the top quarter for combined EPA and DHA intake were 46 per cent less likely to have elevated CRP than those in the bottom quarter. Similar results were found when EPA and DHA were analyzed separately. Finally, the results were interpreted assuming a causal relation between n-3 FA intake and high CRP concentrations. This suggested that about 30 per cent of high CRP concentrations could be due to a lower intake of n-3 FAs.
The researchers conclude that these results support the majority of previous studies which reported an inverse relation between CRP concentrations and n-3 FAs, and suggest that even very high intakes of n-3 FAs may lower serum CRP. They add that the link between fatty acids found in fish/fish oil seemed stronger among diabetics, and encourage further work in this area.
Niu, K. et al. Dietary long-chain n-3 fatty acids of marine origin and serum C-reactive protein concentrations are associated in a population with a diet rich in marine products. The American Journal of Clinical Nutrition, Vol. 84, July 1, 2006, pp. 223-29