Chronic inflammation, brought about by an over-expression or lack of control of the normal protective mechanism, can lead to a range of inflammatory related disease, particularly cardiovascular disease.
The new study, published in the journal Life Sciences (Vol. 78, pp. 2523-2532), looked at the effects of fish oil and/or a calorie-restricted diet on various markers of inflammation for old and young female mice.
The diets were adopted when the mice were two months old and formulated to contain either corn oil (5 per cent) or fish oil (5 per cent containing DHA, EPA, palmitic acid), and the calorie-restriction diets (60 per cent) were fed the same levels of fish or corn oil as the controls.
At the end of the study the researchers measured various markers of inflammation, such as levels of lipid oxidation, and concentrations of reactive superoxide species, prostaglandins, and leukotriene B4, for both the young mice (four months old) and old mice (nine months old).
Mice eating the corn oil diet had superoxides levels about 18 per cent higher than corn oil fed young mice. Young mice receiving the fish oil-containing diet had superoxides levels almost 60 per cent lower. Calorie-restricted young mice had a 35 per cent level of superoxides, while young mice consuming the calorie-restricted fish oil diet had levels 90 per cent lower than the young controls.
The effect of calorie-restriction and fish oil on superoxide concentrations was also significant in the older mice. Both dietary interventions reduced levels of reactive superoxide reduced by 94 per cent.
Similar reductions were observed for both prostaglandin production levels and the age-related production of leukotriene B4.
"The major findings of our present study are that dietary fish oil and/or a 40 per cent reduced food intake, ie. calorie-restriction, effectively suppressed age-related inflammatory process," wrote the authors, led by Hae Young Chung from Pusan National University, Korea.
"One other interesting finding is that fish oil feeding seems more effective than calorie-restriction in its antioxidative and anti-inflammatory effects," they said.
The researchers also measured the expression of pro-inflammatory COX-2 and iNOS on gene expression. Both were suppressed compared to the corn oil, normal diet control mice.
The suppression of both COX-2 and iNOS reduced the expression of the pro-inflammatory prostaglandin and leukotriene, both of which are established mediators of inflammation.
The results of the study are in-line with previous research looking at either calorie-restriction or omega-3 fatty acids on markers of inflammation.
A study published recently in the Journal of the American College of Cardiology (Vol. 47, Issue 2, pp. 398-402) reported that a calorie-restricted diet could slow down heart aging and prolong the lifespan of people. However, an accompanying editorial questioned whether the majority of people would be able to adopt and sustain such a strict diet.