Fish oils reduce exercise-induced muscle damage
URMIA, IRAN. It is well established that some forms of exercise result in acute inflammation and muscle damage. Eccentric exercises (exercises whereby the muscle under load is lengthened) such as stair stepping are particularly likely to induce inflammation, muscle soreness, injury, pain and edema. A group of German and Iranian sports medicine physicians report that supplementing with fish oils prior to, during, and following an eccentric exercise program markedly reduces biomarkers of inflammation and tissue injury.

Their study included 45 young, healthy, untrained male volunteers. All participants had blood samples drawn at baseline and were then assigned to one of three groups – fish oil group, placebo group or control group. Members of the fish oil group supplemented with a natural fish oil product providing 324 mg/day of EPA (eicosapentaenoic acid) and 216 mg/day of DHA (docosahexaenoic acid) for 30 days before the exercise session and also during the 48 hours following the end of the exercise. The placebo group received capsules containing a soybean/corn oil mixture, and the control group received no supplements for the 30 days + 48-hour period. The fish oil and placebo groups also received 100 IU of vitamin E to minimize oxidation of long-chain fatty acids.

The exercise session consisted of 40 minutes of bench stepping (knee height step, 50 cm on average, at a rate of 15 steps a minute), with 5 minutes of stepping, and 1 minute of rest between stepping periods. Blood samples were taken from all study participants immediately before the exercise session, immediately after, and 24 and 48 hours later. The samples were analyzed for the following markers of inflammation/muscle damage:

• Interleukin-6 (IL-6)
• Tumour necrosis factor alpha (TNF)
• Prostaglandin E2 (PGE)
• Lactate dehydrogenase (LDH)
• Creatine kinase (CK)
• Myoglobin (Mb)

There were no significant differences between groups in these markers either at baseline or immediately prior to the exercise session. However, levels of TNF, PGE and LDH in the fish oil group were substantially lower immediately post-exercise and at 24 and 48 hours than were levels in the placebo and control groups. Levels of IL-6, CK and Mb were substantially lower at 24 and 48 hours than were levels in the placebo and control groups. NOTE: There were no differences in inflammation marker levels between the placebo and control groups; however, these levels did increase after the exercise session.

The researchers conclude that fish oil supplementation taken before, during and following eccentric exercise provides potent anti-inflammatory protection and might serve as a potential agent to reduce exercise-induced muscle damage.
Tartibian, B, et al. Omega-3 fatty acids supplementation attenuates inflammatory markers after eccentric exercise in untrained men. Clinical Journal of Sport Medicine, Vol. 21, No. 2, March 2011, pp. 131-37

Fish protects against elevated C-reactive protein
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 plus 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 (EPA, DHA and ALA) had a 56 per cent lower incidence of elevated CRP than those in the bottom quarter. Those in the top quarter for combined EPA plus 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 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

Eating fish may lower inflammation in the blood vessels
ATHENS, GREECE. Consuming fish has long been thought to help protect against heart disease, possibly through reducing inflammation in blood vessels. However, study results on the effects of fish on inflammatory markers are mixed, so a team of researchers from Harokopio University set out to examine the relationship in a population-based group of men and women free of heart disease. They gathered data on 1,514 men and 1,528 women aged 18 to 89, taking part in the ongoing ATTICA study into the benefits of a Mediterranean diet on heart health. Compared to those who did not eat fish, those who ate the most (10.5 ounces per week or more) had an average 33 per cent lower level of C-reactive protein, a widely-used marker for inflammation. They also had a 33 per cent lower level of interleukin-6, another inflammatory marker found in the plasma. This group had 21 per cent lower tumor necrosis factor-alpha, which affects lipid metabolism, coagulation, and insulin resistance, and 28 per cent lower serum amyloid A, a blood protein increased by inflammation. Significantly lower levels of these markers were also found in people who ate about 5 to 10 ounces of fish per week.

This clear and strong inverse association between fish consumption and inflammatory markers may help explain why people who eat fish tend to have lower rates of heart disease, say the authors. The benefits remained once many risk factors were taken into account and were observed even in people with high blood pressure or diabetes, but not high cholesterol. Nevertheless, it was a cross-sectional study which did not follow people over time, so cannot prove causation. These results support recommendations that people eat more fish, the authors write, particularly oily fish with their high levels of omega-3 fatty acids. One or two portions per week may be sufficient, but the fish should not be fried. In some cases, omega-3 fatty acid supplements may be appropriate to achieve an optimal intake of 0.6 grams of omega-3 fatty acids per day.
Zampelas, A. et al. Fish consumption among healthy adults is associated with decreased levels of inflammatory markers related to cardiovascular disease: The ATTICA Study. Journal of the American College of Cardiology, Vol. 46, July 2005, pp. 120-24