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Food, Health, and Eco-news
Fish Nutrients Seen to Inhibit Inflammation

Omega-3s and vitamin D show strong anti-inflammatory effects in separate studies

by Craig Weatherby

We'll be publishing this issue of Vital Choices from New York City, where we're attending the 3rd annual Nutrition and Health Conference organized by Andrew Weil, M.D to inform physicians and other health professionals about the current state of nutrition science.

Inflammation has been an increasingly important focus of Dr. Weil's Nutrition and Health conferences, and it's the subject of two research reports that further document the strong anti-inflammatory effects of the omega-3s and vitamin D abundant in wild salmon.

The new research findings further verify the anti-inflammatory impact of fish, and especially sockeye salmon, which, thanks to their unique natural diet of D-rich zooplankton, are incredibly rich in vitamin D as well omega-3s.

Key Points

  • All of four recent research studies in mice indicate that fish oil exerts potent anti-inflammatory effects.
  • A clinical study in heart patients shows that supplemental vitamin D exerts potent anti-inflammatory effects.

Fish oil and low-calorie diets reduce inflammation in mice

Chronic inflammation, which results from diet-, age-, and genetics-related dysfunctions of the body's immune system, can lead to a range of inflammation-related conditions: particularly cancer and cardiovascular disease.

Starting in 2003, researchers in South Korea (Kim YJ, 2005) and at the University of Texas (Bhattacharya A, 2003) published a series of reports that support the value of fish oil as an inflammation fighter.

The most recent Korean study (Kim YJ, 2006) examined at the effects of supplemental fish oil with or without a very-low-calorie diet on important bodily markers of inflammation. The experiments involved mice, whose basic physiologies are very similar to humans.

Starting when the mice were two months old, they were divided into five groups, each of which was fed a different diet:

  1. Standard mouse diet
  2. Standard mouse diet with five percent of calories from corn oil
  3. Standard mouse diet with five percent of calories from fish oil
  4. Extreme low-calorie diet, with five percent of calories from corn oil
  5. Extreme low-calorie diet, with five percent of calories from fish oil

Some of the mice received these special diets for four months, while others stayed on them for nine months, to detect any differences attributable to great duration. The low-calorie diets contained 60 per cent fewer calories than normal.

At the end of the study period the researchers measured various markers of inflammation. And across the board, regardless of which level of calories they received, the mice fed fish oil enjoyed lower levels of all of the inflammatory marker chemicals.

For example, mice that ate the fish oil-containing diet had levels of inflammatory superoxides almost 60 per cent lower than the control animals fed normal mouse chow.

And the effects of fish oil and calorie-restriction were additive. Mice fed fish oil had levels of superoxides 35 percent lower than the controls, while mice on the calorie-restricted/fish oil diet had levels 90 per cent lower than the controls.

Similar reductions were seen in the animals' levels of inflammatory prostaglandins (PGE-2) and leukotrienes (LTB-4). In addition, both the fish oil and low-calorie diets reduced production of inflammatory TBARS, COX-1, COX-2, and iNOS (inducible nitric oxide synthase).

According to lead author Hae Young Chung of Korea's Pusan National University, “The major findings of our present study are that dietary fish oil and/or a 40 per cent reduced food intake… effectively suppressed age-related inflammatory process.”

Better yet, since it would be both hard and unhealthy to cut caloric intake by 60 percent, the Koreans found that supplemental fish oil was more effective than calorie restriction at producing beneficial antioxidant and anti-inflammatory effects.

Vitamin D curbs inflammation in congestive heart failure patients

A landmark clinical trial from Germany indicates that vitamin D may reduce inflammation in congestive heart failure (CHF) patients (Schleithoff SS, 2006).

The German team examined the effects of supplemental vitamin D in 123 patients with CHF who were randomly assigned to receive either 50 mcg of vitamin D3 per day plus 500 mg of calcium, or a placebo plus 500 mg calcium, for nine months.

They looked for effects on the patients' survival rate after 15 months and on various inflammation-related biochemical variables after nine months.

The survival rate did not differ significantly between the study groups: an outcome that which was not surprising, given the advanced illness of the participants.

However, the researchers did detect a series of beneficial outcomes that would likely hold more significance for healthier people, and for people who followed the vitamin D regimen for a longer period of time:

  • The vitamin D group showed significantly higher levels of the anti-inflammatory cytokine called interleukin-10, compared to levels at the study's starting point.
  • The pro-inflammatory cytokine called tumor necrosis factor alpha increased in the placebo group but not in the vitamin D group.

The German researchers concluded that supplemental vitamin D reduces inflammation in CHF patients and could serve as a powerful new anti-inflammatory agent.

The vitamin D group also showed significantly lower levels of parathyroid hormone: an effect believed to retard the progression of congestive heart failure, since abnormally high secretion of parathyroid hormone can impair performance of the heart muscle.


  • Kim YJ, Kim HJ, No JK, Chung HY, Fernandes G. Anti-inflammatory action of dietary fish oil and calorie restriction. Life Sci. 2006 Apr 18;78(21):2523-2532. Epub 2006 Jan 24.
  • Kim YJ, Yokozawa T, Chung HY. Suppression of oxidative stress in aging NZB/NZW mice: effect of fish oil feeding on hepatic antioxidant status and guanidino compounds. Free Radic Res. 2005 Oct;39(10):1101-10.
  • Kim YJ, Yokozawa T, Chung HY. Effects of energy restriction and fish oil supplementation on renal guanidino levels and antioxidant defences in aged lupus-prone B/W mice. Br J Nutr. 2005 Jun;93(6):835-44.
  • Bhattacharya A, Lawrence RA, Krishnan A, Zaman K, Sun D, Fernandes G. Effect of dietary n-3 and n-6 oils with and without food restriction on activity of antioxidant enzymes and lipid peroxidation in livers of cyclophosphamide treated autoimmune-prone NZB/W female mice. J Am Coll Nutr. 2003 Oct;22(5):388-99.
  • Schleithoff SS, Zittermann A, Tenderich G, Berthold HK, Stehle P, Koerfer R. Vitamin D supplementation improves cytokine profiles in patients with congestive heart failure: a double-blind, randomized, placebo-controlled trial. Am J Clin Nutr. 2006 Apr;83(4):754-9.
  • Stefenelli T, Pacher R, Woloszczuk W, Glogar D, Kaindl F. Parathyroid hormone and calcium behavior in advanced congestive heart failure. Z Kardiol. 1992 Feb;81(2):121-5.