“I hate fish.” So said Lee Haney, six-time Mr.Olympia, when I asked him about his protein preferences. Since that interview took place nearly 20 years ago, it’s likely that these days he’s getting his omega-3 fatty acids from some source—and for good reason. Research concerning the health benefits of omega-3s is extensive, especially in relation to optimal brain function and preventing cardiovascular disease. While all the benefits of omega-3 fats are easily obtained by taking a fish oil supplement, many experts still extol the value of eating actual fish.
Despite Haney’s dislike of fish, it’s a staple of most bodybuilding diets, particularly during precontest prep. Fish is devoid of carbohydrates and low in fat and calories while being high in protein. Indeed, as contest time approaches, many competitive bodybuilders habitually eschew beef and even chicken in favor of baked or broiled (never fried) fish.
Fish species differ in their nutrient content. Only fatty fish contain generous levels of omega-3 fats—sardines, mackerel, salmon and halibut, for example. The lean fish favored by bodybuilders, such as mahimahi, tuna and orange roughy, have almost no omega-3s.
In a recent study, researchers purchased 30 species of wild and farmed fish from supermarkets, wholesale distributors and commercial fish farms in the United States and abroad.1 They found that the omega-3 content ranged from “practically none” to nearly 4,000 milligrams per 100 grams—about five ounces—of fish. When they compared the four most common farmed fish—Atlantic salmon, trout, tilapia and catfish—they found that the tilapia and catfish were not only low in omega-3s but also high in omega-6 fats and had higher percentages of saturated and monounsaturated fats.
The fat profile of tilapia and catfish is problematic because omega-6 fats are a precursor of arachidonic acid, which in turn is the primary precursor of fatlike chemicals called eicosanoids, many of which have potent inflammatory effects. The fish had more omega-6 fats because they were fed food rich in them. Tilapia and catfish are low in omega-3s naturally, but the authors considered their omega-6 content to be a true health liability. Inflammation is now accepted as the cornerstone of most degenerative diseases, including cardiovascular disease and cancer.
The study also found that the tilapia and catfish were high in linoleic acid (an omega-6 fat) and arachidonic acid. Many analgesic, or painkilling, drugs, including aspirin and ibuprofen, work by interfering with the activity of the enzyme cyclooxygenase-2, or COX-2, that converts arachidonic acid into eicosanoids. If you lower the inflammatory eicosanoids, you also reduce pain. Examples of such inflammatory eicosanoids include prostaglandin E2, thromboxane A2 and leukotriene B4. On the other hand, arachidonic acid is also the precursor of anti-inflammatory eicosanoids, such as prostacyclin and lipoxin A4.
The findings have body-building implications. Arachi-donic acid is the precursor of prostaglandin F2A, which is involved in muscle protein synthesis and muscle repair processes after intense exercise. Indeed, some studies show that when you take analgesics before or after training, you short-circuit the anabolic effects of exercise because you inhibit the production of PF2A from arachidonic acid. In fact, arachidonic acid is even offered in supplement form under the supposition that intense exercise may deplete it in the body. More on that later.
Since linoleic acid is the primary dietary precursor of arachidonic acid synthesis, the body tightly regulates production of arachidonic acid from linoleic acid. Thus, taking large amounts of linoleic acid doesn’t directly translate into more arachidonic acid in body tissue. As for omega-6 fats and inflammation, human-subject studies reveal an opposite effect: less inflammation after a high intake of omega-6 fats. Other studies that have looked directly at arachidonic acid intake show that taking up to 1.5 grams a day is not harmful to humans. That’s good news, as the suggested dose for supplemental arachidonic acid is 1,000 milligrams daily.
A salient question arises: If arachidonic acid is the precursor of PGF2A, which is anabolic, would supplementing with a direct source of it build more muscle? That question was examined in a study published about a year ago.2 Thirty-one men, all actively engaged in weight training, took either a placebo or one gram a day of a commercial arachidonic acid supplement. The study was sponsored by a company that sells the arachidonic acid supplement that researchers used. The subjects underwent such testing procedures as body composition, one-rep-max bench press, one-rep-max leg press and the Wingate anaerobic test, which measures anaerobic capacity. The subjects also provided muscle biopsies obtained from their front-thigh muscles.
Those in the arachidonic acid group had an 8.5 percent increase in peak anaerobic power by day 50 of the study. Their bodies also experienced a decline in interleukin-6, a marker of inflammation, that didn’t occur in the placebo group. The arachidonic acid group also had more prostaglandin E2, indicating that the supplement did affect eicosanoid synthesis. On the other hand, the supplement didn’t produce any significant changes in body composition, circulating anabolic hormones or intramuscular markers of muscle gains. Nor did it improve strength. Add it all up, and you find that using an arachidonic acid supplement may improve training efficiency through increasing anaerobic capacity and lowering inflammation, but supplement-driven muscle gains appear to be zilch. One possible reason is that the arachidonic acid supplement didn’t affect or change the amount of PGF2A in the body. Whether using a higher dose of the supplement or taking it longer would change the results remains to be examined.
1 Weaver, K.L., et al. (2008). The content of favorable and unfavorable polyunsaturated fatty acids found in commonly eaten fish. J Am Diet Assoc. 108:1178-1185.
2 Roberts, M., et al. (2007). Effects of arachidonic acid supplementation on training adaptations in resistance-trained males. J Int Soc Sports Nutr. 4:21.