Recent health concerns over mercury levels found in some seafood prompted the U.S. Food and Drug Administration (FDA) and the Environmental Protection Agency to issue an advisory that young children and women who are pregnant, nursing or may become pregnant, should limit their intake of tuna and other seafood because the mercury content can harm developing nervous systems. The advisory also stressed that fish, especially tuna, offered health benefits that should not be ignored. For this group, the agencies issued these new guidelines:

• Do not eat shark, swordfish, king mackerel or tilefish, which can have significant mercury levels.
• Eat no more than 12 ounces a week of fish lower in mercury, such as salmon, shrimp and canned light tuna.
• Canned albacore, or “white,” tuna has more mercury than canned light tuna.
• Check advisories for the safety of fish caught in local waters.

More information about the risks of mercury in fish is available from the FDA at (888) SAFEFOOD or www.cfsan.fda.gov. Or search for the term “omega-6” at www.americanheart.org for a breakdown of mercury content in different types of fish.

Fundamental Fatty Acids

Even though the human body needs essential fatty acids to function, it cannot produce them. Instead, the body absorbs fatty acids through food and breaks them down into a variety of biochemicals.

Omega-3 (n-3) polyunsaturated fatty acids are found in foods such as beans, nuts and cooking oils, but the forms found in seafood such as salmon, herring and oysters are thought to be particularly beneficial.

Omega-6 (n-6) polyunsaturated fatty acids can be found in soybean and other plant oils, as well as meat, fowl, fish and some processed foods.

The n-3 and n-6 fatty acids are so chemically similar that they may jockey with each other for position within the body. Researchers suspect that n-6 fatty acid products wield more powerful, yet negative, effects on the body than n-3 fatty acid products, and can actually spur on disease.

Scientists are investigating n-3 fatty acids for their potential in helping with mental illnesses, immune problems, cardiovascular health and other disorders. Meanwhile, excess products from n-6 fatty acids have been implicated in arthritis, asthma, colitis, heart attack, inflammation and menstrual pain, among other problems.

For more information on how essential fatty acids work, including free menu-planning software for improving the balance of fatty acids in the diet, visit http://efaeducation.nih.gov/sig/ods.html. The American Heart Association also offers guidelines on fish and omega-3 fatty acids on its Web site.