On Nutrition by Ed Blonz

Getting Omega-3 Fats: Flaxseed or Fish Oil?

DEAR DR. BLONZ: I do not eat much fish, and my doctor suggested taking fish oil capsules. My question is whether flaxseed oil is an effective alternative source of omega-3 fatty acids. This would be preferable to me, as it does not come with the risk of containing mercury or other contaminants, and there is no fishy smell. -- S.M., Phoenix

DEAR S.M.: Our body requires certain specially built fatty acids in the same way it requires vitamins, minerals and protein. Fatty acids are long chains of carbon atoms bound together. In chemistry, the term “omega” refers to the location of the first double bond along the chain. If it begins on the third carbon, it is called an omega-3 fatty acid. If it starts on the sixth, it’s an omega-6, and beginning at the ninth carbon, it’s an omega-9 fat. The precise point of that first double bond and the length of the chain affect what the substance can do in the body. We can make double bonds in some locations along a chain (such as at the omega-9 position), but not at carbon 3 or 6. We need fats built this way for various functions, and this is what makes omega-3 and omega-6 fatty acids dietary essentials.

Omega-6 fats are found in many vegetables, such as corn, soy, sunflower and safflower. The richest dietary source of omega-3 fatty acids is coldwater fish, such as salmon. There are also plant sources, and flaxseed is among the highest. Omega-3s can be found in lesser amounts in walnut, canola, soy and other plants, but these are shorter cousins to the ones found in fish oil, and it’s that longer version that the body requires for certain functions.

That means that while fish oil omega-3s are ready for the job, our bodies need to elongate plant omega-3s before using them. This can be done, but it is not an efficient process. Eating fish rich in omega-3 is definitely the best and most efficient way of getting these essential fats; the highest levels are found in salmon, tuna, mackerel, sardines and herring.

I consider fish oil capsules to be a lesser alternative. Concerns about contaminants are legitimate, so be sure to find a provider that goes the extra distance to assure the purity of the supplement before you buy.

Regardless of the source, omega-3 fatty acids must be stored properly as they are quite reactive. If they react with oxygen -- become oxidized -- they turn rancid and develop the odor characteristic of rotten fish. At that point, they change from an asset to a health liability. Refrigeration is ideal protection for these fats.

One final note: The intake of omega-3 fatty acids can affect how blood clots. Anyone using anticoagulant medications, such as Coumadin, or those at risk for issues involving blood clotting should get clearance from their health professional before starting or increasing their intake of omega-3 fatty acids.

For more information on omega-3 fatty acids from the National Institutes of Health, see b.link/EFAs.

Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.