By Jean Hofve, DVM
The headline read: “Omega-3 Fats Shown to Decrease Risk of Dying from Inflammatory Diseases.”
This study is a big deal, as it involved more than 2,500 human participants tracked over 15 years. Their diet was assessed using a food-frequency questionnaire.
The research, published in the American Journal of Clinical Nutrition, found that: “Women in the highest tertiles of total [omega-3] intake, compared with those in the lowest tertile of intake at baseline, had a 44 percent reduced risk of inflammatory disease mortality….” This particular study found a specific benefit of alpha-linolenic acid, the plant-based form of Omega-3.
Earlier research published in the same journal concluded that “Among the fatty acids, it is the omega-3 polyunsaturated fatty acids (PUFA) which possess the most potent immunomodulatory activities, and among the omega-3 PUFA, those from fish oil — eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) — are more biologically potent than alpha-linolenic acid (ALA).”
So what does this mean for our pets? Virtually all cats and dogs eating commercial pet food are deficient in Omega-3 fatty acids. Quite a few of the better foods are adding Omega-3 sources such as flaxseed meal. Ground flaxseeds are a source of alpha-linolenic acid, which has benefits in its own right. However, claims that it is a good substitute for EPA and DHA are false. Dogs and cats cannot convert more than 1-2% of it to essential EPA, and none to DHA. (See our article on Omega-3s for pets for details on these oils.) Therefore, our pets still need a direct (animal-based) source of those vital fatty acids. Those sources include:
Fish oil – This is the most well-known source of EPA and DHA. In some pet foods, fish meal is used to provide fish oil, but quality is an issue–it turns rancid quickly–and it is not as effective as direct supplementation. The quality and freshness of fish used in pet foods is of great concern. For instance, salmon should be a good source, but nearly all the salmon and salmon oil in today’s market comes from fish raised in “factory farms” where they are overcrowded, heavily parasitized, and loaded with toxins. “Atlantic” and “Norwegian” salmon oils are from farmed salmon. Moreover, salmon (as well as tuna, tilapia, grouper, bass, mackerel, and many others) are predatory (eat other fish), so in polluted waters, environmental toxins become concentrated in their flesh and fat. However, wild salmon oil from the clean waters of Alaska is still a good source. Additionally, Nordic Naturals draws from sustainable stocks of abundant small non-predatory fish (sardines and anchovies) to create pure fish oil products for pets in both liquid and capsule forms.
Cod liver oil – Some of us “older” folks remember getting a giant spoonful of cod liver oil every day when we were kids. Since I grew up in a first-generation Norwegian family, you can bet I got my share! Nowadays, cod liver oil for people comes in different flavors, from lemon to peach, with added vitamins A and D. However, human products are not suitable for pets due to additives and the excessive A and D, which can lead to toxicity. More deceptively, since cod fishing in the Atlantic has been banned for years due to severe depletion of wild stocks (which have not recovered), the law allows other fish species to be referred to as cod. For cats and dogs, the safest and best quality cod liver oil is made by Nordic Naturals, which are sustainably harvested under strict supervision, and processed right on the dock for absolute freshness.
Krill oil – This product is making waves in the Omega-3 market. Krill are small shrimp-like crustaceans that live in the coldest waters. They are a major food source for whales and other marine mammals. Krill oil does contain EPA and DHA comparable to fish oil. There are only two major manufacturers of krill oil capsules (and a couple of minor ones); so the highest-priced product is not significantly different from the cheaper ones. I tried krill oil for a while a few years ago. I liked the smaller capsules and the lack of “fish burps.” Then I found out that “fish burps” are actually a sign of rancidity, and they don’t occur if you use a better quality product in the first place!
Krill oil proponents point out that krill are one of the largest biomasses on the planet, so they “can’t” be over-harvested. That’s true to some extent, but the real environmental concern is that krill are being harvested in the same areas that whales, fish, seabirds, and other animals feed, without concern for sustainability. Whales and penguins are already being affected by this irresponsible harvesting; we cannot recommend krill oil for this reason.
Green-lipped mussel oil – A relative newcomer to the market, these mussels come from New Zealand and are specifically and sustainably grown for food, not taken from the wild, so there is no danger of over-harvesting. These shellfish contain not only EPA and DHA but more than a dozen other long-chain PUFAs (poly-unsaturated fatty acids) that have simply not yet been studied. It will be interesting to see how the research develops. The capsules are very small, so this may be advantageous for some pets, especially cats. At least one product also contains extra antioxidants.
Whatever form of Omega-3 supplementation you choose, you must provide these essential fatty acids to your pet to ensure a long and healthy life!