Fish and fish oils are the main dietary source of omega-3 polyunsaturated fatty acids. Omega-3 fats are known as essential fatty acids and since we're unable to make them in our bodies, it's essential that we obtain them from our diet.
The problem is most North Americans don't get enough of these dietary omega-3s, and to make matters worse, consume an excess of omega-6 fats found in vegetable oil and many processed foods. This imbalance of high omega-6 to omega-3 leads to inflammation, which is associated with many chronic diseases and is considered a key driver of the aging process.
In the 1970s, Danish epidemiologists found that heart disease was virtually non-existent in Inuit populations who consumed high amounts of omega-3 fats from cold-water fish.
This prompted extensive research into the role of fish oils in heart disease and other conditions. The two most well studied omega-3 fats are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both of which have anti-inflammatory properties and contribute to healthy aging and disease prevention.
Conditions That Can Benefit From Fish Oils
1. Joint Health and Arthritis
There's a common notion that fish oils help "lubricate" joints, and while this is a somewhat simplified explanation, omega-3s do appear to be beneficial for joint health. Osteoarthritis is a chronic inflammatory condition that increases with age and fish oils can help reduce pain and inflammation. In one study, eight weeks of EPA and DHA supplementation significantly improved knee function in individuals with knee osteoarthritis.
2. Cardiovascular Health
The most common and well-researched use of fish oils is for the prevention and treatment of cardiovascular disease. EPA and DHA have been shown to help lower blood pressure, reduce triglycerides, and decrease blood clotting. While both omega-3 fats are essential, DHA appears to be particularly beneficial for cardiovascular disease and atherosclerosis (the hardening and narrowing of the arteries).
3. Memory and Cognition
The brain is highly concentrated in EPA and DHA, and it appears that consuming adequate DHA mitigates age-related cognitive decline. One study found that supplementing with DHA for 12 months significantly improved short-term memory in older individuals with mild cognitive impairment, while a separate study concluded that supplementing with EPA and DHA improved mood in adults over 65 with mild cognitive impairment.
4. Our Muscles and Bones
When we think of strong bones, the nutrient that first comes to mind is calcium. However, there's more to bone health than our mineral stores, and it turns out chronic inflammation is one of the main causes of osteoporosis. Therefore, it makes sense that the anti-inflammatory effects of omega-3 fatty acids could help protect against osteoporosis and low bone mass. Research in this field is still limited, but studies have shown that higher omega-3 intake is associated with higher bone mineral density, grip strength and may increase muscle protein synthesis, useful for the prevention and treatment of sarcopenia.
5. Aging and Telomere Length
Telomere length is a marker of biological aging, and slowing this process may be one of the keys to slowing the aging process. Researchers found that individuals with the highest blood levels of EPA and DHA experienced the slowest rate of telomere shortening. Another study found that those with the lowest blood levels of EPA and DHA had smaller brain volumes and vascular patterns of cognitive impairment.
How to Choose the Right Fish Oil
It can be overwhelming to choose between the myriad options of omega-3 supplements. Not all fish oils are made equally, so here are some common questions and considerations to help decide which type is best for you.
Although further research is required to determine specific dosages, men and women age 60+ should aim for at least 500mg EPA and 500mg DHA as part of a healthy aging regimen.
Fish Oil vs. Cod Liver Oil
Although both come from fish, fish oil and cod liver oil have some key differences. Fish oil is made from the body of fish and is a highly concentrated source of EPA and DHA. Cod liver oil doesn't contain as much EPA and DHA, but it does contain the fat-soluble vitamins D and A.
Fish Oil vs. Krill Oil
Krill oil is touted as a better-absorbed form of omega-3 fats, and contains the natural antioxidant astaxanthin. The downside is that it contains significantly less EPA and DHA than other fish oils, and the cost tends to be much higher. Add to that concerns over the sustainability of krill harvesting and it's difficult to recommend krill oil over other forms of fish oils.
Fish Oils and Blood Clotting
As fish oils are known to reduce blood clotting, there's a concern for those taking blood thinners or with known clotting disorders. However, one study showed that use of high dose fish oils (4g/day) didn't affect bleeding in patients taking aspirin or Warfarin. Another smaller study reported that fish oil supplements did not affect clotting time in those on long-term Warfarin therapy. There is one case report of fish oils interacting with Warfarin therapy, so if you're taking anticoagulant medications it's recommended that you speak with your health care provider before taking fish oils.
Fish Oil Quality and Purity
One concern with fish oil supplements is heavy metal contamination. It's imperative when choosing a fish oil that the company provides a certificate of analysis (preferably by an independent third party) that checks for contaminants such as heavy metals, dioxins, and polychlorinated biphenyls (PCBs).
Metals tend to accumulate more in larger fish such as tuna and salmon, and less so for small fish such as anchovies and sardines. Also, as polyunsaturated fats are prone to oxidation, it's easy for fish oils to go rancid. A strong "fishy" taste or odor is a sign of rancidity. To ensure high quality control standards, check to see if your fish oil has third party testing through the International Fish Oil Standards (IFOS) program or similar independent laboratory.
EPA and DHA Levels
If you look closely at a fish oil label, you'll likely see 'total omega-3,' 'EPA' and 'DHA' levels listed. A higher quality product will have a high content of EPA and DHA compared to the total omega-3, and since most of the research is done on EPA and DHA, that's what we want to get out of a fish oil supplement.
Dietary Sources of Omega-3s
Those who consume cold water fish (i.e. salmon, tuna, sardines) two to three times per week are likely meeting their omega-3 quota. You may have also heard that flax seed oil and other vegetarian foods are a good source of omega-3 fats, and while this is true, most plant sources are rich in alpha-linolenic acid (ALA), which does not readily convert to EPA and DHA in our bodies.
So while flax seeds and other plant sources may have additional health benefits, they're not the best source of EPA and DHA.
It's clear from the research that the omega-3 fats EPA and DHA are essential for healthy aging, and particularly beneficial for cardiovascular health, cognition and memory. For healthy adults who don't consume cold-water fish at least twice a week, a high-quality supplement containing at least 500 mg of EPA and DHA appears to be beneficial.
Those who are at a higher risk for cardiovascular disease or cognitive disorders may benefit from a higher dose, but it's best to discuss this with a licensed health care practitioner.
Dr. Tomah Phillips is a licensed Naturopathic Doctor at Kinetic Patterns Medical Clinic in Vancouver, BC. In addition to clinical practice, Dr. Tomah teaches Biomedical Sciences at the Boucher Institute of Naturopathic Medicine. He holds a BSc. in Physiology from McGill University and obtained his Naturopathic degree from the Boucher Institute of Naturopathic Medicine.
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