Fish oils, flax seeds and krill oil

Paul Johnson



Essential fatty acids can be found in fish oils, flax seeds and krill oil and have a number of important benefits in sports nutrition, says Paul Johnson MSc, BSc, SENr. Following on from my previous blog about coconut oil, this article will be focusing on the other "good fats" that we need in our diet to improve both health and athletic performance. These include fish oils, flax seed and krill oil. Fish oils, flax seed and krill oil all contain Essential Fatty Acids (EFAs). They are given this name because they are required for life but our bodies cannot make them and they have to be obtained through the food we eat. These EFAs can be used to make hormone like substances called prostglandins, which help to regulate a number of important bodily functions and reactions. The most common EFAs are omega 3 (alpha linolenic acid) and omega 6 (linoleic acid).

Essential Fatty Acids

The balance between the types of fat we eat is of huge importance to both health and body composition. Our intakes of the right fats are often unbalanced because of the way that modern food and livestock are farmed: The natural ratio between omega 3 and omega 6 has increased to around 1:20, but ideally we want this ratio to be 1:3 (1). Omega 6 is a pro inflammatory fat as it competes for the same receptor site as omega 3. This means if you have lots of omega 6 (vegetable oil) and not enough omega 3 (fish oils, flax seed, krill oil) then your body is at a risk of increased inflammation (which is bad). The result being that the body is at increased risk of chronic inflammation which is linked to cancers, heart conditions, hypertension and diabetes. Correcting this balance can be achieved by increasing your intake of omega 3 and reducing your intake of omega 6 if excessive amounts are currently being consumed. The research behind the use of fish oils to obtain sufficient intakes of omega 3 is extremely impressive and extensive. The active compounds in fish oils are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The health benefits of fish oils on health, body composition, cognitive function and athletic performance are hugely significant. As omega 3 is an essential fatty acid it needs to be consumed daily to exert its effects. The suggested intake of fish oils is 3 grams of fish oils per day which provides 1200mg of EPA and 1800mg of DHA (3). When obtaining this from supplements it is important to note that the number of capsules required to achieve this amount of active EPA and DHA will vary depending on the source of omega 3. Six standard fish oils capsules will achieve this whereas the same amount of EPA and DHA can be achieved with a lower dose of krill oil due to its high bioavailability. Positive effects that fish oils and krill oil and flax seed may have on the body include:
  • Improved insulin sensitivity
  • Reduced blood pressure
  • Improvement in blood lipids (HDL and LDL cholesterol)
  • Improved cardiovascular health
  • Reduced inflammation
  • Improve cognitive function and memory
  • Improve calorie partitioning
  • Increased fat oxidation and metabolic rate and weight loss

Omega 3 fatty acids

Omega 3s also play a hugely significant role in weight management and reducing body fat. They do this by a number of mechanisms, which make them highly effective for fat loss for a wide range of people, particularly those that are sensitive to stimulant based weight loss products. 1. Increasing your intake of EFA helps to reduce levels of triglycerides (stored fats), this then helps improve insulin sensitivity, meaning that less insulin is required to push carbohydrates and amino acids into muscle cells. As a result the body is less likely to push carbohydrates and fats into fat cells (3, 4). 2. Improved fuel partioning, meaning that the body gets better at storing calories in muscle tissue for later use (this is good) and more efficient at directing calories away from triglycerides meaning that are available to be more readily burnt (4). 3. Fish oils can directly improve the body's ability to burn fat by boosting the enzyme that is responsible for carrying fat into a cell for it to be burnt (by expending it as heat rather then storing it as fat). At the same time it also down regulates the enzyme fatty acid synthase, which is responsible for encouraging fat storage. This means that body is less efficient at storing calories as fat (5). 4. Improved recovery from exercise due to aiding protein synthesis posted exercise when combined with increased levels of amino acids and insulin (i.e a post training meal) while reducing post exercise oxidative stress (6, 7, 8).

Flax seed oil

While flax seed is a good source of omega 3, it is low in the active compounds EPA and DHA and relies on the conversion of Alpha-Linolenic Acid (ALA) to form EPA and DHA. This is an inefficient process, meaning that higher intakes of flax seed are required to achieve effective levels of EPA and DHA, because only between 5 – 15% of ALA is converted to the active form required to achieve the proposed benefits of omega 3 (9). On the plus side, an often under reported benefit of flax seed is its ability to help remove excess estrogen from the body due to its lignans and phenols content. This is of particular use to women looking to reduce body fat from hips and thighs due to estrogens effect of activating the alpha receptors in the fat cells of these areas which make them less sensitive to the actions of catecholamines resulting in a much slower release of fat from the cells. [caption id="attachment_1321" align="aligncenter" width="530"]Flax seeds Flax seeds have fat burning potential. Picture © Healthaliciousness.[/caption] For men it could have potential use for those looking to reduce body fat from the pec area. Although we cannot specifically spot reduce where fat is lost from, we can do as much as possible to help regulate the hormones responsible for fat storage in certain areas. Finally flax seed may have a positive effect on two hormones called leptin and adiponectin. This results in a boost to the muscles metabolism and their energy uptake while adiponectin makes muscle cells more sensitive to insulin. This is a win-win for improving body composition: Improved fat burning potential while improving where in coming calories are directed to (10). Adding ground flax seeds (they need to be ground as they cannot be digested whole) to shakes, smoothies or other recipes is an easy way to increase fibre intake while gaining all the additional benefits that flax seeds have to offer.

Krill oil: The up and coming star

Krill oil is oil that is derived from krill (a small sea crustacean that fish eat, hence how they get their omega 3). It contains high levels EPA, and DHA. However, a large portion of the EPA and DHA in krill is in the form of a phospholipid, with a phosphate group on the end of the fatty acid. This results in a higher rate of absorption of EPA and DHA, hence the same effects of fish oil can be obtained with krill oil but at approximately half the dose compared to standard fish oil capsules (11). It also contains a substance called astaxanthin which is potent anti-inflammatory and has more anti-oxidant capabilities than vitamin A and E, while also encouraging the body to use more fat and less glucose during exercise, this may have a performance enhancing effects (12). While fish oils are better studied, research on both krill and astaxanthin is still in its early stages, but at present it looks promising for improving health, body composition and performance.

Essential fatty acids

There are very few supplements that are a "must have" for such a wide range of different populations and goals, but supplementing with a source of omega 3 is one that has something to offer that will benefit everyone. Regardless of which source of omega 3 is chosen to boost overall intake, extra benefits can also be obtained and alternating sources ensures that you can obtain the full range. Omega 3 supplementation is cheap, safe, effective and extensively researched for a wide range of different situations meaning it truly is a sports nutrition superstar.

What you need to know

Omega 3 fatty acids are classed as essential, as the body cannot make then, meaning they need to be obtained from our diet. Due to our modern western diet, the balance between omega 6 and omega 3 is often skewed, promoting inflammation. To achieve an optimum balance we should aim to reduce our intake of processed vegetable oil and increase our omega 3 intake. The active compounds in fish oils are eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), which can easily and safely be achieved via supplementation. Omega 3 has been shown to have positive effect on insulin sensitivity, blood pressure, cardiovascular health markers, inflammation, cognitive function, fat burning, calorie partitioning and recovery from exercise. Flaxseed, although not supplying as much EPA and DHA as fish or krill oil has additional benefits that cannot be achieved with these oils, and is a great additional to shake, smoothies and home baking. Krill oil is more bioaviable and less prone to oxidation then regular fish oils, meaning a smaller doses is require to achieve the same active amount of EPA and DHA, while also other providing additional anti-oxidant qualities due to its high levels of vitamin A, E and astaxanthin.

Further reading on fish oils, krill oil and flax seed

1. Jew S, AbuMweis SS, Jones PJ. Evolution of the human diet: linking our ancestral diet to modern functional foods as a means of chronic disease prevention. J Med Food. 2009 Oct;12(5):925-34 2. Simopoulos AP. Human requirement for N-3 polyunsaturated fatty acids. Poult Sci. 2000 Jul;79(7):961-70 3. Hill AM, et al. combining fish-oil supplements with regular aerobic exercise improves body composition and cardiovascular disease risk factors. Am J Clin Nutr. 2007 May;85(5):1267- 4. Defina LF, et al. Effects of omega-3 supplementation in combination with diet and exercise on weight loss and body composition. Am J Clin Nutr. 2010 Dec 15. 5. Noreen EE, et al. Effects of supplemental fish oil on resting metabolic rate, body composition, and salivary cortisol in healthy adults. J Int Soc Sports Nutr. 2010 Oct 8;7(1):31 6. Rodacki CL, et al. Fish-oil supplementation enhances the effects of strength training in elderly women. Am J Clin Nutr. 2012 Jan 4 7. McAnulty SR, et al. Effect of n-3 fatty acids and antioxidants on oxidative stress after exercise. Med Sci Sports Exerc. 2010 Feb 13 8. Smith GI, et al. Omega-3 polyunsaturated fatty acids augment the muscle protein anabolic response to hyperinsulinaemia-hyperaminoacidaemia in healthy young and middle-aged men and women. Clin Sci (Lond). 2011 Sep 1;121(6):267-78 9. Gerster H. Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3). Int J Vitam Nutr Res. (1998) 10. Fukumitsu S, Aida K, Ueno N, Ozawa S, Takahashi Y, Kobori M. Flaxseed lignan attenuates high-fat diet-induced fat accumulation and induces adiponectin expression in mice. Br J Nutr. 2008 Sep; 100(3):669-76. doi: 10.1017/S0007114508911570 11. Maki KC, Reeves MS, Farmer M, Griinari M, Berge K, Vik H, Hubacher R, Rains TM. Krill oil supplementation increases plasma concentrations of eicosapentaenoic and docosahexaenoic acids in overweight and obese men and women. Nutr Res. 2009 Sep;29(9):609-15. doi: 10.1016/j.nutres.2009.09.004 12. Aoi W, Naito Y, Takanami Y, Ishii T, Kawai Y, Akagiri S, Kato Y, Osawa T, Yoshikawa T. Astaxanthin improves muscle lipid metabolism in exercise via inhibitory effect of oxidative CPT I modification. Biochem Biophys Res Commun. 2008 Feb 22;366(4):892-7. Epub 2007

Tagged: Nutrition

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