Mods, if you could make this a sticky, i'd appreciate it because it is too time consuming to post again. Hopefully you can get all the info you need right here. I'll try to make this very detailed so it only has to be posted once. Fish Oil Vs Flax Oil Q. Is flax a complete source of Omega 3's? A. Flax, nuts and vegetable oils can only provide you with the Omega-3 called ALA (Apha-Linolenic acid), which is not nearly as valuable to the body as the Omega-3s EPA (Eicosapentaenoic Acid) and DHA (Docosahexaenoic Acid). Unlike DHA, ALA does not accumulate, to any significant extent, in the critical tissues of the body (e.g. brain, retina, nervous system). Therefore, you need to consume fatty fish, such as mackerel, sardines, and salmon, or foods containing their fish oils, or supplements. Q. I hear our bodies can convert ALA into DHA and EPA, is this correct? A. Your body can make EPA and DHA from ALA, found in flax and vegetable oils. However, the conversion rate is so low that you cannot consume enough vegetables, vegetable oils, or flax for your body to provide the necessary, optimal levels of EPA and DHA that it needs. You need to obtain EPA and DHA directly from fatty fish, fish oil supplements or foods. Q. Can you tell me conversion rates? A. The conversion of ALA to EPA is usually described as limited and somewhat slow in humans (43). In truth, there is great variability in the conversion rate reported by researchers, with one estimate as high as 6% converted to EPA (44) and one as low as 0.2% converted (45). The 30-fold difference between these conversion rates reflects key differences in the studies’ methods and underscores the need for more research to resolve the issue of how much ALA is converted to longer-chain omega-3 fatty acids in humans. By comparison, chickens readily convert ALA to EPA and DHA, a fact exploited by egg producers in developing the omega-3-enriched egg (46,47). Q. Are there any studies done on Flax and Fish combined? A. The findings of clinical studies suggest that alpha-linolenic acid (ALA) is not as potent in its biologic effects as the longer-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In other words, the health benefits of fish oil and fatty fish rich in EPA and DHA appear to be stronger than those obtained from flax and flax oil rich in ALA. However, the design of most clinical studies may not allow for a good comparison of the effects of EPA and DHA found in fatty fish and fish oil versus ALA found in flax. For example, consider the data shown... In this study, volunteers consumed flax oil daily for eight weeks (74). At week four, volunteers added nine fish oil capsules daily to their flax oil diets. Thus, during the first four weeks of the study volunteers ate only flax oil; during the second four weeks, volunteers ate both flax oil and fish oil. The mean intake of ALA from flax oil was 13.7 g/day. The mean intake of EPA + DHA from fish oil was 2.7 g/day. Effects of flax oil versus fish oil (a) Inflammatory agent Type of agent Change in cell concentration of inflammatory agent (b) Numbers below (%) represent a DECREASE Thromboxane B2 eicosanoid 30%* 58%** Tumor necrosis factor-α cytokine 26%* 76%** Interleukin -1-β cytokine 28%* 81%** (a)Adapted from Caughey et al. (74). (b)Healthy men consumed flax oil for four weeks (weeks 0-4), followed by flax oil plus fish oil capsules for four weeks (weeks 4-8). The concentrations of the inflammatory agents were measured in immune cells. *Significantly different from baseline (week 0). **Significantly different from baseline (week 0) and fromthe flax oil only period (week 4). The findings in the table indicate that fish oil had a significantly greater effect on three measures of inflammation than flax oil. One interpretation of these findings is that, even though the diet contained five times more ALA than EPA + DHA, the biologic effects of EPA and DHA were superior to those of ALA. However, the biologic effects of ALA in this study were achieved by consuming a reasonable level (13/4 tbsp) of flax oil daily, whereas the effects observed during the fish oil period were achieved with an EPA + DHA intake equivalent to eating about 21/2 3-ounce servings of salmon, 12 servings of tuna fish canned in water or 20 servings of cod every day for four weeks. In other words, a reasonable level of ALA obtained from flax oil was compared with a pharmacologic or drug level of EPA and DHA obtained from fish oil in this study. Q. So it looks like I should take both correct? A. For optimal health results, its probably best to take 1-2g of each per day. There are other benefits from flax as well that is left out in fish oil, and vice versa. For instance, take the following... Using the Trolox Equivalence method (an analysis that uses vitamin-E as its benchmark), flaxseed contains roughly twice the antioxidant value of blueberries or blackberries, berries which are celebrated for their antioxidant value. The antioxidant content of flaxseed bran is even higher. Flaxseed's antioxidants include about 1% by weight of lignans (complex polyphenolics) and an additional 1% of simple polyphenolics. In addition, flaxseed contains significant concentrations of tocopherols, tocotrienols and phytic acid. Q. I'm scared of the PCB and mercury contaminants in fish, what is the scoop on this? A. Most products on the market exceed government regulations on safety. If you still have concerns, check the company where you get your stuff from. Q. What about this fish taste? A. Many Omega-3 fish oil capsules are now enteric coated and provide no aftertaste. There are also many microencapsulated formulas avaiable in milk, juice, yogurt, etc etc where the taste is non existent. Coromega makes a GREAT orange and choc one that has NO taste of fish. Q. What about this Krill stuff and micro algae stuff, is it the same? A. Krill is a shrimp like crustacean that contains EPA and DHA, and algae contains DHA. Both of these are unique in their own way and are becoming more popular in the market. Algae for one for vegetarians, and Krill for the reason it contains astaxanthin even though it isn't as high in EPA and DHA as fish. References: 43. Gerster H. 1998. Can adults adequately convert α-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? Internat. J. Vit. Nutr. Res. 68: 159-173. 44. Emken EA, Adlof RO, Gulley RM. 1994. Dietary linoleic acid influences desaturation and acylation of deuterium-labeled linoleic and linolenic acids in young adult males. Biochim. Biophys. Acta 1213: 277-288. 45. Pawlosky RJ, Hibbeln JR, Novotny JA, Salem Jr N. 2001. Physiological compartmental analysis of α-linolenic acid metabolism in adult humans. J. Lipid Res. 42: 1257-1265. 46. Ferrier LK, Caston LJ, Leeson S, et al. 1995. α-Linolenic acid- and docosahexaenoic acid-enriched eggs from hens fed flaxseed: Influence on blood lipids and platelet phospholipid fatty acids in humans. Am. J. Clin. Nutr. 62:81-86. 47. Scheideler SE, Froning GW. 1996. The combined influence of dietary flaxseed variety, level, form, and storage conditions on egg production and composition among vitamin E-supplemented hens. Poult. Sci. 75: 1221-1226. 74. Caughey GE, Mantzioris E, Gibson RA, et al. 1996. The effect on human tumornecrosis factor α and interleukin 1β production of diets enriched in n-3 fatty acids from vegetable oil or fish oil. Am. J. Clin. Nutr. 63: 116-122.