Fish oils seem to help reduce some fat levels in the blood. These fats are called triglycerides. Birth control pills might decrease the effectiveness of fish oils by reducing these fat levels in the blood.Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.
The randomized trials assessing the efficacy of fish oil supplementation on secondary prevention of CAD lend further evidence to the findings that fish oil may protect from sudden cardiac death.36 The Diet and Reinfarction Trial (DART),37 one of the first randomized trials of fish oil in CAD, has been interpreted as potential support for fish oil’s role in sudden death reduction because the primary outcome of all-cause mortality occurred within 2 months of the trial’s onset.38 After such a short time span, it was believed that atherosclerosis would not be altered and therefore another mechanism was reducing mortality. This was further supported by the fact that nonfatal MIs were not reduced. Although the actual modes of death other than CAD-related deaths were not documented, it has been postulated to be secondary to a reduction in sudden death.39 The Gruppo Italiano per lo Studio della Sopravvivenza nell’Infarto Miocardico-Prevenzione40 (GISSI-Prevenzione) trial, a larger randomized trial of fish oil in CAD, has also been interpreted as evidence for fish oil’s protection against sudden death. Sudden death, however, was not a primary end point. Rather, the reduction in fatal events was driven by a reduction in cardiovascular death, which included coronary death, cardiac death, and sudden death.
So for those people who will not eat liver, cod liver oil on a daily basis can be a very good way of getting that. And you do benefit from the omega-3 fatty acids, and with the cod liver oil, it may even be unimportant to eat fish if you’re getting the cod liver oil, although it’s still better to focus on the fish, the egg yolks, and just add some of the cod liver oil.
Causing unsafe conditions. Fish oil may increase the risk of bleeding, which can lead to an unsafe condition. Excessive bleeding inside the body may also lead to conditions such as ulcers or liver disease which could be quite dangerous. Be aware of the signs and symptoms of this condition such as bruising easily or nosebleeds which could be a sign that you are developing this condition. If you begin to bleed more easily than usual then you should reduce the amount of fish oil you take regularly to reduce this condition.
Bell, J. G., Miller, D., MacDonald, D. J., MacKinlay, E. E., Dick, J. R., Cheseldine, S., Boyle, R. M., Graham, C., and O'Hare, A. E. The fatty acid compositions of erythrocyte and plasma polar lipids in children with autism, developmental delay or typically developing controls and the effect of fish oil intake. Br J Nutr 2010;103(8):1160-1167. View abstract.

In a U.K. study, children of mothers who ate more than 12 ounces a week actually scored better on tests of verbal I.Q., social behavior, and development and communication than children of mothers who ate none. In the Seychelles Islands, where people average 12 fish meals -- not ounces -- a week, there are no reports of links between mercury exposure and poor outcomes in children. These studies suggest that eating less than 12 ounces of fish each week could do more harm to a child's developing neurological system than mercury poisoning.

Secondly, when we consume EPA, it inhibits the production of AA from DGLA and also competes with AA for uptake into cell membranes and can therefore lower the amount of AA in membranes by literally saturating the cell – in essence, it takes up more of the available ‘space’ and displaces AA. When there is less AA present, there is a reduced capacity for it to produce inflammatory products.
"Fish is still the mainstay of the diet in many parts of the world where there is very little heart disease," he says. "I think when you replace higher fat foods and highly processed foods with fish there is going to be some benefit.'' So it may be that by substituting fish for red meats, bacon and luncheon meats, and similar high-fat foods, you are making a change that will lead to improving your health outcomes, he says.

The effect of fish oil on incident atrial fibrillation has not been studied in large randomized trials, and observational population-based trials show mixed results. The Danish Diet, Cancer and Health Study, and the Rotterdam Study followed 47,000 and 5100 middle-aged adults, respectively.45,46 Neither study found that the consumption of fish oil affected the incidence of atrial fibrillation. Similar findings were seen in the Women’s Health Initiative where there was no association between fish and omega-3 FA intake regarding incident atrial fibrillation.47 However, in a 12-year prospective, observational study of 4815 adults over the age of 65, daily fish consumption was associated with a 31% risk reduction in incident atrial fibrillation.48
Hanwell, H. E., Kay, C. D., Lampe, J. W., Holub, B. J., and Duncan, A. M. Acute fish oil and soy isoflavone supplementation increase postprandial serum (n-3) polyunsaturated fatty acids and isoflavones but do not affect triacylglycerols or biomarkers of oxidative stress in overweight and obese hypertriglyceridemic men. J Nutr 2009;139(6):1128-1134. View abstract.
Finally, in order for AA to be converted into inflammatory products it must be released from phospholipids (part of the cell membrane) using the enzyme phospholipase A2 and then converted by the enzyme cyclooxygenase. EPA utilises both of these enzymes, so if EPA levels are increased in the diet, it attracts enzyme away from AA to EPA – again giving rise to anti-inflammatory products instead of inflammatory ones.

It is also believed that women who do not have a sufficient intake of EPA and DHA in their diet suffer from depression after childbirth, as there is a transfer of some amount of brain mass from the mother to the child in the last stages of pregnancy. Thus, it is very beneficial to consume fish oil either by eating fish or taking fish oil supplements, tablets, capsules, or pills during pregnancy for the overall development of the child and the well-being of the mother. However, it should be noted that fish oil obtained from the liver of the fish, example – cod liver oil, should not be consumed during pregnancy as cod liver oil is high in retinol and vitamin A, which are usually known to cause birth defects.
Maclean, C. H., Mojica, W. A., Morton, S. C., Pencharz, J., Hasenfeld, Garland R., Tu, W., Newberry, S. J., Jungvig, L. K., Grossman, J., Khanna, P., Rhodes, S., and Shekelle, P. Effects of omega-3 fatty acids on lipids and glycemic control in type II diabetes and the metabolic syndrome and on inflammatory bowel disease, rheumatoid arthritis, renal disease, systemic lupus erythematosus, and osteoporosis. Evid.Rep.Technol.Assess.(Summ.) 2004;(89):1-4. View abstract.
The human body can make most of the types of fats it needs from other fats or raw materials. That isn’t the case for omega-3 fatty acids (also called omega-3 fats and n-3 fats). These are essential fats—the body can’t make them from scratch but must get them from food. Foods high in Omega-3 include fish, vegetable oils, nuts (especially walnuts), flax seeds, flaxseed oil, and leafy vegetables.
Nonetheless, large population studies with solid data both on the participants’ diets and causes of disease and death bolstered the beliefs that eating fish often was a heart-healthy practice linked to reduced rates of cardiovascular disease. For example, a comprehensive analysis conducted by Dr. Dariush Mozaffarian and Eric Rimm of the Harvard T.H. Chan School of Public Health found that eating two servings of fatty fish a week — equal to about two grams of omega-3 fatty acids — lowered the risk of death from heart disease by more than a third and total deaths by 17 percent.

Mozaffarian D, Marchioli R, Macchia A, Silletta MG, Ferrazzi P, Gardner TJ, Latini R, Libby P, Lombardi F, O'Gara PT, Page RL, Tavazzi L, Tognoni G; OPERA Investigators. Fish oil and postoperative atrial fibrillation: the Omega-3 Fatty Acids for Prevention of Post-operative Atrial Fibrillation (OPERA) randomized trial. JAMA 2012;308(19):2001-11. View abstract.

Thanks to fatdog11 for that informative post about PCB’s in fish-oil supplements. Are these same toxicity levels found in fish themselves, or possibly are these levels so high only in highly concentrated fish-oil products? Also, can fatdog11 please inform us more about algae-derived omega-3. What are the DHA and EPA levels in these capsules? What is the cost, and where can they be purchased?
These conversions occur competitively with omega−6 fatty acids, which are essential closely related chemical analogues that are derived from linoleic acid. They both utilize the same desaturase and elongase proteins in order to synthesize inflammatory regulatory proteins.[50] The products of both pathways are vital for growth making a balanced diet of omega−3 and omega−6 important to an individual's health.[77] A balanced intake ratio of 1:1 was believed to be ideal in order for proteins to be able to synthesize both pathways sufficiently, but this has been controversial as of recent research.[78]
Keck, P. E., Jr., Mintz, J., McElroy, S. L., Freeman, M. P., Suppes, T., Frye, M. A., Altshuler, L. L., Kupka, R., Nolen, W. A., Leverich, G. S., Denicoff, K. D., Grunze, H., Duan, N., and Post, R. M. Double-blind, randomized, placebo-controlled trials of ethyl-eicosapentanoate in the treatment of bipolar depression and rapid cycling bipolar disorder. Biol.Psychiatry 11-1-2006;60(9):1020-1022. View abstract.
Omega−3 fatty acids are important for normal metabolism.[8] Mammals are unable to synthesize omega−3 fatty acids, but can obtain the shorter-chain omega−3 fatty acid ALA (18 carbons and 3 double bonds) through diet and use it to form the more important long-chain omega−3 fatty acids, EPA (20 carbons and 5 double bonds) and then from EPA, the most crucial, DHA (22 carbons and 6 double bonds).[8] The ability to make the longer-chain omega−3 fatty acids from ALA may be impaired in aging.[9][10] In foods exposed to air, unsaturated fatty acids are vulnerable to oxidation and rancidity.[11]
Recent studies have shown that the consumption of fish oil (or, more specifically, the omega-3 fatty acids found in fish oil) can improve fertility in both men and women. DHA, which is a byproduct of omega-3 fatty acids, plays a key role in the mobility of sperm and health of sperm in men. Low blood levels of DHA have been linked to decreased fertility. Animal studies have found that the DHA in fish is vital to changing dysfunctional round-headed sperm into strong swimmers with cone-shaped heads packed with egg-opening proteins. (29)
The reason why fish oil could increase a man’s risk of prostate cancer is IMBALANCE. Like I said earlier, omega-6 fatty acids aren’t bad for you. In fact, if your diet contains too many omega-3 fatty acids, your immune system wouldn’t work very well because omega-3 and omega-6 fatty acids are meant to work in a system of checks and balances. Omega-3 fatty acids suppress inflammation, and omega-6 fatty acids promote inflammation, which actually supports your body’s natural system of defense like activating your white blood cells.
Maclean, C. H., Mojica, W. A., Morton, S. C., Pencharz, J., Hasenfeld, Garland R., Tu, W., Newberry, S. J., Jungvig, L. K., Grossman, J., Khanna, P., Rhodes, S., and Shekelle, P. Effects of omega-3 fatty acids on lipids and glycemic control in type II diabetes and the metabolic syndrome and on inflammatory bowel disease, rheumatoid arthritis, renal disease, systemic lupus erythematosus, and osteoporosis. Evid.Rep.Technol.Assess.(Summ.) 2004;(89):1-4. View abstract.
AAKG β-hydroxy β-methylbutyrate Carnitine Chondroitin sulfate Cod liver oil Copper gluconate Creatine/Creatine supplements Dietary fiber Echinacea Elemental calcium Ephedra Fish oil Folic acid Ginseng Glucosamine Glutamine Grape seed extract Guarana Iron supplements Japanese Honeysuckle Krill oil Lingzhi Linseed oil Lipoic acid Milk thistle Melatonin Red yeast rice Royal jelly Saw palmetto Spirulina St John's wort Taurine Wheatgrass Wolfberry Yohimbine Zinc gluconate
Researchers are taking a hard look at a different sort of balance, this one between possible effects of marine and plant omega-3 fats on prostate cancer. Results from the Health Professionals Follow-up Study and others show that men whose diets are rich in EPA and DHA (mainly from fish and seafood) are less likely to develop advanced prostate cancer than those with low intake of EPA and DHA. (6) At the same time, some-but not all-studies show an increase in prostate cancer and advanced prostate cancer among men with high intakes of ALA (mainly from supplements). However, this effect is inconsistent. In the very large Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, for example, there was no link between ALA intake and early, late, or advanced prostate cancer. (7)
Heart rate variability, a possible surrogate outcome for the risk of sudden death, was assessed in a randomized trial of myocardial infarction (MI) survivors with an ejection fraction of 40%. In the 49 patients that were randomized to either fish oil or olive oil, Holter monitor recordings showed an increase in heart rate variability in the fish oil group.31 In a larger cohort assessed in the Japan EPA Lipid Intervention Study (JELIS),32 however, no difference in heart rate variability could be attributed to fish oil.
Australian researchers published results of a study examining the effects of fish oil on weight loss in combination with diet and exercise in the May 2007 issue of American Journal of Clinical Nutrition. The results show that a combination of fish oil supplements and regular exercise can reduce body fat while also improving heart and metabolic health. The fish supplementation group had lowered triglycerides, increased HDL cholesterol and improved blood flow. Overall, adding fish oil to a current exercise program (and a overall healthy lifestyle) looks like it can decrease body fat as well as cardiovascular disease risk. (32)
Stiefel, P., Ruiz-Gutierrez, V., Gajon, E., Acosta, D., Garcia-Donas, M. A., Madrazo, J., Villar, J., and Carneado, J. Sodium transport kinetics, cell membrane lipid composition, neural conduction and metabolic control in type 1 diabetic patients. Changes after a low-dose n-3 fatty acid dietary intervention. Ann Nutr Metab 1999;43(2):113-120. View abstract.
Jump up ^ Naliwaiko, K.; Araújo, R.L.F.; Da Fonseca, R.V.; Castilho, J.C.; Andreatini, R.; Bellissimo, M.I.; Oliveira, B.H.; Martins, E.F.; Curi, R.; Fernandes, L.C.; Ferraz, A.C. (2004). "Effects of Fish Oil on the Central Nervous System: A New Potential Antidepressant?". Nutritional Neuroscience. 7 (2): 91–99. doi:10.1080/10284150410001704525. PMID 15279495.
Even healthy oils form trans fats when heated. Each oil has a different temperature at which it forms its own trans fats. Generally, when the oil begins to smoke is when trans fats are formed. Did this study consider how and at what temperatures the fish were cooked? Are some of the suppliments heated before being made into capsules? Did it also consider that many types of fish have dangerous levels of mercury?
The FDA product label on Lovaza warns of potential bleeding complications with the coadministration of anticoagulants. This warning is based on observational studies that suggested a prolonged bleeding time in populations ingesting high levels of fish oil77 and on in vitro studies that demonstrated an effect on pro-thrombotic mediators such as a reduction in thromboxane A2 production78 and platelet activation factor.79 The same trend, however, has not been clearly demonstrated in measurements of clotting times or in factors of fibrinolysis.80 In addition, in randomized clinical trials of patients undergoing coronary artery bypass graft surgery, percutaneous transluminal coronary angioplasty, endarterectomy and diagnostic angiography, no adverse bleeding related events have been demonstrated.81 For example, in a trial of 500 patients randomized to pretreatment with 6.9 g of DHA and EPA preparation 2 weeks before balloon percutaneous transluminal coronary angioplasty (where all the patients received 325 mg/d of aspirin and heparin bolus periprocedure), no difference was seen in bleeding complications.82 Similar results were seen in a trial of 610 patients undergoing coronary artery bypass graft surgery, randomized to either placebo or 4 g/d of fish oil and then further randomized to aspirin or warfarin (dosed to an international normalized ratio [INR] goal of 2.5–4.2). At 1 year, the number of bleeding complications was not increased.15 The effect of fish oil on INR values has not been studied extensively, but a small, randomized trial showed that fish oil did not alter the Coumadin dosing regimen.83 There is very little evidence that a lower target INR is necessary in patients receiving chronic warfarin therapy and fish oil.
A study published in Brain Research shows how far-reaching fish oil can be for people with diabetes. Researches found that fish oil can help reduce the risk of diabetics from developing cognitive deficit because it protects the hippocampus cells from being destroyed. The study also showed that fish oil could help reduce oxidative stress, which plays a central role in the development of diabetes complications, both microvascular and cardiovascular. (22)
“The review provides good evidence that taking long-chain omega 3 (fish oil, EPA or DHA) supplements does not benefit heart health or reduce our risk of stroke or death from any cause.  The most trustworthy studies consistently showed little or no effect of long-chain omega 3 fats on cardiovascular health. On the other hand, while oily fish is a healthy food, it is unclear from the small number of trials whether eating more oily fish is protective of our hearts. 
The two key omega-3 fatty acids are docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Fatty fish like salmon, mackerel, and sardines are rich in these omega-3s. Some plants are rich in another type of omega-3 fatty acid, alpha-linolenic acid, which the body can convert to DHA and EPA. Good sources of these are flaxseeds, chia seeds, walnuts, pumpkin seeds, and canola oil.
The current American diet has changed over time to be high in SFA and low in omega-3 fatty acids (12). This change in eating habits is centered on fast food containing high amounts of saturated fat, which has small amounts of essential omega-3 PUFA compared with food prepared in the home (13). Seafood sources such as fish and fish-oil supplements are the primary contributors of the 2 biologically important dietary omega-3 fatty acids, EPA and DHA (14–16). This low intake of dietary EPA and DHA is thought to be associated with increased inflammatory processes as well as poor fetal development, general cardiovascular health, and risk of the development of Alzheimer's disease (AD).
Samsonov, M. A., Vasil'ev, A. V., Pogozheva, A. V., Pokrovskaia, G. R., Mal'tsev, G. I., Biiasheva, I. R., and Orlova, L. A. [The effect of a soy protein isolate and sources of polyunsaturated omega-3 fatty acids in an anti-atherosclerotic diet on the lipid spectrum of blood serum and immunological indicators in patients with ischemic heart disease and hypertension]. Vopr.Med Khim. 1992;38(5):47-50. View abstract.

Macchia, A., Levantesi, G., Franzosi, M. G., Geraci, E., Maggioni, A. P., Marfisi, R., Nicolosi, G. L., Schweiger, C., Tavazzi, L., Tognoni, G., Valagussa, F., and Marchioli, R. Left ventricular systolic dysfunction, total mortality, and sudden death in patients with myocardial infarction treated with n-3 polyunsaturated fatty acids. Eur.J.Heart Fail. 2005;7(5):904-909. View abstract.
After just seven days, those supplementing with krill had their CRP levels reduced by 19.3%, while in the placebo group, CRP levels rose by 15.7%. Even more impressive, the krill benefit was long-lasting. The krill group’s CRP levels continued to fall by 29.7% at 14 days, and 30.9% at 30 days. More importantly from the patients’ points of view, the krill oil supplement reduced pain scores by 28.9%, reduced stiffness by 20.3%, and reduced functional impairment by 22.8%.
Funding/Support: The work was supported in part by grant 17H04253, Grant-in-Aid for Scientific Research (B) from the Japan Society for the Promotion of Science; grant 30-A-17 from the National Cancer Center Research and Development Fund; grants MOST106-2314-B-039-027-MY, 106-2314-B-038-049, 106-2314-B-039-031, 106-2314-B-039-035, 104-2314-B-039-022-MY2, and 104-2314-B-039-050-MY3 from the Ministry of Science and Technology, Taiwan; grant HRI-EX105-10528NI from the National Health Research Institutes, Taiwan; and grants CRS-106-063, DMR-107-202, and DMR-107-204 from the China Medical University, Taiwan.
There was a significantly greater association of treatment with reduced anxiety symptoms in participants receiving omega-3 PUFAs than in those not receiving omega-3 PUFAs in the subgroup with an EPA percentage less than 60% (k, 11; Hedges g, 0.485; 95% CI, 0.017-0.954; P = .04; Figure 4)35,49,52,54-61 but no significant difference in the association of treatment with reduced anxiety symptoms between participants receiving omega-3 PUFAs and those not receiving omega-3 PUFAs in the subgroup with an EPA percentage of at least 60% (k, 9; Hedges g, 0.092; 95% CI, –0.102 to 0.285; P = .35) (Figure 4).33,34,36,47,48,50,51,53,60 There were no significantly different estimated effect sizes between these 2 subgroups by the interaction test (P = .13).

There’s evidence that points to the mechanism behind the effects of fish oil on body composition, showing that fat burning at rest is increased with 6 grams/day of fish oil supplementation, and additional research suggests that higher omega-3 levels may be helpful for enhancing satiety during weight loss efforts. Other evidence suggests that fat loss may be a side-effect of the reduction in inflammation that fish oil can help with. Any way you look at it, supporting your dietary habits with 4 or more grams of fish oil per day is probably a good idea!


Most brands of fish oil have been proven safe, free of detectable traces of mercury, and do not contain unsafe levels of PCBs (polychlorinated biphenyls), a toxin and pollutant believed to pose various health threats. To avoid contaminants in an unrefined supplement, it's best to choose a fish-oil supplement made from small, oily fish like anchovy, sardines or menhaden.
About the only exception are wild-caught Alaskan salmon and very small fish like sardines. The highest concentrations of mercury are found in large carnivorous fish like tuna, sea bass, and marlin. You may need to be especially cautious of canned tuna as well, as independent testing by the Mercury Policy Project found that the average mercury concentration in canned tuna is far over the "safe limits" of the Environmental Protection Agency (EPA).

Scaly, itchy skin (eczema). Fish oil might help PREVENT eczema, but research is not consistent. Some early research suggests that mothers who take fish oil supplements during pregnancy reduce the risk of severe eczema in their infants. Also, population research suggests that children who eat fish at least once weekly from 1 to 2 years of age have a lower risk of developing eczema. But other research, including recent studies, suggests that neither supplementation during pregnancy nor supplementation during infancy reduces the risk of eczema. Overall, research suggests that fish oil does not help TREAT eczema once it has developed.


Jump up ^ Bloch MH, Qawasmi A (October 2011). "Omega-3 fatty acid supplementation for the treatment of children with attention-deficit/hyperactivity disorder symptomatology: systematic review and meta-analysis". Journal of the American Academy of Child and Adolescent Psychiatry. 50 (10): 991–1000. doi:10.1016/j.jaac.2011.06.008. PMC 3625948. PMID 21961774.
The Cochrane researchers found that increasing long-chain omega 3 provides little if any benefit on most outcomes that they looked at. They found high certainty evidence that long-chain omega 3 fats had little or no meaningful effect on the risk of death from any cause. The risk of death from any cause was 8.8% in people who had increased their intake of omega 3 fats, compared with 9% in people in the control groups.
To evaluate the potential placebo effect, we made further subgrouping analyses. In the subgroups of studies using placebo controls, the omega-3 PUFAs still revealed a consistent positive anxiolytic association with anxiety symptoms. These phenomena meant that the anxiolytic effect of omega-3 PUFAs is probably not entirely owing to the placebo effect.
Metagenics offers a wide range of educational opportunities including webinars, group meetings, and seminars as part of our commitment to continuing functional medicine education. Our goal is to give our practitioners further insight to help address their patients’ unique health needs for a higher level of personalized, lifetime wellness care. We have been sharing this ever-growing body of nutritional and lifestyle research for over 25 years.
Nielsen, A. A., Jorgensen, L. G., Nielsen, J. N., Eivindson, M., Gronbaek, H., Vind, I., Hougaard, D. M., Skogstrand, K., Jensen, S., Munkholm, P., Brandslund, I., and Hey, H. Omega-3 fatty acids inhibit an increase of proinflammatory cytokines in patients with active Crohn's disease compared with omega-6 fatty acids. Aliment.Pharmacol.Ther. 2005;22(11-12):1121-1128. View abstract.
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