ACS Breast Cancer Screening Guideline CDC Guideline for Prescribing Opioids CDC Guideline for Prevention of Surgical Site Infections Consensus Definitions for Sepsis and Septic Shock Global Burden of Cancer, 1990-2016 Global Burden of Disease in Children, 1990-2013 Global Burden of Hypertension, 1990-2015 Global Firearm Mortality, 1990-2016 Health Care Spending in the US and Other High-Income Countries Income and Life Expectancy in the US JNC 8 Guideline for Management of High Blood Pressure President Obama on US Health Care Reform Screening for Colorectal Cancer Screening for Depression in Adults Screening for Prostate Cancer Statins for Primary Prevention of Cardiovascular Disease The State of US Health, 1990-2016 US Burden of Cardiovascular Disease, 1990-2016 WMA Declaration of Helsinki, 7th Revision
Both omega−6 and omega−3 fatty acids are essential: humans must consume them in their diet. Omega−6 and omega−3 eighteen-carbon polyunsaturated fatty acids compete for the same metabolic enzymes, thus the omega−6:omega−3 ratio of ingested fatty acids has significant influence on the ratio and rate of production of eicosanoids, a group of hormones intimately involved in the body's inflammatory and homeostatic processes, which include the prostaglandins, leukotrienes, and thromboxanes, among others. Altering this ratio can change the body's metabolic and inflammatory state.[16] In general, grass-fed animals accumulate more omega−3 than do grain-fed animals, which accumulate relatively more omega−6.[86] Metabolites of omega−6 are more inflammatory (esp. arachidonic acid) than those of omega−3. This necessitates that omega−6 and omega−3 be consumed in a balanced proportion; healthy ratios of omega−6:omega−3, according to some authors, range from 1:1 to 1:4.[87] Other authors believe that a ratio of 4:1 (4 times as much omega−6 as omega−3) is already healthy.[88][89] Studies suggest the evolutionary human diet, rich in game animals, seafood, and other sources of omega−3, may have provided such a ratio.[90][91]
However, the researchers do have some good news. They concluded that omega 3 fatty acids do appear to reduce the type of blood cholesterol known as triglycerides, but that supplements probably are not useful for preventing or improving heart and circulatory problems. And, upping your intake of plant-based omega 3s high in ALA (ie, walnuts, flaxseed and flax oil, chia seeds) may help your heart somewhat.2
Jatoi, A., Rowland, K., Loprinzi, C. L., Sloan, J. A., Dakhil, S. R., MacDonald, N., Gagnon, B., Novotny, P. J., Mailliard, J. A., Bushey, T. I., Nair, S., and Christensen, B. An eicosapentaenoic acid supplement versus megestrol acetate versus both for patients with cancer-associated wasting: a North Central Cancer Treatment Group and National Cancer Institute of Canada collaborative effort. J.Clin.Oncol. 6-15-2004;22(12):2469-2476. View abstract.

Dornstauder, B., Suh, M., Kuny, S., Gaillard, F., MacDonald, I., Michael T. Clandinin, M. T., & Sauvé, Y. (2012, June). Dietary docosahexaenoic acid supplementation prevents age-related functional losses and A2E accumulation in the retina. Investigative Ophthalmology and Visual Science. Retrieved from http://iovs.arvojournals.org/article.aspx?articleid=2188773

for canned sardines i noticed the omega 3 EPA/DHA levels (written on the can) varied between the different company brands (sometimes by a lot!) , and also, the EPA/DHA amounts varied depending on what was added in the can with the sardines (sunflower oil, olive oil, brine, spring water, etc --- little note: there's more fat in the oily fish, than found in the brine/spring water)
The various enzymes (COX and LOX) that make inflammatory eicosanoids can accommodate both AA and EPA, but again due to the greater spatial size of DHA, these enzymes will have difficulty in converting DHA into eicosanoids. This makes DHA a poor substrate for these key inflammatory enzymes. Thus DHA again has little effect on cellular inflammation whereas EPA can have a powerful impact.

A 2014 meta-analysis of eleven trials conducted respectively on patients with a DSM-defined diagnosis of major depressive disorder (MDD) and of eight trials with patients with depressive symptomatology but no diagnosis of MDD demonstrated significant clinical benefit of omega-3 PUFA treatment compared to placebo. The study concluded that: "The use of omega-3 PUFA is effective in patients with diagnosis of MDD and on depressive patients without diagnosis of MDD."[42]
ADD ADHD Ageing Allergies Alzheimer's Arthritis Autism baby Behaviour Brain function Cancer CFS Chronic Fatigue Concentration Dementia Depression Diabetes Digestion Dyslexia Dyspraxia Energy EPA Fertility Fibromyalgia General Health Good fats Healthy omega-3 Heart health Hormones IBS Immune System Inflammation Joints M.E. Mental health Mood Omega-3 Pregnancy Psoriasis Skin Sleep Stress Vegetarian nutrients Vegetarian Omega-3 Weight management

Increased consumption of omega 3 fats is widely promoted globally because of a common belief that that it will protect against heart disease. There is more than one possible mechanism for how they might help prevent heart disease, including reducing blood pressure or reducing cholesterol. Omega 3 fats are readily available as over-the-counter supplements and they are widely bought and used.


The most extensive data of the effect of fish oil on lipoprotein subfractions are based on trials performed before the widespread use of statins. This data were aggregated over a decade ago in a meta-analysis of 16 randomized trials including over 1500 patients.17 In this analysis, low-density lipoprotein (LDL) was increased by an average of 5% and high-density lipoprotein was marginally changed. Although a shift toward less atherogenic, larger and more buoyant LDL particle composition has been shown,74 this has been offset by the observation that the number of apolipoprotein B 100 particles increases and may be more susceptible to oxidation.75 Increased conversion of remnant particles (intermediate density lipoprotein) to LDL has also been observed.76
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.
Another recent study shows that fatty fish consumption can cut the risk of eye-diabetes complications. The researches tracked the seafood consumption of about 3,600 diabetic men and women between the ages of 55 and 80 for nearly five years. The researchers found that people who regularly consumed 500 milligrams each day of omega-3 fatty acid in their diets (equal to two servings of fatty fish per week) were 48 percent less likely to develop diabetic retinopathy than those who consumed less. (23)
Both omega−6 and omega−3 fatty acids are essential: humans must consume them in their diet. Omega−6 and omega−3 eighteen-carbon polyunsaturated fatty acids compete for the same metabolic enzymes, thus the omega−6:omega−3 ratio of ingested fatty acids has significant influence on the ratio and rate of production of eicosanoids, a group of hormones intimately involved in the body's inflammatory and homeostatic processes, which include the prostaglandins, leukotrienes, and thromboxanes, among others. Altering this ratio can change the body's metabolic and inflammatory state.[16] In general, grass-fed animals accumulate more omega−3 than do grain-fed animals, which accumulate relatively more omega−6.[86] Metabolites of omega−6 are more inflammatory (esp. arachidonic acid) than those of omega−3. This necessitates that omega−6 and omega−3 be consumed in a balanced proportion; healthy ratios of omega−6:omega−3, according to some authors, range from 1:1 to 1:4.[87] Other authors believe that a ratio of 4:1 (4 times as much omega−6 as omega−3) is already healthy.[88][89] Studies suggest the evolutionary human diet, rich in game animals, seafood, and other sources of omega−3, may have provided such a ratio.[90][91]

In addition to depression, chronic stress leads to loss of volume of the hippocampus—and also causes enlargement of the amygdala, the portion of the brain that regulates anxiety and anger.24 When rats were supplemented with omega-3s during exposure to stress, they showed lower corticosterone levels (a marker of stress), and improved learning on a maze—indicating that the omega-3s helped preserve memory and reduce anxiety.24
Keep in mind that APA found in plant-based foods takes a lot of energy for your body to convert to EPA and DHA. I understand that many people following a vegan diet struggle with the concept of fish oil or eating fish, but animal products contain the necessary omega-3 fatty acids to allow your body to absorb and synthesize what you take in. However, there are plant-based options — you’ll just need more APA because of the way your body processes the medium-chain fatty acid.
Depression. There is inconsistent evidence on the effect of taking fish oil for depression. Some research shows that taking fish oil along with an antidepressant might help improve symptoms in some people. Other research shows that taking fish oil does not improve depression symptoms. The conflicting results may be due to the amount of EPA and DHA in the supplement or the severity of depression before treatment.
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