Home > Anti-aging Research > Linolenic Acid

Omega-6 (Linoleic Acid, Gamma linolenic acid, Dihommagamma-linolenic Acid, Arachidonic Acid)

Note:  Please take a minute to read my essential fatty acids (EFA) page, which will clear up some of the confusion regarding EFAs.

Related Topics:

• omega-3 (alpha linolenic acid) / omega-6 (linoleic acid) / omega-9 (oleic acid) / gamma linolenic acid / evening primrose oil / flaxseed oil / Conjugated Linoleic Acid (CLA) / canola oil

CME:

• Omega 3: Implications in human health and disease - PowerPak, exp. 8/1/03 - "The omega 6 LA comprises 7% to 9% of our daily caloric intake, while the omega 3 LNA makes up about 0.7% of energy. It is therefore estimated that the dietary ratio of LA to LNA ranges from 10 to 20:1, at which level the metabolism of LNA is strongly suppressed. Again, this is far more than the recommended ratio of 2.3:1 ... From an evolutionary perspective, a significant change in the diet has occurred in a very short time. The diet of our ancestors in the Paleolithic period (400,000 to 45,000 years ago) was lower in fat and balanced in omega 6 and omega 3—a ratio of 1:1, or 10- to 20-fold lower than today's standard."

News & Research:

• Don't overdo omega-6 fat consumption during pregnancy - Science Daily, 5/25/19 - "In Western societies, we are eating more omega 6 fats, particularly linoleic acid, which are commonly present in foods such as potato chips and vegetable oil. Other research has shown that linoleic acid can promote inflammation and may be associated with an increased risk of heart disease"
• Seed oils are best for LDL cholesterol - Science Daily, 10/10/18 - "The best alternatives are oils from seeds. "Sunflower oil, rapeseed oil, safflower oil and flaxseed oil performed best," said Schwingshackl. "Some people from Mediterranean countries probably are not so happy with this result, because they would prefer to see olive oil at the top. But this is not the case." ... There are a few important caveats to the research. For starters, it measured only blood lipids. "This is not a hard clinical outcome," said Schwingshackl. "LDL is a causal risk factor for coronary heart disease, but it's not coronary heart disease." However, he said, it might be difficult to conduct a study comparing those clinical outcomes -- for starters, someone would need to find study participants willing to eat just one type of fat for years at a time ... Meta-analyses run the risk of misleading by combining several pieces of low-confidence data into a falsely confident-sounding ranking. In this case, for example, there was not enough evidence to choose a "winner" confidently among the seed oils. What's more, the oils best at lowering LDL were not the most beneficial for triglycerides and HDL cholesterol. However, with the appropriate caveats in mind, Schwingshackl is optimistic about the potential for network meta-analysis to help researchers synthesize disparate clinical studies in the future." - Note:  I wouldn't read too much into that.  Those oils are mostly omega-6 and some argue that the average American has an omega-6 to omega-3 ratio of 20 to 1 when it should be more like 3 to 1.
• Studies link healthy brain aging to omega-3 and omega-6 fatty acids in the blood - Science Daily, 5/18/17 - "The team found correlations between blood levels of three omega-3 fatty acids -- ALA, stearidonic acid and ecosatrienoic acid -- and fluid intelligence in these adults. Further analyses revealed that the size of the left frontoparietal cortex played a mediating role in this relationship. People with higher blood levels of these three nutrients tended to have larger left frontoparietal cortices, and the size of the frontoparietal cortex predicted the subjects' performance on tests of fluid intelligence ... A lot of research tells us that people need to be eating fish and fish oil to get neuroprotective effects from these particular fats, but this new finding suggests that even the fats that we get from nuts, seeds and oils can also make a difference in the brain ... These findings have important implications for the Western diet, which tends to be misbalanced with high amounts of omega-6 fatty acids and low amounts of omega-3 fatty acids" - See fish oil supplements at Amazon.com.
  • Stearidonic acid - Wikipedia - "Stearidonic acid (SDA) is an ω-3 fatty acid, sometimes called moroctic acid. It is biosynthesized from alpha-linolenic acid by the enzyme delta-6-desaturase. Natural sources of this fatty acid are the seed oils of hemp, blackcurrant, corn gromwell[1] and echium (although the plant is a source of stearidonic acid, it is toxic for human consumption), and the cyanobacterium Spirulina"
• Could a Diet High in Fish and Flax Help Prevent Broken Hips? - Science Daily, 6/27/13 - "The study showed that higher levels of omega-3 fatty acids from both plant and fish sources in those blood cells were associated with a lower likelihood of having fractured a hip ... The study also showed that as the ratio of omega-6 fatty acids to omega-3s increased, so did the risk for hip fracture ... Inflammation is associated with an increased risk of bone loss and fractures, and omega-3 fatty acids are believed to reduce inflammation ... omega-3 fatty acids have anti-inflammatory properties and omega-6 fatty acids seem to have both anti- and pro-inflammatory effects ... women who had the highest ratio of omega-6 to omega-3 fatty acids had nearly twice the risk of hip fractures compared to women with the lowest ratios. The current typical American diet contains between 15 and 17 times more omega-6 than omega-3, a ratio that previous research has suggested should be lowered to 4-to-1, or even 2-to-1, by increasing omega-3s, to improve overall health. The primary omega-6 fatty acid in the diet is linoleic acid, which composes about 99 percent of Americans' omega-6 intake and is found in corn, soybean, safflower and sunflower oils" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Re-Analysis Refutes Diet Guidelines Favoring Vegetable Fats - WebMD, 2/6/13 - "The first group was told to consume linoleic acid, in the form of safflower oil and safflower oil polyunsaturated margarine, at levels equal to 15 percent of total calorie intake. This, said Ramsden, is equivalent to roughly twice the amount that Americans currently consume ... While omega-3 consumption was not affected, the men were also asked to lower their saturated fat intake so that it made up less than 10 percent of their diets. They did so by substituting safflower oil for animal fats ... The second group continued their routine nutritional habits ... By newly crunching all the original data the NIH team found that, compared to the no-dietary-change group, the linoleic acid group faced a higher risk of death, from both heart disease specifically as well as from all causes overall ... the NIH team found no evidence to support the notion that linoleic acid confers health benefits. The review highlighted the possibility that boosting omega-6 consumption may actually increase the risk for developing heart disease ... Polyunsaturates are not just involved in cholesterol-lowering. They may also be involved in inflammation, oxidation or clotting"
• Limiting Polyunsaturated Fatty Acid Levels in Pregnancy May Influence Body Fat of Children - Science Daily, 1/10/13 - "mothers who have higher levels of n-6 polyunsaturated fatty acids (PUFAs), which are found in cooking oils and nuts, during pregnancy have fatter children ... assessed the fat and muscle mass of 293 boys and girls at four and six years, who are part of the Southampton Women's Survey (SWS), a large prospective mother-offspring cohort ... the higher the level of n-3 the less fat and more muscle and bone in the baby ... This could suggest that a pregnancy supplementation strategy would be beneficial" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Omega-3 supplements may slow a biological effect of aging - Science Daily, 10/1/12 - "In the study, lengthening of telomeres in immune system cells was more prevalent in people who substantially improved the ratio of omega-3s to other fatty acids in their diet ... Omega-3 supplementation also reduced oxidative stress, caused by excessive free radicals in the blood, by about 15 percent compared to effects seen in the placebo group ... Study participants took either 2.5 grams or 1.25 grams of active omega-3 polyunsaturated fatty acids ... The supplements were calibrated to contain a ratio of the two cold-water fish oil fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), of seven to one ... the typical American diet tends to be heavy on omega-6 fatty acids and comparatively low in omega-3s that are naturally found in cold-water fish such as salmon and tuna. While the ratio of omega-6 to omega-3 fatty acids averages about 15-to-1, researchers tend to agree that for maximum benefit, this ratio should be lowered to 4-to-1, or even 2-to-1 ... when the researchers analyzed the participants' omega-6 to omega-3 ratio in relationship to telomere lengthening, a lower ratio was clearly associated with lengthened telomeres ... omega-3 supplements lowered IL-6 by 10 to 12 percent, depending on the dose. By comparison, those taking a placebo saw an overall 36 percent increase in IL-6 by the end of the study ... This finding strongly suggests that inflammation is what's driving the changes in the telomeres"
• Can Vitamin D Treat Pain? - Medscape, 2/27/12 - "Dysmenorrhea affects almost one half of menstruating women. The pelvic pain is believed to be triggered by excessive uterine production of prostaglandins, synthesized from omega-6 fatty acids before menses, that control vasoconstriction and uterine contractions ... vitamin D may act as an anti-inflammatory and may regulate the expression of key genes involved in the prostaglandin pathway, causing decreased biological activity of prostaglandins ... The women were randomly assigned to receive a single oral dose of 300,000 IUs of vitamin D (cholecalciferol) or placebo 5 days before the time they expected to begin their next menstrual period ... After 2 months, baseline pain scores decreased 41% among women in the vitamin D group; there was no difference in scores among women taking placebo ... The 300,000 IU dose of vitamin D used in the study is probably harmless if taken every month or 2, and even perhaps every week, but it could cause hypercalcemia if taken daily" - See vitamin D at Amazon.com.
• 7 easy ways to boost your immune system - MSNBC, 11/12/11 - "Cook with olive and canola oils ... Research shows that people who consume disproportionately more 6s (found in the soybean oil used in most processed snack foods) than 3s are at higher risk for inflammation and immune system problems"
• A dose of safflower oil each day might help keep heart disease at bay - Science Daily, 3/21/11 - "safflower oil reduced abdominal fat and increased muscle tissue in this group of women after 16 weeks of daily supplementation ... Safflower oil contains linoleic acid, which is a PUFA -- a polyunsaturated fatty acid ... For this current research, the scientists performed a secondary analysis of data collected from that clinical trial, applying a powerful statistical analysis to the results and also checking to see how long it took for any effects of the oils to appear in the women's health profiles" - Note:  It was in the news so I included it but I'm not buying it.  American's already get about 10 to 20 times too much omega-6.  So using their theory they should already be healthy.
• Omega-3 fatty acid intake linked with reduced risk of age-related macular degeneration in women - Science Daily, 3/14/11 - "Brigham and Women's Hospital and Harvard Medical School, Boston, and colleagues collected data on 38,022 women who had not been diagnosed with age-related macular degeneration. Information on women's eating habits was obtained via questionnaire at the beginning of the study and included information on intake of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) [Omega-3 fatty acids found in fish], and arachidonic acid and linoleic acid (omega-6 fatty acids). During ten years of follow-up, additional questionnaires tracked the women's eye health, with specific focus on diagnosis of age-related macular degeneration ... women who consumed the most DHA compared with women who consumed the lowest amount had a 38 percent lower risk of developing age-related macular degeneration. Similar results were observed for higher intake of EPA and for higher consumption of both types of acid together ... consumption of one or more servings of fish per week, when compared to less than one per month, was associated with a 42 percent lower risk of age-related macular degeneration ... For omega-6 fatty acids, higher intake of linoleic acid but not arachidonic acid was associated with an increased risk of age-related macular degeneration, however this association was non-significant after adjustment for other risk factors and fats" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Essential oil pill prevents PMS, study suggests - Science Daily, 1/16/11 - "Women who were given capsules containing 2 grams of a combination of gamma linolenic acid, oleic acid, linoleic acid, other polyunsaturated acids and vitamin E reported significantly eased PMS symptoms at both 3 and 6 months after they began the treatment" - See borage oil at Amazon.com (GLA) and Jarrow FamilE (contains all eight members of the vitamin E family, includes Tocomin) at Amazon.com.  Oleic acid is omega-9 in which olive oil is a good source.  Linoleic acid is omega-6.  Most Americans get about 10 to 20 times too much omega-6 to begin with.  I don't know why they included it.  It makes me wonder about some of the researchers.  If they are showing a benefit, I would guess it's from the other ingredients and not the omega-6.  Gamma linolenic acid is an omega-6 also but it's a form that most don't get enough of.
• Excessive intake of omega 6 and deficiencies in omega 3 induce obesity down the generations - Science Daily, 7/26/10 - "Chronic excess of linoleic acid (omega 6), coupled with a deficiency in alpha-linoleic acid (omega 3), can increase obesity down the generations ... In the past forty years, there has been a steady rise in obesity over the generations in Western societies. During the same period, the diet in industrialized countries has seen a quantitative increase in the calories ingested (lipids account for 35 to 40% of food intake), high levels of linoleic acid (omega 6) and low levels of alpha-linoleic acid (omega 3). Indeed, the amount of omega 6 consumed during the past forty years has rocketed (+250%) while that of omega 3 has fallen by 40%, thus destabilizing the omega 6/omega 3 ratio when compared with the recommended intakes. While the French Food Safety Agency (AFSSA) recommends an omega 6/omega 3 ratio of 5/1, actual consumption is 15 omega 6 for 1 omega 3. In the USA, this ratio can even reach 40 omega 6 for 1 omega 3 ... researchers exposed four generations of mice to a Western-style diet, characterized by these same omega 6/omega 3 ratios. As a result, they saw a gradual increase in fat mass over several generations"
• Cutting fat and calories can lower cancer risk in dogs and people - Science Daily, 7/22/10 - "As many as 1 out of 3 cancer deaths in both humans and dogs could be prevented by reducing Omega-6 fatty acids and cutting calories ... Omega-6, such as corn oil, vegetable oil and grain-fed red meat. Too much Omega-6 fatty acid can lead to inflammation, which creates an environment conducive to cancer in dogs and people ... obesity in both dogs and humans limits the production of adiponectin, a hormone that has been shown to inhibit cancer cell growth. He recommended reducing calories, particularly those from sugar, which has the additional danger of not only causing obesity, but also feeding cancer cells and encouraging their growth ... the ideal blend of fiber for dog food is about 75 to 80 percent insoluble and 20 to 25 percent soluble. In addition, adding quality prebiotics to pet foods can enhance their gut health"
• Lack of omega-6 fatty acid linked to severe dermatitis - Science Daily, 4/14/10 - "Without arachidonic acid, the mice developed severe ulcerative dermatitis. The animals were very itchy, they scratched themselves continuously, and they developed a lot of bleeding sores" - Note:  I doubt if that's a problem in America where they get way to much omega-6 already.
• More omega-3, less omega-6 for colorectal protection - Nutra USA, 8/12/09 - "the dietary total omega-6 to omega-3 PUFA ratio was strongly associated with colorectal cancer risk ... Compared to women with the lowest ratio, women with the highest ratio of omega-6 to -3 had a relative risk 95 per cent higher" - [Abstract]
• Omega Fatty Acid Balance Can Alter Immunity And Gene Expression - Science Daily, 5/29/09 - "Anthropological evidence suggests that human ancestors maintained a 2:1 w6/w3 ratio for much of history, but in Western countries today the ratio has spiked to as high as 10:1. Since these omega fatty acids can be converted into inflammatory molecules, this dietary change is believed to also disrupt the proper balance of pro- and anti- inflammatory agents, resulting in increased systemic inflammation and a higher incidence of problems including asthma, allergies, diabetes, and arthritis ... many key signaling genes that promote inflammation were markedly reduced compared to a normal diet, including a signaling gene for a protein called PI3K, a critical early step in autoimmune and allergic inflammation responses" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Expert Panel: Omega-6 Won't Hurt Heart - WebMD, 1/26/09 - "reducing omega-6 polyunsaturated fatty acids (PUFAs) from their current levels would be more likely to increase the typical American's risk for heart disease than decrease it" - I don't know if I'd go by that.  It contradicts everything I've read but on the other hand I couldn't find anything on my omega-6 page to support that but sometimes I wonder if they read just what they want to read. - Ben
• Canola Oil May Affect Breast Cancer Risk - WebMD, 11/18/08 - "Could the type of oil a woman consumes during pregnancy influence her daughter's breast cancer risk years later? ... pregnant women may be better off choosing canola oil over most other vegetable oils ... Corn oil has 50% omega-6 and almost no omega-3, while canola oil has 20% omega-6 and 10% omega-3,""
• Reducing Intake Of Dietary Fat Prevents Prostate Cancer In Mice - Science Daily, 5/15/08 - "focused on fat from corn oil, which is made up primarily of omega-6 fatty acids, or the polyunsaturated fat commonly found in the Western diet ... Researchers fed one group of mice a diet with about 40 percent of calories coming from fat, a percentage typical in men eating a Western diet. The other group received 12 percent of their calories from fat, a figure considered to be a very low fat diet. Researchers found there was a 27 percent reduced incidence of prostate cancer in the low-fat diet group. Aronson also studied cells in the prostate that were precancerous, or would soon become cancer, and found that the cells in the mice eating the low-fat diet were growing much more slowly than those in the high-fat group"
• Diets With High Omega-6:Omega-3 Ratios Enhance Risk for Depression, Inflammatory Disease - Medscape, 4/25/08 - "Whereas the early hunter-gatherers had a dietary omega-6:omega-3 ratio of 2:1 to 3:1, this ratio is now 15:1 to 17:1 in North America today ... It is believed that these dietary changes might be related to increases in inflammatory-related diseases, including depression and cardiovascular disease ... at higher levels of depressive symptoms, as the omega-6:omega-3 ratio increased, there was a marked increase in proinflammatory cytokine levels ... compared with the study participants who did not have syndromal depression, the 6 participants who had depression had significantly higher omega-6:omega-3 ratios and higher levels of proinflammatory cytokines" - See Mega Twin EPA at Amazon.com.
• Omega-3 Fatty Acids Protect Against Parkinson's, Study Says - Science Daily, 11/26/07 - "Omega-3 fatty acids protect the brain against Parkinson's disease ... omega-3 fatty acids--in particular DHA (docosahexaenoic acid), a specific type of omega-3--had replaced the omega-6 fatty acids already present in the brains of the mice that had been given omega-3 supplementation" - See Jarrow Max DHA at Amazon.com.
• Nutrient intake and risk of squamous cell carcinoma of the esophagus: a case-control study in Uruguay - Nutr Cancer. 2006;56(2):149-57 - "The odds ratio (OR) for high intake of linoleic acid was 1.4 (95% confidence interval, CI = 1.2-1.6), whereas lycopene displayed a strong protective effect (OR = 0.7; 95% CI = 0.6-0.9)"
• Vitamin C May Slow Skin Wrinkling - WebMD, 10/8/07 - "After adjusting for other factors likely to influence skin aging, such as sun exposure and smoking, vitamin C and linoleic acid were independently associated with skin aging ... After digestion, linoleic acid is converted to DHA and EPA -- two fatty acids" - See vitamin C products at Amazon.com and Mega Twin EPA at Amazon.com. - Note:  I'm not sure that is correct.  Linoleic acid is an omega-6, which is not converted to DHA and EPA.  Most Americans get about ten time too much omega-6 already.
• Corn oil, omega-6 could speed up prostate cancer, study - Nutra USA, 2/1/06 - "After we added omega-6 fatty acids to the growth medium in the dish, and only omega-6, we observed that tumors grew twice as fast as those without omega-6" - [HealthDay] [WebMD]
• Fatty Acids May Ward Off Alzheimer's Disease - WebMD, 9/27/05 - "In people who did not have the gene, eating a diet rich in linoleic acids reduced the risk of developing Alzheimer's disease by about 50%. But in those who carried the disease-causing gene, linoleic acids appeared to raise the risk of developing the mind-robbing disease even further"
• Balance of Essential Fats May Prevent Bone Loss After Menopause - Doctor's Guide, 7/13/05 - "After 12 weeks, rats with the lowest ratio of omega-6 to omega-3 fatty acids in their diet experienced significantly less bone loss than rats in the other dietary groups ... A 5-to-1 dietary ratio of omega-6 to omega-3 fatty acids led to a conservation of bone mineral content that we didn't see with a 10-to-1 ratio" -  See Mega Twin EPA at iHerb.
• Modern diet may be causing depression - Nutra USA, 5/26/05 - "The finding lends itself nicely to the theory that increased omega-3 fatty acid intake may shift the balance between the two fatty acid families in the brain, since it has been demonstrated in animal studies that increased omega-3 fatty acid intake may result in decreased brain arachidonic acid"
• One 'Good Fat' May Also Have A Downside - CBS 2 Chicago, 5/25/05 - "It's an omega-6 fatty acid called arachidonic acid found in most oils and meat. When levels of it are high in the brains of rats, they showed signs of depression ... the ill effects may be diluted by adding more omega-3 fatty acids"
• Understanding Essential Fatty Acids - Health Supplement Retailer 01/03 - "The omega-6 LA is fairly prevalent in the human diet, as it is found in a wide variety of vegetable and seed oils. However, many people do not have good enzymatic conversion by the delta-6 desaturase enzyme of LA to GLA. GLA and dihomogamma linolenic acid (DGLA) are the precursors for the series 1 prostaglandins. As such, they regulate a number of body functions, including skin integrity and joint lubrication"
• Sunflower Seed May Hold Key To Reducing Hypertension And Preventing Debilitating Strokes - Intelihealth, 8/27/02 - "One of the leading contributors to a stroke is hypertension. Before a stroke occurs, prolonged hypertension has been associated with a range of impairments and cognitive ability ... Now a researcher suggests that linoleic acid, a doubly unsaturated fatty acid, which is essential in nutrition in mammals. It cannot be produced in animals, the sources of this needed nutrient are vegetable seed oils, such as: safflower, sunflower, and hemp seed ... Linoleic acid administration seems to significantly decrease the systolic blood pressures of SHRs [spontaneously hypertensive rats] at three and six months ... This further supports the assertion that administering linoleic acid to SHRs did not only result in improvement of spatial reference memory but also significantly increased Bmax of D1 dopamine receptors"
• Linoleic Acid Intake May Help Cut Stroke Risk - Intelihealth, 8/2/02
• Fatty Acid Lowers Stroke Risk - WebMD, 8/1/02 - "a fatty acid found in corn, sunflower, and safflower oils and soybeans may help prevent strokes ... the fatty acid known as linoleic acid may reduce the risk of strokes, especially those caused by blood clots ... for every 5% increase in the level of linoleic acid, there was a 28% reduction in the risk of either type of stroke, a 34% drop in the risk of clot-related strokes, and 19% decline in hemorrhagic strokes"
• Essential Fatty Acids Improve Thought Process and Behavior in Children with ADHD - New Hope Natural Media Online, 6/13/02 - "ADHD is characterized by impulsive behavior, lack of concentration, restlessness and, in some cases, learning disabilities ... The children were given either a supplement containing 186 mg of eicosapentaenoic acid (EPA), 480 mg of docosahexaenoic acid (DHA), 96 mg of gamma-linolenic acid (GLA), 864 mg of linoleic acid, and 60 IU of vitamin E per day, or a placebo ... the children who took the essential fatty acid supplement had significant improvement in symptom scores related to learning and behavior"
• Study: Snacks May be Bad for Vision - Intelihealth, 8/15/01 - "The study found that diets high in omega-3 fatty acids, found primarily in albacore tuna and salmon, could lessen the risk for age-related macular degeneration, as long as fish eaters maintain a low intake of linoleic acid (found in processed food and margarine)."
• GLA (Gamma Linolenic Acid): The Good Omega-6 Essential Fatty Acid - Total Health for Longevity Magazine, 9/00

Abstracts:

• Linoleic acid, an omega-6 fatty acid that reduces risk for cardiometabolic diseases: premise, promise and practical implications - Curr Opin Clin Nutr Metab Care 2023 May 1 - "Clinical interventions consistently show that dietary the addition of LA to the diet improves body composition, dyslipidemia, and insulin sensitivity while reducing systemic inflammation and fatty liver ... Unraveling the cellular mechanism(s) of LA to impact PPAR activity may reset a false dogma that LA, as a member of the omega-6 fatty acid family, promotes inflammation in humans. In fact, LA appears to reduce inflammation and reduce risk for CMD"
• A low n-6 to n-3 polyunsaturated fatty acid ratio diet improves hyperinsulinemia by restoring insulin clearance in obese youth - Diabetes Obes Metab 2022 Mar 17 - "A low n-6 to n-3 polyunsaturated fatty acid (PUFA) ratio diet reduces hyperinsulinemia in insulin-resistant adolescents even in the absence of change in body weight and glucose metabolis ... We demonstrated that a 12-week low n-6:n-3 PUFA ratio diet improves hyperinsulinemia by increasing fasting and post-load insulin clearance in obese youth, independently of weight loss, glucose concentrations and insulin secretion"
• Chronic consumption of a high linoleic acid diet during pregnancy, lactation and post-weaning period increases depression-like behavior in male, but not female offspring - Behav Brain Res 2021 Aug 18 - "Polyunsaturated fatty acids (PUFAs) play an essential role in brain development. Emerging data have suggested a possible link between an imbalance in PUFAs and cognitive behavioral deficits in offspring. A diet rich in high linoleic acid (HLA), typically from preconception to lactation, leads to an increase in the ratio of omega-6 (n-6) to omega-3 (n-3) fatty acids in the fetus. Arising research has suggested that a deficiency in omega-3 fatty acids is a potential risk factor for inducing autism spectrum disorder (ASD)-like behavioral deficits. However, the impact of a high n- diet during preconception, pregnancy, lactation, and post-weaning on the brain development of adolescent offspring are yet to determine ... Female Wistar Kyoto rats were fed with either an HLA or low linoleic acid (LLA) control diet for 10 weeks before mating, then continued with the same diet throughout the pregnancy and lactation period. Female and male offspring at 5 weeks old were subjected to behavioral tests to assess social interaction behavior and depression-/anxiety-like behavior. Our result showed that chronic consumption of an HLA diet did not affect sociability and social recognition memory, but induce depression-like behavior in male but not in female offspring" - Note: Linoleic acid is an omega-6.
• The Effects of a 6-Month High Dose Omega-3 and Omega-6 Polyunsaturated Fatty Acids and Antioxidant Vitamins Supplementation on Cognitive Function and Functional Capacity in Older Adults with Mild Cognitive Impairment - Nutrients. 2020 Jan 26;12(2) - "The aim of the present study was to examine the effects of a high-dose omega-3 and omega-6 fatty acids supplementation, in combination with antioxidant vitamins, on cognitive function and functional capacity of older adults with mild cognitive impairment (MCI), over a 6-month period in a randomized, double-blind, placebo-controlled trial. Forty-six older adults with MCI (age: 78.8 ± 7.3 years) were randomized 1:1 to receive either a 20 mL dose of a formula containing a mixture of omega-3 (810 mg Eicosapentaenoic acid and 4140 mg Docosahexaenoic acid) and omega-6 fatty acids (1800 mg gamma-Linolenic acid and 3150 mg Linoleic acid) (1:1 w/w), with 0.6 mg vitamin A, vitamin E (22 mg) plus pure γ-tocopherol (760 mg), or 20mL placebo containing olive oil. Participants completed assessments of cognitive function, functional capacity, body composition and various aspects of quality of life at baseline and following three and six months of supplementation. Thirty-six participants completed the study (eighteen from each group). A significant interaction between supplementation and time was found on cognitive function (Addenbrooke's Cognitive Examination -Revised (ACE-R), Mini-Mental State Examination (MMSE) and Stroop Color and Word Test (STROOP) color test; p < 0.001, p = 0.011 and p = 0.037, respectively), functional capacity (6-min walk test and sit-to-stand-60; p = 0.028 and p = 0.032, respectively), fatigue (p < 0.001), physical health (p = 0.007), and daily sleepiness (p = 0.007)-showing a favorable improvement for the participants receiving the supplement. The results indicate that this nutritional modality could be promising for reducing cognitive and functional decline in the elderly with MCI"
• Biomarkers of Dietary Omega-6 Fatty Acids and Incident Cardiovascular Disease and Mortality: An Individual-Level Pooled Analysis of 30 Cohort Studies - Circulation. 2019 Apr 11 - "linoleic acid (LA) and arachidonic acid (AA) ... Higher levels of LA were significantly associated with lower risks of total CVD, cardiovascular mortality, and ischemic stroke, with hazard ratios per interquintile range of 0.93 (95% CI: 0.88-0.99), 0.78 (0.70-0.85), and 0.88 (0.79-0.98), respectively, and nonsignificantly with lower CHD risk (0.94; 0.88-1.00). Relationships were similar for LA evaluated across quintiles. AA levels were not associated with higher risk of cardiovascular outcomes; comparing extreme quintiles, higher levels were associated with lower risk of total CVD (0.92 ... In pooled global analyses, higher in vivo circulating and tissue levels of LA and possibly AA were associated with lower risk of major cardiovascular events. These results support a favorable role for LA in CVD prevention" - Note: This surprised me. Many studies claim that the ratio of omega-6 to omega-3 should be 3:1 yet most Americans are consuming 10 - 20:1 which they claim is harmful.  I just report the studies.
• The effect of replacing saturated fat with mostly n-6 polyunsaturated fat on coronary heart disease: a meta-analysis of randomised controlled trials - Nutr J. 2017 May 19;16(1):30 - "Available evidence from adequately controlled randomised controlled trials suggest replacing SFA with mostly n-6 PUFA is unlikely to reduce CHD events, CHD mortality or total mortality. The suggestion of benefits reported in earlier meta-analyses is due to the inclusion of inadequately controlled trials"
• An Increase in the Omega-6/Omega-3 Fatty Acid Ratio Increases the Risk for Obesity - Nutrients. 2016 Mar 2;8(3) - "In the past three decades, total fat and saturated fat intake as a percentage of total calories has continuously decreased in Western diets, while the intake of omega-6 fatty acid increased and the omega-3 fatty acid decreased, resulting in a large increase in the omega-6/omega-3 ratio from 1:1 during evolution to 20:1 today or even higher ... Experimental studies have suggested that omega-6 and omega-3 fatty acids elicit divergent effects on body fat gain through mechanisms of adipogenesis, browning of adipose tissue, lipid homeostasis, brain-gut-adipose tissue axis, and most importantly systemic inflammation. Prospective studies clearly show an increase in the risk of obesity as the level of omega-6 fatty acids and the omega-6/omega-3 ratio increase in red blood cell (RBC) membrane phospholipids, whereas high omega-3 RBC membrane phospholipids decrease the risk of obesity. Recent studies in humans show that in addition to absolute amounts of omega-6 and omega-3 fatty acid intake, the omega-6/omega-3 ratio plays an important role in increasing the development of obesity via both AA eicosanoid metabolites and hyperactivity of the cannabinoid system, which can be reversed with increased intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)" - See fish oil supplements at Amazon.com.
• Low n-6/n-3 PUFA Ratio Improves Lipid Metabolism, Inflammation, Oxidative Stress and Endothelial Function in Rats Using Plant Oils as n-3 Fatty Acid Source - Lipids. 2015 Nov 2 - "The 1:1 and 5:1 ratio groups had significantly decreased serum levels of total cholesterol, low-density lipoprotein cholesterol, and proinflammatory cytokines compared with the 20:1 group ... The 1:1 group had a significantly decreased lipid peroxide level compared with the other groups ... We demonstrated that low n-6/n-3 PUFA ratio (1:1 and 5:1) had a beneficial effect on cardiovascular risk factors by enhancing favorable lipid profiles, having anti-inflammatory and anti-oxidative stress effects, and improving endothelial function. A high n-6/n-3 PUFA ratio (20:1) had adverse effects"
  • Omega-6 fatty acids - University of Maryland Medical Center - "The typical American diet tends to contain 14 - 25 times more omega-6 fatty acids than omega-3 fatty acids"
• An Investigation into the Association between DNA Damage and Dietary Fatty Acid in Men with Prostate Cancer - Nutrients. 2015;7(1):405-422 - "20 men with prostate cancer adhered to a modified Mediterranean style diet for three months ... DNA damage was inversely correlated with dietary adherence (p = 0.013) and whole blood monounsaturated fatty acids (p = 0.009) and oleic acid (p = 0.020). DNA damage was positively correlated with the intake of dairy products (p = 0.043), red meat (p = 0.007) and whole blood omega-6 polyunsaturated fatty acids (p = 0.015). Both the source and type of dietary fat changed significantly over the course of the dietary intervention"
• Fatty Acid Status and Its Relationship to Cognitive Decline and Homocysteine Levels in the Elderly - Nutrients. 2014 Sep 12;6(9):3624-3640 - "Forty-five elderly persons (age ≥60 years) were included and divided into two groups based on their Mini-Mental Status Examination score adjusted for educational level: the case group (n = 12) and the control group (n = 33) ... Cognitive function was positively associated with the 24:1n-9, DHA and total n-3 PUFAs, while 14:0, 16:0 and 16:1n-7 fatty acids, the n-6/n-3 ratio and Hcy were inversely associated. In addition, n-3 PUFAs, particularly DHA, were inversely associated with cardiovascular risk, assessed by Hcy levels in the elderly" - See docosahexaenoic acid at Amazon.com.
• Significance of Imbalance in the Ratio of Serum n-3 to n-6 Polyunsaturated Fatty Acids in Patients With Acute Coronary Syndrome - Am J Cardiol. 2013 Nov 7 - "We enrolled 1,119 patients who were treated and in whom serum PUFA level was evaluated in 5 divisions of cardiology in a metropolitan area in Japan ... eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and arachidonic acid (AA) ... According to multivariate logistic regression analysis, the group with the lowest EPA/AA (≤0.33) had a greater probability of ACS (odds ratio 3.14, 95% confidence interval 1.16 to 8.49), but this was not true for DHA/AA. In conclusion, an imbalance in the ratio of serum EPA to AA, but not in the ratio of DHA to AA, was significantly associated with ACS" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Omega 3:6 ratio intake and incidence of glaucoma: The SUN cohort - Clin Nutr. 2013 Nov 12 - "followed-up 17,128 participants initially free of glaucoma for a median time of 8.2 years. Validated data of diet were collected at baseline with a 136-item semi-quantitative food-frequency questionnaire and information of new diagnosis of glaucoma in biennial follow-up questionnaires ... median follow-up time of 8.2 years ... Participants in the highest quintile of omega 3:6 ratio intake had a significantly higher risk of glaucoma than participants in the lowest quintile (hazard ratio (HR): 1.91 [95%CI: 1.05-3.46], p for trend 0.03). The association became stronger (HR for the comparison of the 5th versus the 1st quintile: 2.43 [95%CI: 1.17-5.03], p for trend 0.02) when we considered only those participants who were ≥40 years old"
• Omega-3 Fatty Acid Intakes Are Inversely Related to Elevated Depressive Symptoms among United States Women - J Nutr. 2013 Sep 4 - "assessed whether self-reported depressive symptoms were inversely associated with n-3 fatty acid intakes by using a cross-sectional study in 1746 adults (aged 30-65 y) in Baltimore City, MD (2004-2009). The 20-item Center for Epidemiologic Studies-Depression Scale (CES-D) was used, with a CES-D score ≥16 suggestive of elevated depressive symptoms (EDS) ... In sum, among United States women, higher intakes of n-3 fatty acids [absolute (n-3) and relative to n-6 fatty acids (n-3:n-6)] were associated with lower risk of elevated depressive symptoms, specifically in domains of somatic complaints (mainly n-3 PUFAs) and positive affect (mainly n-3 HUFAs)" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Stimulation of Wound Healing by n-3 Fatty Acids - Medscape, 8/27/13 - "Four-week-old male Wistar rats were subjected to full-thickness skin wounds and assigned to 3 experimental diet groups (an n-3 fatty acid-fortified diet, a diet with a 1:3 ratio of n-3 to n-6 fatty acids, and an n-6 fatty acid-fortified diet) ... The number of days to wound healing in the n-3/n-6 fatty acid group (18.4 +/- 1.8 days) was significantly shorter than in the n-3 fatty acid-fortified diet (21.6 +/- 1.6 days) and n-6 fatty acid-fortified diet groups (21.9 +/- 1.8 days). This suggests that the n-3/n-6 fatty acid diet stimulates wound healing (P < 0.05). Changes in wound area, however, were not significantly different. The n-3 fatty acid-fortified diet was found to have potent immunopotentiating and anti-inflammatory effects in the group receiving this diet, as evidenced by total blood lymphocyte count and plasma levels of interleukin-1 beta (IL-1β) and sialic acid on day 1 after wounding. The plasma hydroxyproline concentrations noted in the groups with a diet containing n-3 fatty acids indicate that this fatty acid type stimulates wound healing" - Note:  It claims the 1:3 ratio of n-3 to n-6 fatty acids but the average ratio for American's is something like 1:16.  See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• n-6:n-3 PUFA ratio is involved in regulating lipid metabolism and inflammation in pigs - Br J Nutr. 2013 Aug 15:1-7 - "A total of ninety-six cross-bred (Large White × Landrace) growing-finishing pigs (73.8 (sem 1.6) kg) were chosen and fed one of the four isoenergetic diets with n-6:n-3 PUFA ratios of 1:1, 2.5:1, 5:1 and 10:1. The growth performance of pigs fed the diet with an n-6:n-3 PUFA ratio of 5:1 was the best, but the group fed the diet with an n-6:n-3 PUFA ratio of 1:1 had the highest muscle mass and the lowest adipose tissue mass"
• Plasma phospholipid fatty acids, dietary fatty acids and prostate cancer risk - Int J Cancer. 2013 Apr 11 - "Animal and experimental studies have demonstrated that long-chain n-3 fatty acids inhibit the development of prostate cancer, whereas n-6 fatty acids might promote it ... Collaborative Cohort Study using a random sample of 1,717 men and 464 prostate cancer cases to investigate associations between fatty acids assessed in plasma phospholipids (PPLs) or diet (estimated using a 121-item food frequency questionnaire) and prostate cancer risk ... Prostate cancer risk was positively associated with %PPL saturated fatty acids (SFAs); HR [95% CI] = 1.51 [1.06, 2.16] (Q5 vs. Q1, fifth vs. first quintile); p-trend = 0.003. HRs (Q5 to Q2 vs. Q1) were significantly elevated for %PPL palmitic acid. %PPL oleic acid was inversely associated with risk, HR = 0.62 [0.43, 0.91] (Q5 vs. Q1); p-trend = 0.04. No statistically significant linear trends were observed for dietary intakes. The HRs were elevated for moderate intakes of linoleic acid (Q2 and Q3 vs. Q1, 1.58 [1.10, 2.28] and 1.70 [1.18, 2.46], respectively), but the increase was not significant for higher intakes (Q4 and Q5). No association varied significantly by tumour aggressiveness (all p-homogeneity > 0.1). Prostate cancer risk was positively associated with %PPL SFA, largely attributable to palmitic acid and inversely associated with %PPL monounsaturated fatty acids, largely attributable to oleic acid. Higher risks were also observed for dietary n-6 polyunsaturated fats, primarily linoleic acid"
• Effects of long-chain PUFA supplementation in infant formula on cognitive function in later childhood - Am J Clin Nutr. 2013 Jun 19 - "Infants were randomly assigned to receive formula containing either docosahexaenoic acid and arachidonic acid or no LC-PUFAs for a period of 4 mo. A reference breastfed group was also included. In a follow-up conducted at age 6 y, children received assessments of intelligence quotient (IQ), attention control (Day-Night Test), and speed of processing on the Matching Familiar Figures Test (MFFT) ... IQ scores of children who were fed a formula containing either LC-PUFAs or no LC-PUFAs did not differ at age 6 y. However, children who received LC-PUFAs were faster at processing information compared with children who received unsupplemented formula. Variation in the dietary supply of LC-PUFAs in the first months of life may have long-term consequences for the development of some cognitive functions in later childhood" - See Jarrow Max DHA at Amazon.com.
  • Arachidonic acid - Wikipedia, the free encyclopedia - "Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6). It is the counterpart to the saturated arachidic acid found in peanut oil"
• Lipid content in hepatic and gonadal adipose tissue parallel aortic cholesterol accumulation in mice fed diets with different omega-6 PUFA to EPA plus DHA ratios - Clin Nutr. 2013 Apr 24 - "Dietary ω-6:EPA+DHA ratios did not affect body weight, but lower ω-6:EPA+DHA ratio diets decreased liver lipid accumulation, which possibly contributed to the lower aortic cholesterol accumulation" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• A low dietary ratio of omega-6 to omega-3 Fatty acids may delay progression of prostate cancer - Nutr Cancer. 2013;65(4):556-62 - "High amounts of omega-6 fatty acids have been linked with increased prostate cancer risk, whereas omega-3 fatty acids have been shown to inhibit PCa growth. However, because omega-3 and omega-6 are both essential fatty acids and part of a complete diet, it is more relevant to determine the ideal ratio of the two that would allow patients to benefit from the therapeutic properties of omega-3 fatty acids. LNCaP prostate cancer cells were treated with dietary-based ratios of omega-6 to omega-3 fatty acids under hormone-deprivation conditions, and effects on various cellular processes were determined. A low omega-6 to omega-3 PUFA ratio can delay the progression of cells toward castration-resistance by suppressing pathways involved in prostate cancer progression, such as the Akt/mTOR/NFκB axis. It also suppresses the expression of cyclin D1, and activation of caspase-3 and annexin V staining shows induction of proapoptotic events. Taken together, our data demonstrates that maintaining a low omega-6 to omega-3 fatty acids ratio can enhance efficacy of hormone ablation therapy" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Effect of different dietary omega-3/omega-6 fatty acid ratios on reproduction in male rats - Lipids Health Dis. 2013 Mar 13;12(1):33 - "These findings demonstrated that a balanced n-3/n-6 ratio was important in male rat reproduction. Therefore there is a necessity to determine an appropriate n-3/n-6 PUFA ratio in man and different male animals in the future" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Diets rich in n-6 PUFA induce intestinal microbial dysbiosis in aged mice - Br J Nutr. 2013 Jan 8:1-9 - "With present 'Western' diets predominantly composed of n-6 PUFA, we hypothesised that PUFA-rich diets cause intestinal dysbiosis in an aged population. C57BL/6 mice (aged 2 years) were fed a high-fat (40 % energy), isoenergetic and isonitrogenous diet composed of rapeseed oil, maize oil or maize oil supplemented with fish oil ... feeding high-fat diets rich in n-6 PUFA promoted bacterial overgrowth but depleted microbes from the Bacteroidetes and Firmicutes phyla. This corresponded with increased body mass and infiltration of macrophages and neutrophils. Fish oil supplementation (rich in long-chain n-3 PUFA like DHA and EPA) restored the microbiota and inflammatory cell infiltration and promoted regulatory T-cell recruitment. However, fish oil supplementation was associated with increased oxidative stress, evident by the increased presence of 4-hydroxynonenal, a product of lipid peroxidation. These results suggest that an n-6 PUFA-rich diet can cause dysbiosis and intestinal inflammation in aged mice. However, while fish oil supplementation on an n-6 PUFA diet reverses dysbiosis, the combination of n-6 and n-3 PUFA, like DHA/EPA, leads to increased oxidative stress, which could exacerbate gastrointestinal disorders in the elderly" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Effects of fish oil supplementation on inflammatory acne - Lipids Health Dis. 2012 Dec 3;11(1):165 - "Given that acne is a rare condition in societies with higher consumption of omega-3 (n-3) relative to omega-6 (n-6) fatty acids, supplementation with n-3 may suppress inflammatory cytokine production and thereby reduce acne severity ... 13 individuals with inflammatory acne were given three grams of fish oil containing 930 mg of EPA to their unchanged diet and existing acne remedies for 12 weeks ... There was no significant change in acne grading and inflammatory counts at week 12 compared to baseline. However, there was a broad range of response to the intervention on an individual basis. The results showed that acne severity improved in 8 individuals, worsened in 4, and remained unchanged in 1. Interestingly, among the individuals who showed improvement, 7 were classified as having moderate to severe acne at baseline, while 3 of the 4 whose acne deteriorated were classified as having mild acne" - See Mega Twin EPA at Amazon.com.
• Effects of EPA, γ-linolenic acid or coenzyme Q10 on serum prostate-specific antigen levels: a randomised, double-blind trial - Br J Nutr. 2012 Nov 30:1-8 - "A total of 504 healthy men with serum PSA level ≤ 2.5 ng/ml were recruited into the study ... Participants were randomly assigned to a daily dietary supplement containing n-3 fatty acids (1.12 g of EPA and 0.72 g of DHA per capsule) (group 1, n 126), n-6 fatty acid (600 mg γ-linolenic acid (GLA) each capsule) (group 2, n 126), CoQ10 (100 mg per capsule) (group 3, n 126) or a similar regimen of placebo (group 4, n 126) for 12 weeks ... EPA treatment significantly reduced serum PSA level by 30.0 (95 % CI 25, 36) % (P = 0.004) from baseline. In contrast, GLA therapy significantly increased serum PSA concentration by 15.0 (95 % CI 11, 20) % (P = 0.02). CoQ10 therapy also significantly reduced serum PSA level by 33.0 (95 % CI 27, 40) % (P = 0.002). In multivariable analysis, serum values of PSA were strongly correlated with duration of EPA (r - 0.62; 95 % CI - 0.42, - 0.77; P = 0.003), n-6 (r 0.42; 95 % CI 0.31, 0.58; P = 0.02) and CoQ10 use (r - 0.77; 95 % CI - 0.56, - 0.87; P = 0.001). There were also significant correlations between serum values of DHA, EPA, GLA and CoQ10 and serum PSA levels. The present study demonstrates that dietary supplements containing EPA, GLA or CoQ10 may significantly affect serum PSA levels" - See ubiquinol products at Amazon.com and Mega Twin EPA at Amazon.com.
• Effects of Serum n-3 to n-6 Polyunsaturated Fatty Acids Ratios on Coronary Atherosclerosis in Statin-Treated Patients With Coronary Artery Disease - Am J Cardiol. 2012 Oct 2 - "A low ratio of n-3 to n-6 polyunsaturated fatty acids has been associated with cardiovascular events ... Coronary atherosclerosis in nonculprit lesions in the percutaneous coronary intervention vessel was evaluated using virtual histology intravascular ultrasound in 101 patients at the time of percutaneous coronary intervention and 8 months after statin therapy ... decreases in serum n-3 to n-6 polyunsaturated fatty acid ratios are associated with progression in coronary atherosclerosis evaluated using virtual histology intravascular ultrasound in statin-treated patients with coronary artery disease" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• The association of red blood cell n-3 and n-6 fatty acids to dietary fatty acid intake, bone mineral density and hip fracture risk in the Women's Health Initiative - J Bone Miner Res. 2012 Sep 27 - "Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFA) in red blood cells (RBC) are an objective indicator of PUFA status and may be related to hip fracture risk ... A nested case-control study (n=400 pairs) was completed within the Women's Health Initiative (WHI) using 201 incident hip fracture cases from the Bone Mineral Density (BMD) cohort, along with 199 additional incident hip fracture cases randomly selected from the WHI Observational Study ... In adjusted hazard models, lower hip fracture risk was associated with higher RBC a-linolenic acid [Hazard ratio (HR) Tertile 3 (T3): 0.44; 95% CI: 0.23-0.85; p for linear trend 0.0154)], eicosapentaenoic acid (HR T3: 0.46; 95% CI: 0.24-0.87; p for linear trend 0.0181) and total n-3 PUFAs (HR T3: 0.55; 95% CI: 0.30-1.01; p for linear trend 0.0492). Conversely, hip fracture nearly doubled with the highest RBC n-6/n-3 ratio (HR T3: 1.96; 95% CI: 1.03-3.70; p for linear trend 0.0399). RBC PUFAs were not associated with BMD. RBC PUFAs were indicative of dietary intake of marine n-3 PUFAs (Spearman's rho=0.45, p<0.0001), total n-6 PUFAs (rho=0.17, p<0.0001) and linoleic acid (rho= 0.09, p<0.05). These results suggest that higher RBC a-linolenic acid, as well as eicosapentaenoic acid and total n-3 PUFAs, may predict lower hip fracture risk. Contrastingly, a higher RBC n-6/n-3 ratio may predict higher hip fracture risk in postmenopausal women"
• Dietary linoleic acid elevates endogenous 2-arachidonoylglycerol and anandamide in Atlantic salmon (Salmo salar L.) and mice, and induces weight gain and inflammation in mice - Br J Nutr. 2012 Aug 10:1-10 - "Dietary intake of linoleic acid (LA) has increased dramatically during the twentieth century and is associated with a greater prevalence of obesity. Vegetable oils are recognised as suitable alternatives to fish oil (FO) in feed for Atlantic salmon (Salmo salar L.) but introduce high amounts of LA in the salmon fillet. The effect on fish consumers of such a replacement remains to be elucidated ... In conclusion, excessive dietary LA elevates endocannabinoids in the liver of salmon and mice, and increases weight gain and counteracts the anti-inflammatory properties of EPA and DHA in mice" - Note: linoleic acid is an omega-6.
• ω-3 and ω-6 polyunsaturated fatty acid intakes and the risk of breast cancer in Mexican women: impact of obesity status - Cancer Epidemiol Biomarkers Prev. 2011 Dec 22 - "Overall, there was no significant association between ω-3 PUFA intake and breast cancer risk (p=0.31). An increased risk of breast cancer was associated with increasing ω-6 PUFA intake in pre-menopausal women (OR=1.92, 95% CI=1.13;3.26; p=0.04). A decreased risk of breast cancer was significantly associated with increasing ω-3 PUFA intake in obese women (OR=0.58, 95%CI=0.39;0.87; p=0.008), but not in normoweight nor in overweight women (p for heterogeneity = 0.017)"
• Dietary Omega-3 Fatty Acid, Ratio of Omega-6 to Omega-3 Intake, Inflammation, and Survival in Long-term Hemodialysis Patients - Am J Kidney Dis. 2011 Jun 7 - "each 1-unit higher ratio of omega-6 to omega-3 intake was associated with a 0.55-mg/L increase in serum CRP level (P = 0.03). In the fully adjusted model, death HRs for the first (1.7-<7.6), second (7.6-<9.3), third (9.3-<11.3), and fourth (11.3-17.4) quartiles of dietary omega-6 to omega-3 ratio were 0.39 (95% CI, 0.14-1.18), 0.30 (95% CI, 0.09-0.99), 0.67 (95% CI, 0.25-1.79), and 1.00 (reference), respectively (P for trend = 0.06) ... Higher dietary omega-6 to omega-3 ratio appears to be associated with both worsening inflammation over time and a trend toward higher death risk in hemodialysis patients"
• Omega-3 status in pregnancy linked to childhood obesity: Study - Nutra USA, 5/6/11 - "A higher ratio of cord plasma omega-6 to omega-3 polyunsaturated fatty acids (PUFAs) was associated with higher subscapular and triceps [skinfold thicknesses] and odds of obesity ... around one fifth expectant mothers ate more than 2 fish meals per week at mid-pregnancy, however only about half of these women achieved the recommend intake of DHA of 200 mg per day ... Only three per cent of pregnant women in the study were found to consume the recommended intake of 200 mg/day of DHA in the last month of pregnancy ... this is the time when large amounts of DHA are transferred from the mother to the infant to support brain development ... the odds of obesity in 3-year-olds were between two and four times higher when cord blood had a high ratio of omega-6 to omega-3 fatty acids ... In contrast, the odds of obesity were 32 per cent lower when maternal consumption of omega-3s was high or if the ratio of omega-3 to omega-6 was at close to recommended levels" - [Abstract] - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Dietary polyunsaturated fatty acids and breast cancer risk in Chinese women: A prospective cohort study - Int J Cancer. 2010 Sep 28 - "We found no association of breast cancer risk to dietary intake of linoleic acid, arachidonic acid, α-linolenic acid, or marine-derived n-3 PUFA. We found a statistically significant interaction between n-6 PUFA intake, marine-derived n-3 PUFA intake and breast cancer risk (p = 0.008). Women with lower intake (the lowest tertile) of marine-derived n-3 PUFA and higher intake (the highest tertile) of n-6 PUFA had an increase risk for breast cancer (RR=2.06; 95% CI=1.27-3.34) compared to women with higher intake (the highest tertile) of marine-derived n-3 PUFAs and lower intake (the lowest tertile) of n-6 PUFAs after adjusting for potential confounders. The relative amounts of n-6 PUFA to marine-derived n-3 PUFAs may be more important for breast cancer risk than individual dietary amounts of these fatty acids" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• A prospective study of dietary polyunsaturated fatty acids and colorectal cancer risk in Chinese women - Cancer Epidemiol Biomarkers Prev. 2009 Aug;18(8):2283-91 - "The dietary total n-6 to n-3 PUFA ratio was strongly associated with colorectal cancer risk. Compared with women in the lowest quintile group, elevated relative risks (RR) were observed for the second [RR, 1.52; 95% confidence intervals (CI), 1.00-2.32], third (RR, 2.20; 95% CI, 1.41-3.45), fourth (RR, 1.65; 95% CI, 0.99-2.75), and fifth (RR, 1.95; 95% CI, 1.07-3.54) quintile groups. Arachidonic acid was associated with colorectal cancer risk with elevated RRs of 1.20(Q2-Q1) (95% CI, 0.87-1.64), 1.44(Q3-Q1) (95% CI, 1.05-1.98), 1.61(Q4-Q1) (95% CI, 1.17-2.23), and 1.39(Q5-Q1) (95% CI, 0.97-1.99; P(trend) = 0.03) with increasing dietary quintile"
• Dietary intakes of omega-6 and omega-3 polyunsaturated fatty acids and the risk of breast cancer - Int J Cancer. 2008 Sep 9 - "Breast cancer risk was not related to any dietary PUFA overall; however, opposite associations were seen according to food sources, suggesting other potential effects than PUFA per se. Breast cancer risk was inversely associated with alpha-linolenic acid (ALA) intake from fruit and vegetables [highest vs. lowest quintile, hazard ratio (HR) 0.74; 95% confidence interval (CI) 0.63, 0.88; p trend < 0.0001], and from vegetable oils (HR 0.83; 95% CI 0.71, 0.97; p trend 0.017). Conversely, breast cancer risk was positively related to ALA intake from nut mixes (p trend 0.004) and processed foods (p trend 0.068), as was total ALA intake among women in the highest quintile of dietary vitamin E (p trend 0.036). A significant interaction was also found between omega-6 and long-chain omega-3 PUFAs, with breast cancer risk inversely related to long-chain omega-3 PUFAs in women belonging to the highest quintile of omega-6 PUFAs (p interaction 0.042). These results emphasize the need to consider food sources, as well as interactions between fatty acids and with antioxidants, when evaluating associations between PUFA intakes and breast cancer risk" - Note:  Alpha-linolenic acid is the vegetable form of omega-3.
• Low plasma eicosapentaenoic acid and depressive symptomatology are independent predictors of dementia risk - Am J Clin Nutr. 2008 Sep;88(3):714-21 - "A high plasma EPA concentration may decrease the risk of dementia, whereas high ratios of n-6 to n-3 fatty acids and of AA to DHA may increase the risk of dementia, especially in depressed older persons. The role of EPA in dementia warrants further research" - See Mega Twin EPA at Amazon.com and Jarrow Max DHA at Amazon.com.
• Very Low n-3 Long-Chain Polyunsaturated Fatty Acid Status in Austrian Vegetarians and Vegans - Ann Nutr Metab. 2008 Feb 28;52(1):37-47 - "The vegetarian diet, with an average n-6/n-3 ratio of 10/1, promotes biochemical n-3 tissue decline. To ensure physical, mental and neurological health vegetarians have to reduce the n-6/n-3 ratio with an additional intake of direct sources of EPA and DHA, regardless of age and gender" - See Mega Twin EPA at Amazon.com.
• Depressive Symptoms, omega-6:omega-3 Fatty Acids, and Inflammation in Older Adults - Psychosom Med. 2007 Mar 30 - "Diets with high n-6:n-3 PUFA ratios may enhance the risk for both depression and inflammatory diseases"
• Dietary Fatty acids correlate with prostate cancer biopsy grade and volume in jamaican men - J Urol. 2007 Jan;177(1):97-101 - "Omega6 polyunsaturated fatty acids stimulate and Omega3 polyunsaturated fatty acids inhibit prostate cancer growth"
• Habitual Dietary Intake of n-3 and n-6 Fatty Acids in Relation to Inflammatory Markers Among US Men and Women - Circulation. 2003 Jun 23 - "These results suggest that n-6 fatty acids do not inhibit the antiinflammatory effects of n-3 fatty acids and that the combination of both types of fatty acids is associated with the lowest levels of inflammation. The inhibition of inflammatory cytokines may be one possible mechanism for the observed beneficial effects of these fatty acids on chronic inflammatory-related diseases" - See TwinLab Mega Twin EPA at Amazon.com
• Essential fatty acids and the brain - Can J Psychiatry 2003 Apr;48(3):195-203 - "The ratio of membrane omega-3 to omega-6 PUFAs can be modulated by dietary intake. This ratio influences neurotransmission and prostaglandin formation, processes that are vital in the maintenance of normal brain function"
• Cognitive decline and fatty acid composition of erythrocyte membranes - Am J Clin Nutr. 2003 Apr;77(4):803-8 - "studied the relation between erythrocyte membrane fatty acid composition and cognitive decline in free-living volunteers ... Higher proportions of both stearic acid (saturated, 18:0) and total n-6 polyunsaturated fatty acids were associated with greater risk of cognitive decline ... Conversely, a higher proportion of total n-3 fatty acids was associated with a lower risk of cognitive decline"
• Dietary Fats and the Risk of Incident Alzheimer Disease - Archives of Neurology, 2/03 - "Intakes of saturated fat and trans-unsaturated fat were positively associated with risk of Alzheimer disease, whereas intakes of -6 polyunsaturated fat and monounsaturated fat were inversely associated. Persons in the upper fifth of saturated-fat intake had 2.2 times the risk of incident Alzheimer disease compared with persons in the lowest fifth" - See the tables on my fatty acids page.  For example, palm oil is 51% saturated fat while canola oil is 8% saturated.