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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:

• 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 iHerb and Jarrow Max DHA at iHerb.
• 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 iHerb.
• 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 iHerb.
• 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 iHerb and Mega Twin EPA at iHerb. - 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:

• 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 iHerb and Jarrow Max DHA at iHerb.
• 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 iHerb.
• 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 iHerb or Vitacost.
• 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.

Related Searches:

• Doctor's Guide search of linoleic acid
• Doctor's Guide (2) search of linoleic acid
• Intelihealth search of linoleic acid
• Life Extension Foundation search
• Medline search of linoleic acid
• Medscape search of linoleic acid
• The Natural Pharmacist search of linoleic acid
• Nutrition Science News search
• WebMD search of linoleic acid

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