HUFA Balance with Mood, Behavior, Obesity & Pain
All truths are easy to understand once they are discovered; the point is to discover them. – Galileo

Blood HUFA proportions
American military personnel generally under-consume n-3 fatty acids and overconsume n-6 fatty acids. Three volunteer groups ate different diets for 10 weeks. Control participants consumed meals from the US Military’s Standard Garrison Dining Facility Menu. Replacing high linoleic acid (LA) foods in dining facility menus with similar foods that were high oleic acid/low LA and high n-3 lowered the n-6:n-3 blood fatty acid status after 5 weeks, and further lowering occurred by 10 weeks. The modified diets were well-accepted and suitable for implementation in large feeding settings like military dining facilities and civilian cafeterias. Young AJ, Marriott BP, Champagne CM, Hawes MR, Montain SJ, Johannsen NM, Berry K, Hibbeln JR.  Blood fatty acid changes in healthy young Americans in response to a 10-week diet that increased n-3 and reduced n-6 fatty acid consumption: a randomised controlled trial. Br J Nutr. 2017 May;117(9):1257-1269. doi: 10.1017/S0007114517001003.

The proportions of omega-3 (n-3) and omega-6 (n-6) in 20- and 22-carbon highly unsaturated fatty acids with 3 or more double bonds (HUFA) accumulated in tissue (e.g., %n-6 in HUFA) are biomarkers reflecting intakes of n-6 and n-3 nutrients. An empirical equation (Lands’ Equation) was developed previously to use dietary intakes of n-6 and n-3 HUFA and their 18-carbon precursors to predict the %n-6 in HUFA of humans. From the PubMed database, we identified clinical trials reporting dietary intakes and the amounts of HUFA in plasma, serum, or red blood cells. Linear regression analyses comparing reported and predicted %n-6 in HUFA gave a correlation coefficient of 0.73 (p<0.000000) for nearly 4,000 people in 92 subject groups in 34 published studies from 11 different countries. Strandjord SE, Lands B, Hibbeln JR.  Validation of an equation predicting highly unsaturated fatty acid (HUFA) compositions of human blood fractions from dietary intakes of both HUFAs and their precursors.  Prostaglandins Leukot Essent Fatty Acids. 2017 Mar 8. pii: S0952-3278(16)30157-0. doi: 10.1016/j.plefa.2017.03.005.

Following an oral dose of deuterium-labeled 18:2n-6 and 18:3n-3, the concentrations of their HUFA metabolites in plasma total lipids were quantified by GC/MS negative chemical ionization (expressed as the percentage of oral dosage). Female rats accumulated more deuterated 22:6n-3 and 22:5n-6 in plasma than did male rats. Lin YH, Brown JA, DiMartino C, Dahms I, Salem N Jr, Hibbeln JR. Differences in long chain polyunsaturates composition and metabolism in male and female rats. Prostaglandins Leukot Essent Fatty Acids. 2016 Oct;113:19-27. doi: 10.1016/j.plefa.2016.08.008.

A methodology combining finger-tip blood sampling, microwave accelerated fatty acid assay, fast gas chromatography data acquisition, and automated data processing was developed, evaluated and applied to a population study. The mean mol% was 22.6 for 18:2n-6, 9.5 for 20:4n-6, 0.51 for 18:3n-3, 0.42 for 20:5n-3, and 1.67 for 22:6n-3. Lin YH, Hanson JA, Strandjord SE, Salem NM, Dretsch MN, Haub MD, Hibbeln JR.  Fast transmethylation of total lipids in dried blood by microwave irradiation and its application to a population study. Lipids. 2014 Aug;49(8):839-51. doi: 10.1007/s11745-014-3918-3.

Subjects were randomized for 12 weeks to two diets: (1) average n-3, low n-6 (L6) diet; or (2) high n-3 HUFA, low n-6 LA (H3-L6) diet. Compared to baseline, the L6 diet reduced esterified LA and increased esterified n-3 HUFA concentrations (expressed as nmol/ml plasma). The H3-L6 diet decreased LA and AA concentrations, and produced marked increases in esterified n-3 HUFA concentrations. Decreased AA concentration in plasma phospholipid, triglyceride and cholesteryl esters with the H3–L6 diet likely reflects reduced AA synthesis and secretion.  Taha AY, Cheon Y, Faurot KF, Macintosh B, Majchrzak-Hong SF, Mann  JD, Hibbeln JR, Ringel A, Ramsden CE. Dietary omega-6 fatty acid lowering increases bioavailability of omega-3 polyunsaturated fatty acids in human plasma lipid pools. Prostaglandins Leukot Essent Fatty Acids. 2014 May;90(5):151-7. doi: 10.1016/j.plefa.2014.02.003. Epub 2014 Feb 24.

An automated high-throughput fatty acid analysis was developed from a previous procedure based on direct trans-esterification including the automation of chemical procedures, data acquisition and automatic data processing. The method was validated and applied to umbilical cord serum samples in an epidemiological study. The method was linear in the range of 1-600 μg/mL serum with r² ≥ 0.99. This is the first report of a complete, validated, cost-effective, automated, high-throughput fatty acid measurement method applied to a population-based study. Lin YH, Salem N Jr, Wells EM, Zhou W, Loewke JD, Brown JA, Lands WE, Goldman LR, Hibbeln JR.  Automated high-throughput fatty acid analysis of umbilical cord serum and application to an epidemiological study. Lipids. 2012 May;47(5):527-39. doi: 10.1007/s11745-012-3661-6.

HUFA, endocannabinoids and pain
Omega-3 and omega-6 nutrients are precursors of endocannabinoids that have anti-nociceptive, anxiolytic, and neurogenic properties. Diets increasing omega-3 fatty acids while reducing omega-6 linoleic acid (the H3-L6 intervention) reduced headache pain and psychological distress among 55 chronic headache patients. The intervention significantly increased 22:6n-3 derivatives, 2-docosahexaenoylglycerol (+65%, P < .001) and docosahexaenoylethanolamide (+99%, P < .001), and reduced the 20:4n-6 derivative, 2-arachidonoylglycerol (-25%, P = .001). Diet-induced changes in endocannabinoid derivatives of omega-3 docosahexaenoic acid correlated with reductions in physical pain and psychological distress. Ramsden CE, Zamora D, Makriyannis A, Wood JT, Mann JD, Faurot KR, MacIntosh BA, Majchrzak-Hong SF, Gross JR, Courville AB, Davis JM, Hibbeln JR. Diet-induced changes in n-3- and n-6-derived endocannabinoids and reductions in headache pain and psychological distress. J Pain. 2015 Aug;16(8):707-16. doi: 10.1016/j.jpain.2015.04.007.  

Omega-3 and omega-6 fatty acids are precursors of bioactive lipid mediators posited to modulate both physical pain and psychological distress. A randomized trial of 67 subjects with severe headaches demonstrated that targeted dietary manipulation-increasing omega-3 fatty acids with concurrent reduction in omega-6 linoleic acid (the H3-L6 intervention)-produced major reductions in headache. At 12 weeks, the proportion of subjects experiencing substantial impairment was significantly lower in the H3-L6 group. Dietary manipulation of n-3 and n-6 fatty acids, shown previously to produce major improvements in headache, also reduced psychological distress and improved quality of life. Ramsden CE, Faurot KR, Zamora D, Palsson OS, MacIntosh BA, Gaylord S, Taha AY, Rapoport SI, Hibbeln JR, Davis JM, Mann JD. Targeted alterations in dietary n-3 and n-6 fatty acids improve life functioning and reduce psychological distress among patients with chronic headache: a secondary analysis of a randomized trial. Pain. 2015 Apr;156(4):587-96. doi: 10.1097/01.j.pain.0000460348.84965.47.

A randomized, single-blinded, parallel-group clinical trial assessed clinical and biochemical effects of altering dietary n-3 and n-6 fatty acids for treatment of chronic headaches. After a 4-week pre-intervention phase, ambulatory patients with chronic daily headache undergoing usual care were randomized to two intensive, 12-week dietary interventions: a high n-3 plus low n-6 (H3-L6) intervention, or a low n-6 (L6) intervention. Fifty-six of 67 patients completed the intervention. The H3-L6 intervention produced significantly greater improvement in the HIT-6 score (-7.5 vs -2.1; P<0.001) and the number of Headache Days per month (-8.8 vs -4.0; P=0.02), compared to the L6 group. The H3-L6 intervention also gave reductions of -4.6 headache hours per day and -21% n-6 in HUFA plus increases in antinociceptive n-3 pathway markers 18-hydroxy-eicosapentaenoic acid (+118%) and 17-hydroxy-docosahexaenoic acid (+170%). Ramsden CE, Faurot KR, Zamora D, Suchindran CM, Macintosh BA, Gaylord S, Ringel A, Hibbeln JR, Feldstein AE, Mori TA, Barden A, Lynch C, Coble R, Mas E, Palsson O, Barrow DA, Mann JD. Targeted alteration of dietary n-3 and n-6 fatty acids for the treatment of chronic headaches: a randomized trial. Pain. 2013 Nov;154(11):2441-51. doi: 10.1016/j.pain.2013.07.028.

HUFA levels in depression and mood disorders
Depressive symptoms are inversely related to n-3 (ω-3) fatty acids among United States adults. A cross-sectional study of 1,746 adults (aged 30-65 y) in Baltimore City, MD (2004-2009) showed elevated depressive symptom (EDS) prevalence was 18.1% among men and 25.6% among women. In women, the uppermost tertile (tertile 3) of n-3 PUFAs (compared with tertile 1) was associated with reduced odds of EDS by 49%. Among United States women, higher intakes of n-3 fatty acids 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). Beydoun MA, Fanelli Kuczmarski MT, Beydoun HA, Hibbeln JR, Evans MK, Zonderman AB. ω-3 fatty acid intakes are inversely related to elevated depressive symptoms among United States women. J Nutr. 2013 Nov;143(11):1743-52. doi: 10.3945/jn.113.179119.     

Pregnant women enrolled from 1991-1992 in ALSPAC (n=9,530) answered a food frequency questionnaire used to define food habit patterns. Multivariate results showed that women in the highest tertile of the health-conscious (OR 0.77; 0.65-0.93) and the traditional (OR 0.84; 0.73-0.97) pattern scores were less likely to report high levels of anxiety symptoms. Women in the highest tertile of the vegetarian pattern score (OR 1.25; 1.08-1.44) were more likely to have high levels of anxiety, as well as those with no n-3 PUFA intake from seafood when compared with those with intake of  >1.5 grams n-3 PUFA /week.The present study suggests that dietary interventions could be used to reduce high anxiety symptoms during pregnancy.  Vaz Jdos S, Kac G, Emmett P, Davis JM, Golding J, Hibbeln JR. Dietary patterns, n-3 fatty acids intake from seafood and high levels of anxiety symptoms during pregnancy: findings from the Avon Longitudinal Study of Parents and Children. PLoS One. 2013 Jul 12;8(7):e67671. doi: 10.1371/journal.pone.0067671.

Male children with (n=29) and without (n=43) a clinical diagnosis of ADHD were compared in their plasma levels of LC-PUFA. Callous-unemotional (CU) traits were significantly negatively related to both eicosapentaenoic acid (EPA), and total omega-3 in the ADHD group. Gow RV, Vallee-Tourangeau F, Crawford MA, Taylor E, Ghebremeskel K, Bueno AA,  Hibbeln JR, Sumich A, Rubia K.  Omega-3 fatty acids are inversely related to callous and unemotional traits in adolescent boys with attention deficit hyperactivity disorder. Prostaglandins Leukot Essent Fatty Acids. 2013 Jun;88(6):411-8.

Attention deficit hyperactivity disorder (ADHD) is associated with poor emotion regulation. Children with (n=31) and without ADHD (n=32) were compared in their plasma omega-3/6 indices and corresponding ERPs during an emotion processing task. ERP abnormalities were significantly associated with lower omega-3 levels in the ADHD group. Gow RV, Sumich A, Vallee-Tourangeau F, Crawford MA, Ghebremeskel K, Bueno AA,  Hibbeln JR, Taylor E, Wilson DA, Rubia K. Omega-3 fatty acids are related to abnormal emotion processing in adolescent boys with attention deficit hyperactivity disorder. Prostaglandins Leukot Essent Fatty Acids. 2013 Jun;88(6):419-29. doi: 10.1016/j.plefa.2013.03.008.

Although common in western countries, depression appears to be virtually absent in countries with high seafood intake. Data were prospectively collected from women in the Avon Longitudinal Study of Parents and Children during 1991-1992. Lower maternal intake of omega-3 from seafood was associated with high levels of depressive symptoms. Compared with women consuming more than 1.5 g omega-3 from seafood per week, those consuming none were more likely to have high levels of depressive symptoms at 32 weeks’ gestation (adjusted odds ratios = 1.54). Eating seafood during pregnancy may have beneficial effects on mental well-being. Golding J, Steer C, Emmett P, Davis JM, Hibbeln JR. High levels of depressive symptoms in pregnancy with low omega-3 fatty acid intake from fish. Epidemiology. 2009 Jul;20(4):598-603.

Worldwide diversity in dietary intakes of n-6 and n-3 nutrients affects tissue compositions of n-3 and n-6 HUFA as well as risks for cardiovascular and mental illnesses. We estimated healthy dietary allowances for n-3 HUFA that would meet the nutrient requirements of 97-98% of the population. We defined deficiency in n-3 HUFA as attributable risk from 13 morbidity and mortality outcomes, including all causes, coronary heart disease, stroke, cardiovascular disease, homicide, bipolar disorder, and major and postpartum depressions. The potential attributable burden of disease ranged from 20.8% (all-cause mortality in men) to 99.9% (bipolar disorder). The n-3 HUFA intake for Japan (0.37% of energy, or 750 mg/d) met criteria for uniformly protecting >98% of the populations worldwide. n-3 HUFA intakes needed to meet a tissue target representative of Japan (60% n-3 in HUFA) ranged from 278 mg/d for the Philippines to 3667 mg/d for the United States. The USA allowance for n-3 HUFA can likely be reduced to one-tenth of that amount by consuming fewer n-6 fats. Hibbeln JR, Nieminen LR, Blasbalg TL, Riggs JA, Lands WE. Healthy intakes of n-3 and n-6 fatty acids: estimations considering worldwide diversity. Am J Clin Nutr. 2006 Jun;83(6 Suppl):1483S-1493S.

Greater apparent consumption of linoleic acid correlated with higher rates of homicide mortality over a 20-fold range (0.51-10.2/100,000) across countries and time. Low linoleate diets may prevent behavioral maladies that correctional institutions, social service programs, and mental health providers intend to treat. Hibbeln JR, Nieminen LR, Lands WE.  Increasing homicide rates and linoleic acid consumption among five Western countries, 1961-2000. Lipids. 2004 Dec;39(12):1207-13. PMID: 15736917

Omega-6 nutrients, endocannabinoids, and obesity
Linoleic acid (LA, 18:2n-6) is a precursor for arachidonic acid (AA, 20:4n-6) that is, in turn, a precursor for endocannabinoids, 2-arachidonoyl glycerol (2-AG) and arachidonoylethanolamide (AEA; anandamide). Increasing dietary LA from 1 to 8 en% in 12.5 en% fat and 35 en% fat diets significantly increased AA in phospholipids, elevated 2-AG and AEA in liver, elevated plasma leptin, and resulted in larger adipocytes and more macrophage infiltration in adipose tissue. 8 en% LA caused greater gain in weight than did isocaloric 1 en% LNA. Thus, a high dietary content of LA (8 en%) increases feed efficiency and the adipogenic properties of a low-fat diet. Alvheim AR, Torstensen BE, Lin YH, Lillefosse HH, Lock EJ, Madsen L, Frøyland  L, Hibbeln JR, Malde MK. Dietary linoleic acid elevates the endocannabinoids 2-AG and anandamide and promotes weight gain in mice fed a low fat diet. Lipids. 2014 Jan;49(1):59-69. doi: 10.1007/s11745-013-3842-y.

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. Alvheim AR, Torstensen BE, Lin YH, Lillefosse HH, Lock EJ, Madsen L, Hibbeln JR, Malde MK. 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. 2013 Apr 28;109(8):1508-17. doi: 10.1017/S0007114512003364. Epub 2012  Aug 10.

Suppressing hyperactive endocannabinoid tone is a critical target for reducing obesity. The backbone of both endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA) is the n-6 HUFA, arachidonic acid (AA). Here we posited that excessive dietary intake of linoleic acid (LA), the precursor of AA, would induce endocannabinoid hyperactivity and promote obesity. LA was isolated as an independent variable to reflect the dietary increase in LA from 1 percent of energy (en%) to 8 en% occurring in the United States during the 20th century and correlated with increased prevalence rates of obesity. Mice were fed diets containing 1 en% LA, 8 en% LA, and 8 en% LA + 1 en% eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) in medium-fat diets (35  en% fat) and high-fat diets (60 en%) for 14 weeks from weaning. Increasing LA from 1 en% to 8 en% elevated AA-phospholipids (PL) in liver and erythrocytes, tripled 2-AG + 1-AG and AEA associated with increased food intake, feed efficiency, and adiposity in mice. Selectively reducing LA to 1 en% reversed the obesogenic properties of a 60 en% fat diet. The adipogenic effect of LA can be prevented by consuming sufficient EPA and DHA to reduce the AA-PL pool and normalize endocannabinoid tone. Alvheim AR, Malde MK, Osei-Hyiaman D, Lin YH, Pawlosky RJ, Madsen L, Kristiansen K, Frøyland L, Hibbeln JR.  Dietary linoleic acid elevates endogenous 2-AG and anandamide and induces obesity. Obesity (Silver Spring). 2012 Oct;20(10):1984-94. doi: 10.1038/oby.2012.38.

Feeding 3 generations of mice an equicaloric diet in which alpha-linolenic acid(18:3n-3), the dietary precursor of n-3 HUFA, was substituted by linoleic acid (18:2n-6), the dietary precursor of n-6 HUFA, significantly increased body weight throughout life when compared with standard diet-fed mice. Adipogenesis in mice fed low n-3 fatty acid was accompanied by a 6-fold upregulation of stearoyl-coenzyme A desaturase 1 (Scd1), whose activity is correlated to plasma triglyceride levels. In total liver lipid and phospholipid extracts, the n-3 HUFA, 20:5n-3, 22:5n-3, and 22:6n-3, were significantly decreased, whereas arachidonic acid (20:4n-6) was significantly increased. Overall, reducing dietary alpha-linolenic acid from 1.02 energy % to 0.16 energy % combined with raising linoleic acid intake resulted in obesity and had detrimental consequences on organ function. Hanbauer I, Rivero-Covelo I, Maloku E, Baca A, Hu Q, Hibbeln JR, Davis JM. Decrease of n-3 Fatty Acid Energy Percentage in an Equicaloric Diet Fed to B6C3Fe Mice for Three Generations Elicits Obesity. Cardiovasc Psychiatry Neurol. 2009;2009:867041. doi: 10.1155/2009/867041.

We estimated per capita consumption of food commodities and availability of essential fatty acids from 373 food commodities by using economic disappearance data for each year from 1909 to 1999. The estimated per capita consumption of soybean oil increased >1000-fold from 1909 to 1999. The availability of linoleic acid (LA) increased from 2.79% to 7.21% of energy (P < 0.000001) while availability of α-linolenic acid (ALA) increased from 0.39% to 0.72% of energy. The apparent increased consumption of LA, primarily from soybean oil, has likely decreased tissue concentrations of n-3 HUFA, EPA and DHA, during the 20th century. Blasbalg TL, Hibbeln JR, Ramsden CE, Majchrzak SF, Rawlings RR. Changes in consumption of omega-3 and omega-6 fatty acids in the United States during the 20th century.  Am J Clin Nutr. 2011 May;93(5):950-62. doi: 10.3945/ajcn.110.006643.


updated October, 2017