Dietary alteration of n-3 and n-6 fatty acids for headache reduction in adults with migraine: randomized controlled trial.

OBJECTIVE: To determine whether dietary interventions that increase n-3 fatty acids with and without reduction in n-6 linoleic acid can alter circulating lipid mediators implicated in headache pathogenesis, and decrease headache in adults with migraine. DESIGN: Three arm, parallel group, randomized, modified double blind, controlled trial. SETTING: Ambulatory, academic medical center in the United States over 16 weeks. PARTICIPANTS: 182 participants (88% women, mean age 38 years) with migraines on 5-20 days per month (67% met criteria for chronic migraine). INTERVENTIONS: Three diets designed with eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid altered as controlled variables: H3 diet (n=61)-increase EPA+DHA to 1.5 g/day and maintain linoleic acid at around 7% of energy; H3-L6 diet (n=61)-increase n-3 EPA+DHA to 1.5 g/day and decrease linoleic acid to ≤1.8% of energy; control diet (n=60)-maintain EPA+DHA at <150 mg/day and linoleic acid at around 7% of energy. All participants received foods accounting for two thirds of daily food energy and continued usual care. MAIN OUTCOME MEASURES: The primary endpoints (week 16) were the antinociceptive mediator 17-hydroxydocosahexaenoic acid (17-HDHA) in blood and the headache impact test (HIT-6), a six item questionnaire assessing headache impact on quality of life. Headache frequency was assessed daily with an electronic diary. RESULTS: In intention-to-treat analyses (n=182), the H3-L6 and H3 diets increased circulating 17-HDHA (log ng/mL) compared with the control diet (baseline-adjusted mean difference 0.6, 95% confidence interval 0.2 to 0.9; 0.7, 0.4 to 1.1, respectively). The observed improvement in HIT-6 scores in the H3-L6 and H3 groups was not statistically significant (-1.6, -4.2 to 1.0, and -1.5, -4.2 to 1.2, respectively). Compared with the control diet, the H3-L6 and H3 diets decreased total headache hours per day (-1.7, -2.5 to -0.9, and -1.3, -2.1 to -0.5, respectively), moderate to severe headache hours per day (-0.8, -1.2 to -0.4, and -0.7, -1.1 to -0.3, respectively), and headache days per month (-4.0, -5.2 to -2.7, and -2.0, -3.3 to -0.7, respectively). The H3-L6 diet decreased headache days per month more than the H3 diet (-2.0, -3.2 to -0.8), suggesting additional benefit from lowering dietary linoleic acid. The H3-L6 and H3 diets altered n-3 and n-6 fatty acids and several of their nociceptive oxylipin derivatives in plasma, serum, erythrocytes or immune cells, but did not alter classic headache mediators calcitonin gene related peptide and prostaglandin E2. CONCLUSIONS: The H3-L6 and H3 interventions altered bioactive mediators implicated in headache pathogenesis and decreased frequency and severity of headaches, but did not significantly improve quality of life. TRIAL REGISTRATION: ClinicalTrials.gov NCT02012790.

Dietary linoleic acid-induced alterations in pro- and anti-nociceptive lipid autacoids: Implications for idiopathic pain syndromes?

BACKGROUND: Chronic idiopathic pain syndromes are major causes of personal suffering, disability, and societal expense. Dietary n-6 linoleic acid has increased markedly in modern industrialized populations over the past century. These high amounts of linoleic acid could hypothetically predispose to physical pain by increasing the production of pro-nociceptive linoleic acid-derived lipid autacoids and by interfering with the production of anti-nociceptive lipid autacoids derived from n-3 fatty acids. Here, we used a rat model to determine the effect of increasing dietary linoleic acid as a controlled variable for 15 weeks on nociceptive lipid autacoids and their precursor n-6 and n-3 fatty acids in tissues associated with idiopathic pain syndromes. RESULTS: Increasing dietary linoleic acid markedly increased the abundance of linoleic acid and its pro-nociceptive derivatives and reduced the abundance of n-3 eicosapentaenoic acid and docosahexaenoic acid and their anti-nociceptive monoepoxide derivatives. Diet-induced changes occurred in a tissue-specific manner, with marked alterations of nociceptive lipid autacoids in both peripheral and central tissues, and the most pronounced changes in their fatty acid precursors in peripheral tissues. CONCLUSIONS: The present findings provide biochemical support for the hypothesis that the high linoleic acid content of modern industrialized diets may create a biochemical susceptibility to develop chronic pain. Dietary linoleic acid lowering should be further investigated as part of an integrative strategy for the prevention and management of idiopathic pain syndromes.

Fast transmethylation of serum lipids using microwave irradiation.

Microwave irradiation as the energy source for one-step direct transesterification of fatty acids in human serum lipids was examined in a solvent system of methanol: hexane: acetyl chloride based on a Lepage & Roy assay. Innovative and explosion proof single-mode or multimode microwave accelerated reaction system was employed. Recoveries were calculated as the percentage of fatty acid concentrations measured by microwave assay to those by the reference method of the Lepage & Roy assay that utilized conductive heating at 100 °C for 60 min. Under conditions of 100 °C for 1 min in Single-mode (S4-100 × 1), or 125 °C for 5 min in Multimode (M5-125 × 5), the recoveries were 100-103 % for the total fatty acids and 96-106 % for each categorized fatty acid, including saturates, monounsaturates, n-6 PUFA, and n-3 PUFA. For individual PUFA, the mean recoveries were 102-105 % for 18:2n-6 and 18:3n-3; 99, 109, and 95 % for 20:4n-6, 20:5n-3, and 22:6n-3, respectively. Thus, fatty acid concentrations determined by microwave fatty acid assay were accurate to those results by the reference method, when the microwave conditions were optimal. In summary, the microwave irradiation could replace conductive heating in one-step direct transesterification, and reduce the duration from 60 min to 5 min or less. This methodology may be applied in both the absolute and relative quantification of serum total fatty acids.

Automated high-throughput fatty acid analysis of umbilical cord serum and application to an epidemiological study.

Large population studies show that polyunsaturated fatty acids are important for human health, but determining relationships between the health benefits and the fatty acid content has been hampered by the unavailability of labor-effective high-throughput technologies. An automated high throughput fatty acid analysis was developed from a previous procedure based on direct transesterification 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. The within-run CV was <5.4% for 23 fatty acids and a range of recoveries over three concentrations were 76-119% in a low-lipid matrix with the exception of 14:0. The fatty acid concentration as measured by the robotic method for human plasma was in good agreement with the Lepage & Roy method. The fatty acid profile in umbilical cord serum from American subjects (n = 287) showed an average of 38.0, 24.9, 32.0 and 4.6% of total fatty acids for saturates, monounsaturates, n-6 and n-3 polyunsaturates, respectively. This is the first report of a complete, validated, cost-effective, automated, high throughput fatty acid measurement method along with application to a population-based study. Automated fatty acid analysis coupled with automated data processing greatly facilitates the high throughput, 72 samples transesterified in 6 h, required for large population-based studies.

Suicide deaths of active-duty US military and omega-3 fatty-acid status: a case-control comparison.

BACKGROUND: The recent escalation of US military suicide deaths to record numbers has been a sentinel for impaired force efficacy and has accelerated the search for reversible risk factors. OBJECTIVE: To determine whether deficiencies of neuroactive, highly unsaturated omega-3 essential fatty acids (n-3 HUFAs), in particular docosahexaenoic acid (DHA), are associated with increased risk of suicide death among a large random sample of active-duty US military. METHOD: In this retrospective case-control study, serum fatty acids were quantified as a percentage of total fatty acids among US military suicide deaths (n = 800) and controls (n = 800) matched for age, date of collection of sera, sex, rank, and year of incident. Participants were active-duty US military personnel (2002-2008). For cases, age at death ranged from 17-59 years (mean = 27.3 years, SD = 7.3 years). Outcome measures included death by suicide, postdeployment health assessment questionnaire (Department of Defense Form 2796), and ICD-9 mental health diagnosis data. RESULTS: Risk of suicide death was 14% higher per SD of lower DHA percentage (OR = 1.14; 95% CI, 1.02-1.27; P < .03) in adjusted logistic regressions. Among men, risk of suicide death was 62% greater with low serum DHA status (adjusted OR = 1.62; 95% CI, 1.12-2.34; P < .01, comparing DHA below 1.75% [n = 1,389] to DHA of 1.75% and above [n = 141]). Risk of suicide death was 52% greater in those who reported having seen wounded, dead, or killed coalition personnel (OR = 1.52; 95% CI, 1.11-2.09; P < .01). CONCLUSION: This US military population had a very low and narrow range of n-3 HUFA status. Although these data suggest that low serum DHA may be a risk factor for suicide, well-designed intervention trials are needed to evaluate causality.

Low omega-6 vs. low omega-6 plus high omega-3 dietary intervention for chronic daily headache: protocol for a randomized clinical trial.

BACKGROUND: Targeted analgesic dietary interventions are a promising strategy for alleviating pain and improving quality of life in patients with persistent pain syndromes, such as chronic daily headache (CDH). High intakes of the omega-6 (n-6) polyunsaturated fatty acids (PUFAs), linoleic acid (LA) and arachidonic acid (AA) may promote physical pain by increasing the abundance, and subsequent metabolism, of LA and AA in immune and nervous system tissues. Here we describe methodology for an ongoing randomized clinical trial comparing the metabolic and clinical effects of a low n-6, average n-3 PUFA diet, to the effects of a low n-6 plus high n-3 PUFA diet, in patients with CDH. Our primary aim is to determine if: A) both diets reduce n-6 PUFAs in plasma and erythrocyte lipid pools, compared to baseline; and B) the low n-6 plus high n-3 diet produces a greater decline in n-6 PUFAs, compared to the low n-6 diet alone. Secondary clinical outcomes include headache-specific quality-of-life, and headache frequency and intensity. METHODS: Adults meeting the International Classification of Headache Disorders criteria for CDH are included. After a 6-week baseline phase, participants are randomized to a low n-6 diet, or a low n-6 plus high n-3 diet, for 12 weeks. Foods meeting nutrient intake targets are provided for 2 meals and 2 snacks per day. A research dietitian provides intensive dietary counseling at 2-week intervals. Web-based intervention materials complement dietitian advice. Blood and clinical outcome data are collected every 4 weeks. RESULTS: Subject recruitment and retention has been excellent; 35 of 40 randomized participants completed the 12-week intervention. Preliminary blinded analysis of composite data from the first 20 participants found significant reductions in erythrocyte n-6 LA, AA and %n-6 in HUFA, and increases in n-3 EPA, DHA and the omega-3 index, indicating adherence. TRIAL REGISTRATION: ClinicalTrials.gov (NCT01157208).

Preferential effect of lead exposure during lactation on non-essential fatty acids in maternal organs.

This study determined the effects of lead exposure during the lactational period on maternal organ FA compositions in rat dams that were fed either an n-3 adequate (n-3 Adq) or deficient (n-3 Def) diet prior to conception. On giving birth, dams were subdivided into four groups in a 2 x 2 design with n-3 FA supply and Pb exposure as the dependent variables. Pb acetate (0.2 wt%) was administered in the drinking water from the time they gave birth to weaning 3 wk later. Following weaning, the dams were decapitated, and the liver, plasma, kidney, brain, and retina analyzed for FA composition. The n-3 deficient diets markedly decreased the percentages of total n-3 FA, including docosahexaenoic acid (DHA), and increased total n-6 FA including both arachidonic (AA) and n-6 docosapentaenoic acids in all tissues (P < 0.05). The principal effects of Pb occurred in the liver and plasma, where 20-32% losses in total FA concentration concurrent with increased relative percentages of AA (P < 0.05) were observed. In kidney, the percentages of AA and DHA also increased after Pb exposure (P < 0.05) with lesser effects in the nervous system. There was a diet x Pb interaction for liver, plasma, and retinal 20-C n-6 PUFA (P < 0.05). Generally, shorter-chain saturated and monounsaturated FA concentrations were decreased after Pb exposure. An analysis of the changes in the tissue concentrations induced by Pb indicated that the increases in the percentages of PUFA likely reflected a preferential loss of non-EFA. The mechanisms by which Pb affects saturated and monounsaturated FA concentration are unknown.

Incomplete replacement of docosahexaenoic acid by n-6 docosapentaenoic acid in the rat retina after an n-3 fatty acid deficient diet.

When sources of n-3 fatty acids are not present in the diet, nervous system docosahexaenoic acid (22:6n3) is replaced by docosapentaenoic acid (22:5n6). Dams were fed either an n-3 deficient diet or one containing alpha-linolenic acid (18:3n3) and 22:6n3 throughout pregnancy and lactation. Their male offspring at weaning also received either the n-3 deficient or n-3 adequate diets and were sacrificed at 5, 10, 20, 50 and 91 days of age. Retinal lipids were extracted and analysed by gas chromatography for fatty acyl content. The percentage of retinal 22:6n3 increased continuously over the 13 week course of the experiment but reached its maximal concentration around day 20. Non-reciprocal replacement of 22:6n3 by 22:5n6 was observed at postnatal day 20 and 50 but not at other time points. Complete replacement of 22:6n3 was apparent if elevations in both 22:5n6 and docosatetraenoic acid (22:4n6) were considered. These data indicate that during the rapid period of accretion of retinal 22:6n3 around postnatal day 20, the supply of 22:5n6 to the retina was inadequate to completely replace 22:6n3 in n-3 deficient rats.

Effects of an n-3-deficient diet on brain, retina, and liver fatty acyl composition in artificially reared rats.

Rat pups born to dams fed a diet with 3.1% of total fatty acids as alpha-linolenic acid (LNA) were fed, using an artificial rearing system, either an n-3-deficient (n-3-Def) or an n-3-adequate (n-3-Adq) diet. Both diets contained 17.1% linoleic acid, but the n-3-Adq diet also contained 3.1% LNA. The percentage of brain docosahexaenoic acid (DHA) continuously decreased (71%) with time over the 29 days of the experiment, with concomitant increases in docosapentaenoic acid (DPAn-6). In the retina, the percentage of DHA rose in the n-3-Adq group, with an apparent increased rate around the time of eye opening. However, there was a flat curve for the percentage of DHA in the n-3-Def group and a rising DPAn-6 with time. Liver DHA was highest at the time of birth in the n-3-Adq group but fell off somewhat over the course of 29 days. This decrease was more pronounced in the n-3-Def group, and the DPAn-6 rose considerably during the second half of the experiment. This method presents a first-generation model for n-3 deficiency that is more similar to the case of human nutrition than is the commonly employed two-generation model.