Impact of Docosahexaenoic Acid Therapy on Subgingival Plaque Microbiota.

BACKGROUND: Oral docosahexaenoic acid (DHA) + aspirin therapy has been shown to reduce periodontal probing depth (PD) and local inflammatory mediators in gingival crevicular fluid (GCF) among patients with untreated chronic periodontal disease. Whether DHA + aspirin therapy influences specific bacterial burden in this setting is unknown. Thus, the aim of this study is to evaluate the impact of DHA with low-dose aspirin therapy on periodontal bacterial profile in patients with periodontitis. METHODS: Fifty-five adults with moderate-to-severe periodontitis were enrolled in a randomized, 3-month double-masked, placebo-controlled trial of daily 2 g DHA or placebo capsules enriched with 81 mg aspirin; 46 enrollees completed the trial. In addition to clinical measurements and GCF sampling, subgingival plaque samples were collected from four posterior sites in all participants and analyzed by the checkerboard DNA-DNA hybridization technique. Presence of 40 periodontal bacterial species at baseline and 3 months was semiquantitatively estimated. RESULTS: Despite broad improvements in clinical parameters, total bacteria and individual species counts in dental plaque did not differ significantly between baseline and 3 months in either group (P >0.1 for all). A modest effect of DHA + aspirin on Porphyromonas gingivalis counts was associated with 14% (95% confidence interval: 3% to 35%) of the observed benefit of DHA on PD. DHA + aspirin had no significant effect on individual plaque bacterial counts in unadjusted models or those adjusted for age, sex, and race (P >0.1 for all). CONCLUSIONS: This pilot randomized, controlled trial suggests that DHA + aspirin therapy improves periodontitis largely by modulating host inflammatory response. Changes in individual species levels in subgingival plaque microbiota were not detectable; however, a small portion of the benefit appears to stem from changes in P. gingivalis levels in the DHA + aspirin treatment group. Whether this change in P. gingivalis levels leads to biofilm alteration with reversal of dysbiosis requires further longitudinal and more specific investigations.

Erythrocyte saturated fatty acids and systemic inflammation in adults.

OBJECTIVE: The role of saturated fatty acids (SFAs) in chronic disease remains controversial; inflammation is one pathway by which SFAs influence the risk for chronic disease. The aim of this study was to investigate the associations between red blood cell (RBC) phospholipid SFAs and systemic inflammation. METHODS: As part of a randomized controlled trial, we measured RBC phospholipid FA composition in 55 generally healthy adults twice at 3-mo intervals. We estimated associations of RBC total SFAs and two major SFA subtypes, palmitic and stearic acids, with C-reactive protein (CRP), interleukin (IL)-6, white blood count (WBC), and a composite inflammation measure using generalized estimating equations in multivariable FA substitution models. RESULTS: Mean (±SD) SFA level across both visits was 45% ± 3% of the total RBC FAs, mainly palmitic (21% ± 1%) and stearic (17% ± 3%) acids. In models adjusted for age, sex, race, smoking, body mass index, statin use, aspirin use, transunsaturated FAs, and ω-3 FAs, SFAs were significantly associated with IL-6 (20% increase per 1 SD increment; 95% confidence interval [CI], 0.03%-43%; P = 0.05) and the composite inflammation measure (P = 0.05) and marginally associated with CRP (34% increase; 95% CI, -1% to 81%; P = 0.06), but not associated with WBC. Stearic acid was positively associated with CRP (35% increase; 95% CI, 2%-79%; P = 0.04). Palmitic acid was marginally associated with the composite inflammation measure (P = 0.06) and, upon additional ω-6 FA adjustment, significantly associated with IL-6 (15% increase; 95% CI, 0.4%-27%; P = 0.006). CONCLUSIONS: RBC SFAs, which represent longer-term dietary intake, are positively associated with inflammation. In particular, palmitic acid was associated with IL-6, and stearic acid was associated with CRP after multivariable adjustment.

Nutrient intake and peripheral artery disease in adults: key considerations in cross-sectional studies.

BACKGROUND & AIMS: There are limited studies of nutrient intake and peripheral artery disease (PAD). Some studies have not accounted for the functional consequences of PAD, potentially leading to biased results. To determine the associations between intakes of dietary fiber, folate, vitamins A, C, E, and B6 and PAD. METHODS: Cross-sectional analysis of 6534 adults aged 40 years and older in the U.S. National Health and Nutrition Examination Survey between 1999 and 2004, including measurement of ankle-brachial index (ABI) and nutrient intake by 24-h dietary recall. Weighted multivariable logistic regression models to determine odds ratios and 95% confidence intervals. RESULTS: The prevalence of PAD (ABI < 0.9) was 5.3% (4.7-5.9). Inverse associations between PAD and intakes of fiber, folate, and vitamins A, B6, C, and E were statistically significant when adjusting for age, sex, hypertension, diabetes and smoking. In models further adjusted for energy intake and physical activity, these odds ratios all became null (p ≥ 0.1). CONCLUSIONS: In this sample, dietary fiber, folate, and vitamins B6, C, and E were not associated with PAD after accounting for energy intake and activity. Adjustment for energy and physical activity are essential to avoid bias due to reverse causation in cross-sectional studies of diet and PAD.

Dietary fatty acids and peripheral artery disease in adults.

BACKGROUND: Peripheral artery disease (PAD) is a debilitating condition involving atherosclerosis. Although saturated, monounsaturated and polyunsaturated fatty acids have strong associations with atherosclerosis, it is unclear if diets high in these fatty acids affect PAD. METHODS: We studied 6352 adults aged 40 years and older who participated in the U.S. National Health and Nutrition Examination Survey between 1999 and 2004. Ankle brachial index (ABI) was assessed by standardized blood pressure measurements, and we defined PAD as an ABI<0.9. Fatty acid intake was assessed by validated 24-h dietary recall. We used multivariable linear and logistic regression to estimate associations between intakes of dietary saturated fatty acids (SFAs), monounsaturated fatty acids (MFAs), marine omega-3 fatty acids (N-3), linolenic acid (LNA), and omega-6 fatty acids (N-6) and ABI/PAD. RESULTS: The prevalence and 95% confidence interval (CI) of PAD was 5.2% (95% CI 4.6-5.8). There were no associations between ABI and intakes of marine N-3 (p=0.83) or N-6 (p=0.19) in adjusted models. In contrast, LNA was associated with higher ABI (p=0.04) and SFA tended to be associated with lower ABI (p=0.06) in adjusted models. In addition, higher SFA was associated with a higher prevalence of PAD: adjusted odds ratio 1.30 (95% CI 1.01-1.67; p=0.04) and a trend toward slower gait speed (p=0.08). CONCLUSION: In this nationally representative sample, higher dietary intakes of LNA and SFAs were associated with higher and lower ABI, respectively. Prospective studies are needed to confirm the potential protective effects of dietary LNA and detrimental effects of dietary SFAs on PAD.

Monounsaturated, trans, and saturated Fatty acids and cognitive decline in women.

OBJECTIVES: To prospectively assess effects of select dietary fats on cognitive decline. DESIGN: Prospective observational; 3-year follow-up. SETTING: Northwestern University. PARTICIPANTS: Four hundred eighty-two women aged 60 and older who participated in the Women's Health Initiative (WHI) Observational Study or in the control group of the WHI Diet Modification arm. MEASUREMENTS: Dietary intake from a validated food frequency questionnaire (FFQ) administered twice (mean 2.7 years apart) before baseline cognitive assessment (mean 2.9 years after second FFQ) was averaged. Testing of memory, vision, executive function, language, and attention was performed twice, 3 years apart. A global Z-score was created for both time points by averaging all Z-scores for each participant, and global cognitive change was defined as the difference between follow-up and baseline Z-scores. RESULTS: Median intake of saturated fat (SFA), trans-fat, (TFA), dietary cholesterol (DC), and monounsaturated fat (MUFA) was 18.53, 3.45, 0.201, and 19.39 g/d, respectively. There were no associations between degree of cognitive decline and intake of SFA (P=.69), TFA (P=.54), or DC (P=.64) after adjusting for baseline cognition, total energy intake, age, education, reading ability, apolipoprotein E ɛ4 allele, body mass index, estrogen and beta-blocker use, and intake of caffeine and other fatty acids. In contrast, MUFA intake was associated with lower cognitive decline in fully adjusted linear regression models, with mean decline (standard error) of 0.21 (0.05) in the lowest and 0.05 (0.05) in the highest quartiles (P=.02). This effect of MUFA intake was primarily in the visual and memory domains (P=.03 for both). CONCLUSION: Greater intake of SFA, TFA, and DC was not associated with cognitive decline, whereas greater MUFA intake was associated with less cognitive decline.

n-3 fatty acids and periodontitis in US adults.

BACKGROUND: Periodontitis is a common, chronic inflammatory disease. Although n-3 fatty acids have anti-inflammatory properties, it is unclear whether n-3 fatty acids can treat or prevent periodontitis. METHOD: We studied 9,182 adults aged 20 years and older who participated in the National Health and Nutrition Examination Survey between 1999 and 2004. Periodontitis was assessed by dental exam and was defined as >4 mm pocket depth and >3 mm attachment loss in any one tooth. Intake of n-3 fatty acids was assessed by 24-hour dietary recall. We used multivariable logistic regression to estimate the associations between periodontitis and intakes of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and linolenic acid (LNA). RESULTS: The weighted prevalence and 95% confidence interval (CI) of periodontitis was 8.2% (95% CI 7.0 to 9.4). Compared with the lowest tertiles, the adjusted odds ratios for periodontitis associated with the highest tertiles of dietary n-3 intake were 0.78 (95% CI 0.61 to 1.00; P=0.009) for DHA, 0.85 (95% CI 0.67 to 1.08; P=0.10) for EPA, and 0.86 (95% CI 0.60 to 1.23; P=0.28) for LNA. The associations were little changed by multivariable adjustment or exclusion of individuals reporting use of dietary supplements containing DHA, EPA, or LNA. CONCLUSIONS: In this nationally representative sample, higher dietary intakes of DHA and, to a lesser degree, EPA, were associated with lower prevalence of periodontitis. Interventional studies are needed to confirm the potential protective effects of n-3 fatty acids on periodontitis.