Associations of serum n-3 and n-6 polyunsaturated fatty acids with prevalence and incidence of nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a major cause of liver diseases worldwide, and lifestyle and diet are significant factors in its development. Recent studies have suggested that dietary fat quality is associated with the development of NAFLD.

OBJECTIVES

Our purpose was to investigate the cross-sectional and longitudinal associations of serum n-3 (ω-3) and n-6 (ω-6) PUFAs with NAFLD among middle-aged and older men and women from eastern Finland. We also investigated the associations of estimated Δ5-desaturase and Δ6-desaturase activities, enzymes involved in PUFA metabolism, with NAFLD.

METHODS

After exclusions, the cross-sectional analyses included 1533 men examined in 1984-1989 and 674 men and 870 women examined in 1998-2001 in the Kuopio Ischaemic Heart Disease Risk Factor Study. The longitudinal analyses included 520 men examined in 1991-1993 and 301 men and 466 women examined in 2005-2008. Fatty liver index (FLI) was used as a surrogate for NAFLD. Hepatic steatosis was defined as FLI >60. ANCOVA and logistic regression were used for analyses.

RESULTS

In the longitudinal analyses, participants with higher serum concentrations of total n-6 PUFA and linoleic acid, the major n-6 PUFA, had markedly lower FLI and lower odds for hepatic steatosis (e.g., odds ratios for incident hepatic steatosis in the highest compared with lowest quartiles were ≤0.41), whereas serum γ-linolenic acid concentration was associated with a higher FLI and higher odds for hepatic steatosis. The associations with the other PUFAs were generally weaker and nonsignificant. In the cross-sectional analyses, also the long-chain n-3 PUFAs had inverse associations. In most analyses, high estimated Δ5-desaturase activity was associated with lower risk and high estimated Δ6-desaturase activity with higher risk for NAFLD.

CONCLUSIONS

In middle-aged and older Finnish adults, higher serum concentrations of total n-6 PUFAs and linoleic acid were associated with lower odds for future NAFLD.

Affordability influences nutritional quality of seafood consumption among income and race/ethnicity groups in the United States

BACKGROUND

The 2020 US Dietary Guidelines for Americans recommend that the US population consume more seafood. Most analyses of seafood consumption ignore heterogeneity in consumption patterns by species, nutritional content, production methods, and price, which have implications for applying recommendations.

OBJECTIVES

We assessed seafood intake among adults by socioeconomic and demographic groups, as well as the cost of seafood at retail to identify affordable and nutritious options.

METHODS

NHANES 2011-2018 dietary data (n = 17,559 total, n = 3285 eating seafood) were used to assess adult (≥20 y) intake of seafood in relation to income and race/ethnicity. Multivariable linear regression assessed the association between seafood consumption and income, adjusted for age, sex, and race/ethnicity, and the association between nutrients and seafood price, using Nielsen 2017-2019 retail sales data, adjusted for sales volume.

RESULTS

Low-income groups consume slightly less seafood than high-income groups [low income: mean 120.2 (95% CI: 103.5, 137.2) g/wk; high income: 141.8 (119.1, 164.1) g/wk] but substantially less seafood that is high in long-chain n-3 (ω-3) PUFAs [lower income: 21.3 (17.3, 25.5) g/wk; higher income: 46.8 (35.4, 57.8) g/wk]. Intake rates, species, and production method choices varied by race/ethnicity groups and within race/ethnicity groups by income. Retail seafood as a whole costs more than other protein foods (e.g., meat, poultry, eggs, beans), and fresh seafood high in n-3 PUFAs costs more (P < 0.002) than fresh seafood low in n-3 PUFAs. Retail seafood is available in a wide range of price points and product forms, and some lower-cost fish and shellfish were high in n-3 PUFAs, calcium, iron, selenium, and vitamins B-12 and D.

CONCLUSIONS

New insights into the relation between seafood affordability and consumption patterns among income and ethnicity groups suggest that specific policies and interventions may be needed to enhance the consumption of seafood by different groups.

Serum ω-3 Fatty Acids and Cognitive Domains in Community-Dwelling Older Adults from the NuAge Study: Exploring the Associations with Other Fatty Acids and Sex

BACKGROUND

Omega-3 (n-3) PUFAs are suggested to play a role in the prevention of cognitive decline. The evidence may be inconsistent due to methodologic issues, including interrelations with other long-chain (14 or more carbons) fatty acids (LCFAs) and use of sex as a confounding factor rather than an effect modifier.

OBJECTIVES

This study evaluated the association between serum n-3 PUFAs and performance across 4 cognitive domains, overall and by sex, while controlling for other LCFAs.

METHODS

In total, 386 healthy older adults (aged 77.4 ± 3.8 y; 53% females) from the Quebec Longitudinal Study on Nutrition and Successful Aging underwent a cognitive evaluation and blood sampling. Verbal and nonverbal episodic memory, executive functioning, and processing speed were evaluated. Serum LCFA concentrations were measured by gas chromatography. LCFAs were grouped according to standard fatty acid classes and factor analysis using principal component analysis (FA-PCA). Multivariate linear regression models were performed, including unadjusted and adjusted models for other LCFAs.

RESULTS

Higher n-3 PUFA concentrations were associated with better nonverbal memory and processing speed in fully adjusted models not including other LCFAs (βs of 0.21 and 0.19, respectively). The magnitude of these associations varied when other LCFAs were entered in the model (βs of 0.27 and 0.32, respectively) or when FA-PCA factors were considered (βs of 0.27 and 0.21, respectively). Associations with verbal episodic memory were limited to higher concentrations of EPA, whereas there was no association between n-3 PUFAs and executive functioning. Higher n-3 PUFAs were associated with better verbal and nonverbal episodic memory in females and with better executive functioning and processing speed in males.

CONCLUSIONS

These results suggest that other LCFAs should be considered when evaluating the association between n-3 PUFAs and cognitive performance in healthy older adults. Sex differences across cognitive domains warrant further investigation.