Relationship between dietary fiber to carbohydrate ratio and mortality risk in US adults: NHANES 2007-2018

Dietary Carbohydrate Intake, Carbohydrate Quality, and Healthy Aging in Women

Importance

Dietary carbohydrate quality is inversely associated with risks of chronic disease and all-cause mortality. However, limited evidence exists regarding the role of carbohydrate quality and dietary carbohydrate types in promoting healthy aging.

Objective

To evaluate the long-term role of dietary carbohydrate intake and carbohydrate quality in healthy aging.

Design, Setting, and Participants

This prospective cohort study used data from the Nurses' Health Study (NHS) from January 1984 to December 2016 and included participants aged younger than 60 years in 1984. Data were analyzed from January 2023 to February 2025.

Exposure

Intakes of total carbohydrates; refined carbohydrates; high-quality carbohydrates from whole grains, fruits, vegetables, and legumes; dietary fiber; and the dietary glycemic index (GI) and glycemic load (GL).

Main Outcomes and Measures

Nutrient intakes were derived from 1984 and 1986 food frequency questionnaires. The primary outcome was healthy aging, defined as the absence of major chronic diseases, lack of cognitive and physical function impairments, and having good mental health, according to 2014 or 2016 NHS questionnaire data. Multivariate logistic regression was used to calculate associations of each carbohydrate variable with healthy aging.

Results

Among 47 513 participants (mean [SD] baseline age, 48.5 [6.2] years), 3706 (7.8%) met our healthy aging definition. Every 10%-calorie increment in intakes of total carbohydrates (odds ratio [OR], 1.17; 95% CI, 1.10-1.25) and high-quality carbohydrates (OR, 1.31; 95% CI, 1.22-1.41) was positively associated with healthy aging. Refined carbohydrates were associated with lower odds of healthy aging (OR, 0.87; 95% CI, 0.80-0.95). Intakes of carbohydrates from fruits, vegetables, and whole grains were positively associated with odds of healthy aging (ORs ranging from 1.11; 95% CI, 1.07-1.15 to 1.37; 95% CI, 1.20-1.57 per 5% energy increment). Additionally, intakes of total dietary fiber and fiber from fruits, vegetables, and cereals were associated with higher odds of healthy aging (ORs ranging from 1.07; 95% CI, 1.03-1.11 to 1.17; 95% CI, 1.13-1.22 per 1-SD increment). GL was positively associated with healthy aging, which was attenuated by dietary fiber adjustment. A higher GI (OR, 0.76; 95% CI, 0.67-0.87) and carbohydrate-to-fiber ratio (OR, 0.71; 95% CI, 0.62-0.81) were inversely associated with healthy aging when comparing extreme quintiles. There were positive associations for isocaloric replacements of refined carbohydrates, animal protein, total fat, or trans fats with high-quality carbohydrates (ORs ranging from 1.08; 95% CI, 1.01-1.16 to 1.16; 95% CI, 1.11-1.21).

Conclusions and Relevance

In this cohort study of women, intakes of high-quality carbohydrates and dietary fiber were associated with positive health status in older adulthood, suggesting that dietary carbohydrate quality may be an important determinant of healthy aging.

Associations Between Dietary Potassium Intake From Different Food Sources and Hyperkalemia in Patients With Chronic Kidney Disease

OBJECTIVE

Previous studies reported mixed results on associations between dietary potassium intake and hyperkalemia in patients with chronic kidney disease (CKD). This study investigated the association between potassium intake from different food sources and hyperkalemia in patients with non-dialysis-dependent CKD.

METHODS

A total of 285 patients were recruited at a university hospital and 2 city hospitals in Tokyo. Dietary potassium intake was estimated by a validated diet history questionnaire. Associations of potassium intake from all foods and individual food groups with serum potassium were examined by multivariable linear regression among potassium binder nonusers. An association between tertile groups of potassium intake and hyperkalemia, defined as serum potassium ≥5.0 mEq/L, was evaluated by multivariable logistic regression.

RESULTS

Among 245 potassium binder nonusers, total potassium intake was weakly associated with serum potassium (regression coefficient = 0.147, 95% confidence interval (CI): 0.018-0.277), while an association with hyperkalemia was not observed (first vs third tertile: adjusted odds ratio = 0.98, 95% CI: 0.29-3.26). As for food groups, potassium intakes from potatoes, pulses, and green/yellow vegetables were positively associated with serum potassium. Patients in the highest tertile of potassium intake from potatoes had higher odds of hyperkalemia as compared to those in the lowest tertile (adjusted odds ratio = 4.12, 95% CI: 1.19-14.34).

CONCLUSION

Total potassium intake was weakly associated with serum potassium, but not with hyperkalemia. Potassium intake from potatoes was associated with hyperkalemia. These findings highlight the importance of considering food sources of potassium in the management of hyperkalemia in CKD.

Association between dietary carbohydrate to fiber ratio and metabolic dysfunction associated fatty liver disease in adults: evidence from the NHANES 2017-2020

This study aimed to explore the association of carbohydrate to fiber ratio (CFR) with metabolic dysfunction-associated fatty liver disease (MAFLD) in adults. In this study, data from the 2 cycles (2017-2018 and 2019-2020) of the NHANES were used. Univariate and multivariate weighted logistic regression analyses were applied to evaluate the association between CFR and MAFLD. Odds ratios (ORs) and 95% confidence levels (CIs) were estimated. Subgroup analysis was further performed in terms of gender, age and comorbidity (diabetes, hypertension). A total of 3180 individuals were included, with 1408 (44.28%) in the non-MAFLD group and 1772 (55.72%) in the MAFLD group. After adjusting different variables, a dietary fiber intake of 11.15-18.40 g was associated with significantly lower odds of MAFLD compared with a fiber intake < 11.15 g (OR = 0.71, 95% CI 0.54-0.93). In contrast to a dietary CFR < 12.58, a CFR > 19.91 was associated with significantly higher odds of MAFLD (OR = 1.57, 95% CI 1.09-2.27). Compared with females with a dietary CFR < 12.58, those with a CFR > 19.91 had significantly increased odds of MAFLD (OR = 1.87, 95% CI 1.29-2.73). Among individuals aged < 65 years, a dietary CFR > 19.91 was associated with higher odds of MAFLD than a dietary CFR < 12.58 (OR = 1.52, 95% CI 1.02-2.25). For participants without diabetes (OR = 1.79, 95% CI 1.26-2.54) or hypertension (OR = 1.93, 95% CI 1.02-3.65), a dietary CFR > 19.91 was associated with elevated odds of MAFLD than a CFR < 12.58. In summary, a higher CFR was associated with significantly greater odds of MAFLD, indicating the negative association between carbohydrate quality and MAFLD. The research would be conducive to metabolic dysfunction-associated fatty liver disease treatment.