Highlight
– In 3,171 CARDIA participants followed across young to middle adulthood, higher carbohydrate quality (lower carbohydrate:fibre ratio) and a higher fibre-rich food score were independently associated with more favorable left ventricular (LV) structure and function measured by echocardiography at years 25 and 30.
– Key echocardiographic associations included lower LV mass index, better global longitudinal strain (GLS), higher ejection fraction for higher fibre-food intake, and more favorable diastolic indices (E/e’ and left atrial volume index).
– Effect sizes were modest but potentially clinically meaningful (approximately 0.10–0.26 SD), consistent with population-level cardiovascular risk reduction achievable through dietary shifts toward whole foods and fibre.
Background and clinical context
Heart failure remains a major public health burden globally. Identifying modifiable lifestyle factors that influence early changes in cardiac structure and function — before symptomatic heart failure develops — is a priority for prevention. Dietary patterns exert broad effects on cardiovascular risk factors such as blood pressure, lipids, body weight, glucose metabolism and systemic inflammation. However, relatively little is known about how carbohydrate (CHO) quality and specific fibre-rich foods relate to subclinical cardiac remodeling and function.
The Coronary Artery Risk Development in Young Adults (CARDIA) study provides a unique opportunity to examine these relationships. CARDIA enrolled Black and White men and women aged 18–30 years in 1985–86 and has followed participants for decades with serial dietary assessments and later-life echocardiographic phenotyping. The recent analysis by Yi et al. (Eur Heart J. 2025) explores whether long-term CHO quality and intake of fibre-rich foods predicts LV structure and function measured 25–30 years after baseline diet assessments.
Study design and methods
The CARDIA analysis included 3,171 participants with dietary data collected at exam years 0, 7 and 20 using a standardized CARDIA Diet History administered by trained interviewers. Diet exposures were summarized as:
- a carbohydrate quality metric defined by the ratio of carbohydrate to fibre (CHO:fibre), where lower ratios indicate higher carbohydrate quality; and
- a fibre-rich food score based on daily intakes of whole grains, fruit, vegetables, nuts, and legumes.
Echocardiographic measures of cardiac phenotype were obtained at exam years 25 and 30 and included left ventricular mass index, left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), E/e’ ratio (an index of filling pressures/diastolic function), and left atrial volume index. The primary analytical approach used linear mixed effects regression models to evaluate associations between the averaged dietary exposures (years 0, 7 and 20) and cardiac phenotypes at years 25 and 30, adjusting for demographic and lifestyle covariates.
Key findings
In this long-term prospective analysis, higher carbohydrate quality (lower CHO:fibre ratio) and greater intake of fibre-rich foods were both associated with more favorable LV structure and function. Major results included:
- Carbohydrate quality: Quartiles of CHO quality were favorably associated with LV mass index (Ptrend < .001) and GLS (Ptrend < .001) after adjustment for demographic and lifestyle factors. Better CHO quality corresponded to lower indexed LV mass and improved longitudinal systolic deformation (more negative GLS).
- Fibre-rich food score: Higher quartiles of the fibre-food score were favorably associated with multiple echocardiographic endpoints: LV mass index (Ptrend < .001), LVEF (Ptrend = .008), GLS (Ptrend < .001), E/e’ ratio (Ptrend = .02), and left atrial volume index (Ptrend = .02).
- Effect sizes: The reported cardiac phenotype effect sizes ranged roughly between 10% and 26% of the respective standard deviations for each measure. Expressed as standardized differences, these correspond to small-to-moderate associations (approximately 0.10–0.26 SD) across exposure quartiles.
Collectively these findings suggest that higher-quality carbohydrates and diets richer in fibre-containing foods are associated with less LV hypertrophy, better systolic mechanics (GLS), preserved ejection fraction, and more favorable diastolic indices decades later.
Interpretation and clinical significance
The observed associations are biologically plausible and consistent with prior data linking whole grains, fruits, vegetables, and dietary fibre with lower cardiovascular risk. Small shifts in cardiac structure and function at the population level can translate into meaningful differences in heart failure incidence over time. A 0.1–0.26 SD shift in an echocardiographic parameter is modest for an individual, but when applied across a population it may reduce aggregate heart failure risk when combined with other risk-reduction strategies.
Importantly, CHO quality here emphasizes nutrient-dense carbohydrate sources (e.g., whole grains, fruits, legumes) rather than total carbohydrate quantity. This distinction has clinical relevance: low-carbohydrate diets that reduce carbohydrates by increasing animal-derived fats or processed foods may not confer the same cardiac benefit as diets that improve carbohydrate quality while increasing fibre-rich plant foods.
Biological plausibility and mechanisms
Potential mechanisms linking fibre-rich diets and higher carbohydrate quality with preserved cardiac structure and function include:
- Improvements in blood pressure and endothelial function associated with whole grains, fruits, and vegetables.
- Beneficial effects on insulin sensitivity and glycaemic control; chronic hyperglycaemia and insulin resistance promote myocardial hypertrophy and fibrosis.
- Favourable lipid changes (lower LDL cholesterol and triglycerides) with higher fibre intake and whole-food carbohydrate sources.
- Anti-inflammatory effects and modulation of gut microbiota producing short-chain fatty acids, which have been implicated in systemic metabolic regulation and may influence myocardial remodeling.
Strengths and limitations
Strengths of the CARDIA analysis include the large, well-characterized cohort with repeated dietary assessments across decades, standardized echocardiographic measures at two time points, and robust statistical modeling. Averaging diet over multiple exams reduces random measurement error and better represents habitual intake over life stages.
However, several limitations merit consideration:
- Observational design: The study cannot establish causality. Residual confounding by unmeasured or imprecisely measured factors (socioeconomic status, overall dietary pattern, health behaviors) is possible despite multivariable adjustment.
- Dietary assessment: Self-reported diet history has known limitations (recall bias, misreporting), although repeated measures help mitigate these issues.
- Generalizability: CARDIA enrolled Black and White participants in the United States; results may not generalize to other racial/ethnic groups or global settings.
- Effect size interpretation: Associations were modest in magnitude. Whether these translate to clinically meaningful reductions in heart failure or other outcomes requires further study.
How this fits with existing evidence
The findings reinforce broader epidemiologic evidence linking higher dietary fibre and whole-food, plant-rich patterns to reduced cardiovascular disease risk. Systematic reviews and meta-analyses have shown inverse associations between dietary fibre intake and cardiovascular events and mortality. Current U.S. and international guidelines similarly endorse whole grains, fruits, vegetables, legumes, and nuts as components of cardioprotective dietary patterns (e.g., Mediterranean, DASH).
Implications for clinical practice and public health
For clinicians counseling patients on diet for cardiovascular prevention, the CARDIA findings provide mechanistic and longitudinal support for emphasizing carbohydrate quality and fibre-rich foods beginning early in adult life. Practical recommendations include:
- Prefer whole grains over refined grains (e.g., whole oats, brown rice, whole-wheat products).
- Encourage daily consumption of fruits, vegetables, legumes and nuts as routine replacements for refined carbohydrates and processed snacks.
- Be cautious when recommending low-carbohydrate diets; consider the source of replacement calories (plant-based fats and proteins versus saturated fats and processed meats) and prioritize overall dietary pattern quality.
Research gaps and next steps
Key areas for future research include:
- Randomized controlled trials that test the effect of high-fibre, high-quality carbohydrate diets on intermediate cardiac remodeling endpoints and on incident heart failure.
- Studies in more diverse international populations to assess generalizability across different dietary traditions and genetic backgrounds.
- Mechanistic investigations using advanced imaging, biomarkers of myocardial fibrosis and inflammation, and metabolomics to clarify pathways linking diet to myocardial remodeling.
Conclusion
This CARDIA analysis links long-term higher carbohydrate quality and greater intake of fibre-rich foods with more favorable left ventricular structure and function in midlife. The associations are modest but consistent with a preventive paradigm that emphasizes whole foods and dietary fibre as components of cardioprotective dietary patterns. While causality cannot be confirmed from observational data alone, these findings support existing guideline recommendations to prioritize whole grains, fruits, vegetables, legumes and nuts as part of cardiovascular prevention strategies, and they highlight the need for intervention trials focused on cardiac remodeling outcomes.
Funding and registry
The CARDIA study and the referenced analysis were supported by funding sources and institutional approvals described in the original publication (Yi SY et al., Eur Heart J. 2025). The CARDIA study has been supported by the National Heart, Lung, and Blood Institute and other NIH bodies; details are available in the primary report.
Selected references
1. Yi SY, Steffen LM, Guan W, Duprez D, Lakshminarayan K, Jacobs DR Jr. Dietary carbohydrate quality, fibre-rich food intake, and left ventricular structure and function: the CARDIA study. Eur Heart J. 2025 Nov 3;46(41):4329-4337. doi: 10.1093/eurheartj/ehaf406. PMID: 40626880; PMCID: PMC12579980.
2. Threapleton DE, Greenwood DC, Evans CE, et al. Dietary fibre intake and risk of cardiovascular disease: systematic review and meta-analysis. BMJ. 2013;347:f6879.
3. Arnett DK, Blumenthal RS, Albert MA, et al. 2019 ACC/AHA Guideline on the Primary Prevention of Cardiovascular Disease. Circulation. 2019;140:e596-e646.
Author note
This article is a clinical-scientific interpretation of the CARDIA study findings intended for clinicians, researchers and health professionals. It synthesizes the reported results, places them in context, and highlights implications for practice and future research.
