Carmen P Ortega-Santos, Sonia Vega-López, Alex E Mohr, Corrie M Whisner, Bethany Liedike, Maissa Khatib, Baharak Tabarsi, Michelle Harris, Shannon L Wilson
Journal: The Journal of nutrition 2024;154(8):2437-2447
PMID: 38880174
High levels of low-density lipoprotein (LDL) cholesterol, often referred to as the bad cholesterol, increase the risk of heart disease. Whole grains are generally associated with improved heart health, but not all grain products have the same effects. Corn flour is widely consumed around the world, yet there is limited research on how different types of corn flour products influence cholesterol levels and gut health (the community of bacteria in the digestive system). This randomised control trial was carried out to better understand whether consuming specific corn flour products could improve cardiometabolic health and alter the gut microbiota in adults with elevated LDL cholesterol.
The results showed that certain corn flour products led to improvements in some cardiometabolic markers, including changes in LDL cholesterol levels. The study also found shifts in the composition of the gut microbiota, suggesting that the fibre and bioactive compounds in corn may influence gut bacteria balance.
In conclusion, specific corn flour products may support heart health and positively influence gut bacteria in adults with elevated cholesterol. Healthcare professionals may consider whole-grain corn-based products as part of dietary strategies to manage cholesterol levels. However, dietary advice should be personalised and incorporated into broader lifestyle interventions that include overall diet quality and physical activity.
BACKGROUND
Consumption of whole grains is associated with a reduction in chronic diseases and offers benefits for cardiovascular health and metabolic regulation. The relationship between whole-grain corn and corn bran with the gut microbiota (GM) remains an area of growing interest, particularly regarding their influence on cardiometabolic health.
OBJECTIVES
To investigate the effects of different corn flours on cardiometabolic outcomes and GM changes in adults with elevated low-density lipoprotein cholesterol (LDL cholesterol) concentrations.
METHODS
In this crossover study, 36 adults with LDL cholesterol above 110 mg/dL consumed 48 g/d of 3 corn flour types for 4 wk: whole-grain corn meal, refined corn meal (RCM), and a blend of RCM and corn bran (RCM + B). We assessed the impact on cardiometabolic markers [LDL cholesterol, high-density lipoprotein cholesterol (HDL cholesterol), total cholesterol, and triglycerides)] and GM composition and estimated function. Statistical analyses included mixed-effects modeling and responder (>5% decrease in LDL cholesterol) analysis to evaluate changes in GM related to lipid profile improvements.
RESULTS
Of the 3 corn flour types, only RCM + B significantly decreased LDL cholesterol over time (-10.4 ± 3.6 mg/dL, P = 0.005) and marginally decreased total cholesterol (-9.2 ± 3.9 mg/dL, P = 0.072) over time. There were no significant effects on HDL cholesterol or triglyceride concentrations. No significant changes were observed in GM alpha diversity, whereas beta diversity metrics indicated individual variability. Two genera, unclassified Lachnospiraceae and Agathobaculum (P ≤ 0.096), differed significantly by treatment, but only Agathobaculum remained significantly elevated in the whole-grain corn meal, compared to RCM and RCM + B, after adjustment for multiple comparisons.
CONCLUSIONS
The type of corn flour, particularly RCM + B, notably influenced LDL cholesterol concentrations in adults with elevated LDL cholesterol. This study suggests that incorporating milled fractions (e.g., bran) of whole-grain corn with refined corn flour may be a viable alternative to supplementing manufactured grain products with isolated or synthetic fibers for improved metabolic health. This trial was registered at clinicaltrials.gov as NCT03967990.
Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.
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