Consumption of a High‐fiber Diet Improves Systolic Blood Pressure and Vascular Endothelial Function and May Reduce Oxidative Stress in Middle‐aged to Older Adults

• Published in: The FASEB journal 2022-05, Vol.36 (S1), p.n/a
• Main Authors: Casso, Abigail G., Burnsed‐Torres, Marissa L., Lubieniecki, Kara L., Rossman, Matthew J., Adam, Emily C., Lally, Hannah M., Chonchol, Michel, Davy, Kevin P., Seals, Douglas R., Brunt, Vienna E.
• Format: Article
• Language: English
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.2022.36.S1.R4104

Aging is the primary risk factor for the development of cardiovascular diseases (CVD), largely due to increases in systolic blood pressure (SBP) and oxidative stress‐related impairments in vascular endothelial function. Higher intake of dietary fiber is associated with reduced CVD risk. In healthy late middle‐aged to older (MA/O) adults, limited evidence indicates high‐fiber diet interventions improve SBP, but whether a high‐fiber diet improves endothelial function with aging is unknown. Purpose We tested the hypothesis that a high‐fiber diet would, in addition to reducing SBP, improve endothelial function and reduce oxidative stress in healthy MA/O adults. Methods We performed a controlled feeding study in which 14 MA/O adults (8F/6M; age: 69 ± 5 years) consumed an isocaloric high‐fiber diet (30‐35 g/day) for 7 days. Diets also contained 60% total carbohydrates, 15% protein, 25% fat, and 12‐15% sugar. Baseline (pre) measures were performed under habitual diet conditions (26 ± 6 g fiber/day). On days 0 (pre) and 7 (post) of the diet, endothelial cells were collected via venous endovascular biopsy, and endothelial function was assessed by brachial artery flow‐mediated dilation (FMD) following 20 minutes of intravenous infusion of saline (volume control) or the antioxidant ascorbic acid (0.06 g/kg fat‐free mass in 100 mL saline at 5 mL/min; N=12), to determine whether any improvements in endothelial functional following the high‐fiber diet were due to reduced oxidative stress. Results Consumption of a high‐fiber diet reduced SBP (pre vs. post: 120 ± 3 vs. 116 ± 3 mmHg, p