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Network Analysis Of 48 Trials Ranks Grape Seed Extract For Artery Stiffness

A new analysis combining 48 trials and 2,719 people ranks which dietary approaches moved a key marker of artery stiffness the most.

By Dr. Axe Editorial Team · October 26, 2026 · 1 source · Watch

A network meta-analysis published October 20, 2026 in Food & Function pooled 48 randomized controlled trials and ranked 31 dietary interventions for arterial stiffness, finding grape seed extract and vitamin B9 came out on top for one key measurement.

Researchers pooled 48 randomized controlled trials covering 2,719 people with cardiovascular disease or hypertension, comparing 31 dietary interventions against placebo. Using network meta-analysis, which ranks many treatments without head-to-head testing, the team measured pulse wave velocity (PWV), timing how fast pressure waves travel through arteries, and augmentation index (AIx), reflecting how much a reflected wave adds to heart workload. For PWV, grape seed extract lowered it by 1.70 meters per second versus placebo (95% CI: -3.36 to -0.04), and vitamin B9 (folic acid) lowered it by 1.46 m/s (95% CI: -2.61 to -0.31), both moderate-certainty evidence. No intervention reached significance for augmentation index, though alpha-linolenic acid, dietary nitrate, and wine extract showed the largest numerical, non-significant shifts.

Arterial stiffness warns of cardiovascular strain, since stiffer vessels force the heart to pump against more resistance. Grape seed extract's proanthocyanidins and folate's role in vessel relaxation are established background mechanisms, not pathways directly tested here. The authors concluded grape seed extract and folic acid show potential to reduce arterial stiffness, based on the PWV results.

Pulse Wave Velocity Change vs Placebo (m/s)

Food & Function, 2026, Norouzzadeh et al.

This is a pooled analysis of existing trials, not a new controlled trial, so differences in dose, duration, and populations limit how directly the ranking applies to any one person. No significant finding for augmentation index means these interventions didn't show a clear edge on that second marker; the authors call for dose-optimized trials next.

Dr. Axe’s Take

Grape seed extract and folate landing at the top of this ranking fits what I'd expect from two nutrients with a long track record for vascular support. Grape seed extract's proanthocyanidins help protect the lining of blood vessels from oxidative stress, and folate keeps homocysteine in check, a compound that can stiffen arteries when it runs high. I'd look for a grape seed extract supplement standardized for proanthocyanidin content, paired with folate-rich foods like lentils, spinach, and asparagus. Pulse wave velocity improving while the other marker didn't move is a reminder to track more than one number when working on vascular health with your doctor.

— Dr. Axe

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Study summary

Who: 2,719 adults with cardiovascular disease or hypertension across 48 randomized controlled trials
Design: Network meta-analysis comparing 31 dietary interventions against placebo for two arterial stiffness markers
Dose: Varied by trial; grape seed extract and vitamin B9 (folic acid) doses not specified in abstract
Primary result: Pulse wave velocity down 1.70 m/s with grape seed extract and 1.46 m/s with vitamin B9 vs placebo
Secondary: No intervention reached significance for augmentation index; alpha-linolenic acid, dietary nitrate, and wine extract showed the largest numerical but non-significant shifts
Funding / conflicts: Funder listed in the journal record: Bushehr University of Medical Sciences. Conflicts not reported in the abstract.
Date: Oct 20, 2026