Peptides From Amaranth Grain Show Promise for Lowering Blood Pressure by Targeting Multiple Pathways | Research

The takeaway

Three peptides derived from amaranth grain potently inhibited ACE (a key blood pressure enzyme) and can cross the intestinal barrier, making them candidates for functional foods that could help reduce hypertension.

IC₅₀ = 0.055 mM
The amaranth peptide FNLPILR's concentration needed to inhibit half of ACE activity, demonstrating potent enzyme inhibition relevant to blood pressure control

What the researchers found

Two amaranth-derived peptides, SFNLPILR and FNLPILR, demonstrated potent ACE inhibition with IC₅₀ values of 0.075 mM and 0.055 mM, respectively. Both peptides showed selective or minimal modulation of ACE2 enzymatic activity, suggesting they can suppress the harmful arm of the renin-angiotensin system while preserving the protective arm.

Molecular docking revealed that both peptides interact with ACE's catalytic residues through their shared LR motif. Transepithelial transport studies using Caco-2 cell monolayers confirmed that peptide fragments can cross the intestinal barrier, supporting potential oral bioavailability.

Why it matters

Hypertension affects over a billion people worldwide and is a leading cause of heart disease and stroke. Food-derived bioactive peptides that can inhibit ACE offer a natural, preventive approach to blood pressure management. Identifying peptides that both inhibit ACE and cross the gut barrier brings the concept of 'blood pressure-lowering food' closer to scientific reality.

How the study worked

The study combined multiple approaches: in vitro enzymatic assays to measure ACE inhibition and ACE2 modulation; bioinformatic analysis to identify encrypted bioactive motifs within the peptide sequences; molecular docking simulations to model how the peptides bind to ACE's active site; and Caco-2 cell monolayer transepithelial transport studies to assess whether peptide fragments can cross the intestinal barrier (a standard model for oral bioavailability).

What this study cannot tell us

This is an in vitro and computational study — the peptides have not been tested in animals or humans for actual blood pressure reduction. The Caco-2 transport studies showed that peptide fragments (not intact peptides) cross the intestinal barrier, so the active forms reaching the bloodstream may differ from what was tested. IC₅₀ values in vitro may not predict clinical potency. The third peptide (AFEDGFEWVSFK) was not as well characterized.

How to read the evidence

This is a preclinical in vitro and computational study. While the multi-method approach (enzymatic assays, molecular docking, Caco-2 transport) provides strong mechanistic evidence, no animal or human studies have been conducted to confirm blood pressure-lowering effects.

When this study was published

Published in 2026, this is a very recent study reflecting the cutting edge of food-derived bioactive peptide research for cardiovascular health.

The bigger picture

Food-derived bioactive peptides are an emerging field at the intersection of nutrition science and pharmacology. While pharmaceutical ACE inhibitors are well established, finding natural peptides in foods like amaranth that can replicate some of this activity opens the door to functional foods and nutraceuticals for cardiovascular health prevention — an approach that could complement medication for the billions living with or at risk for hypertension.

Questions still open

Do these amaranth peptides actually lower blood pressure when consumed as part of a diet or supplement in humans?
Are the peptide fragments that cross the intestinal wall still active as ACE inhibitors?
How do the ACE-inhibitory effects of amaranth peptides compare to those from other food sources like milk or soy?

Common questions

Can eating amaranth lower blood pressure?

This study found that specific peptides in amaranth can inhibit ACE, the same enzyme targeted by common blood pressure medications, and that fragments of these peptides can cross the intestinal wall. However, whether eating amaranth in normal dietary amounts produces meaningful blood pressure reduction in humans has not been tested. The research supports the potential for developing amaranth-based functional foods or supplements, but clinical studies are still needed.

How do amaranth peptides compare to blood pressure medications?

Pharmaceutical ACE inhibitors like lisinopril are much more potent and have decades of clinical evidence behind them. Amaranth peptides show promising ACE inhibition in lab tests, but they would likely be far weaker than prescription drugs. They are better understood as potential preventive or complementary approaches rather than replacements for medication. Their advantage is that they could be incorporated into everyday foods for population-level cardiovascular health benefit.

Read the original research

Multitarget Amaranth Peptides: ACE Inhibition, ACE2 Modulation, and Bioavailability Assessment.

Plant foods for human nutrition (Dordrecht, Netherlands), 81(1), 7

View on PubMed ↗Publisher’s paper ↗

Citation

Nardo, Agustina E; Suárez, Santiago E; García Fillería, Susan F; Añón, M Cristina; Quiroga, Alejandra V. (2026). Multitarget Amaranth Peptides: ACE Inhibition, ACE2 Modulation, and Bioavailability Assessment.. Plant foods for human nutrition (Dordrecht, Netherlands), 81(1), 7. https://doi.org/10.1007/s11130-025-01456-y