Small peptides extracted from wheat bran protein reduced systolic blood pressure by 35 mmHg in hypertensive rats after a single oral dose, while also showing strong antioxidant activity.
-35 mmHgSystolic blood pressure reduction in hypertensive rats from a single oral dose of small wheat bran peptides (under 1 kDa)
What the researchers found
Peptides derived from wheat bran protein demonstrated significant blood pressure-lowering and antioxidant effects. When wheat bran protein was enzymatically digested and separated by size, the smallest fraction (under 1 kDa) showed the strongest activity — reducing systolic blood pressure by 35 mmHg in spontaneously hypertensive rats after a single oral dose, compared to 20 mmHg for the unfractionated hydrolysate.
The small peptide fraction also showed superior ACE-inhibitory and renin-inhibitory activity in lab tests. Seven specific peptides were identified (NL, QL, FL, HAL, AAVL, AKTVF, and TPLTR), suggesting these short peptide sequences are responsible for the blood pressure-lowering effect.
Why it matters
High blood pressure affects over a billion people worldwide. Finding natural, food-derived peptides that can lower blood pressure offers the possibility of functional foods or nutraceuticals with fewer side effects than pharmaceutical drugs. Wheat bran is an abundant agricultural byproduct, making these peptides potentially scalable and affordable.
The numbers in context
<1 kDa fraction: -35 mmHg SBP reduction · WPH: -20 mmHg SBP reduction · Dose: 100 mg/kg oral · 7 peptides identified · 6 hr measurement period
How the study worked
Researchers extracted protein from wheat bran and digested it with the enzyme alcalase to produce a protein hydrolysate. This was then separated through ultrafiltration membranes into fractions of different molecular sizes (above and below 1 kDa). Each fraction was tested for ACE inhibition, renin inhibition, and antioxidant capacity in the lab. The most promising fraction was then given orally to spontaneously hypertensive rats at 100 mg/kg body weight, and blood pressure was monitored for 6 hours. Individual peptides were identified using mass spectrometry.
Who was studied
Spontaneously hypertensive rats (SHRs)
What this study cannot tell us
This was an animal study using spontaneously hypertensive rats — blood pressure effects may not translate directly to humans. Only a single oral dose was tested, so long-term effects and safety are unknown. The bioavailability and stability of these peptides in the human digestive system was not confirmed.
How to read the evidence
This is an animal study using spontaneously hypertensive rats with in vitro enzyme inhibition assays. While the blood pressure reduction was significant, animal results require human validation before clinical relevance can be established.
When this study was published
Published in 2020, this is a relatively recent study in the active field of food-derived bioactive peptides. Research in this area continues to advance toward human trials.
The bigger picture
Food-derived bioactive peptides represent a growing frontier in functional nutrition. This study adds wheat bran to the list of food sources (alongside milk, fish, and soy) that produce peptides capable of inhibiting ACE — the same target as widely prescribed blood pressure medications like lisinopril. If these results translate to humans, wheat bran peptides could become an affordable, natural approach to blood pressure management.
Questions still open
- Do these wheat bran peptides survive human digestion and reach the bloodstream intact?
- Would chronic daily supplementation with these peptides produce sustained blood pressure reduction in humans?
- How do wheat bran-derived ACE-inhibitory peptides compare in potency to those from milk (lactotripeptides) or fish sources?
Common questions
Could eating wheat bran lower blood pressure?
How do these peptides lower blood pressure?
Read the original research
Antihypertensive and antioxidant activities of enzymatic wheat bran protein hydrolysates.
Journal of food biochemistry, 44(1), e13090
Citation
Zou, Zhipeng; Wang, Mingjie; Wang, Zhigao; Aluko, Rotimi E; He, Rong. (2020). Antihypertensive and antioxidant activities of enzymatic wheat bran protein hydrolysates.. Journal of food biochemistry, 44(1), e13090. https://doi.org/10.1111/jfbc.13090