Onion Extract Can Help Lower Blood Sugar Levels, Study Shows

by DailyHealthPost Editorial

red and yellow onion bulbs

A recent study has researchers wondering if onion extract could be the key to new therapies for individuals with diabetes.

According to the study, which was funded by Nigeria’s Tertiary Education Trust Fund, onion extract was shown to significantly lower blood sugar and cholesterol levels in diabetic rats.

The study gave onion extract to three groups of rats with medically induced diabetes, as well as to a control group of nondiabetic rats. Although the sample sizes were relatively small, researchers are optimistic about the results.


Onion is cheap and available and has been used as a nutritional supplement,” the lead researcher on the study, Anthony Ojieh, said in a recent press release. “It has the potential for use in treating patients with diabetes.”(1)

Anti-Diabetic Potential

This isn’t the first case of onion extract being investigated for its potential in treating diabetes.

In 2009, a meta-analysis in the Journal of Medicinal Food looked at the anti-diabetic effects of onion and garlic extracts, concluding that “The single component intake and onion extract intake may be effective for lowering plasma glucose concentrations and body weight”(2) – a similar outcome to the more recent study.

Other Therapeutic Potential Of Onion

An earlier study – from 2005 – looked at the antioxidant and anytihypertensive effects of Welsh onion on rats fed a high-fat, high-sucrose diet, and found that leafy green Welsh onion could effectively lower blood pressure in rats(3).

A 2011 study elaborated on this research, focusing on the nutrient quercetin, which is found in onion skin, and its effects on cardiometabolic risks in male smokers.

“We tested the hypothesis that quercetin-rich supplementation, derived from onion peel extract, improves cardiometabolic risk components in healthy male smokers in a randomized, double blinded, placebo-controlled parallel design,” the study explains.

Their conclusion was that “Daily quercetin-rich supplementation from onion peel extract improved blood lipid profiles, glucose, and blood pressure, suggesting a beneficial role for quercetin as a preventive measure against cardiovascular risk.”(4)


Onion extract has also been evaluated for its efficacy in reducing redness, itchiness, and pain in keloid scars: “Onion extract improved hypertrophic and keloid scars via multiple mechanisms,” one study concluded(5).

More Research Needed

While researchers on the recent study are positive about their results, what they aren’t sure of yet is how onion actually works to lower blood glucose levels.

“We need to investigate the mechanism by which onion brought about the blood glucose reduction,” Ojieh said in the press release. “We do not yet have an explanation.”

The onion extract used for this study was a preparation from onion bulb, which was chosen due to its ready availability at stores and markets.

[mks_toggle title=”sources” state=”close “]
  1. https://www.eurekalert.org/pub_releases/2015-03/tes-oem030515.php
  2. https://www.ncbi.nlm.nih.gov/pubmed/19627203
  3. https://www.ncbi.nlm.nih.gov/pubmed/16041136
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3061266/
  5. https://www.ncbi.nlm.nih.gov/pubmed/17722521