Besides being a familiar ingredient in the kitchen, onions also contain bioactive compounds that help protect the kidneys, especially in high-risk individuals such as those with gout, type 2 diabetes, or hypertension.
Onions are one of the most common and readily available foods in any kitchen. However, not everyone knows that this pungent bulb offers many benefits for the kidneys, the organs silently responsible for filtering blood, excreting waste, and maintaining homeostasis in the body.
Onions are a prominent source of antioxidants.
Onions are one of the most common and readily available foods in any kitchen (Photo: Getty).
According to research published in the American Journal of Nephrology , quercetin, a naturally occurring flavonoid, is abundant in the peel and roots of onions.
This is a key factor in its kidney-protective effect. It helps eliminate free radicals, inhibits inflammatory responses, and slows down glomerular fibrosis, which is a cause of impaired kidney function.
Quercetin also has the ability to inhibit the activity of the enzyme xanthine oxidase, thereby reducing uric acid production. This substance is a factor in gout and directly affects the kidneys.
A study in Frontiers in Pharmacology showed that quercetin improved kidney function in mice with uric acid-induced kidney damage.
In addition, quercetin in onions inhibits nephroinflammatory factors such as TNF-α, IL-6, and TGF-β1, cytokines associated with tissue damage and renal fibrosis.
A clinical study indicated that supplementing with approximately 150–162 mg of quercetin daily for 6 weeks can help reduce systolic blood pressure by 3–4 mmHg, while also improving factors that burden the kidneys, such as blood glucose and HbA1c levels, in people with type 2 diabetes.
Spicy Bodyguard
The pungent, spicy smell characteristic of chopped onions actually comes from volatile sulfur compounds, produced when the enzyme alliinase breaks down sulfur-containing amino acids. These compounds not only cause tearing but also offer many biological benefits.
Studies published in the journal Nutrients show that sulfur compounds in onions have strong anti-inflammatory and antibacterial effects, and also inhibit the formation of fibrotic tissue in the kidneys, one of the main mechanisms leading to chronic kidney disease.
In addition, these compounds stimulate the production of endogenous glutathione, an important antioxidant that helps protect kidney cells from damage caused by oxidative stress.
Some things to keep in mind when using onions to support kidney health.
Eating onions raw or lightly cooked retains more quercetin than cooking them thoroughly. However, those with sensitive stomachs should lightly cook them for easier digestion.
Onion peels contain the highest amount of quercetin. Some nutritionists recommend cooking soups or stews with washed onion peels, then straining them out, to take advantage of the nutrients.
Patients with chronic kidney disease should consult their doctor before increasing their onion intake, especially if they are on a low-potassium or low-phosphorus diet.
Source: https://dantri.com.vn/suc-khoe/cach-an-hanh-tay-dac-biet-tot-cho-than-20250726072501810.htm
