You don’t have to be a cook to know how delicious onions are. If you’re looking for mouthwatering, savory flavor to enhance other foods, cooked or raw, onions are your go-to veggie. Or, when you cut them into slices and bake or sauté them whole, all by themselves, drizzled with olive oil or avocado oil and sprinkled with dried thyme, rosemary and/or basil, the fragrance and flavor are simply heavenly.

Onions are also impressive because they’re such a healthy food, imparting vitamins, minerals and powerful compounds that, besides making your eyes water when you cut into them, also help heal your body. The knife you use to slice them can make all the difference. When certain vegetables get nicked or cut, they’ll produce even more polyphenols to protect against damage. Cutting with ceramic knives can help slow the browning process that naturally occurs when slicing certain vegetables and fruits such as avocados.

Antioxidants, including flavonoids, polyphenols and quercetin, help enhance your health in numerous ways. The minerals iron, folate, thiamin and potassium, plus vitamin B6, or pyridoxine and vitamin B5 (better known as pantothenic acid), join forces to positively impact the way your entire body functions, from your brain to your gut to your heart. But it gets better than that.

These anti-inflammatory, antifungal, antimicrobial (inhibiting the bacteria Helicobacter pylori¹), antibacterial, antiviral, antidiabetic and anticarcinogenic compounds can actually minimize, treat and even help prevent disease, including coronary artery disease, diabetes, stroke and cancer, and numerous so-called “lesser” ailments that lead to those more serious conditions. It can’t get better than that, right? What if they’re red onions? What if they’re organic, as well?

The Curious Power Behind Red Onions

Well, as it happens, studies show that when red onions, specifically, were pitted against white onions (while yellow onions, having more pigment than the white ones, also contained more disease-fighting flavonoids), the aforementioned nutrients went way beyond what scientists had already known they could do. In short, the Canadian study reported:

“Flavonoids, which are found in high levels in onions, have been shown to exert antiproliferative and potentially anticancer activities. To test their therapeutic potential, we assessed the antiproliferative, cytotoxic, apoptosis-inducing, and anti-migratory activities of five onion varieties grown in Ontario against human adenocarcinoma cells.”²

Adenocarcinoma is a type of cancerous tumor that begins in the glands, against which the Stanley onion variety demonstrated the strongest anti-cancer effects. The scientists compared the properties of the onion extracts to pure flavonoid extracts, containing principally the antioxidant flavonols quercetin, myricetin and kaempferol. All five onion varieties showed antiproliferative activity (which Dictionary.com describes as “a substance used to prevent or retard the spread of cells, especially malignant cells”³).

How Quercitin in Onions Can Impact Your Health

Quercitin contains molecules that can zap harmful free radicals in your system caused by toxic substances you might encounter from day to day, such as pollution, chemicals in your water and food and even stress. The effects of these can lead not only to cancer but many other debilitating conditions exacerbated by inflammation.

One study on obese and overweight patients who had a higher heart disease risk returned particularly encouraging results in regard to eating onions versus taking quercetin supplements. Scientists found that 150 milligrams of quercetin a day was enough to lower both blood pressure and cholesterol oxidation. As Natural Society quips: “In other words, it was shown to help prevent cardiovascular disease. To put this in persective — the average quercetin supplement contains 500 milligrams, while a particularly potent onion may contain 100 milligrams.”⁴

Research has also revealed quercitin’s association with cancer prevention, inhibiting the growth of breast, prostate, stomach,⁵ endometrial, esophageal, ovarian, lung and colon cancer cells, and many more. A University of Maryland Medical Center article⁶ listed several more findings in regard to this powerful compound, in terms of prevention and treatment:

Allergies, asthma, hay fever and hives, as it prevents immune cells from releasing histamines

Optimized cholesterol, as it prevents damage to LDL cholesterol

Interstitial cystitis and accompanying bladder pain

Inflammation of the prostate (prostatitis), due to fewer symptoms

Rheumatoid arthritis (RA) — “There are reports of people with RA who had fewer symptoms when they switched from a typical Western diet to … [one] with lots of uncooked berries, fruits, vegetables, nuts, roots, seeds and sprouts containing quercetin and other antioxidants.”⁷