The East London Garden Society

All about Onions


As one of the oldest cultivated plants, onions do not disappoint in terms of nutrition. They are a very good source of vitamin C and B6, iron, folate, and potassium. But it’s their phytochemicals, including the flavonoid quercetin and allyl disulphide, that are most exciting to researchers.

To date, onions have shown a wealth of beneficial properties; they are anti‐allergic, anti‐histaminic, anti‐inflammatory, and antioxidant, all rolled into one. And if you take even a quick glance at the available research, you will quickly understand why onions deserve to make a very frequent appearance at your dinner table.

Onions are Polyphenol Superstars

Polyphenols are plant compounds recognised for their disease prevention, antioxidant, and anti-aging properties. Onions have a particularly high concentration, with more polyphenols than garlic, leeks, tomatoes, carrots, and red bell peppers.
In particular, onions are especially rich in quercetin which is an antioxidant that many believe prevents histamine release‐making quercetin‐rich foods called ‘natural antihistamines’.

According to The World's Healthiest Foods:
"On an ounce-for-ounce basis, onions rank in the top ten of commonly eaten vegetables in their quercetin content. Although the average onion is likely to contain less than 100 milligrams of quercetin per three ounces, some onions do provide this amount."

Quercetin is available in supplement form but there are a couple of reasons why getting this flavonoid naturally from onions makes more sense:

  • One study found that animals received greater protection against oxidative stress when they consumed yellow onion in their diet, as opposed to consuming quercetin extracts.
  • Quercetin is not degraded by low-heat cooking, such as simmering. When preparing a soup with onions, the quercetin will be transferred into the broth of the soup, making onion soup an easy-to-make super food.

Onions are beneficial for bones, digestive tract & diabetes prevention

The more we learn about onions, the more it becomes clear that they offer whole body benefits. That is the beauty of eating whole foods because they typically contain many beneficial phytochemicals that enhance your health in numerous synergistic ways. As for onions, research has shown that including onions in your diet may offer the following benefits:

Prevents inflammatory processes associated with asthma Reduces symptoms associated with diabetes Lowers levels of cholesterol and triglycerides
Reduces symptoms associated with osteoporosis and improves bone health Maintains gastrointestinal health by sustaining beneficial bacteria Diminishes replication of HIV
Reduces risk of neurodegenerative disorders Lowers your risk of cataract formation Provide antimicrobial properties that may help reduce the rate of food-borne illness
Improved intestinal flora, improved absorption of calcium and magnesium due to the fructans they contain Provide antibacterial and antifungal properties Lowers the risk of certain cancers

Onions were a prehistoric staple food

If there was any doubt as to how valuable onions have been through the ages, it is thought that wild onions have been enjoyed since the very early ages and was probably a staple in the prehistoric diet.

The National Onion Association stated:
"Most researchers agree the onion has been cultivated for 5,000 years or more. Since onions grew wild in various regions, they were probably consumed for thousands of years and domesticated simultaneously all over the world. Onions may be one of the earliest cultivated crops because they were less perishable than other foods of the time, were transportable, were easy to grow, and could be grown in a variety of soils and climates.

In addition, the onion was useful for sustaining human life. Onions prevented thirst and could be dried and preserved for later consumption when food might be scarce. While the place and time of the onion's origin is still a mystery, many documents from very early times describe its importance as a food and its use in art, medicine, and mummification."

Since ancient times, onions have been enjoyed around the world for many uses:

  • The onion symbolized ‘eternity’ to Egyptians who would bury them along with their Pharaohs.
  • In India, onions were valued as a diuretic and good for digestion, the heart, the eyes, and the joints.
  • During the Middle Ages in Europe, onions were widely consumed and prescribed medicinally for headaches, snakebites, and hair loss.
  • Native American Indians used wild onions in cooking as well as in poultices, dyes, and even as toys.