Dr. Maya Rozman Highlights Onions’ Health Benefits Against Cancer and Diabetes
Dr. Maya Rozman, scientific advisor to the Plant Council, emphasizes the significant health benefits of onions, a vegetable often undervalued due to its strong taste and smell. Onions contain sulfur compounds like allicin, which exhibit antimicrobial properties by inhibiting bacterial and fungal growth, according to research published in Planta Medica. Additionally, onions are rich in quercetin, an antioxidant with anti-inflammatory and antiviral effects, particularly abundant in red onions.
Epidemiological studies published in oncology journals link increased consumption of onions and garlic to a reduced risk of colorectal cancer. Furthermore, research presented at the 97th annual meeting of The Endocrine Society showed that onion extract, combined with the diabetes medication metformin, significantly lowered blood sugar and cholesterol levels, enhancing the drug’s effectiveness.
The nutritional value of onions varies with preparation methods. While heating can reduce some sulfur compounds, it may increase the availability of phenolic compounds like quercetin. For example, boiling causes some loss of quercetin glycosides into cooking water, but consuming the broth retains these nutrients. Frying and roasting can increase measurable phenolic content due to changes in tissue structure.
Onions contain 4-7 grams of sugar per 100 grams, with white onions having less and red or purple onions more, mainly fructose. The caramelization process during frying breaks down complex sugars into simpler ones, giving fried onions their sweet taste and golden color. This explains why raw onions taste less sweet despite their sugar content.
Rozman also dispels myths about onions turning toxic when stored cut in the refrigerator. Scientific evidence shows cut onions do not become poisonous or absorb harmful bacteria if stored properly in airtight containers. They may dry out or absorb odors but do not pose a poisoning risk. To reduce tearing when cutting onions, she recommends chilling them before cutting, using a sharp knife, and soaking or cutting them under running water to minimize irritant release.
