Anti-Inflammatory Power of Red Onions
Onions are one of the most popular vegetables worldwide. While most children dislike their pungent and bity flavor, most adults embrace and use them regularly. Red onions contain twice as many anti-oxidants as any other form of onion making them a powerful part of an anti-inflammatory diet and lifestyle.
Red onions get their bite from the many sulfur groups they contain. These sulfur groups include the diallyl sulfides: DMS, DDS, DTS & DTTS. These sulfur groups help produce cysteine within the body that aids in weight loss, detoxification and cancer prevention (1, 2). Additional research has shown that sulfur compounds have a strong anti-oxidant capacity that inhibits blood cell clumping (3).
The sulfur compounds in red onions also lower LDL cholesterol & triglycerides while boosting HDL levels (4). They are associated with improving cell membrane function in red blood cells and improving oxygen utilization. This improves cardiovascular function as well as fat metabolism.
Rich in Anti-Oxidant PhytoNutrients
Red onions are also a rich source of the flavonoid anti-oxidant quercetin and the polyphenol anti-oxidant anthocyanin. These anti-oxidants prevent the oxidation of dietary and cellular fatty acids. They are very powerful free radical scavengers that neutralize cancer cell growth and dramatically reduce whole body inflammation (5, 6).
Many believe that consuming quercetin from onions is more effective than taking quercetin extracts in supplement form. The body is able to better recognize the nutrient when it is in a natural form and has other synergistic components associated with it.
Red Onions are Rich in Chromium:
Red onions are also a fantastic source of chromium which lowers blood sugar and enhances cellular insulin sensitivity. Nearly 50% of the US population is deficient in chromium which is greater than any other developed nation (7). This is due to over cropping that has stripped the land of chromium and processed food consumption. Chromium deficiencies lead to diabetes and heart disease.
The anti-oxidant flavonoids are extremely rich in the outer layers of the onion. Many people will peel off the first few layers and lose much of these critical nutrients. Be sure to utilize the outer, fleshy edible portions as much as possible. Overpeeling, by taking off the outer 2 layers of flesh will cost one about 20% of its quercetin and over 75% of its anthocyanins.
How many Red Onions to Eat?
Simmering onions in a soup or broth will damage some of the anthocyanins but not the quercetin. The quercetin moves into the soup or broth. The lower the heat the more nutrients will be contained in the soup or broth. Studies have shown that 4-7 servings of red onions each week (equivalent to about 2-3 onions) has been associated with the greatest benefit in reducing colorectal, oral, laryngeal, esophageal & ovarian cancer (8).
Red onions should be stored in a cool, dry area with good airflow. Until they are opened they should not be stored in a refrigerator or plastic bag as both of these have been shown to speed up spoilage. Once opened, it is best to store in refrigeration. Avoid any onions that are wet, soft, bruised or have dark spots or mold on them.
Frequently Asked Questions With Onions:
1. Do I Need to Purchase Organic Onions?
Because onions are covered in a thin skin and are very sharp and pungent they repel pests. They are not highly sprayed with toxic herbicides and pesticides and therefore can be purchased non-organic without significant risk for toxic chemical exposure.
2. How Do I Reduce the Effect Onions Have on My Breath?
You can reduce the negative effects onions and other sulfur rich foods (garlic, shallots, radishes) have on your breath by consuming green veggies, bitter herbs such as dandelion, parsley or cilantro and herbs such as rosemary, fennel and peppermint.
I often advise my clients to consume parsley or make a green drink on days when you are consuming a lot of raw onion.
3. Do I Get the Same Benefits from Cooked Onions as I Do with Raw Onions?
No, you will certainly lose much of the nutrient content but you will still get some of the benefits so it is better to consume cooked onions than no onions at all.
4. What if Onions Give Me Gas When I Eat Them?
Onions have very healthy polyphenols (quercetin) that help to improve the make up of our gut microflora. For most individuals, they are extremely good for the gut microbiome. However, they also contain fructan sugars that are part of the FODMAP group. Some individuals with small intestinal bacterial overgrowth (SIBO) and other digestive issues can struggle to digest these sugars. This can lead to gas and bloating.
If you notice gas, bloating, cramping when consuming onions than take them out of your diet and follow a low FODMAP diet for a period of time while you work to heal your gut.
5. Do Vidalia Onions and White Onions Have the Same Benefits as Red Onions?
The vidalia and white onions are very healthy as they do contain the sulfur compounds, quercetin and chromium. However, red onions are the only onions that have anthocyanins and therefore they are more nutrient dense than any other form of onion.
Sources For This Article Include:
- Munday R, Munday CM. Relative activities of organosulfur compounds derived from onions and garlic in increasing tissue activities of quinone reductase and glutathione transferase in rat tissues. Nutr Cancer. 2001;40(2):205-10. PMID: 11962257
- Fukushima S, Takada N, Hori T, Wanibuchi H. Cancer prevention by organosulfur compounds from garlic and onion. J Cell Biochem Suppl. 1997;27:100-5. PMID: 9591199
- Vazquez-Prieto MA, Miatello RM. Organosulfur compounds and cardiovascular disease. Mol Aspects Med. 2010 Dec;31(6):540-5. PMID: 20940019
- Yeh YY, Liu L. Cholesterol-lowering effect of garlic extracts and organosulfur compounds: human and animal studies. J Nutr. 2001 Mar;131(3s):989S-93S. PMID: 11238803
- Sak K. Site-specific anticancer effects of dietary flavonoid quercetin. Nutr Cancer. 2014;66(2):177-93. PMID: 24377461
- Wang LS, Stoner GD. Anthocyanins and their role in cancer prevention. Cancer Lett. 2008 Oct 8;269(2):281-90. PMID: 18571839
- Cefalu WT, Hu FB. Role of chromium in human health and in diabetes. Diabetes Care. 2004 Nov;27(11):2741-51. Erratum in: Diabetes Care. 2013 Sep;36(9):2872. PMID: 1550501
- Galeone C, Pelucchi C, Levi F, Negri E, Franceschi S, Talamini R, Giacosa A, La Vecchia C. Onion and garlic use and human cancer. Am J Clin Nutr. 2006 Nov;84(5):1027-32. PMID: 17093154