The Effects of Onions on Cholesterol & Blood Sugar
It's obvious that onions are more than a garnish in the United States; the National Onion Association reports that Americans eat 20 pounds of onions per capita each year. Whether you enjoy the strong flavor of raw onions or their sweetness once caramelized, you may not realize that onions also have a history of therapeutic use. Their effects on both cholesterol and blood sugar have been the focus of scientific study, but solid conclusions are still elusive.
Onions belong to the same biological category as garlic, leeks and chives. They are grown throughout the world, although they are thought to be native to Europe and Asia. Onions' healing power can be traced to the 17th century, when New World explorer Pere Marquette ate them to prevent starvation. Onions' sulfur content gives them their characteristic odor and may play a role in their health benefits.
- Onions belong to the same biological category as garlic, leeks and chives.
- Onions' sulfur content gives them their characteristic odor and may play a role in their health benefits.
Onion Effects on Cholesterol
Onions contain the antioxidant called quercetin. Quercetin intake is associated with decreasing heart risks such as arterial hardening, high blood pressure and heart attack. Cholesterol accumulation contributes to clogging and hardening of the arteries. Cholesterol also is a major component of gallstones. Findings published in June 2009 in the "British Journal of Nutrition" revealed that both raw and heated onions reduced cholesterol gallstone development up to 39 percent, although the study was conducted on mice. Much of the research on onions' efficacy has been done on animals, so it's unclear how effective they may be in reducing cholesterol in humans.
- Onions contain the antioxidant called quercetin.
- Cholesterol also is a major component of gallstones.
Research on how onions affect blood sugar in humans has been more extensive. The sulfur compound called allyl propyl disulphide may increase insulin production and lower blood glucose levels. An October 2010 preliminary study published in the journal "Environmental Health Insights" found that red onion was effective at reducing blood sugar in people with diabetes. Glucose readings in type 1 and type 2 diabetics fell and remained lowered for four hours after eating. More research is needed, but these findings suggest that onion could be helpful in diabetes management.
- Research on how onions affect blood sugar in humans has been more extensive.
- An October 2010 preliminary study published in the journal "Environmental Health Insights" found that red onion was effective at reducing blood sugar in people with diabetes.
Can Onions Make You Lose Weight?
Onions are a popular food throughout the world and are generally safe. Like most things that can be consumed, however, side effects exist. This is particularly a concern if you're consuming large amounts of onions daily. Symptoms associated with heartburn may worsen if you already have this condition. You may be at higher risk for an allergic reaction, such as itchy eyes and a skin rash, if you have asthma. Much of the scientific evidence regarding onions' benefits for cholesterol, blood sugar and other health concerns are still inconclusive, so don't stop taking any medications your doctor prescribes.
- Onions are a popular food throughout the world and are generally safe.
- Much of the scientific evidence regarding onions' benefits for cholesterol, blood sugar and other health concerns are still inconclusive, so don't stop taking any medications your doctor prescribes.
Onion Effects on Cholesterol
Can Onions Make You Lose Weight?
What Peppers Are Good for Lowering Cholesterol?
Benefits From Purple Onion Tea
Onion & Garlic for Asthma Relief
How to Eat Raw Onions for a Cold and Stuffy Nose
Does a Cut-Up Onion Clear Sinuses?
Garlic and Gallstones
Do Onions Thin Blood?
Carbohydrates and Fiber in Onions
- "British Journal of Nutrition"; Dietary Garlic and Onion Reduce the Incidence of Atherogenic Diet-induced Cholesterol Gallstones in Experimental Mice; S Vidyashankar, et al.; June 2009
- "Environmental Health Insights"; Preliminary Study of the Clinical Hypoglycemic Effects of Allium cepa (Red Onion) in Type 1 and Type 2 Diabetic Patients; Imad M. Taj Eldin, et al.; October 2010
- Onions, raw. FoodData Central. U.S. Department of Agriculture. Published April 1, 2019.
- Anderson GH, Soeandy CD, Smith CE. White vegetables: Glycemia and satiety. Adv Nutr. 2013;4(3):356S-67S. doi:10.3945/an.112.003509
- Exploring aromatics. Academy of Nutrition and Dietetics. Updated 2020.
- Dabeek WM, Marra MV. Dietary quercetin and kaempferol: Bioavailability and potential cardiovascular-related bioactivity in humans. Nutrients. 2019;11(10). doi:10.3390/nu11102288
- Puccinelli MT, Stan SD. Dietary bioactive diallyl trisulfide in cancer prevention and treatment. Int J Mol Sci. 2017;18(8). doi:10.3390/ijms18081645
- Marrelli M, Amodeo V, Statti G, Conforti F. Biological properties and bioactive components of Allium cepa L.: Focus on potential benefits in the treatment of obesity and related comorbidities. Molecules. 2018;24(1). doi:10.3390/molecules24010119
- Chae MR, Kang SJ, Lee KP, et al. Onion (Allium cepa L.) peel extract (OPE) regulates human sperm motility via protein kinase C-mediated activation of the human voltage-gated proton channel. Andrology. 2017;5(5):979-989. doi:10.1111/andr.12406
- Smith AP, Sutherland D, Hewlett P. An investigation of the acute effects of oligofructose-enriched inulin on subjective wellbeing, mood and cognitive performance. Nutrients. 2015;7(11):8887-96. doi:10.3390/nu7115441
- Albanesi M, Pasculli C, Giliberti L, et al. Immunological characterization of onion (Allium cepa) allergy. Postepy Dermatol Alergol. 2019;36(1):98-103. doi:10.5114/ada.2019.82829
- Cooking with onions without crying. University of Nebraska-Lincoln. Updated 2020.
- What is the low FODMAP diet?. Academy of Nutrition and Dietetics. Updated 2019.
- Onions. RxList. Updated 2019.
- Shock CC, Cheatham NE, Harden JL, Mahony, AC, Shock BM. Types of onions and varieties. Oregon State University. College of Agricultural Sciences. Updated 2020.
- Dowdy S. Stored properly Vidalia onions can still be around this winter. University of Georgia. College of Agriculture and Environmental Science. Updated 2019.
Previously working for the North Carolina Community College System, Rachel Morgan has been a freelance writer and editor for over six years. She has a bachelor's degree in public health as well as a master's degree in English.