Fact Check: Can Onion relieve constipation?

An Instagram post claiming that Onion can relieve constipation is Mostly False.

Claim: In an Instagram post, the user claims that onions can relieve constipation. In the Instagram post by ayurvedic_cures, the user says that regular consumption of raw onions as salads relieves constipation. As per the post, the fibers in raw onion help to flush out toxins and hard food particles that get stuck in the intestines. The post can be accessed here.

Fact Check

This claim is Misleading. While onion are rich in fibre, consuming high amounts of onion can also worsen IBS symptoms such as bloating. The post seems to exaggerate role of onions in "flushing out toxins" and hence is misleading

What is Constipation?

As per Johns Hopkins Medicine, “Constipation is a condition in which a person has uncomfortable or infrequent bowel movements. Generally, a person is considered to be constipated when bowel movements result in passage of small amounts of hard, dry stool, usually fewer than three times a week.”

Constipation can be caused by medications, lack of exercise, insufficient liquids or fiber, IBS, ignoring bowel urges, lifestyle changes (like travel, pregnancy, and aging), intestinal function issues, and laxative abuse. (1)

Medical Dialogues Fact Check Team spoke with Dr. Arun P, Associate Consultant, Department of Gastroenterology, KIMSHEALTH and he said, "Basic management of constipation includes lifestyle changes, adequate exercise, sufficient fluid intake, and dietary fiber. It is recommended to consume around 25 to 30 grams of fiber per day and to limit highly refined and processed foods. Along with dietary measures, medications such as osmotic and stimulant laxatives are advised. Onions contain around 1.9 grams of dietary fiber, but they also contain fructans, which are high FODMAP and may cause bloating and gas in patients with IBS."

Nutritional Benefits of Onions

Onions add abundant flavor to a wide variety of food, yet are low in calories. With only 45 calories per serving, onions are naturally fat and cholesterol-free. They are a source of dietary fiber, vitamin C, vitamin B6, potassium, and other key nutrients including folate, calcium and iron.

Onions contain a variety of other naturally occurring chemicals known as organosulfur compounds linked to lowering blood pressure and cholesterol levels.

Among some of their best-known benefits, onions contain the flavonoid quercetin which acts as an anti-inflammatory in the body, inhibits low-density lipoprotein oxidation (an important reaction in atherosclerosis and coronary heart disease), protects and regenerates vitamin E (a powerful antioxidant), and protects from many forms of cancer. (2)

Can onions relieve constipation?

Several studies have shown that dietary fiber can help improve bowel regularity. Onions are a rich source of dietary fiber which can help in the management of constipation.

An article published in the World Journal of Gastroenterology by Jing Yang et. al. it was found that dietary fiber intake can increase stool frequency in patients with constipation. (3)

In a study conducted by Amin Galavi et. al. published in the Iranian Journal of Basic Medical Sciences it was concluded that onion can be helpful in the prevention and management of dyslipidemia, high blood pressure, diabetes mellitus, and obesity as metabolic syndrome disorders and subsequently CVDs on account of antioxidant, anti-inflammatory, and vasodilatory properties, increasing insulin release and response, reduction of cholesterol and glucose absorption, modulating the metabolism of lipids and carbohydrates, and inhibition of adipogenesis. (4)

Scientific evidence was found about the benefits of onions, as they have a high fiber content, but no scientific evidence or medical consensus was found that consumption of onions alone can relieve constipation.

Medical Dialogues Fact Check Team spoke with Dr. Arun P, Associate Consultant, Department of Gastroenterology, KIMSHEALTH he said, "Onion alone will not improve constipation, consumption of vegetables and fruits which contain an adequate amount of fiber will help to relieve constipation to some extent."

Dr. Harish Kareem, Senior Consultant in the Department of Gastroenterology, Kimshealth said, "Raw onions contain dietary fiber, which is crucial for proper digestion and elimination of waste from the body. The fiber enhances nutrient absorption and can help manage various ailments like constipation. However, people with irritable bowel syndrome (IBS), who often experience either constipation or diarrhea, may experience worsening symptoms. A low FODMAP diet is generally advised for IBS. Some of the most common high-FODMAP foods are garlic and onions."   

Medical Dialogues Final Take

Onions can contribute to a diet that supports digestive health due to their fiber content. Incorporating onions as part of a balanced diet rich in various sources of dietary fiber can help relieve constipation but no medical consensus was found that onions alone can relieve constipation. The post seems to oversimplify the role of onions in relieving constipation whereas medical experts stress on the role of a balanced diet of which onion may be a part. Also, the claim exaggerates the role of onions in "flushing out toxins", which is not scientifically backed. Hence, this claim is Misleading.

References

1. https://www.hopkinsmedicine.org/health/conditions-and-diseases/constipation
2. https://www.onions-usa.org/all-about-onions/onion-nutrition/
3. Yang J, Wang HP, Zhou L, Xu CF. Effect of dietary fiber on constipation: a meta analysis. World J Gastroenterol. 2012 Dec 28;18(48):7378-83. doi: 10.3748/wjg.v18.i48.7378. PMID: 23326148; PMCID: PMC3544045.
4. Galavi A, Hosseinzadeh H, Razavi BM. The effects of Allium cepa L. (onion) and its active constituents on metabolic syndrome: A review. Iran J Basic Med Sci. 2021 Jan;24(1):3-16. doi: 10.22038/ijbms.2020.46956.10843. PMID: 33643564; PMCID: PMC7894628.