Common Causes of Bloating & Gas

Up to 25% of the general population experiences episodes of bloating and gas. While these episodes are often transient and happen for no discernable reason, there are some known causes of bloating and gas that, if properly diagnosed and treated, can improve, or resolve. Here are some common causes of bloating and why people experience these symptoms.

1) Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is an intestinal condition in which the muscles that control the large intestine tend to contract more frequently than they do in people without IBS.

There are three main forms of IBS: IBS-C, which causes intermittent constipation, IBS-D, which causes intermittent diarrhea, and IBS-M, which causes a mixture of constipation and diarrhea. Other symptoms of IBS include abdominal pain, cramping, bloating, and gas.

Medications are available to treat IBS. Also, as many as 86% of people with IBS reported improved symptoms when they followed a low FODMAP diet (which is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols).

The low FODMAP diet reduces the intake of foods with short-chain carbohydrates that are poorly digested in the small intestine. Click here to see a list of common FODMAP foods.

2) Food Intolerance

Food intolerance happens when the digestive tract lacks the ability to properly digest certain foods. Common causes of food intolerance include lactose, gluten, and food additives like MSG, sulfites, and nitrates.

Common food intolerance symptoms include headaches, fatigue, rashes, diarrhea, bloating, gas, and brain fog.

Two tools that are often used to help patients identify food intolerances are a food diary and a food elimination challenge. In a food diary, people record what they’ve had to eat and drink, and what symptoms they experienced. The diary is then reviewed to see if there’s a correlation between specific foods and the symptoms a patient experiences.

In an elimination challenge, one food group at a time is eliminated from the diet to see if removing that food group from a person’s diet alleviates their symptoms.

3) Hormones

Hormones can cause bloating and gas, too -- especially in menstruating females. In the days before and during menstruation, a rise in estrogen and a drop in progesterone affect the estrogen receptors in the GI tract, which can cause increased gas, bloating, and constipation. Additionally, these hormones can cause fluid retention, which can cause bloating as well. 

To combat menstrual-related GI symptoms, healthcare professionals recommend avoiding foods that are most likely to cause gas before and during menstruation. Avoiding foods like broccoli, Brussel sprouts, lentils, onions, and cabbage can reduce the incidence of gas and bloat during this part of the cycle. 

4) Anxiety & Stress

Stress hormones and neurotransmitters affect the gut as well as the brain. In fact, the GI tract contains more nerve endings than any other body part outside of the brain. This is why the GI tract is sometimes called “The Second Nervous System.”

When someone experiences anxiety or stress, the rise in stress hormones like adrenaline and cortisol diminishes the activity of healthy gut bacteria and causes chemical imbalances that can lead to nausea, stomach cramps, diarrhea, or constipation.

Practicing stress-reduction and self-soothing techniques can lower levels of stress hormones and increase the release of neurotransmitters like serotonin and dopamine, which can improve anxiety and depression and alleviate the effect of stress on the GI tract.

5) Unhealthy Eating

Eating a diet high in unhealthy fats can increase bloating because fat is digested slower than protein or carbohydrates, which means it takes the stomach longer to empty after a fatty meal. Vomiting and diarrhea can indicate a foodborne illness or other potentially serious causes of abdominal pain.

Eating a meal high in carbohydrates can also cause gas and bloating because the breakdown of carbohydrates in the large intestine causes air to build up in the colon.

To avoid diet-related gas and bloating, try to eat smaller portions that have a balance of healthy fats, complex carbohydrates, and lean protein.






Written by Sarah Thebarge, Physician Assistant