Flatulence
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We all do it, like it or not.Flatulence or passing gas is normal. Everyone passes gas. In fact, the norm is to pass gas 10-20 times per day.
There are many people who feel that they pass an excessive amount of gas but there are studies that show that there is no difference in the amount of intestinal gas between people who claim they pass a little or a lot of gas. |
Where does this gas come from?The gas that we pass comes from 2 sources: the air we swallow and the gas formed by colonic bacteria.
Whenever we swallow even our saliva, we swallow air at the same time. We swallow up to 2 litres of air per day. Some gets burped up and some gets absorbed but about 500 ml passes all the way through. If we drink carbonated sodas, then we will obviously pass more gas. We all have bacteria that live in our colon. There are foods we eat that are not well digested by the small intestine. The bacteria in our colon digest these foods and release 3 main gases: hydrogen (H), carbon dioxide (CO2) and methane (CH4). Most of the gas we pass comes as a result of this bacterial digestion. |
What foods will give me more gas?There are foods that we call flatulogenic meaning they cause higher gas production from colonic bacteria.
Foods thought to increase gas include legumes, brussel sprouts, onions, celery, carrots, raisins, bananas, fermentable fibers, and complex starches like wheat and potatoes. Diets low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) have been proposed. In general, the scientific data to support all these diets is weak but a trial of a restricted diet is worthwhile. |
But why does it smell so bad sometimes?
The most common reason for the bad smell is sulfur containing gases related to an overly proficient sulfate-reducing bacteria and the availability of sulfate-containing foods.
The foods that contain sulfate are primarily cruciferous vegetables, cauliflower, cabbage, garden cress, bok choy, broccoli, brussel sprouts and similar green leafy vegetables. Beer and proteins also contain sulfates.
The foods that contain sulfate are primarily cruciferous vegetables, cauliflower, cabbage, garden cress, bok choy, broccoli, brussel sprouts and similar green leafy vegetables. Beer and proteins also contain sulfates.
I never used to pass so much gas. Why now?
This is a common question and concern because the sudden change is distressing.
There are 3 principle causes for this change:
1. The foods you are eating have changed.
You may have started to eat a healthier diet that includes more fruits and vegetables. You may have reduced your meat intake but added more grains. Perhaps you were eating foods with artificial sweeteners. All of these changes increased the amount of foods that are flatulogenic and lead to increased bacterial gas production.
2. The bacteria in your colon could have changed.
You may have had a recent viral illness or you took a medication such as an antibiotic that could have changed temporarily or even permanently the colonic bacteria leading to bacteria that produce more or different types of gas. A change in diet can also promote certain bacteria over others leading again to a change in the type of bacteria.
3. The sensitivity of your colon may have changed.
The main reason some people feel that they have more gas than others is that they have higher intestinal sensitivity and feel more uncomfortable with the gas. This causes them to need to pass gas more often. The sensitivity or the irritability of your colon could change because of a recent illness, medication use, and even stress. Patients with irritable bowel syndrome often complain of flatulence for this reason.
There are 3 principle causes for this change:
1. The foods you are eating have changed.
You may have started to eat a healthier diet that includes more fruits and vegetables. You may have reduced your meat intake but added more grains. Perhaps you were eating foods with artificial sweeteners. All of these changes increased the amount of foods that are flatulogenic and lead to increased bacterial gas production.
2. The bacteria in your colon could have changed.
You may have had a recent viral illness or you took a medication such as an antibiotic that could have changed temporarily or even permanently the colonic bacteria leading to bacteria that produce more or different types of gas. A change in diet can also promote certain bacteria over others leading again to a change in the type of bacteria.
3. The sensitivity of your colon may have changed.
The main reason some people feel that they have more gas than others is that they have higher intestinal sensitivity and feel more uncomfortable with the gas. This causes them to need to pass gas more often. The sensitivity or the irritability of your colon could change because of a recent illness, medication use, and even stress. Patients with irritable bowel syndrome often complain of flatulence for this reason.
What can I do to help myself?The most obvious first answer is to change your diet to minimize foods that are flatulogenic or that can increase the irritability of your intestines. Following a diet for irritable bowel syndrome or a low FODMAP diet is often a good start. Changing the bacteria in your colon is difficult. A trial of a probiotic is worthwhile. Probiotics are live bacteria and yeasts that are good for your health, especially your digestive system. The problem is that there is not enough data to know which probiotic is helpful, how much is needed and how long to take them. They can also be expensive. Occasionally a patient will ask me about antibiotics to change the bacteria. It is true that some patients notice a reduction in gas after they have used an antibiotic for another reason. The problem with antibiotics is that the effect tends to be temporary and after a few months the usual bacteria return and the flatulence returns. Sometimes, the opposite occurs and the flatulence worsens due to the effect of the antibiotics. There is other over the counter products of potential but often limited value. Bismuth containing products, such as Pepto Bismol, can help decrease flatulence temporarily. It is not recommended to take it for long periods due to potential nervous system side effects. Also remember that your stool will turn black because of the bismuth but it is a harmless colour change. Activated charcoal may work for some but it also should be used for temporary problems. Activated charcoal can interfere with the absorption of some medications so speak to your pharmacist before using it. Simethicone is an anti-foaming agent that decreases the surface tension of gas bubbles, causing them to combine into larger bubbles in the stomach that can be passed more easily. Simethicone does not reduce or prevent the formation of gas in the digestive tract, rather; it increases the rate at which it exits the body. Simethicone helps more to decrease the pain due to intestinal gas rather than decrease flatulence. Simethicone is found in a variety of brands such as Gas-X, Ovol and Phazyme. Overall the value of simethicone is weak but it is harmless to try. Beano contains the enzyme alpha-galactosidase. The enzyme works in the digestive tract to break down the complex sugars in foods such as legumes (beans and peanuts) and cruciferous vegetables into simple sugars, making these foods somewhat more digestible, and reducing intestinal gas. Beano needs to be taken when you eat these foods. Its value is also weak overall but harmless to try. |
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Is flatulence ever a sign of something serious?
A sudden change in the level of flatulence can be a sign of a malabsorption of nutrients such as a lactose, fructose or sorbitol maldigestion. It could also be seen in celiac disease. Usually, the increased flatulence will be accompanied by bloating and diarrhea. Weight loss with no change at all in diet should prompt an investigation.
If there is any concern, the first step is to follow the above instructions and if it improves, there is little to worry about. If you are still concerned, a visit to your family doctor for blood tests would be sufficient.
If there is any concern, the first step is to follow the above instructions and if it improves, there is little to worry about. If you are still concerned, a visit to your family doctor for blood tests would be sufficient.