Milks to Avoid with IBS

Why Milk Can Be a Digestive Problem

three glasses of milk
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Milk - our first food. Certainly mother's milk is the preferred food for the digestive systems of newborns. However, once we are past the age of weaning, the digestion of milk is not always so optimal.

With IBS, typically the problem with milk, whether it be dairy or non-dairy, has to do with carbohydrates known collectively as FODMAPs. When these carbohydrates are not well-digested, they are available to be acted upon by gut bacteria. In people who have IBS, these interactions can lead to abdominal pain, motility problems, bloating and excessive intestinal gas.

In this article, we will look at milks that are high in FODMAPs and thus more likely to cause unwanted digestive symptoms.

1. Cow's Milk

glass of milk with toy cow
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Many people who have IBS have difficulty digesting cow's milk due to lactose intolerance, a condition in which a person does not have enough of the enzyme lactase to digsest lactose. Lactose is also included on the list of FODMAPs.

The FODMAP researchers at Monash University have classified both cow's milk and goat milk as being high in FODMAPs and therefore are not allowed during the elimination phase of the diet.

Cow's milk might still be an option for you if you determine, either through an elimination diet or through hydrogen breath testing, that you are not lactose intolerant. If you do have lactose intolerance, lactose-free cow's milk might be a good option.

There is one more thing to consider with cow's milk - the possibilitity of an allergy or intolerance to the proteins in milk, most notably casein. For most people with a casein allergy, the symptoms are what you would expect from an allergic reaction - hives, wheezing, and difficulty breathing. Less is known as to gastrointestinal symptoms in reaction to casein, and such cases are considered rare.

2. Soy Milk

soy milk
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Soy milk is a non-diary milk that is made from soybeans. Soy milk makes this naughty list for IBS because it contains high levels of the FODMAP GOS. You don't have to feel too bad that you can't drink soy milk as there are a lot of questions as to whether soy milk is actually good for us.

Interestingly, there is a type of soy milk available in Australia, that is made from soy proteins as opposed to beans. This option has been found to be low in FODMAPs.

3. Rice Milk

rice milk
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Rice milk is a non-dairy milk made typically with brown rice. You will find rice milk on many low-FODMAP food lists. However recent testing by Monash University researchers has indicated that rice milk contains high levels of the FODMAPs GOS and fructans and therefore is now classified as a high-FODMAP food.

4. Oat Milk

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Oat milk made this list, but its inclusion is not as clear-cut as the previous milk options. At higher levels, oat milk contains the FODMAP GOS. However, a small amount - no more than 1/8 cup - is considered to be low-FODMAP by the Monash researchers.

However, there is another thing to consider when talking about oat milk. Oat milk is not necessarily gluten-free as oats are often cross-contaminated by gluten-containing foods during storage or processing. Although there is a debate as to whether it is the gluten or the FODMAP fructan in wheat and other gluten-containing grains that is problematic for IBS, you personally may have found that you feel better when you avoid gluten.

So I definitely debated whether to put oat milk on the friendly or the unfriendly list. If you choose to include oat milk in your diet, use it in small amounts and make sure that you buy (or make) your oat milk using gluten-free oats.


Gibson, P. & Shepherd, S. "Evidence-based dietary management of functional gastrointestinal symptoms: The FODMAP approach" Journal of Gastroenterology and Hepatology 2010 25:252-258.

Monash University Low FODMAP Diet App Accessed Nov. 5, 2015.

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