Easily identified by complaints such as stomach pain, diarrhea, increased bloating and constipation, lactose intolerance can make a person’s life very uncomfortable. Not to be confused with a life-threatening milk allergy (or casein allergy), which is when the immune system overreacts to one or two proteins present in milk (i.e., casein and whey); a lactose intolerance is the inability to properly or fully digest lactose, which is a type of milk sugar present in animal milk.

Although signs may range from mild to severe, these are the most common symptoms of lactose intolerance:

1. Diarrhea or loose stools
Diarrhea resulting from lactose intolerance, happens because lactose increases the amount of water present in the colon, which increases frequency of passing stools in a 24-hour period. Diarrhea if left untreated, can lead to severe dehydration and cause fatigue and a general sense of weakness. To cope with this symptom, it is important to consult with a physician to determine whether dairy products should be removed from the diet altogether, and to decide which foods could be a good dairy replacement.

2. Increased gas or bloating
When lactose is not assimilated before it reaches the colon, once it reaches it, lactose begins to ferment there, thus causing the accumulation of gases and subsequent lower abdominal pain. Besides the physical discomfort associated with bloating, increased bloating can cause social anxiety and negatively impact the sufferer’s mental health and quality of life. Consumption of plant-based beverage replacements such as almond or soy milk can help prevent the occurrence of this complaint.

3. Stomach pain
Most likely one of the more common signs of lactose intolerance. It normally occurs a few minutes to one to two hours later after consuming dairy products, such as cow milk, yogurt, or a dessert such as cheesecake. Though not permanent, it can be quite impairing to the point of limiting movement and causing emotional upset if not addressed promptly. An effective way to cope with this complaint is to undertake the consumption of lactose free products such as milk without lactose, or lactose free organic milk.

4. Constipation
Although it is a less common sign of lactose intolerance compared to loose stools, constipation cannot be fully ruled out when it is observed as a symptom. This is because fermented lactose in the colon generates methane gas, that can delay the passing of waste through the digestive tract, as a result causing fecal matter to become impacted. This symptom can cause a great deal of lower abdominal pain, and in severe cases can make trying to walk a difficult task. In this case, it is recommended to increase consumption of fiber and clear fluids to ease the passing of food through the bowels and alleviate intestinal back-up.

5. Mouth ulcers
There have been a handful of research studies that point to the possibility that the immune system reacts to proteins present in cow’s milk, and as a result, ulcers form inside the mouth. It was noted that mouth ulcers stopped recurring when the research participants stopped all intake of cow milk products.

6. Headaches
There is such a thing as migraines caused by the body’s inability to digest certain proteins or sugars in foods. In a research study in the United States, it was observed that migraines stopped after participants discontinued the consumption of dairy products. This has to do with blood vessels contracting and relaxing during the consumption of lactose. It is recommended to follow up closely with a primary physician in order to determine if dairy needs to be removed from a patient’s diet.