Most Common Symptoms Of Lactose Intolerance

Most Common Symptoms Of Lactose Intolerance A natural sugar found in almost all kinds of milk, lactose is a source of energy for your cells. Lactose is made up of two smaller sugar compounds namely glucose and galactose. In your body, lactose from food sources is broken down to these simple sugar units, which are then absorbed by your body.

This breakdown of the sugar is carried out by the enzyme lactase. An insufficiency of the enzyme lactase in your system causes lactose intolerance. Lactose intolerance is the inability of your body to digest lactose. This condition is often mistaken as a common allergy to milk or other milk products. While an allergy to milk can cause itches or other allergic reactions, lactose intolerance involves certain abdominal signs of illness.

Common Symptoms of Lactose Intolerance

Lactose intolerance in adults starts during early teens and progresses into adult life. Newborns can also be lactose intolerant. The symptoms of lactose intolerance appear within two hours of consumption of lactose rich food products. The following symptoms occur when unsimplified lactose passes through the intestine into the colon.

Pain or Cramps in the Abdomen

Abdominal pain is one among the most common symptoms of lactose intolerance. The pain or cramps can be mild or severe. The presence of unabsorbed lactose in the intestine causes pain or cramps.

Most Common Symptoms Of Lactose Intolerance

However, not all kinds of abdominal pain can be associated with lactose intolerance.


Flatulence or passing of gas is another common symptom. This is due to the activity of certain bacteria in the large intestine. When unbroken lactose passes through the large intestine, the bacterium present in the intestine metabolizes this sugar. The end products of this reaction are several gases of which Hydrogen is the most prominent. The release of hydrogen through the rectum causes excessive flatulence.

Loose Stools

Not all the lactose molecules are metabolized by bacteria. The undivided lactose molecules in the colon imbibe water into the colon through osmosis. When this water is excreted, loose stools are caused. Therefore, diarrhoea is common among people with lactose intolerance. In some cases, stools can be foamy.

Vomiting and Nausea

Nausea is not a very common symptom. The presence of lactose in the gut causes inflammation and irritation. Lactose can also cause inflammation in the intestinal lining.

Most Common Symptoms Of Lactose Intolerance

This inflammation results in nausea. Nausea and vomiting do not last for long. Once the lactose is eliminated from the body, vomiting subsides.


Bloating in the abdomen is found in some people with lactose intolerance. Bloating is an uncomfortable sensation that makes you feel full all the time. The several kinds of gas released in the intestine during lactose metabolization causes bloating in the abdomen.

Stomach Rumbling

Stomach growling or sounds in the stomach is not a very common symptom of lactose intolerance. However, a few people experience this kind of discomfort. When the excess gases that are produced due to incomplete breakdown of lactose move through the intestine, the food items are pushed against the intestinal lining, creating the rumbling noise.

These symptoms can be mild in some people, while it can be severe in others. The severity of the symptoms depends on the amount of lactose in the diet. Higher amounts of lactose, increases the severity of the symptoms. The symptoms can also vary according to the level of lactase deficiency. People with severe lactase deficiency can get affected with these symptoms even with a low amount of lactose, whereas people with mild lactase deficiency can tolerate a little higher amount of lactose.

Lactose intolerance is quite common and it is not dangerous. This condition is more common among people with Mediterranean, Native American, African and Asian ancestry.