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 What is Lactose Intolerance

Lactose intolerance, or less commonly, milk-alkali syndrome, is the inability to digest lactose.

People with this condition have a problem digesting lactose, the sugar found in dairy products. Lactose intolerance is relatively common. 

This is due to a temporary lack of required lactase as an enzyme needed for digestion of dairy products such as milk and yogurt. 

Common sources include milk products made from cow’s milk; there are lesser-known sources such as goat’s and sheep’s milk. 

Lactose can also be found in larger amounts in processed foods with a longer shelf life such as canned vegetables, sausages, baked goods, and frozen dinners. 

Rarely, lactose can be found in minute amounts in certain other foods including yeast extract (marmite), certain brands of muesli bars, soy, and soybean products like soymilk ice cream (watch out for faux ice cream) vegan animal free dairy alternatives like coconut-based products including rice alternatives that use coconut extract instead of real sugar.

It can sometimes result in stomach pain or nausea, but usually these symptoms won’t be too severe and will go away after eating only small amounts of the offending foods.

The condition affects between 30 and 50 million Americans – or up to 75 percent of all adults worldwide. 

If you have a sensitivity to lactose, then it’s possible that you will have loose or even watery stool after eating foods that contain the sugar such as milk and ice cream. 

It can sometimes result in stomach pain or nausea, but usually these symptoms won’t be too severe and will go away after eating only small amounts of the offending foods. 

 lactose intolerance symptoms - Lactose Intolerance: Causes, Symptoms, and Treatment


Causes of Lactose Intolerance

Lactose intolerance is caused by a shortage of lactase, an enzyme produced in the small intestine which helps to break down lactose for easy digestion.

There are two main types of lactose intolerance, and both have different causes: 

Primary Lactose Intolerance

Primary lactose intolerance is an inability of the body to digest lactose.

Lactose is broken down by an enzyme called lactase, which is produced by cells in the small intestine.

If people have primary lactose intolerance, they don’t produce enough of this enzyme to break down the amount of lactose reaching the bowel, causing symptoms such as diarrhoea and cramps.

An absence of lactase doesn’t usually cause any health problems until babies start drinking cows’ milk – a baby will stop producing its own supply by five years old.

However, some adults are born with primary lactose intolerance due to a gene mutation that can be passed from parent to child.

Alternatively it could develop as part of another digestive problem such as Crohn’s or Celiac disease or in people with irritable bowel syndrome (IBS).

Secondary Lactose Intolerance

Secondary is lactose intolerance (LI) which is caused by an underlying issue, such as surgery, illness, or a virus.

In these cases, the body loses the ability to digest lactose with normal fluid production of the enzyme that breaks down lactose.

Secondary LI can happen at any age and happens most commonly due to damage to the small intestine or following surgery.

Without enough lactase, undigested lactose is unable to pass through into the colon where it is broken down by bacteria, producing toxins and causing discomfort as a result. 

This leads to the illness known as lactose intolerance. 

These cases can result in severe cases of food allergies or symptoms that mimic other diseases like Crohn’s disease.

It should be stressed that not everyone that drinks milk will develop lactose intolerance, but there are several risk factors and causes that can leave people with the condition.

These include:

  • Newborn babies produce little or no lactase and must be introduced slowly in their diets over time to avoid symptoms
  • Being younger when first ingesting lactose in large quantities
  • Being unable to produce the right amount of lactase
  • People over 40 have lower levels of production
  • Some cases can also be caused by injury or surgery on the small intestines
  • Some people are simply born without adequate amounts of lactase for digestion
  • Being unable to produce the right amount of lactase needed for digesting dairy products

For those who can’t tolerate the lactose in dairy products, they should completely avoid it and seek another source of nutrients. 

 lactose intolerance causes - Lactose Intolerance: Causes, Symptoms, and Treatment


Symptoms of Lactose Intolerance



Symptoms of lactose intolerance can usually start from 30 minutes to two hours after eating or drinking lactose contained foods. 

In such cases, undigested lactose remains in the bowel where it draws water and ferments, leading to unpleasant symptoms such as: 

  • Diarrhea
  • Nausea
  • Vomiting
  • Stomach Cramps
  • Bloating
  • Gas 

The symptoms of lactose intolerance vary from person to person and can be mild or severe depending on the amount of lactose you’re able to consume in one sitting. 

Most people are unaware they have a problem with dairy products until they feel symptoms, and once they start avoiding dairy foods, it can take anywhere from four days to two weeks before they feel normal again. 

For others that have a more severe problem and process the enzyme lactase inefficiently, symptoms may occur more quickly after consuming milk or dairy products.

Treatment of Lactose Intolerance


Awareness of lactose intolerance is increasing at a rapid pace, but many people still don’t know about it or exactly what causes it.

There are many treatment options available for those intolerants to lactose.

The first is to cut out products which contain lactose and if you don’t like doing that, drink Lactase Enzyme Milk with your dairy products.

This reduces symptoms such as bloating and diarrhea.

Now that you know the symptoms of being lactose intolerant, let’s look at some treatment options available: 

  • Limit milk and other dairy products
  • Consume small servings of dairy products in your meals
  • Adding lactase enzyme to milk to break down the lactose
  • Probiotics or prebiotics

lactose intolerance foods to avoid - Lactose Intolerance: Causes, Symptoms, and Treatment


Lactose Intolerant Diet


Avoiding dairy products like milk, cheese and yogurt can seem difficult for lactose intolerant people.

Many people aren’t aware that there are certain foods that can help to relieve lactose intolerance, in addition to avoiding high lactose-containing foods.

Foods to Eat:

  • Fruits: Oranges, Apples, Berries, Peaches, Plums, Grapes, Pineapples
  • Nuts: Almonds, Walnuts, Pistachios, Cashews, Brazil nuts, Hazelnuts
  • Vegetables: Garlic, Kale, Spinach, Arugula, Zucchini, Carrots, Onions
  • Whole Grains: Barley, Buckwheat, Quinoa, Couscous, Wheat, Oats
  • Meat: Beef, Lamb, Pork, Veal
  • Poultry: Chicken, Turkey, Goose, Duck
  • Beverages: Water, Tea, Brewed Coffee, Coconut Water
  • Seafood: Tuna, Mackerel, Salmon, Anchovies, Lobster, Sardines, Clams

 Foods to Avoid:

  • Milk: Cow’s Milk, Goat’s Milk
  • Cheese: Soft Cheeses – Cream Cheese, Cottage Cheese, Mozzarella, Ricotta
  • Butter
  • Yogurt
  • Whipped Cream
  • Sour Cream
  • Buttermilk
  • Ice Cream
  • Frozen Yogurt

However, you must remember to always test dairy items before ingesting them because there continues to be some debate as to whether all people lactose intolerant are sensitive to dairy items. 

Also remember not to eliminate all dairy items at once so as not cause adverse reactions or ‘rebound intolerance’.  

lactose intolerance infographic - Lactose Intolerance: Causes, Symptoms, and Treatment



Being lactose intolerant can be challenging, but it does not necessarily mean that it needs to have a negative effect on your quality of life.

There are however lifestyle and dietary changes which can be implemented, along with the medicinal prescriptions from a doctor, that can alleviate most, if not all, of the suffering experienced by those with lactose intolerance.

At GiDoc JHB, we know digestive problems can affect your quality of life, but it doesn’t have to. 

Dr. Schneider is dedicated to providing compassionate, comprehensive and personalized care for all patients.

For more information contact Dr. Schneider or visit www.gidocjhb.co.za and book your consultation today.



The information on this website is to provide general guidance. In no way does any of the information provided reflect definitive medical advice and self-diagnoses should not be made based on information obtained online. It is important to consult a Gastroenterologist or medical doctor regarding ANY and ALL symptoms or signs including, but not limited to: abdominal pain, haemorrhoids or anal / rectal bleeding as it may a sign of a serious illness or condition. A thorough consultation and examination should ALWAYS be performed for an accurate diagnosis and treatment plan. Be sure to call a physician or call our office today and schedule a consultation.