Dairy Products: Seven Myths

Dairy products are a key component of many of our everyday diets. Some of us are convinced that they are very important to our health, while others suffer side effects after eating them and try to avoid them. Assistant Clinical Professor Yael Kopelman, Director of the Gastroenterology Institute at Hillel Yaffe Medical Center, tries to set the record straight and addresses several common assumptions and myths regarding milk and dairy products:

1. Myth: Although I am not lactose intolerant, dairy products give me a stomachache and make me feel bloated.

Right. For many of us, even if our digestion is generally normal, and we don't have any problem eating dairy products, when we ingest lots of dairy products, like when we eat on Shavuot, we may not have a sufficient amount of the enzyme used to digest them in our body. The result is that we feel "heavy," and this translates into being bloated, having gas, stomachaches and even diarrhea. These symptoms are temporary and will pass.

2. Myth: Lactose intolerance and an allergy to milk are the same.

No, they're not. The term, milk allergy, refers to a condition in which a person is born allergic to milk proteins. This is a type of genetic condition, like an allergy to bee stings or peanuts. Exposure to milk protein, when a person is allergic to it, will lead to allergic reactions such as a rash or shortness of breath. Therefore, someone who is allergic to milk from birth is not allowed to consume milk and dairy products.

In contrast, lactose intolerance relates to difficulty in digesting lactose. Lactase is an enzyme found in the lining of the small intestine. It breaks down lactose into its constituent parts, which are then easily absorbed through the intestine (glucose and lactose). Without lactase, our bodies cannot break down the lactose, and it will not be absorbed. The lactose will continue down the digestive tract, and be used by our gut bacteria. When the bacteria break down the lactose, this produces gas, which is what leads to symptoms and makes you not feel well.

3. Myth: Lactose intolerance can appear at any age.

That's right. The most common type of lactose intolerance develops gradually after nursing and appears in adults. The enzyme that breaks down lactose is essential when babies nurse, but when breast milk is replaced with other, diverse products - its quantity is reduced. Therefore, it's possible, that the body will digest milk properly over many years and the deficiency will develop later in life. It is important to note that there is no connection between higher consumption of dairy products over the course of your life and the appearance of the enzyme deficiency at any point in time. However, once the deficiency appears, the symptoms depend on the correlation between the amount of dairy products eaten and the quantity of the enzyme the body is able to produce. Born lactase deficiency is very rare and is a genetic condition. In this case, the symptoms related to a lactose digestion disorder appear in infancy.

There may be a temporary and passing disorder in the break down of lactose, when dealing with other diseases of the small intestine. The production of the enzyme is a secondary effect to the intestinal disease such as in the presence of inflammation. Once recovered from the disease, the body will once again begin producing the enzyme and using it properly. 

4. Myth: There is a link between ethnic origin and lactose intolerance

That's right. In the development of ethnic groups around the globe over thousands of years and the exposure of certain countries to animal-based dairy products, genetic changes appeared in humans. As a result, there are countries in which the majority of the population has a sufficient amount of the enzyme to digest dairy products (for example, in the Scandinavian countries), while there are other cultures in which virtually the entire population is unable to break down lactose properly (for example, East Asia and South Africa). Consequently, consumption of dairy products in these countries is lower.