All about Lactose Intolerance


By Danielle Staub, MS, RD, CDN
Registered Dietitian, Division of Digestive Diseases

Suffering from lactose intolerance? You’re not alone! In fact, roughly 50 million Americans are lactose intolerant and experience the unpleasant symptoms of bloating, cramps, nausea, and diarrhea after consuming foods containing lactose. Though not harmful, it is certainly unpleasant and can significantly impact the quality of your life.  There are many misconceptions surrounding this topic, so let’s dive into the nitty-gritty on lactose intolerance!

What is Lactose Intolerance?

Simply put, lactose is a sugar found in milk and milk products. After consumption, lactose must be broken down by the intestinal enzyme lactase in order to be absorbed in your small intestine. Lactose intolerance occurs when people either do not make the lactase enzyme at all or when they do not make enough for proper absorption, resulting in digestive symptoms. Symptoms often occur 30 minutes to 2 hours after consuming milk and can range in severity based on the amount of lactose consumed.

I often see patients confusing lactose intolerance with a milk allergy and it’s important to differentiate the two: milk allergy is an immune-mediated reaction to one or more milk proteins and is much more serious than an intolerance, as even a small amount can be life-threatening.  Allergies cause a range of symptoms including rashes, hives, itching, trouble breathing, and loss of consciousness. Lactose intolerance on the other hand does not involve the immune system, is not life-threatening, and you can usually still have small quantities of lactose-containing foods without experiencing symptoms. Milk allergies commonly occur during the first year of life, while lactose intolerance occurs more often during adolescence or adulthood. 

Lactose Reduced Diet

You’ve been diagnosed with lactose intolerance, so now what? To help manage symptoms, it’s important to reduce dairy foods that have a high content of lactose from your diet, but it is certainly not necessary to remove ALL dairy from your diet. This is a common mistake people make, and unfortunately by removing all dairy from your diet, you also remove important nutrients, including calcium, vitamin D, and protein.

Many people with lactose intolerance experience digestive symptoms after consuming milk, but can tolerate other forms of dairy that have less lactose, such as hard cheese, butter, or Greek yogurt. Rather than eliminating everything, try to find your individual tolerance to dairy foods by introducing a small amount of lactose containing foods at a time. Since it can be difficult to remember everything you eat, keeping a food journal can help trace symptoms.

There are plenty of lactose-free options available on the market making it super easy to replace your favorite lactose-containing products (and bonus: they help to meet your daily calcium needs too!). Lactaid milk, and milk-alternatives, such as soy, almond, coconut, cashew, and rice milk are fantastic and widely available options. There are even lactose-free yogurts, cheese, kefir (cultured milk product), and ice cream available at most supermarkets. Another option is to take an oral lactase enzyme when consuming milk products. Lactase enzyme pills can be purchased over the counter.

For those who have a dairy allergy and must avoid all dairy, it is important to consume enough calcium and vitamin D to meet daily needs. Most adults require 1,000-1,300 mg calcium per day and at least 600-800 IU vitamin D per day though diet and supplementation. Most non-dairy milks are fortified with calcium and vitamin D. Other non-dairy sources of calcium include almonds, sardines, rhubarb, spinach, salmon, broccoli, orange, green leaf lettuce and canned tuna.  

What products contain lactose?

Lactose is found in foods other than milk and yogurt. Here is a list of the most common lactose containing foods (amounts vary significantly by product).

  • Milk, milkshakes, and other milk-based beverages
  • Yogurt
  • Cheese
  • Ice cream
  • Butter and margarine
  • Bread and other baked goods
  • Creamed soups, cream sauces (e.g., alfredo, beurre blanc sauce)
  • Instant potatoes, soups, and breakfast drinks
  • Processed snack foods
  • Protein powders and bars
  • Chocolate candy
  • Coffee creamer
  • Whipped toppings
  • Puddings, custards
Still have questions about lactose intolerance? Feel free to post a comment below!