What we eat has long been known to impact our health, and a wealth of research suggests that our eating patterns impact our risk for diet-related chronic diseases. More recently, the conversation surrounding how some dietary choices may lead to the development of chronic inflammation in the body has become a hot area in preventative nutrition. In our Food and Inflammation series, we take a closer look at how different dietary factors are related to inflammation. Our first two articles focused on gluten and sugar. In this article, let’s look at the connection between dairy and inflammation.
What is inflammation?
Inflammation is a natural process in the body that involves the immune system’s response to an irritant. It’s one way the body protects and heals itself. If you’ve ever had a paper cut or burned your tongue while drinking a hot cup of coffee, the process of healing those wounds was your body’s inflammatory response in action. Cuts and burns are examples of acute inflammation, which is a relatively short-lived response to injury, irritation, and/or infection. Acute inflammation can be brought on by infectious factors such as bacteria or viruses, non-infectious factors like injuries and chemicals, or psychological factors like stress or excitement.
In contrast, chronic inflammation is a long-term physiological response that can last anywhere from weeks to years. Unlike acute inflammation, chronic inflammation is not always visible to the naked eye. It can be brought on by a number of factors, including autoimmune conditions, chronic stress, long-term exposure to pollutants, physical inactivity, and certain dietary exposures. When the human body experiences a constantly activated inflammatory response, it can play host to destructive reactions that damage cells and are linked to increased risk of health conditions like diabetes, cardiovascular disease, dementia, depression, and certain cancers.
The Connection Between Food and Inflammation
Inflammation is a complicated process, and the connection between food and inflammation is still being studied. Some research shows that certain nutrients, like vitamin E, magnesium, and fiber as well as antioxidants like polyphenols can reduce inflammation. Diets that are high in refined starches, sugar, saturated and artificial trans fats; and that are low in fruits, vegetables, whole grains, and omega-3 fatty acids, have been associated with increased inflammation in the body. However, research suggests that changes to food choices alone are unlikely to solve chronic inflammation completely.
Dairy is one food group that has been accused of increasing inflammation in our bodies. Let’s examine the validity of this claim.
Sources of Dairy
The word dairy refers to foods made from animal milk. In the United States, we often see dairy products made from cow’s milk, but there are also options made with milk from goats, sheep, water buffalos, ewes, and camels, among others.
Common sources of dairy include milk, yogurt, cheese, butter, kefir, cream and ice cream, and proteins from dairy like whey and casein. These foods contain important nutrients like protein, calcium, riboflavin, magnesium, vitamin A, vitamin D, vitamin B12, and conjugated linoleic acid. Fermented dairy products, like yogurt and kefir, can contain probiotics, which are beneficial bacteria that help contribute to a healthy gut microbiota.
Is dairy inflammatory?
Why all the talk about dairy being inflammatory? It may stem from the fact that the main fat found in milk is saturated fat, and diets high in saturated fat can increase inflammation. The 2020–2025 Dietary Guidelines for Americans recommend limiting saturated fat intake to less than 10% of total calories consumed daily. At the same time, other fatty acids in dairy, like short-chain fatty acids, have been associated with health benefits, and some research has called into question whether all saturated fats can have negative health effects. Additional research is needed to better understand the role of dairy’s overall fatty acid profile in human health.
For most people, research does not support a consistent link between dairy and inflammation. There are exceptions, however—like people with a milk allergy or lactose intolerance, which are briefly reviewed below. One of the challenges in this area of research is that often, the study design, methods, research participants, and their diets vary widely, making it difficult to compare results between studies. Some research has found that dairy, particularly in the forms of full-fat varieties and non-fermented products, may be associated with an increase in the risk of pre-diabetes and type 2 diabetes. However, other studies have found no such relationship, and some research even suggests that dairy, especially fermented dairy products, may be linked to reducing the risk of type 2 diabetes and cardiovascular disease. One systematic review published in 2019 found that dairy did not have a pro-inflammatory effect in healthy adults or in adults with metabolic syndrome, obesity, and/or type 2 diabetes. Interestingly, there was a weak anti-inflammatory effect observed with certain fermented dairy products, such as kefir. However, this effect was only observed in a few studies. More high-quality research trials are needed to investigate and confirm this potential relationship.
Some people do experience adverse effects after consuming dairy due to certain health conditions, and this is where inflammation comes into play. These health conditions are outlined below.
Lactose Intolerance
Lactose intolerance is a common condition that refers to a body’s inability to digest lactose, the sugar found naturally in milk. People with lactose intolerance are unable to produce enough of the lactose-digesting enzyme lactase, and this condition leads to physical discomfort, bloating, and/or gastrointestinal distress after consuming dairy. The treatment for lactose intolerance is to avoid dairy, use plant-based dairy alternatives or dairy with lactase already added to the product, and/or to take a lactase supplement when consuming dairy. Lactose intolerance is not directly caused by an inflammatory response, but inflammation can occur when symptoms are present.
Milk Allergy
Milk allergy occurs when the body’s immune system reacts adversely to the proteins in milk and dairy products and activates an inflammatory response, which can range in severity from rashes to gastrointestinal issues to anaphylaxis. Treatment requires avoiding all dairy products and foods and beverages that contain milk-derived ingredients. U.S. law requires that food labels identify the food source of all major food allergens, including milk, used to make the food.
Should I Go Dairy-Free?
If you experience noticeable discomfort after consuming dairy products, consult your doctor to try to find out the cause of your symptoms. If you are diagnosed with lactose intolerance or a milk allergy, you will need to pay more attention to the ingredients lists and look for “dairy-free” labels on your foods and beverages. Learning more about the sources of dairy in your diet can help you manage your symptoms.
For most people, dairy does not cause inflammation, and there is no need to avoid it. Many dairy-containing foods may be eaten as part of a healthy diet. In addition, there are many non-dairy, plant-based milk alternatives on the market for those seeking out other options. However, these alternative products may not contain the same amounts of protein, calcium, or other nutrients found in animal milk. When shopping for plant-based dairy alternatives, look for varieties that have been fortified with calcium, vitamin B12, vitamin A, and vitamin D.
This article was written by Ali Webster, PhD, RD and includes contributions by Debbie Fetter, PhD.