Does Dairy Really Cause Inflammation? It’s Complicated

Photo: Stocksy/Natasa Mandic
When it comes to inflammation, there are certain foods that have a clear connection to helping or hurting it. Sugar is a definite driver of inflammation, while antioxidant-rich berries are for sure in the beneficial camp. But when it comes to dairy, there's a lot of confusion, even among healthy food experts themselves.

For some people, eating dairy can wreck havoc on their bodies. The morning after pizza night, they may wake up to newly sprouted pimples. Or it may mean dealing with bloat or other digestive woes. Other people seem to have no problem with dairy, able to down a glass of milk (yes, from a cow) with absolutely no symptoms whatsoever.

Because dairy seems to cause inflammatory responses in some people but not everyone, it's tricky to know if it can be classified as an inflammatory food or not. It also shouldn't be overlooked at dairy is full of nutritional benefits, containing calcium, vitamin D, and in the case of yogurt, probiotics. Could something so nutrient-rich really cause an inflammatory response? Here, a doctor, a nutrition expert, and a scientific researcher all give their input, based on their professional experience and research.

What makes dairy so complicated

According to nutrition expert Katie Boyd, there are several reasons why dairy is difficult to classify as inflammatory or not. The first reason is that unlike singular foods like sugar or berries, there are a lot of different types of dairy. It's not unusual for someone to not have any negative physical reactions to hard cheeses, for example, but unable to process soft cheeses. Doctor and University of Iowa Carver College of Medicine clinical professor Terry Wahls, MD, says that in her research and clinical work, she's found that many people are able to digest fermented dairy (such as yogurt) easier than milk or cheese.

Boyd also says that the different ways dairy is made play a factor, too. "Some of the clients I work with have a sensitivity to corn or soy, but would only have a negative physical reaction to some types of dairy. It took some detective work to find out that the dairy causing the reaction was not grass-fed, which meant the cows the milk was sourced from likely had a diet full of corn and soy," she says. "Many people often don't think of animal feed playing a part in the end result of their food, but it actually can."

Dr. Wahls says genetics play a role in how well someone can process dairy, too. "People whose ancestors [ate or produced a lot of dairy] have a different set of genes and a different microbiome makeup than those whose ancestors didn't eat much dairy," she says, which can make certain populations more sensitive to dairy products. But regardless of ancestry, she's very clear that dairy has long been proved to be beneficial for infants and children, playing an important role in growth and development.

Does dairy cause inflammation for everyone?

There is still a lot of debate on this topic—because it's not yet totally clear through research whether dairy is inflammatory for everyone (like sugar) or just inflammatory for people who are allergic or sensitive to dairy.

One expert, Suzanne Judd, PhD, a nutritional epidemiologist, used blood samples to analyze the levels of inflammation markers in the blood of thousands of people to create an inflammation score for various food groups. Her research team found that dairy was linked to slightly reducing inflammation—the caveat being the opposite was true for those who had a lactose allergy or sensitivity.

"Dairy gets a bad rap for the same reason gluten gets a bad rap, which is because a portion of the population doesn't tolerate it very well and the immune system gets ramped up in response to that. But there are plenty of people who can eat dairy and not have an immune response," Dr. Judd says.

However, Dr. Wahls is an adamant believer that dairy causes inflammations in the vast majority of adults, even if research hasn't fully caught up yet. As a doctor who specializes in chronic illness, she says she's numerously seen patients' symptoms subside after cutting out dairy. (She also advocates not eating gluten or sugar.) "Some studies correlate high dairy consumption with cognitive impairment, which is a form of inflammation," she says. "Of course it's important to clarify that this is a correlation, not a clear cause-and-effect, but the connection is still there." (It's also important to point out other studies have found the opposite to be true or have found that connection be inconclusive.)

Again, there are definitely some people who struggle with dairy and thus can have an inflammatory response to it. As you can imagine, people who are allergic to cow's milk have been found to have increased inflammation after eating dairy products, since the dairy triggers an inflammation response from the body's immune system. Additionally, people with gut issues (like Chron's disease or celiac disease) might develop something called secondary lactose intolerance, which is where inflammation from these disease impacts the gut's ability to produce lactase, the enzyme that digests lactose. But the dairy itself doesn't cause inflammation; rather, inflammation caused the sensitivity to dairy.

Okay, so should you give up dairy or keep eating it?

While the jury may still be out scientifically on dairy and inflammation, there are some clear ways to know whether or not you should still shop in the dairy aisle. Boyd's biggest piece of advice: Try cutting out dairy for a month and slowly add back in different types to see how your body reacts. "I suggest people keep a food journal writing down the type of dairy they eat—including if it's grass-fed or not—and if they noticed any changes in how they feel." Then, you can use your journal as a guide to help figure out what diet choices make you feel your very best.

To make up for the nutrients that you'd be missing from dairy, Dr. Wahls says there are other ways to get them. "Spinach, for example, is a great source of calcium, and the majority of nut milk-based yogurts have probiotics added to them," she says.

Dr. Wahls generally advises her clients with a family history of cancer, cognitive decline, or other chronic conditions to minimize dairy consumption since they might be more sensitive to it, although she also acknowledges that it can be difficult to do so. "You have to be willing to give up momentary pleasures for potential long-term benefits, so it really is a personal choice," she says.

It's human nature to crave clear cut answers, but the reality is that the truth about dairy is still...well, cloudy. The best you can do is make an informed judgement call about what choice is best for you. But even still, unless you're gravely allergic, one slice of pizza topped with cheese certainly isn't the end of the world.

Watch the video below to see a list of five foods that fight inflammation:

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