Dairy is one of those “big bad wolves,” along with gluten , that tends to get villainized. Many people cut it out of their diets without really understanding how it affects them. Historically, the biggest argument against eating dairy has been that it’s inflammatory, and we know that chronic inflammation is linked to most chronic conditions with which nearly 125 million Americans are living with. But here’s the thing—not all dairy causes inflammation in everyone, newer research shows.
Milking the nutritional truth out of the research around dairy is, ironically, harder than you’d think. We’re diving into exactly what you need to know about the effects of dairy on the body and the connection between dairy and inflammation.
You probably grew up hearing that milk is good for your bones and yogurt is good for your gut. It’s not entirely wrong. Milk contains calcium and vitamin D , which are good for your bones. Yogurt contains probiotics , which are good for your gut. It’s this line of thinking and the fact that dairy is readily accessible that has likely led dairy to be a staple in many diets.
In developed countries, milk and dairy products make up about 14% of overall caloric intake in the diet and in 2018, The Food and Agriculture Organization (FAO) recorded that world milk production has increased to about 843 million tons .
Despite the mass production and consumption of dairy, allergies and sensitivities to milk are common.
Lactose intolerance later in life is extremely prevalent with approximately 65 percent of the human population at large having a reduced ability to digest lactose, experiencing a variety of lactose intolerance symptoms. Rates of lactose intolerance can vary greatly between geographic regions , including incidence of less than 10% in Northern Europe to as high as 95% in parts of Asia and Africa.
Those with lactose intolerance are unable to digest dairy well because they do not produce adequate amounts of the enzyme lactase which is required to break down lactose, a sugar found in milk. As a result, they experience lactose intolerance symptoms such as abdominal pain, bloating , flatulence, nausea, and diarrhea beginning as soon as 30 minutes to 2 hours after consumption.
The severity of dairy allergy symptoms can range, which is why many people with only milk allergy symptoms simply ignore them and continue to eat dairy, while people with more severe dairy allergy symptoms may avoid dairy or take lactose pills to help them break down dairy. Furthermore, some lactose intolerant people can tolerate fermented dairy like yogurt or high-fat dairy products like butter without issue. Despite how common it is though, lactose intolerance isn’t the only reason you may be bothered by dairy.
If you produce the lactase enzyme but still react poorly to dairy, you likely have a milk protein allergy, experiencing an allergic response to one or both of the proteins found in dairy—casein and whey. This type of dairy allergy is most commonly seen in children but can also affect adults and may cause symptoms such as swelling of the mouth, lips or throat, skin reactions such as hives or rashes, or increased nasal congestion and mucus production. People can also experience dairy allergy symptoms in the G.I. tract such as loose stools, diarrhea, vomiting, and/or abdominal cramping.
Since casein has a similar molecular structure to the wheat protein, gluten, 50% of people who have celiac disease also have a casein intolerance , according to older research. Simply put, if you negatively react to gluten, it’s more likely that you’ll also react to milk and dairy products because milk proteins can commonly cross-react with gluten in the intestine .
Additionally, if you have increased intestinal permeability, or “leaky gut ”, it is more likely that your immune system may respond to potentially allergenic components in milk and dairy products. If you have small intestinal bacterial overgrowth (SIBO ) or irritable bowel syndrome (IBS) you might also negatively react to dairy and notice gas , bloating and other digestive symptoms. Going dairy free can often help manage these symptoms, at least until the condition resolves.
If you have a dairy allergy, lactose intolerance, IBS , SIBO, gluten intolerance or intestinal permeability, there is evidence that dairy can promote an inflammatory response when consumed. Additionally, research supports that there is a positive link between milk consumption and the occurrence of acne and potentially eczema . For Parsley Health members with any of these conditions, we usually recommend following a dairy-free diet and eating only dairy substitutes to help alleviate symptoms.
However, overall research does not support the notion that dairy is inflammatory for people who do not have any of these conditions . Similarly, a 2019 review published in Advances in Nutrition found that dairy had no proinflammatory effects on healthy people as well as people who had diabetes or metabolic syndrome. Most recently, a 2020 review reported that eating dairy could even reduce biomarkers of inflammation in some cases, where subjects did not have inflammatory disorders or other conditions.
In fact, a 2017 review that evaluated 52 clinical studies, concluded that dairy generally has anti-inflammatory effects, except in people with known allergies or intolerances.
Additional research has found that total dairy intake could be associated with lower risk of cardiovascular disease and stroke (all diseases that have been linked to increased levels of chronic inflammation).
This is just one reason why personalized nutrition and health recommendations, like those provided by Parsley Health ’s clinicians and health coaches, are so beneficial. Even if you do not have known allergies or intolerances, that doesn’t mean it’s a free-for-all on dairy, though. There are still other considerations.
It’s possible that certain types of dairy cause inflammation, even if you haven’t been diagnosed with lactose intolerance, a dairy allergy, or another intestinal issue. Of course, first pay attention to your digestive symptoms. If you notice bloating, changes in bowel movements, or any other type of digestive upset after eating dairy, this could be a red flag that dairy causes inflammation for you. Then, note other symptoms, like increased mucus production.
Dairy inflammation symptoms may include changes in your skin: You might notice an uptick in acne , or even skin rashes such as eczema and psoriasis after dairy intake.
If you’re super sensitive to dairy (and maybe don’t know it yet), eating dairy could even cause mental health-related symptoms. You may feel extra fatigue , experience brain fog symptoms, or have an energy crash after ingesting dairy products. The best way to test for dairy and inflammation flare-ups would be through an elimination trial of dairy, which would be a minimum of 30 days of completely eliminating dairy from your diet. Then, your health coach would work with you to slowly reintroduce dairy back into your diet to test your reaction to eating it.
While you don’t need dairy in your diet, if you tolerate dairy well, choosing high quality, full-fat, organic, pasture-raised dairy that’s preferably from grass-fed cows, goat or sheep is your best bet. That’s right, if you’re going to eat dairy, you need to be smarter about it (sorry, that means no cheese whiz). Here’s why:
Contrary to previous understanding, full-fat dairy has shown to be more beneficial than low-fat varieties. One study found that there was no concrete association between eating full-fat dairy and cardiovascular disease. Another research article concluded that those who consumed greater amounts of low-fat dairy products had higher rates of obesity and greater risk of developing cardiovascular disease and diabetes—likely because of the higher glycemic index and added sugars in low-fat milk products.
Additionally, a randomized trial in men found that full-fat milk and high-fat dairy products such as cheese and butter specifically, did not significantly impact or increase inflammatory response in study participants.
The source that dairy comes from is also a major factor to consider. Conventional dairy products are made from milk that contains hormones, chemicals, and antibiotics which on their own may have negative consequences to human health, although clinical research on the topic is limited . Therefore, opting for organic and pasture-raised varieties from grass-fed cows is your best bet if you’re going to eat dairy.
Dairy products from goat and sheep are often better tolerated because they contain lower levels of milk proteins since they come from smaller animals. Goat and sheep’s milk also contain the more easily digestible A2 beta-casein , which is a big part of the reason they’re less likely to cause gastrointestinal symptoms and inflammatory responses when consumed. For an added bonus, goat and sheep are also less likely to be factory farmed and therefore, have reduced amounts of added chemicals, hormones, and antibiotics in their feed and environments in comparison to cattle.
Kelly Johnston is a registered Dietitian Nutritionist with six years of experience in the health and wellness field, four of which have been spent right here at Parsley Health supporting members with everything from gut issues and autoimmune disease to cardiometabolic health concerns and fertility. She holds a Master's of Science in Nutrition from one of the leading science-based natural medicine schools in the country, Bastyr University, and completed her dietetic internship at Sea Mar Community Health Center in Seattle, WA.