Dairy: Arthritis Friend or Foe?
Understanding the link between milk and inflammation.
Yogurt at breakfast, cheese pizza for lunch, a late-night ice cream treat. For many Americans, dairy is a star player at every meal. With anti-inflammatory diets for arthritis, though, you may be left wondering how milk (and its many cousins) fits into the mix.
“There is no easy answer,” says Frank Hu, MD, PhD, a professor of epidemiology and nutrition at the Harvard T. H. Chan School of Public Health in Boston. Researchers exploring the link between dairy and inflammation have turned up conflicting evidence. “The picture is murky, and the results are not very consistent,” he says.
It’s clear that a diet high in saturated fats – which are plentiful in cheese and full-fat dairy products – can increase inflammation. But other fatty acids found in dairy have been linked to health benefits such as a reduced risk of diabetes, says Dr. Hu.
A study published in The Journal of Nutrition in 2015 found that eating dairy foods increased low-grade inflammation in a small sample of German adults. And a study of more than 40,000 people with osteoarthritis found that those who ate more dairy products were more likely to need hip replacement surgery. On the other hand, several studies have found that drinking milk and eating yogurt can lower the risk of gout.
Despite conflicting information, the research paints a positive picture for milk-based products overall. A 2017 review of 52 clinical studies, published in Critical Reviews in Food Science and Nutrition, concluded that dairy generally has anti-inflammatory effects, except in people allergic to cow’s milk.
Still, the authors of that review noted there’s surprisingly little known about what components of dairy products might be helpful versus harmful. Milk-based products contain all sorts of nutrients and active compounds, including calcium, vitamin D and a variety of fats and proteins. And the proportions of those nutrients vary from food to food.
It’s hard to draw conclusions, Dr. Hu says, for an important reason: “Dairy isn’t a single food.” The category covers everything from yogurt to cheese to ice cream. Even liquid milk differs from glass to glass, from skim options to full-fat varieties. So far, the research hasn’t drilled down to say which components of which dairy products might be most healthful (or harmful).
The most consistent evidence so far centers on yogurt. “Yogurt is associated with decreased inflammation, decreased insulin resistance and it may prevent type 2 diabetes,” Dr. Hu says. Nutrition researchers believe yogurt’s anti-inflammatory power comes from the probiotics it contains, but that still has to be confirmed with rigorous trials, Dr. Hu says.
Given the conflicting research findings, you might be wondering what types of dairy (if any) you should include in your diet. The short answer: It depends.
Some people are unable to fully digest lactose, the sugar naturally present in milk products. If you’re lactose intolerant, you probably know it already. Symptoms include gas, diarrhea and bloating after drinking milk or eating dairy products.
Some people who can digest lactose might be sensitive to other components of dairy. For example, researchers are exploring a type of protein called A1 beta-casein protein, which is found in most milk in the U.S. Some breeds of cattle, however, produce milk with only the A2 version of beta-casein. A handful of small studies have suggested that people who drink A2-only milk may be less likely to experience digestive upset and might have lower levels of systemic inflammation. But the research is still preliminary, so conclusions can’t be drawn about how A1 might affect people with inflammatory arthritis.
Trying an Elimination Diet
Anecdotally, some people with arthritis and related conditions find that avoiding certain foods can reduce flares. For others, dietary choices don’t seem to make much difference. To find out if you’re sensitive to cow’s milk, you might consider an elimination diet. You simply cut out dairy for a while and then reintroduce it to see how you respond.
If you don’t notice any negative symptoms, you can likely resume shopping the dairy aisle without worry, says Simin Meydani, PhD, a senior scientist at the Nutritional Immunology Laboratory at Tufts University in Medford, Mass.
If you aren’t lactose intolerant or dairy sensitive, Meydani recommends eating yogurt to reap the probiotic benefits. Yet as with just about everything in life, moderation matters for dairy, too, she says. Overeating full-fat dairy or sugar-sweetened dairy can contribute to weight gain – and obesity itself is associated with chronic inflammation. “Controlling weight is important in terms of reducing inflammation,” she says. Sticking to low-fat dairy choices can help.
If you decide to cut back on dairy, make sure you’re choosing other foods with those nutrients. Good sources of calcium include collard greens; kale; soybeans; chickpeas; almonds; and calcium-fortified juices and non-dairy milks (soy, almond, hemp, rice). For Vitamin D, look to eggs and fortified juices, cereals and non-dairy milks.
Make sure to check the label of milk substitutes. Some of them have a lot of added sugars, Dr. Hu warns.
If you eliminate dairy, you should also pay attention to what you’re replacing it with, Dr. Hu notes. By eating donuts for breakfast instead of plain yogurt, you might be setting yourself up for bigger health problems.