Remember those “Milk: It Does a Body Good” ads? If you’re a woman with knee osteoarthritis (KOA), that slogan might be particularly appropriate for you.

A study led by Dr. Bing Lu of Harvard Medical School and Brigham & Women’s Hospital in Boston indicates that drinking milk—albeit what some adults might consider a lot of milk—could slow the progression of KOA in women. Note the words “might” and “could” in that statement. The results of the study are not conclusive and the Milk Might Do You Goodauthors make it clear that further research is necessary .

Still…it’s something to think about.

The four-year study involved 2,148 participants (with 3,064 arthritic knees among them). The evaluation was made based on measurements of joint space width around the knee. Results showed the more milk that was consumed, the more slowly the spaces widened; thus the more slowly the KOA progressed.

How much milk? The best results were among women who drank at least  seven 8-ounce glasses of milk per week. Those who consumed four to six glasses per week also showed an advantage over those who consumed three or fewer glasses of milk per week.

What type of milk? Low-fat (1%) or fat-free (skim) milk are the healthiest choices for adults.

Why does it help? An increase in calcium intake might be the operative factor, but “the biologic mechanism remains unclear,” the researchers say.

What about other dairy products? Here’s where the plot thickens. Consumption of yogurt had no effect on the joint space width. Consumption of cheese (seven or more servings a week) caused the joint space width to increase, possibly because cheese tends to have a high level of saturated fat, which has been shown to speed the progression of KOA.

Who does it help? Women. For reasons yet to be determined, drinking milk had little to no effect on the progression of KOA in men. It’s possible that women are more sensitive to dietary calcium intake than men are. That’s a question requiring further study.

What happens next? The research continues. First an attempt will be made to confirm the original results by replicating the study. If the indications aren’t the same, or nearly the same, the second time around then researchers will try another way to determine whether and how milk consumption has an effect on the progression of KOA. Once it’s been determined whether milk has an effect on KOA, the next steps will be to determine why it has an effect and how to apply that knowledge to patient care.

Should you be drinking milk to slow the progression of your OA? No one disputes that milk is good for bones. This research is a first step toward proving that drinking milk can help manage KOA. Expect more to follow. Until then, assuming your doctor agrees, pour yourself a nice glass of milk. It really might do your body good.

Results of the study were published in “Milk Consumption and Progression of Medial Tibiofemoral Knee Osteoarthritis: Data from the Osteoarthritis Initiative” in the June 2014 issue of Arthritis Care & Research, the journal of the American College of Rheumatology.