No. Your body’s ability to absorb antioxidants from berries is not reduced when consumed with dairy products based on a review of the last year of published medical literature. In fact, casein which is the protein found in milk has antioxidant properties. Cheeses have the highest antioxidant properties due to a higher protein content. Pasteurization (heat treatment to kill bacteria) of milk and dairy products do not affect antioxidant properties either. Higher fat dairy has more antioxidant properties than fat-free dairy than plain milk. Yogurts with lactobacillus (active yogurt cultures), cultured sour cream and fermented milk such as cultured buttermilk, acidophilus milk, and kefir have higher antioxidant properties. than plain milk.
Dark or colorful foods are a good source of antioxidants including blueberries, red grapes, and even red wine. (Note: This is not a definitive list of foods with antioxidants.) Try stirring fresh or frozen berries into plain yogurt.