Q. Awhile back your newsletter reported the effect of whey and casein found on nutrient absorption from blueberries. Do dairy products have the same negative effect on the benefits of colorful fruits and vegetables like tomatoes, peppers, peaches, cantaloupes, spinach, peas, corn, etc.?
A. Jeffrey B. Blumberg, PhD, Tufts professor and senior scientist at the HNRCA Antioxidants Research Laboratory, answers: "The casein and whey proteins found in dairy products may bind with some flavonoids and related polyphenols, although most experimental studies and a very few human studies have examined the almost infinite number of combinations of interactions among the variety of available fruits and vegetables. Importantly, the extent to which these interactions might affect the absorption of these bioactives is dependent on the ratio of the proteins to the phytonutrients, the complex matrices of the dairy product and the plant food, and several variables associated with cooking. It's doubtful that a dollop of sour cream on top of a soup rich in vegetables will have much of an untoward affect - but it will provide a big benefit if it entices you to eat such a nutritious dish."