Q. What's the difference between kefir and yogurt?
A. You can drink kefir as a beverage, but both kefir and yogurt make a great base for smoothies and cold fruit soups, or use them as a topping for cereal or fruit. Both are cultured dairy products that are often tolerated by people who can't consume milk due to lactose intolerance.
Kefir and yogurt provide probiotic cultures that are under study for a variety of potential health benefits. Yogurt's cultures are all bacteria, whereas kefir (pronounced kee-fur or ke-FEAR) is produced with a variety of bacterial cultures plus yeast, and it may provide larger amounts of these probiotic cultures.
Both kefir and yogurt are good sources of protein and calcium. Yogurt tends to be somewhat higher in calories and natural sugar than the same size serving of kefir.
However, the biggest difference in calorie content is not between these two products but between products made from milk differing in fat content and with different amounts of added sugar.
Both yogurt and kefir take significant calorie jumps when plain versions become "fruit" versions, which usually involve added sugar, too. Choose whichever has the taste and texture you like, keeping a watch on fat, sugar and calorie content.
Q. I've heard that strawberries have a lot of natural antioxidant compounds, but also that people can't really absorb them. What's the story?
A. Strawberries do contain multiple phytochemicals (natural plant compounds), including flavonoids such as anthocyanins (which provide the red color), catechins and quercetin, as well as ellagitannins and ellagic acid.
Research does suggest that our blood absorbs from the digestive tract only a small proportion of certain strawberry phytochemicals, including anthocyanins and ellagic acid. However, bacteria in our digestive tract may convert these compounds to others that our bodies do absorb.
For example, ellagitannins and ellagic acid are converted to urolithins, which can be absorbed and do seem to offer antioxidant, anti-inflammatory and direct anti-cancer effects. Further research is under way.
Meanwhile, strawberries are an excellent source of vitamin C. One cup provides enough to meet current recommendations for a whole day -- and we know that eating strawberries does increase blood levels of vitamin C and total antioxidants. Besides, strawberries are a good source of dietary fiber and allow us to eat a hunger-satisfying portion of something sweet with few calories. They definitely have a place as part of eating habits to promote good health.
• Provided by the American Institute of Cancer Research.