Ask Dr. K: Did you know berries are powerhouses of nutrition?

Berries are perhaps the easiest way to follow the fruit part of the “eat more fruit and vegetables” advice you hear all the time, including from me. Berries naturally come in bite-sized portions. They’re sweet but have a nice low calorie count, partly because they contain a lot of water. If you don’t need to watch your calories — yes, there are people who are born thin — you can “pig out” on them. (Just don’t sprinkle much sugar on them.)

Berries contain vitamins (C and a little bit of E, because of the seeds) and some lesser-known nutrients. But they also, somewhat surprisingly, contain a fair amount of fiber. A cup of raspberries contains 8 grams of fiber, which is more fiber than you’ll find in a serving of oatmeal.

But what makes berries stand out nutritionally (and visually) are substances called anthocyanins. These substances give berries their vivid red, blue and purplish colors. Anthocyanins are antioxidants, which keep oxygen ions and other unstable molecules from damaging DNA, messing with cells’ energy-making machinery, stirring up inflammation in the body and having a variety of other harmful effects.

Vitamin supplements with antioxidants in them have generally not been proven to benefit your health as many had hoped. However, there’s still a lot of evidence that antioxidants are good for you, and foods that naturally contain antioxidants are thought to promote better health.

Anthocyanins are concentrated in the skin of berries (as well as other fruits). In general, the more intense the color, the higher the anthocyanin content. So blueberries and blackberries usually contain more anthocyanins than strawberries or raspberries. And wild berries have more antioxidants than their larger, paler, domesticated relations. Raspberries also contain a substance called ellagitannin, which imparts flavor and has antioxidant properties that add to the effects of anthocyanins.

Be sure to wash your berries right before eating them. Berries can harbor viruses, bacteria and other pathogens that cause foodborne illnesses.

For me, the best way to start a day is with a bowl of fresh, delicious berries. In fact, that’s what I had for breakfast today — with toast and coffee.

I have a patient who is very knowledgeable about food and reportedly a good cook. She once chastised me for writing about how healthy certain foods were. “The point you should be emphasizing is that they are delicious, because they are. The fact that they’re also healthy is the icing on the cake.” She’s right. And berries are healthier than the icing on the cake.

Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.