It has been long hailed that colorful vegetables are rich in antioxidants. They help stave off illness, as well as slow down aging. However, we can also add the not-so colorful variety such as portobellos and creminis. These varieties are rated as high as red peppers in antioxidant activity.
It is to be noted though, that button mushrooms are not as potent, although, they beat out tomatoes, green beans and carrots.
Bottom line: Experts recommend that we should eat a variety of mushrooms in addition to our other more colorful vegetables.