Red

At the moment I'm trying to include one cup of red fruit or vegetables in my diet each day.

According to this source, red fruits and vegetables contain nutrients such as lycopene, ellagic acid, Quercetin, and Hesperidin, to name a few. These nutrients reduce the risk of prostate cancer, lower blood pressure, reduce tumor growth and LDL cholesterol levels, scavenge harmful free-radicals, and support join tissue in arthritis cases.

Some examples:
Beets
Blood oranges
Cherries
Cranberries
Guava
Papaya
Pink grapefruit
Pomegranates
Radicchio
Radishes
Raspberries
Red apples
Red capsicums
Red chilli peppers
Red grapes
Red onions
Red pears
Red peppers
Red potatoes
Rhubarb
Strawberries
Tomatoes
Watermelon

link