7 Health-Boosting Food Pairings

In addition to being loaded with vitamin C, broccoli and tomatoes are also prime sources of beta-carotene, which further strengthens your immune system. But you must consume beta-carotene with fat for it to be well absorbed. That's where olive oil comes in. According to a recent study, adding just 1/2 teaspoon of monounsaturated fat (the good fat in olive oil) allows the body to get five times more beta-carotene from the vegetables you eat.

Tip: Steam your veggies for immune-enhancing benefits. Heat loosens beta-carotene from the vegetables' cells, so you soak up even more of it.