• Bell pepper is not only an excellent source of carotenoids, but also a source of over 30 different members of the carotenoid nutrient family. A recent study from Spain took a close look vitamin C, vitamin E, and six of these carotenoids (alpha-carotene, beta-carotene, lycopene, lutein, cryptoxanthin and zeaxanthin) in all commonly eaten foods and found that only two vegetables contained at least two-thirds of all the listed nutrients. One of these foods was tomato, and the other was sweet bell pepper! Bell pepper alone provided 12% of the total zeaxanthin found in the participants’ diets. (Bell pepper also provided 7% of the participants’ total vitamin C intake.)
• If you want to maximize the availability of vitamin C and carotenoids from bell pepper, allow this amazing vegetable to ripen. Recent studies have shown that the vitamin C content and the carotenoid content of bell pepper both increase with ripening. When the vitamin C and carotenoid content of bell peppers increases, so does their total antioxidant capacity, which can be a source of great health benefits. Growers can allow bell peppers to ripen on the plant prior to harvest (which means that you will be able to purchase them in the grocery store in a ripened state). Or, if harvested early in the ripening stage, bell peppers can still be allowed to ripen post-harvest and after you’ve purchased them and brought them home from the market. In one recent study, the vitamin C in not-fully-ripe bell peppers continued to increase during home storage over a period of about 10 days. It can, though, be difficult to tell whether a bell pepper is optimally ripe. Most–but not all–green bell peppers will turn red in color over time, but they may be optimally ripe before shifting over from green to red. A good rule of thumb is to judge less by their basic color and more by their color quality as well as overall texture and feel. Whether green, red, yellow, or orange, optimally ripe bell peppers will have deep, vivid colors, feel heavy for their size, and be firm enough to yield only slightly to pressure.
• Higher heat cooking can damage some of the delicate phytonutrients in bell peppers. In one recent study from Turkey, the effects of grilling on sweet green bell peppers were studied with respect to one particular phytonutrient–the flavonoid called luteolin. Prior to grilling, the bell peppers were found to contain about 46 milligrams/kilogram of this important antioxidant and anti-inflammatory flavonoid. After grilling for 7-8 minutes at a temperature of 150°C (302°F), about 40% of the luteolin was found to be destroyed. This loss of luteolin from higher heat cooking is one of the reasons we like cooking methods for bell peppers that use lower heat for a very short period of time.
• Although we tend to think about cruciferous vegetables like broccoli or allium vegetables like onions and garlic as vegetables that are richest in sulfur-containing compounds, bell peppers can also be valuable sources of health-supportive sulfur compounds. Several recent studies have taken a close look at the presence of enzymes in bell peppers called cysteine S-conjugate beta-lyases and their role in a sulfur-containing metabolic pathway called the thiomethyl shunt. These enzymes and this pathway may be involved in some of the anti-cancer benefits that bell pepper has shown in some animal and lab studies. They may serve as the basis for some of the anti-cancer benefits shown by green, yellow, red and orange vegetable intake in recent studies, including a recent study on risk reduction for gastric cancer and esophageal cancer.