Swapping popular fruit and vegetables for their less common counterparts can greatly improve the healthiness of diets. Even if you already maintain a healthy diet, there are some simple switches that you can employ to greatly boost the average intake of phytonutrients-the substances in fruit and vegetables that help to protect the body from conditions such as heart disease and cancer. According to findings presented at the 2010 Experimental Biology conference in California, the data highlights the importance of "not only the quantity but also the significant impact the quality and variety of the fruits and vegetables you eat can have on your health."
The idea is that by swapping some of your staples, you increase the variety of crucial nutrients required for maximum health and longevity. Since variety is so important, I'd suggest not going for a 100 percent replacement-but as you can according to availability, locality and season.
Keep reading to learn the five "powerhouse" alternative foods the researchers suggest you get into your mix.
1. Sweet potatoes for carrots
One cup of cooked sweet potatoes provides 1,922 micrograms Retinol Activity Equivalents (mcg RAE) of beta carotene, double that of carrots, and 16 times that of broccoli. Sweet potatoes have four times the US Recommended Daily Allowance (USRDA) for beta-carotene when eaten with the skin on. Sweet potatoes are a welspring of vitamin E, and they are virtually fat-free, which makes them a superior Vitamin E source. (Most Vitamin E rich foods, such as vegetable oils, nuts and avocados, contain a hefty dose of fat.) Sweet potatoes provide many other essential nutrients including Vitamin B6, potassium and iron. They are virtually fat-free, cholesterol-free and very low in sodium. One cup (200 grams) of cooked sweet potatoes has 180 calories.
2. Kale for spinach
Kale has the highest antioxidant level per serving of any other fruit or vegetable. Kale has exceedingly high ORACs (Oxygen Radical Absorbance Capacity, the measure of a food's antioxidant level-the higher the ORACs, the more antioxidants the food has), and has about three times as much lutein as spinach. Eating the recommended five-a-day servings of fruits and vegetables will ring up around 1750 ORAC units, but several studies suggest that antioxidant intake be increased to between 3,000 and 5,000 ORAC units to have a significant impact on plasma and tissue antioxidant capacity. A serving of iceberg lettuce contains an ORAC value of 105, a serving of kale has a whopping 1770! Kale can be used in any recipe that calls for spinach.
3. Raspberries for strawberries
Raspberries possess almost 50 percent higher antioxidant activity than strawberries, three times that of kiwis, and ten times the antioxidant activity of tomatoes, according to research conducted in the Netherlands and published in the journal BioFactors. The biggest contribution to raspberries' antioxidant capacity is their ellagitannins, a family of compounds almost exclusive to the raspberry, which are reported to have anti-cancer activity.
4. Papaya for oranges
Papayas are an excellent source of Vitamins C and E and beta-carotene, three strong antioxidants. It has been ranked in the Top 5 fresh fruits (along with guava, watermelon, grapefruit and kiwifruit-well ahead of oranges, apple, and bananas), rated on six key nutrients: vitamin C, folate, potassium, iron, calcium, and fiber plus carotenoids.
Papayas are also rich in enzymes that stimulate stomach secretions and aid digestion. They contain protein-digesting enzymes including papain and chymopapain, and are low in fat and are a good source of fiber-they are also a very good source of calcium, potassium and Vitamins A and B.
5. Watercress for other greens
Watercress is a better source of vitamins C, B1, B6, K, E, Iron, Calcium, Magnesium, Manganese, Zinc, and Potassium than apples, broccoli, and tomatoes. By weight, watercress has more calcium than milk, more vitamin C than an orange and more absorbable iron than spinach (spinach is high in oxlactic acid, which blocks the natural absorption of iron). A single 4-ounce bunch of watercress has more than a full day's RDA for potassium.