You can call them string beans, snap beans or green beans, but no matter which name you prefer, they’re all the same fat-free, low-calorie vegetable. The little beans tucked inside their edible pod are a good source of cholesterol-lowering fiber, but they’re an even better source of several vitamins that contribute to healthy eyes and bones.
The Better to See You With
Even though they don’t show it, string beans contain the same pigments that give vegetables their red, yellow and orange colors. These pigments, called carotenoids, all function as antioxidants, but some also fill other roles. String beans contain three carotenoids: beta-carotene, lutein and zeaxanthin. Beta-carotene is converted into retinol, which is the form of vitamin A essential for normal night vision. Lutein and zeaxanthin absorb blue light, which protects your eyes from damage caused by this high-intensity light. Carotenoids are included in the recommended dietary allowance for vitamin A. You’ll get 29 percent of your daily allowance from 1 cup of boiled string beans.
Vitamin K for Strong Bones
Without vitamin K, you could consume plenty of calcium and still have weak bones. Your body needs vitamin K to produce the proteins that help your bones take in calcium. It also regulates bone metabolism, which prevents the loss of minerals. These combined roles make vitamin K essential for maintaining bone density. Some vitamin K is made by bacteria in your gut, but not enough to meet your needs. Women should consume 90 micrograms of vitamin K daily, while men need 120 micrograms. One cup of boiled string beans contains 20 micrograms of vitamin K.
C is for Collagen
As an antioxidant, vitamin C neutralizes free radicals before they can damage healthy cells. In addition to guarding cells, vitamin C also protects proteins, fats, carbohydrates and DNA from free radicals. But you can thank vitamin C for more than antioxidant protection. Without an adequate supply of vitamin C, your body can’t make collagen. Lack of collagen translates into big problems for your body, because it’s the connective tissue used to support and strengthen your skin, bones, tendons and organs. One cup of boiled string beans contains about 13 percent of your recommended daily allowance of vitamin C.
Spice It Up
Add some spice to your string beans by mixing them with chili paste, red pepper flakes and sesame oil. Roast string beans with onions and top them with sunflower seeds. Steam them until they’re barely tender, and toss them with dried cranberries, walnuts and a touch of balsamic vinegar. Stir-fry string beans with any of your favorite vegetables, add tomatoes and serve over brown rice. While you can substitute canned or frozen string beans, they lose some vitamins during processing. Be sure to buy salt-free canned string beans and don't add salt to the cooking water or you can end up with one-fourth of an entire day's recommended sodium in just one serving.
- Cook’s Thesaurus: Snap Beans
- Linus Pauling Institute: Carotenoids
- Linus Pauling Institute: Vitamin A
- Bastyr University: Vitamin K for Bone Health
- USDA National Nutrient Database for Standard Reference: Beans, Snap, Green, Cooked, Boiled, Drained, Without Salt
- USDA National Nutrient Database for Standard Reference: Beans, Snap, Green, Frozen, Cooked, Boiled, Drained, With Salt
- USDA National Nutrient Database for Standard Reference: Beans, Snap, Green, Canned, Regular Pack, Drained Solids
- Linus Pauling Institute: Vitamin C
- RCSB Protein Data Bank: Collagen