Green beans, also known as French beans or snap beans, are tender, elongated, firm yet flexible edible pods of bean plant. The beans are one of the delight of vegetarian lovers for their wholesome nutritional properties. They are unripe or immature pods belonging within the common Fabaceae family, in the genus, vicia, and known scientifically as Phaseolus vulgaris. Broadly, tender green beans are classified depending on their growth habits as "bush beans" which stand erect without the need of support, and "Pole Beans" that need climb supports (trellis). The other varieties of unripe fruit pods of bean family include shell beans, Pinto or mottled beans, White beans, Red or kidney beans, Black beans, Pink beans and Yellow wax beans. Almost all the varieties of beans can be available year around across the world.
- Fresh green beans are very low in calories (31 calories per 100 g of raw bean pods) and contain no saturated fat. Nevertheless, these lean pod vegetables are a very good source of vitamins, minerals, and plant derived micronutrients.
- The beans are very rich source of dietary fiber (9% per 100g RDA) which acts as a bulk laxative. Fiber helps to protect mucosa in the colon by decreasing its exposure time to toxic substances as well as by binding to cancer-causing chemicals in the gut. Adequate amount of fiber has also been shown to reduce blood cholesterol levels by decreasing reabsorption of cholesterol-binding bile acids in the colon.
- Green beans contain excellent levels of vitamin A, and health promoting flavonoid poly phenolic antioxidants such as lutein, zea-xanthin and ß-carotene in good amounts. These compounds help act as protective scavengers against oxygen-derived free radicals and reactive oxygen species (ROS) that play a role in aging and various disease processes.
- Zea-xanthin, an important dietary carotenoid in the beans, selectively absorbed into the retinal macula lutea in the eyes where it thought to provide antioxidant and protective UV-light filtering functions. It is, therefore, green beans offer some protection in the prevention of age-related macular disease (ARMD) in the elderly.
- Snap beans are a good source of folates. 100 g fresh beans provide 37 µg or 9% of folates. Folate along with vitamin B-12 is one of the essential components of DNA synthesis and cell division. Good folate diet when given during preconception periods and during pregnancy may help prevent neural-tube defects in the newborn babies.
- They also carry good amounts of vitamin-B6 (pyridoxine), thiamin (vitamin B-1), and vitamin-C. Consumption of foods rich in vitamin C helps the body develop resistance against infectious agents and scavenge harmful oxygen-free radicals.
- In addition, beans contain healthy amounts of minerals like iron, calcium, magnesium, manganese, and potassium, which are very essential for body metabolism. Manganese is a co-factor for the antioxidant enzyme, superoxide dismutase, which is a very powerful free radical scavenger. Potassium is an important component of cell and body fluids that helps controlling heart rate and blood pressure.