Wednesday, November 25, 2009

Healthy Choice: Green Beans

Health benefits of Green beans
■Fresh green beans are very low in calories (31 kcal per 100 g of raw beans) and contain no saturated fat; but are very good source of vitamins, minerals and plant derived micro-nutrients.

■They are very rich source of dietary fiber (9% per100g RDA) which acts as bulk laxative that helps to protect the mucous membrane of the colon by decreasing its exposure time to toxic substances as well as by binding to cancer causing chemicals in the colon. Dietary fiber has also been shown to reduce blood cholesterol levels by decreasing re-absorption of cholesterol binding bile acids in the colon.

■Green beans contain excellent levels of vitamin A, and many health promoting flavonoid poly phenolic antioxidants such as lutein, zeaxanthin and beta 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 process.

■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 light-filtering functions. Therefore, it is helpful in preventing age related macular disease (ARMD) of the eyes in old age.

■Fresh snap beans are good source of folates. Folates diet during preconception periods and during pregnancy helps prevent from neural-tube defects in the offsprings.

■It is also contain good amounts of vitamin-B6 (pyridoxine), thiamin (vitamin B-1), vitamin-C. Consumption of foods rich in vitamin C helps body develop resistance against infectious agents and scavenge harmful oxygen free radicals.

■They also contain good amounts of minerals like iron, calcium, magnesium, manganese and potassium which are very essential for body metabolism. Manganese is a co-factor for the enzyme superoxide dismutase, which is a very powerful free radical scavenger. Potassium is important component of cell and body fluids that helps controlling heart rate and blood pressure.

Green beans, while quite low in calories (just 43.75 calories in a whole cup), are loaded with enough nutrients to not only power up the Jolly Green Giant, but to put a big smile on his face. Green beans are an excellent source of vitamin C, vitamin K and manganese. Plus green beans are very good source of vitamin A (notably through their concentration of carotenoids including beta-carotene), dietary fiber, potassium, folate, and iron. And, green beans are a good source of magnesium, thiamin, riboflavin, copper, calcium, phosphorus, protein, omega-3 fatty acids and niacin.

Helping You Bone Up

The vitamin K provided by green beans-25% of the daily value in one cup-is important for maintaining strong bones. Vitamin K1 helps prevent excessive activation of osteoclasts, the cells responsible for breaking down bone. In addition, friendly bacteria in our intestines convert some K1 into K2, which activates osteocalcin, the major non-collagen protein in bone. Osteocalcin anchors calcium molecules inside of the bone.

Offer Cardiovascular Protection

For atherosclerosis and diabetic heart disease, few foods compare to green beans in their number of helpful nutrients. Green beans are a very good source of vitamin A, notably through their concentration of beta-carotene, and an excellent source of vitamin C. These two nutrients are important antioxidants that work to reduce the amounts of free radicals in the body, vitamin C as a water-soluble antioxidant and beta-carotene as a fat-soluble one. This water-and-fat-soluble antioxidant team helps to prevent cholesterol from becoming oxidized. Oxidized cholesterol is able to stick to and build up in blood vessel walls, where it can cause blocked arteries, heart attack or stroke. Getting plenty of beta-carotene and vitamin C can help prevent these complications, and a cup of green beans will provide you with 16.6% of the daily value for vitamin A along with 20.2% of the daily value for vitamin C.

Green beans are also a very good source of fiber, a very good source of potassium and folate, and a good source of magnesium and riboflavin. Each of these nutrients plays a significant cardio-protective role.

Magnesium and potassium work together to help lower high blood pressure, while folate is needed to convert a potentially dangerous molecule called homocysteine into other, benign molecules (the riboflavin in green beans may also serve to protect against the build up of homocysteine in certain individuals). Since homocysteine can directly damage blood vessel walls if not promptly converted, high levels are associated with a significantly increased risk of heart attack and stroke. Lastly, fiber, which is also found in green beans, has been shown to lower high cholesterol levels. A cup of green beans supplies 16.0% of the daily value for fiber, 10.7% of the DV for potassium, 7.8% of the DV for magnesium, and 10.4% of the DV for folate. What this all adds up to is a greatly reduced risk of atherosclerosis, diabetic heart disease, heart attack, and stroke.

Promotes Colon Health

Green beans may also help prevent colon cancer. The vitamin C and beta-carotene in green beans help to protect the colon cells from the damaging effects of free radicals. Green beans' folate helps to prevent DNA damage and mutations in colon cells, even when they are exposed to cancer-causing chemicals. Studies show that people who eat foods high in vitamin C, beta-carotene, and/or folate are at a much lower risk of getting colon cancer than those who don't.

Green beans' fiber can help prevent colon cancer as well, as it has the ability to bind to cancer-causing toxins, removing them from the body before they can harm colon cells.

Anti-Inflammatory Nutrients

Beta-carotene and vitamin C both also have very strong anti-inflammatory effects. This may make green beans helpful for reducing the severity of diseases where inflammation plays a major role, such as asthma, osteoarthritis, and rheumatoid arthritis.

Green beans are a good source of riboflavin, which has been shown to help reduce the frequency of migraine attacks in people who suffer from them. Riboflavin's protective role in energy production may explain why. The oxygen-containing molecules the body uses to produce energy can be highly reactive and can inadvertently cause damage the mitochondria and even the cells themselves. In the mitochondria, such damage is largely prevented by a small, protein-like molecule called glutathione. Like many "antioxidant" molecules, glutathione must be constantly recycled, and it is vitamin B2 that allows this recycling to take place. (Technically, vitamin B2 is a cofactor for the enzyme glutathione reductase that reduces the oxidized form of glutathione back to its reduced version.) A cup of green beans supplies 7.1% of the DV for riboflavin.

Iron for Energy

Green beans are a very good source of iron, an especially important mineral for menstruating women, who are more at risk for iron deficiency. Boosting iron stores with green beans is a good idea, especially because, in comparison to red meat, a well-known source of iron, green beans provide iron for a lot less calories and are totally fat-free. Iron is an integral component of hemoglobin, which transports oxygen from the lungs to all body cells, and is also part of key enzyme systems for energy production and metabolism. And, if you're pregnant or lactating, your needs for iron increase. Growing children and adolescents also have increased needs for iron. In one cup of green beans, you'll be provided with 8.9% of the daily value for iron.

Rich in Minerals for Energy and Antioxidant Protection

As noted above, green beans are a very good source of iron. Iron is as essential part of hemoglobin, a molecule essential to energy production since it is responsible for transporting and releasing oxygen throughout the body. But hemoglobin synthesis also relies on copper. Without copper, iron cannot be properly utilized in red blood cells. Fortunately, both minerals are supplied in green beans, which also contain 6.5% of the daily value for copper.

In addition to its role in hemoglobin synthesis, copper may be helpful in reducing the symptoms of rheumatoid arthritis. Copper, along with manganese (yet another trace mineral for which green beans are an excellent source), is an essential cofactor of a key oxidative enzyme called superoxide dismutase. Superoxide dismutase disarms free radicals produced within the mitochondria (the energy production factories within our cells). Copper is also necessary for the activity of lysyl oxidase, an enzyme involved in cross-linking collagen and elastin, both of which provide the ground substance and flexibility in blood vessels, bones and joints. One cup of green beans provides 18.5% of the DV for manganese.

Vitamins C, A and Zinc for Optimal Immune Function

Green beans' vitamin A (through its concentration of beta-carotene) and vitamin C are part of the sine qua non of a healthy immune system. Beta-carotene and vitamin A are fat-soluble antioxidants, while vitamin C functions as an antioxidant in the water-soluble areas of the body. So, between their beta-carotene and vitamin C content, green beans have all areas covered against damage from oxygen free radicals.

In addition to its antioxidant activity, vitamin C is critical for good immune function. Vitamin C stimulates white cells to fight infection, directly kills many bacteria and viruses, and regenerates vitamin E after it has been inactivated by disarming free radicals.

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