Health benefits of dark green, leafy veggiesDark green, leafy vegetables are great sources of nutrition. Salad greens, kale and spinach are rich in vitamins A, C, E and K, and broccoli, bok choy and mustard are also rich in many B vitamins.
By: Dr. Lin Yan, Grand Forks Herald
People have been eating leafy greens since prehistoric times. But it wasn’t until the first Africans arrived in North America in the early 1600s that America got its first real taste of dark green leafy vegetables, which they grew for themselves and their families. So, over the years, cooked greens developed into a traditional African American food. Ultimately, they became essential in Southern regional diets and are now enjoyed nationwide.
Dark green, leafy vegetables are great sources of nutrition. Salad greens, kale and spinach are rich in vitamins A, C, E and K, and broccoli, bok choy and mustard are also rich in many B vitamins. These vegetables also contain an abundance of carotenoids — antioxidants that protect cells and play roles in blocking the early stages of cancer. They also contain high levels of fiber, iron, magnesium, potassium and calcium. Furthermore, greens have very little carbohydrates, sodium and cholesterol.
The dark greens supply a significant amount of folate, a B vitamin that promotes heart health and helps prevent certain birth defects. Folate is also necessary for DNA duplication and repair which protects against the development of cancer. Several large studies have shown that high intakes of folate may lower the risk of colon polyps by 30 to 40 percent compared to low intakes of this vitamin. Other research suggests that diets low in folate may increase the risk of cancers of the breast, cervix and lung.
Studies have shown that eating 2 to 3 servings of green leafy vegetables per week may lower the risk of stomach, breast and skin cancer. These same antioxidants have also been proven to decrease the risk of heart disease.
The vitamin K contents of dark green leafy vegetables provide a number of health benefits including: protecting bones from osteoporosis and helping to prevent against inflammatory diseases.
Perhaps one of the most appealing benefits of dark green leafy vegetables is their low calorie and carbohydrate contents and their low glycemic index. These features make them an ideal food to facilitate achieving and maintaining a healthy body weight. Adding more green vegetables to a balanced diet increases the intake of dietary fiber which, in turn, regulates the digestive system and aids in bowel health and weight management. These properties are particularly advantageous for those with type-2 diabetes.
The Dietary Guidelines for Americans recommend increasing average intakes of fruits and vegetables, particularly those that provide more vitamins, minerals and fiber. Dark, leafy greens fulfill this need. Many varieties of greens are available in the American markets — the most popular are collards, mustard greens, turnip greens, chard, spinach and kale.
Eating dark green, leafy vegetables is vital to a healthy, balanced diet. There are many ways to enjoy a meal with leafy greens:
• Make a salad: Keep salads interesting by varying colors, textures and varieties. Perk them up with small tender leafy greens such as romaine lettuce, spinach and arugula mixed with different kinds of tomatoes, cucumbers and carrots.
• Wrap it up: Make a wrap with tuna, chicken or turkey and add romaine lettuce, spinach, arugula and other veggies for some extra flavor.
• Add to soup: Add greens with larger, tougher leaves such as collard greens, kale or mustard greens into your favorite soup.
• Stir-fry: Add chopped spinach, bok choy or broccoli to chicken or tofu stir-fried with olive or canola oil with some garlic, onion or ginger.
• Steamed: Steaming collard greens, mustard greens, kale or spinach until they are slightly soft.
• In an omelet: Add steamed broccoli and/or spinach to an egg-white omelet for a vitamin and iron rich meal.
Dr. Yan earned his doctoral degree in Human Nutrition at Texas Tech University. Dr. Yan completed his post-doctoral training in the area of selenium and cancer biology at Rutgers University. Dr. Yan conducts research in the area of diet, physical exercise and cancer prevention. Dr. Yan currently investigates the roles of dietary modification (e.g. energy balance or selenium supplementation) and physical exercise in the prevention of obesity-enhanced secondary tumor development and growth in animal models. Furthermore, Dr. Yan conducts meta-analysis of epidemiologic studies to assess soy consumption in association with cancer risk in human populations.