In Greece, a health agency is in charge of dietary advice, and it recommends nine servings and fruits and vegetables a day, including wild greens. The 2005 US Dietary Guidelines recommend only 1/5 cup of dark green leafies a day for 9-13 year old kids; sadly only 1 in 500 kids eats even the equivalent of a single leaf of Romaine lettuce a day in the US. The First Lady’s Let’s Move campaign recently cited three healthy food categories in a contest: dark green and orange vegetables, whole grains, and dried beans and peas. These dark green and orange vegetables would count towards meeting the current USDA recommendation of a minimum of nine servings of fruits and veggies a day.
Greens, on the whole, are often considered the healthiest vegetables (see also here, here). Variety is important in a plant-based diet because different phytonutrients are found in different plants. These phytonutrients, when taken in supplement form, however, do not have the benefits associated with whole plant food consumption (such as reduced cancer risk). Many phytonutrients found in greens are fat soluble, which means the body needs some fat in order to better absorb them. And a combination of cooked and raw foods is probably the healthiest. Green tea is simply a dark green leafy steeped in water and a great addition to a healthy plant-based diet.
High consumption of cruciferous and green leafy vegetables has been linked to lower rates of cognitive decline. Heart rate variability may even be improved by dark green leafy vegetable consumption. Consuming at least one serving a month of kale or collard greens appears to reduce the risk of glaucoma by 69%; this is thought due to the phytonutrients lutein and zeaxanthin, which appear to not only protect but also improve our vision. Lutein and zeaxanthin also appear to be protective against cataracts and macular degeneration. A single serving of collard greens has 15,000mcg/serving, and kale has almost 24,000mcg/serving; one spoonful of spinach has as much as 9 eggs! Similarly, raw broccoli consumption has been linked to a higher rate of bladder cancer survival. Kale juice appears to increase good cholesterol in the blood and reduce bad cholesterol as well as dramatically increase the antioxidant level in the blood. Kale has also been found to boost the immune system, especially when cooked.
Fruits and vegetables (which contain fat soluble phytonutrients) help our bodies safely produce healthy nitric oxide from nitrates and avoid carcinogenic nitrosamine production (see also here, here). Green leafy vegetables are the best source of nitrates. Nitric oxide may play a role in the prevention of heart disease and high blood pressure.
Vegetables are also high in antioxidants. Beets and bell peppers have been found to be the highest in antioxidant content, ranking even higher than greens (such as kale) in recent tests. Herbs and spices are also incredibly high in antioxidants: marjoram, peppermint, lemon balm, and cloves are very rich.
Greens are also associated with larger bowel movements and increased physical attractiveness. Kale, for instance, increases antioxidant levels in the skin, which in turn has been found to increase attractiveness (see also here).
The calcium in dark green leafies is more effectively absorbed by the body than that found in cow’s milk. Folate in greens appears to be preferable to folic acid supplements. There is now a urine test that determines greens intake, which can help researchers more accurately measure it. Raw cruciferous vegetables each have a different safe upper limit for consumption.
See also the related blog post: Using Greens to Improve Athletic Performance
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