If you think of leafy greens and why they are good for you, what comes to mind? I recently did an informal poll asking what draws you to eating leafy greens. A wide variety of answers came back: “Maybe the green chlorophyll gets into my body?” “The satisfying crunchiness and taste, especially with a good dressing.” “The vitamin K and fiber.” “The dark green color just looks so fresh; it just feels like my body would enjoy that.” Clearly, people believe that leafy greens offer health benefits and tasty appeal, but the benefits don’t stop there. Let’s delve a bit deeper.
“Leafy greens” are vegetables that are both leafy and traditionally green, though sometimes red or purple. The domesticated varieties include lettuce, kale, bok choy, arugula, turnip greens, collard, mustard, senposai and other Asian stir-fry greens, among many others. Wild greens exist, too, and are very important to health (see below). They are not a good source of protein, fat, or carbohydrate. Why eat them? They are a wonderful source of micronutrients, antioxidants, and phytonutrients (plant pigments that have health benefits) while also being high in fiber and low in calories. They are a good source of vitamins, including vitamin C, folate, and vitamin K. They contain the minerals calcium, magnesium, iron, and potassium, all important for health. They are high in carotenoids, which are antioxidants that protect cells and have anti-cancer properties.
Compared to domesticated varieties, wild greens are much more nutritious. They also tend to be more bitter. Lambs quarters and dandelion greens are great examples of this. They were widely consumed by our hunter-gatherer ancestors as well as the Native Americans. Lambs quarters are high in phytonutrients, are anti-viral/anti-bacterial, and they have cancer-fighting properties. When compared to spinach, dandelion greens have eight times more antioxidants, twice as much calcium, as well as more carotenoids, Vitamins K, and E. Greens that have a more intense flavor – bitter, astringent, sour, or spicy – have the most nutritional value. Many modern plants have been bred to be sweeter and less bitter, which unfortunately led to a loss of nutrients as well. Calcium, for example, tastes bitter and is found in lesser quantities in domesticated plants compared to wild plants.
While wild greens reign supreme, all greens have health benefits. Phytonutrients especially are a major powerhouse of nutrition. Lutein, for example, is found in dark green vegetables and is best known for protecting eye health. It also acts as an anti-inflammatory and may have anti-aging properties. Anthocyanins are another phytonutrient that gives fruits and vegetables a reddish, purplish, or brownish hue. They show promise in fighting cancer, maintaining brain health, and regulating blood pressure. Many varieties of leafy greens actually come in these colors. They may be harder to find at the grocery store, but farmer’s markets and seed catalogs for growing your own are good sources. While all phytonutrients have nutritional benefits, the general rule is the darker the color, the better. There is also a hierarchy from most nutritious to less: red/purple, green with red or purple tones, dark green, and light green. All of the above have benefits, but it is still nice to know which ones pack a more powerful punch.
Aside from color, growing habit is also an indicator of quality. In terms of lettuce, varieties that are looser and more spreading, such as loose leaf, are more nutritious. The looser the leaves are, the more exposed to the sun they are. This propels them to produce a botanical sunscreen, which is made of pigmented antioxidants, or phytochemicals. On the other hand, the phytonutrient content of lettuce with tightly wrapped leaves is much lower, such as iceberg. Even the phytonutrients of leaves within one plant can vary greatly depending on whether they are on the outside or inside of the plant.
The longer greens sit after harvest, the fewer nutrients they contain. Arugula has a shorter shelf life than most greens. After just one week, spinach leaves have half their antioxidant value than they had at harvest. Choose greens that are still vibrant and perky, with no signs of wilting or discoloration. When choosing pre-packaged greens, choose the ones with a use-by date furthest in the future.
Once you get home, soak the greens in cold water for ten minutes. Pat dry or use a salad spinner to dry. To maximize the freshness of your greens, place them in a sealable plastic bag. Let as much air out of the bag as you can. Use a pin to prick ten to twenty evenly spaced holes in the bag. This will allow them to continue to “breathe,” keeping it fresh and preserving its vital nutrients. Keep the bag in the crisper drawer of your refrigerator.
Some greens are best raw, while others do best with cooking. Lettuces, arugula, and mustard are well suited to salads. To get the most nutrients out of it, make sure your dressing contains some fat. Fat aids in nutrient absorption of certain compounds. Use a homemade dressing with extra-virgin, preferably unfiltered, olive oil. Add some citrus, which increases iron absorption. Other greens like bok choy, kale, and collards are often eaten cooked. Steaming, stir-frying, and braising are good options. You can also bake greens individually (like kale chips) or in dishes like casseroles or quiches. Greens taste great in soups, and they can also be dehydrated to make veggie “chips” or camping fare. Avoid boiling, which leaches nutrients into the water. Adding fruits, dried or fresh, as well as honey and mustard to dressings also help to dampen bitter or assertive flavors, which is a plus when introducing robust greens to those who tend to shy away from their intense flavors.
The information provided in this article is intended for general use only and is not to be used in place of medical advice from a licensed health professional.