Are baby greens more nutritious than mature greens? Where do microgreens fit in?
Baby-leaf greens are a staple in my fridge. They're just so darn convenient. Prewashed, bite-sized greens are ready to toss into a salad, blend into a smoothie or stir into a pasta sauce.
Of course, I'm a fan of their nutritional benefits, too.
There's no conclusive evidence that baby greens are better for you than their mature counterparts, but some research does suggest they outperform on certain nutrient scores. Tiny microgreens, however, seem to deliver a bigger nutritional bang.
Baby greens, such as baby spinach and baby kale, are harvested early, typically three to four weeks after planting, when the leaves are small, tender and have a milder taste. Mature greens, on the other hand, come from plants harvested four to six weeks after seeding.
Microgreens, younger than baby greens, are usually picked when they're one to three inches tall, seven to 14 days after germination. Some, though, may be harvested 21 days after growth begins.
Harvesting time for greens varies depending on the type of plant and the growing conditions (i.e., temperature, sun and rain).
If leafy greens, baby or otherwise, aren't a regular part of your diet, they should be. Their nutritional profile – and health benefits – are impressive, to say the least.
All leafy greens are excellent sources of vitamin C, bone-strengthening vitamin K, folate, calcium, magnesium and potassium. They also deliver plenty of beneficial phytochemicals including beta-carotene, lutein and flavonoids.
A steady intake of leafy greens has been tied to a lower risk of heart disease, stroke, Type 2 diabetes, hip fracture, cataract, macular degeneration and slower cognitive decline.
And thanks to a natural sugar in leafy greens called sulfoquinovose, eating them helps promote the growth of good, health-promoting bacteria in your gut.
Baby versus grown-up greens
Do baby greens, though, pack a stronger nutritional punch than their mature counterparts? This wasn't an easy question to answer. There are surprisingly few studies that address the question.
One study, published in 2005, found that the earlier baby spinach was harvested, the higher the content of disease-fighting flavonoids, suggesting that baby-leaf spinach delivers more of these compounds than mature spinach leaves.
Flavonoids, also found in apples, berries, red grapes, broccoli, tea and dark chocolate, act as antioxidants, decrease inflammation, inhibit the formation of blood clots and help keep arteries relaxed.
Other research suggests that baby greens (again, baby spinach was analyzed), have higher levels of vitamins C and K, folate, beta-carotene and lutein, a phytochemical that protect the eye's retina from free radical damage.
Even so, differences in the nutrient content between baby and mature greens are likely due to growing conditions, when they're harvested and how they're stored after harvest, factors that affect the synthesis and breakdown of nutrients and phytochemicals.
Once available only to chefs, teensy microgreens such as arugula, amaranth, cilantro, basil, pea tendrils, crimson chard, mustard and radish are now easier to find at farmer's markets and grocery stores.
According to a 2012 study published in the Journal of Agricultural and Food Chemistry, these young, tiny greens may have a nutritional edge over their older cousins.
The researchers tested 25 varieties of microgreens and found that, in general, they had considerably higher levels – about five times greater – of vitamins C, E and K, beta-carotene and lutein than their mature counterparts.
Red-cabbage microgreens, for example, had 40 times more vitamin E than mature red cabbage. Three ounces, about 2.5 to three cups, also supplied 147 mg of vitamin C, more than one day's worth.
Because microgreens are harvested very soon after germination, it's thought that the nutrients they need to grow are highly concentrated.
You probably won't make a salad consisting entirely of microgreens, though. They can be pricey. A 75-gram package (about two cups' worth) of micro arugula, for instance, cost me $6.99.
I use microgreens to add bright colour, flavour and texture to meals. I toss them into salads (made with baby greens or mature lettuces), add them to sandwiches and uses them as garnishes. And I love to top tacos with micro cilantro and garnish tomato salads with micro basil.
Eat your dark, leafy greens: arugula, beet greens, collards, kale, rapini, spinach, Swiss chard, Romaine and leaf lettuce and watercress all count.
Whether greens are grown to be mature-leaf, bite-sized or micro-sized, their unique combination – and concentration – of vitamins, minerals and disease-fighting phytochemicals can't be found in other vegetables.