Chew on this: 07/21

More than picking fresh vegetables

By Jayne Powers


Today, let’s shine a light on vegetables—literally.

Walk into any supermarket, and you may feel worried that the strong lighting causes harm to fresh vegetables in the produce section.

Don’t think that for a minute. While it may sound counterintuitive, the lighting that shines down on vegetables can actually increase their nutrient levels.

In a study conducted by the U.S. Department of Agriculture, researchers found that spinach leaves exposed to continuous light during storage were more nutritionally dense than leaves left in the dark.

They simulated the 24-hour artificial fluorescent lights used by grocery stores to conduct their experiment. Half of the spinach leaves were stored in clear plastic containers and exposed to light for three to nine days. The light replicated the exposure to spinach in packages found at the front of a grocery store display case.

The second group of spinach leaves was placed in two-layer-thick brown grocery-bag paper to represent the “dark treatment.”

After the experiment, the researchers found that the continuous light caused the leaves to synthesize more vitamin C, E, K and B9 or folate. There were also significant increases in levels of carotenoids, which are naturally occurring colorful antioxidant pigments, usually yellow to red, found widely in plants and associated with helping to prevent some forms of cancer.

The levels of folate and vitamin K, for example, rocketed as much as 100 percent after nine days, compared to the nutrients in spinach that were packaged in paper bags. Their nutrient values either declined or remained unchanged.

These findings should also apply to many other fresh leafy vegetables, provided they are kept cool and moist, according to The Wellness Supermarket Buying Guide, a publication of the University of California at Berkeley.

I use this guide with my clients, and I would highly recommend it because it enables you to shop smarter when confronted with an increasing and confusing array of food product choices.

If you’re in the mood to buy spinach or some other leafy vegetable to take advantage of their nutritional values, you’ll likely have other questions when preparing them.

A big one: Should I wash “pre-washed” bagged salad greens? The answer: Debatable.

While some experts say it is better to be safe and rewash them before you eat them, others argue that rewashing bagged greens could introduce other contaminants. After all, the facilities that they are processed in are more sanitary than the typical home kitchen, so why bother?

The wash or not-to-wash debate will be one of those controversial nutritional topics that will crop up from time to time. If you’re a washer, wouldn’t it be less expensive to just buy unwashed greens because pre-washed greens are typically more expensive to begin with?

Speaking of fresh vegetables, produce is most flavorful when it’s in season and grown locally. Now is the time to buy bell peppers, corn, cucumbers, eggplant, summer squash and tomatoes.

And, darker leaf colors are richer in nutrients. They’re packed with vitamins C and K, folate and fiber along with carotenoids. Buy Romaine lettuce over iceberg, for instance. There are many other choices as well: chard, mustard greens and now the omnipresent kale.

My tip on making kale more edible: Sprinkle some kosher salt on top of shredded leaves and add a tablespoon or two or olive oil. Massage the leaves with the salt, and it will begin to soften.

If the vegetables are pre-cut, such as carrots, celery and onions, make sure the supermarket sells them in a refrigerated section or immerses them in ice. Do the same when you get home as well.

Certainly, I hope that we all know by now that eating more vegetables is one of the cornerstones of a healthful diet. Don’t spoil it with the wrong dressing choice.

Salad dressings are typically high in fat and calories. Two tablespoons (and who measures?) will cost you at least 150 calories and provide 16 grams of fat in a single serving.

“Light” or “lite” dressings aren’t necessarily a smarter choice either. While there are fewer calories and less fat in them, you’ll get dosed with sodium—as much as 600 milligrams of sodium in a single serving.

Yes, that is a lot—about one-third to one-fourth of what you should consume a day.

That doesn’t make fat-free dressings an optimal choice, however. While they are the lowest in calories, you need some fat to help your body absorb all the good stuff in salad greens, namely the carotenoids.

You don’t need a lot of fat to do this. Sprinkling on a few nuts or seeds and cutting up some avocado will provide enough healthful fats to ensure that you won’t miss out on fueling your body with the nutritional value from your salad.

Jayne Powers, MA, is a certified nutritionist and personal fitness trainer based in Washington, DC. Her column, Chew on This, speaks from the science of the current state of knowledge about all facets of nutrition. Find her online at, or email your fitness questions to

Tags: , ,

Jayne Powers, MA, is a certified nutritionist and personal fitness trainer based in Washington, DC. Her column, Chew on This, speaks from the science of the current state of knowledge about all facets of nutrition. Find her online at

No comments yet.

Leave a Reply

Got an Opinion?


We are interested to hear what you think.  Please send us a message. [contact-form 4 “Opinion”]  

Yes, Flying Saucers Do Exist!

Allison Maddux (Scandal #5) layout bid against Kathryn Lawson (Riot #38). 2013 USA Ultimate Club National Championships Women's Semifinals

Please don’t call it Frisbee. Colorful flying plastic discs fill the air around this time of year, tossed from hand […]

Debate 7/10: You’ve got mail…for now!


Who in their wildest dreams thought Donald Trump could be a consensus builder? Certainly not me. Donald has done something […]

Bubbles to beat the brunch backlash


I casually peruse food articles, as you might guess. One emerging set of hot takes seems to revolve around brunch. […]

Jump, jive, and wail!


Since 1982, Muse Machine has been a staple of many lives in the Miami Valley. Over 76,000 lives, each year, […]

A Monument to Insurrection


Dayton Society of Artists’ special summer exhibit Alan Pocaro, The Distance Between Us When We Communicate (Detail) By Tim Smith […]