I’ve spent the past 10 years combing through scientific studies for little-known, but important nutritional information about fruits and vegetables. I’ve discovered a great deal of valuable research that has yet to filter down to consumers.
Some of the findings are surprising — and incredibly easy to put to use. Who would have thought you could double the amount of antioxidants in lettuce simply by tearing it into bite-sized pieces a day or so before you eat it? Or that you’ll get even more of the bionutrient lycopene from a watermelon if you leave the melon on the kitchen counter rather than storing it in your refrigerator?
You may need to learn a few new tricks and change some habits, but you’ll be well-rewarded for your effort in the form of boosted flavor and better health. Plus, you don’t have to spend any extra time or money. Here are 10 nutrition tips to take full advantage of all the health benefits fresh produce has to offer. We’ve created a Top Nutrition Tips sheet that you can print or download for easy reference. Pin it to your fridge!
1. Eat Heavy Breathers With a High Rate of Respiration First
Most people assume that fresh fruits and vegetables “die” after they’ve been harvested. Not so. They continue to respire, or “breathe,” even when stored in the depths of your refrigerator. (They’re alive!) When they respire, they absorb oxygen and release carbon dioxide. To fuel this activity, they begin to use up their stores of natural sugars and antioxidants, so by the time you eat them, they will have lost some of their natural sweetness, become more acidic and contain fewer antioxidants.
Some fruits and vegetables respire more quickly than others — I call these “heavy breathers.” These are the foods you should aim to eat as soon as possible after you harvest them or bring them home from the market. Foods that fall into this category include artichokes, arugula, asparagus, broccoli, Brussels sprouts, cherries, corn, kale, lettuce, mushrooms, okra, parsley, raspberries, scallions, snap beans, spinach and strawberries.
2. Fresh and Picked Ripe
Soft vegetables and fruits, such as berries, will provide incomparable flavor and nutrition if grown at home or bought from a local farmer. These foods are easily damaged during mechanical harvest, shipping and storage, so the commercial food industry has found a work-around: harvesting them before they’re ripe. Tomatoes, strawberries, nectarines and peaches are picked while still green so they can arrive in stores unblemished. The problem is that these fruits never develop the full flavor of those that ripen in the field. What you can’t see or taste is that they have fewer nutrients as well.
Berries are naturals for the home garden because they’re delicate and can spoil in a matter of days. Treat yourself to a feast of flavors by growing these at home or embarking on a “U-pick” session at a local farm.
3. Taste the Rainbow: Blue, Red and Purple Vegetables
So-called “novelty” vegetables, such as blue potatoes, purple cauliflower and red carrots, are beginning to show up more often in supermarkets, farmers markets and seed catalogs. I’ve discovered that these are actually the original colors of these vegetables. Throughout the centuries, we’ve bred out the rich hues in favor of white, green and orange. Unwittingly, when we got rid of the blue, purple and red, we were casting away anthocyanins — potent antioxidants that may reduce the risk of cancer, cardiovascular disease, obesity, diabetes and memory loss.
Reclaim these benefits by buying deeply colored fruits and vegetables at the market or growing them in your garden. Our meals should be a riot of colors!
4. How to Harvest Greens: Chill Out
Commercial growers know produce stays fresher longer if it’s chilled right after harvest. Some fruits and vegetables get covered with ice before they leave the field. We would do well to follow that example. Rather than leaving a basket of freshly harvested lettuce or kale sitting on your back porch, bring it in, dunk the greens in ice water, dry them off, and store them in the crisper drawer of your refrigerator.
The same applies to food you bring home from the market. That meat and dairy must be refrigerated ASAP is a well-known fact of food handling, but the heat in a car can also spur the growth of potentially deadly bacteria on fresh produce, and cause the food to lose flavor and nutritional value. Make a habit of shopping for food after you’ve completed all of your other errands. Take along an ice chest if you have a long journey home.
5. Make Mine Crunchy
Asparagus, broccoli, Brussels sprouts and cabbage should be cooked lightly. If they cook for more than five minutes, their natural sweetness disappears, and “off” flavors and sulfurous fumes begin to develop. Most people overcook these vegetables, which is one of the reasons so many people dislike them. To shorten the cooking time, chop the vegetables into smaller pieces. For instance, follow these steps to perfectly steam broccoli: Cut the broccoli into egg-sized clumps and arrange them stem-side-down in a steamer basket over a pot of boiling water. Put on the lid, and set a timer for four minutes. As soon as the timer rings, take off the lid, remove the broccoli from the heat and arrange it in a serving dish. The broccoli will be vibrantly green, a bit crunchy, rich in cancer-fighting bionutrients and oh-so-sweet!
6. Health Benefits From Garlic
To get the biggest health boost from garlic, chop it, slice it or press it, and then let it rest for 10 minutes on your cutting board. Here’s why: Allicin is the main healing ingredient in garlic, and this healthful nutrient forms when two compounds in the clove mingle together. This mingling happens when we bite, chop, slice or press garlic. The reaction of allicin in garlic takes about 10 minutes to complete, but it stops short if you expose the garlic to heat before the time has elapsed. Setting the garlic aside for 10 minutes ensures you get some of the famous medicine garlic has to offer.
7. Smaller May Be Better
Open a seed catalog, and you’ll see fruits and vegetables touted as “extra-large,” “gigantic” and “big enough to fill your plate.” Neighborhood bragging rights typically come from growing the biggest fruits and vegetables on the block, but new research shows that smaller varieties may be more nutritious. This is especially true for tomatoes: The smaller and darker red the tomato, the more lycopene it has per ounce. Small tomatoes are also higher in sugar and have a more intense “tomato” flavor than slicing or beefsteak varieties.
Make your next sauce or salsa out of red cherry or grape tomatoes for a delightful taste and extra health protection. (Yellow cherry tomatoes have no lycopene and are so low in acidity that they can result in a sauce with lackluster flavor.)
8. Onion Nutrition
Use sweet onions — which give you only about one-third of the antioxidant benefits provided by more robust red and yellow varieties — for salads, sandwiches and other foods you eat raw. Use hotter, more pungent onion varieties in all other foods. If you cook them for just five minutes, they will become sweet and mild without losing any nutrients.
Red onions can be either sweet or hot. You can tell them apart at a glance because the hotter ones are oval or round while the milder, “hamburger” onions are flat and wide. ‘Red Baron’ is a small variety with vibrant burgundy bulbs that are extra-high in antioxidants. Yellow onions come in sweet and hot varieties as well, but they can look exactly the same. To identify the milder ones, look for the word “sweet” on the label. ‘Western Yellow’ and ‘New York Bold’ are good pungent yellow varieties.
Scallions (or green onions) are better for your health than full-sized bulbing onions, because the green part of the vegetable is more nutritious than the white bulb. The same is true for leeks.
9. Leaf Lettuce Rules
Of the four main types of lettuce — leaf lettuce, crisphead (iceberg and the like), romaine and bibb — leaf lettuce is the most nutritious. The reason has to do with the arrangement of its leaves. The sun is essential for plant growth, but it also emits damaging UV rays. Plants protect themselves from the harmful part of the sun’s spectrum by creating a chemical sunscreen in shades of red, purple or reddish brown. When we eat the plants, those same chemicals go to work protecting us from UV light and diseases that result from UV exposure. The plant’s protection becomes our protection. Leaf lettuce has most of its leaves open and arrayed to the sun, which makes it highly vulnerable to damage from UV light. To survive, it creates a high concentration of protective chemicals.
Tightly wrapped crisphead lettuce is the opposite, with only the outermost leaves exposed to the sun. Sheltered inner leaves have only 1 percent of the antioxidants found in leaf lettuce. Bibb and romaine lettuces expose some outer leaves to the sun but have encased inner leaves. In terms of nutrition, these lettuce types are midway between leaf lettuce and crisphead varieties. Red leaf varieties are the healthiest of all, because they are rich in anthocyanins.
10. Check the Stems
Grapes and cherries sold in supermarkets are sometimes weeks old, yet they still look fresh. To determine their true age — and thus their health potential — look at the stems, not the fruit. Fresh grapes and cherries have bright green, flexible stems. If they’ve been stored for weeks, the stems will have turned brown and started to wither. I’ve seen grapes in the supermarket that were so old their stems were brittle and almost black. Needless to say, I walked on by.
Top Nutrition Tips to Boost Flavor
Adapted from the book Eating on the Wild Side: The Missing Link to Optimum Health by Jo Robinson
How to Harvest Greens
• Tear lettuce into bite-sized pieces a day or so before you eat it to double the amount of antioxidants.
• Right after harvest, dunk greens such as lettuce and kale in ice water and store immediately in the crisper drawer of your fridge.
• Leaf lettuce is the most nutritious lettuce type. Red leaf lettuce is the best.
• Store watermelon on the kitchen counter rather than in the refrigerator.
• Blackberries, blueberries, nectarines, peaches, raspberries and strawberries should be grown at home or purchased locally.
• Choose grapes and cherries that have bright green, flexible stems; older fruits have brown stems.
• Scallions and leeks are better for your health than full-sized bulb onions, because the green parts are more nutritious than the white parts.
• Choose pungent, robust varieties of yellow and red onions for all cooking.
• Before you expose it to heat, let garlic rest for 10 minutes after chopping, slicing or pressing it.
• Grow tomatoes at home or get them locally to ensure they’ll be picked when ripe.
• Choose smaller and more darkly colored varieties.
• Eat these “heavy breathers” first: artichokes, arugula, asparagus, broccoli, Brussels sprouts, cherries, corn, kale, lettuce, mushrooms, okra, parsley, raspberries, scallions, snap beans, spinach and strawberries.
• Grow or look for blue potatoes; purple cauliflower and broccoli; and red, yellow and purple carrots.
• Always cook asparagus, broccoli, Brussels sprouts and cabbage less than five minutes, if at all.
Jo Robinson is the author of Eating on the Wild Side: The Missing Link to Optimum Health. The book is packed with advice — much of it presented to the public for the first time — about the best ways to select, grow, store, process, and cook fresh fruits and vegetables. Purchase your copy by September 30, 2013, and receive a 25 percent discount; see our store to order. Robinson lives on Vashon Island, Wash., where she grows many of the nutrient-packed foods she writes about.