Choose the fruit and vegetable varieties richest in health-promoting phytonutrients.
I’ve spent the past 10 years scouring scientific articles for information on the most nutritious fruit and vegetable varieties in our modern world. So far, I’ve pinpointed hundreds of stellar choices. The health benefits of eating these specific varieties range from lower risk of cardiovascular disease and cancer — the top two causes of death in the United States — to boosted energy and a more radiant complexion. You might even live longer. Studies suggest that eating the most nutritious varieties of fruits and vegetables may have a bigger impact on our health than how many fruits and vegetables we consume. For example, in a study published in the Journal of Nutrition in 2013, participants 65 years of age and older who consumed highly nutritious fruit and vegetable varieties during a 12-year period had a 30 percent lower mortality rate compared with those who consumed less-nutritious varieties.
Explore the list of 44 Super-Nutritious Varieties for Your Garden.
The reason some varieties of fruits and vegetables are more protective of our health than others, according to 21st-century science, is that they are rich sources of molecular compounds called “phytonutrients.” Phyto means “plant” in Greek, and plants produce phytonutrients to protect themselves from diseases, fungi, insects, harmful ultraviolet light, drought, and other threats. When we eat plants rich in phytonutrients, we receive health benefits, too — the plant’s self-protection becomes our protection.
Decades ago, the prevailing stance among nutritionists was that phytonutrients were of no benefit to human health. This old viewpoint has been flipped on its head, however, and some scientists, including Rui Hai Liu, a professor in the Department of Food Science at Cornell University, now maintain that the majority of the health benefits we get from eating fruits and vegetables come via their phytonutrient content — not from their more often-credited vitamins, minerals, and fiber.
You can find some phytonutrient-rich fruits and vegetables in supermarkets and farmers markets. Home gardeners are in an enviable position, though, because we can fill our plots with the most healthful varieties. Happily, because many of these choice plants are disease-resistant as well as nutritious, they’re often ideal for organic growing. One of my favorite examples of this is the ‘Liberty’ apple, which was released to the public in the 1970s by the New York State Agricultural Experiment Station. This apple has 2 to 3 times more phytonutrients than most supermarket varieties, and it’s crisp and juicy, with a good balance of sweet and tart. The ‘Liberty’ tree is also wonderfully productive and highly resistant to apple scab and fire blight, two destructive apple diseases. Last year, my ‘Fuji,’ ‘Gravenstein,’ and ‘Northern Spy’ apples were covered with scab, but the fruits on my ‘Liberty’ tree remained pristine.
Most phytonutrients are potent antioxidants, which help protect us from tiny particles called “free radicals.” We generate free radicals when we breathe, eat, exercise, fight disease, or are exposed to toxic substances. We can’t avoid free radicals, and, when kept in balance, they can be beneficial. In excess, however, they can turn a normal cell cancerous, promote chronic inflammation, contribute to the blockage of our arteries, or destroy vital neurons in the brain. Fortunately, phytonutrient-rich foods have such potent antioxidant activity that they can limit the damage free radicals cause.
Some phytonutrients do more than provide antioxidant protection, however. In a 2009 test-tube study published in the European Journal of Pharmaceutical Sciences, the phytonutrient quercetin, which is present in apples and onions, killed a flu virus more effectively than the prescription drug Tamiflu. The lycopene in tomatoes has been linked with an improvement in male fertility (International Urology and Nephrology, 2002). A number of phytonutrients, including the catechins in green tea and the flavanols in dark chocolate, have been shown to improve the way our cells handle insulin, which reduces the risk of obesity and diabetes.
Color is sometimes a clue indicating the phytonutrient content of fruits and vegetables. A few red-fleshed foods, including tomatoes, red papayas, and watermelons, contain lycopene. Most dark green leafy vegetables are rich in lutein, which supports eye health. Many phytonutrients are colorless, however, such as the quercetin in onions and apples.
The growing evidence that some varieties of fruits and vegetables provide far more health benefits than others do has far-reaching implications. In addition to choosing so-called “superfoods” for our diets — kale, garlic, pomegranates, and so on — we should be looking for “super varieties.” Spinach, for example, is widely regarded as a superfood. But which variety you choose matters. In a 2006 study from the Journal of Agricultural and Food Chemistry, half the participants were asked to eat five small servings of the ‘Spinner’ variety of spinach each week for three months. The other half consumed the same amount of the ‘Springer’ variety, which has fewer phytonutrients. Tests showed that those who consumed the higher-phytonutrient ‘Spinner’ had a reduced risk of macular degeneration, which is a leading cause of blindness in adults 65 years of age and older. The people who were given the low-phytonutrient variety received no such benefit.
How can you know which varieties to choose? In 44 Super-Nutritious Varieties for Your Garden, you’ll find a list of some of the most healthful fruit and vegetable varieties you can plant in your garden or orchard. Each has been tested for phytonutrient content by an independent lab, with the findings then published in well-regarded scientific journals. (I reference more than 100 additional varieties in my book Eating on the Wild Side, which is available at the Mother Earth Living store.) In addition to this list, let the following four general guidelines help steer your choices.
1. Heirloom isn’t always better. Modern agricultural trends have resulted in fruits and vegetables that are bigger, sweeter, more productive, and easier to store and transport. Unwittingly, these breeding processes have stripped crops of many phytonutrients. The classic, red-leaf Italian lettuce ‘Lollo Rosso,’ for instance, has 10 times more phytonutrients than green-leaf lettuce and 600 times more than modern iceberg lettuce.
Not all heirloom fruits and vegetables are richer in phytonutrients, though. A case in point is the ‘Sultana’ seedless grape, which grew in the Ottoman Empire hundreds of years ago, making it an ancient heirloom. Today it’s known as the ‘Thompson’ seedless grape, and it has become one of the most popular varieties in the United States. Lab studies show that some other grape varieties created within the past 50 years have up to five times more phytonutrients than ‘Thompson.’ Bottom line: Older heirlooms are not necessarily more healthful.
2. Choose small-sized varieties. Many seed catalogs highlight varieties that are “extra-large” or “gigantic.” You’ll see onions weighing more than 2 pounds, blueberries bigger than quarters, and “humongous” tomatoes that clock in at up to 3 pounds.
These super-sized foods are problematic for a number of reasons. First of all, they contain more water per ounce, which reduces their nutrient density and dilutes their flavor. Second, they have less skin per ounce, and phytonutrients are most concentrated in the skin of plants. The lower the skin-to-flesh ratio, the less pronounced the crop’s health benefits.
I’m a big fan of the small ‘Rubel’ blueberry. A 2001 study published in the Journal of Agricultural and Food Chemistry revealed that ‘Rubel’ packs more phytonutrients per ounce than 86 larger varieties of the same blueberry species. I don’t mind the extra time it takes to pick a pint, because the nutrient-dense berries have such a delicious, intense flavor.
3. Intense flavors are better. Compared with those of many other countries, the fruits and vegetables widely cultivated in the United States are relatively mild-tasting. Iceberg and romaine are two of our favorite lettuce types, whereas the Italians revel in radicchio and arugula — sharply flavored greens that contain far more antioxidants. Sweet and mild onions have become our most popular options, yet stronger-flavored yellow and red onions are more beneficial to our health.
The reason that bold is often better is that some of the most beneficial phytonutrients have a bitter, astringent, spicy, or tart flavor. We’ve bred these qualities out of much of our domestic produce at the same time that we’ve increased that produce’s sugar content. When choosing fruit and vegetable varieties for your garden, experiment with varieties that have more sass.
4. Choose red, purple, black, or blue fruits and vegetables. Varieties that fit this color scheme are rich in anthocyanins, a family of phytonutrients that has been linked to a broad range of health benefits. Anthocyanins have been shown to block inflammation, lower blood pressure, lower LDL (bad) cholesterol, and even help preserve memory in people with early-stage dementia. Anthocyanin-rich foods include most berries; red-skinned apples; red and black grapes; red cabbage; red onions; purple asparagus; purple broccoli; purple cauliflower; red, purple, and black sweet peppers; and red and black kale.
In the United States, we used to eat far more anthocyanin-rich berries than we do today. We now consume, on average, only 2 tablespoons of fresh berries per week. Knowing what I now know about phytonutrients, I live on berries. I grow blueberries, strawberries, raspberries, cranberries, marionberries, and a high-phytonutrient blackberry variety called ‘Wild Treasure.’ (Learn more about growing superberries in “Growing Superberries in Your Backyard.”)
Jo Robinson is a journalist who has spent years researching and growing extra-nutritious foods. Her book, Eating on the Wild Side, is available at the Mother Earth Living store.
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