The top four vegetables all come from two botanical power families, the Brassicaceae and Amaranthaceae families. Brassicas are also known as cruciferous vegetables, including broccoli and cauliflower.
Erica Browne Grivas
The Center for Disease Control has evaluated the most nutrient-dense, bioavailable fruits and vegetables, and the winner may surprise you.
The Method
The CDC studied 47 fruits and vegetables to identify “powerhouse fruits and vegetables” offering the most bang for your nutritional buck. Nutrient density is measured relative to a food’s caloric content, pound per pound. The study looked at 17 essential nutrients, including protein, fiber, potassium, calcium, iron, vitamins A, B6, C, E, and K in 100 grams of the food. In other words, these foods are low in calories, but high in nutritional value. Bioavailability means the how easily the body can digest and use these nutrients.
Greens for the Win
The top four vegetables all come from two botanical power families, the Brassicaceae and Amaranthaceae families. Brassicas are also known as cruciferous vegetables, including broccoli and cauliflower, and Amaranths include powerbowl fave quinoa, none of which made the top five. The surprising winner is watercress, a green with round, small leaves often eaten in cucumber sandwiches in British tea rooms.
We’ve all been told at some point to “Eat your greens,” but like “take the stairs,” it tends to be one of those things that falls by the wayside when time gets tight. Unless you are growing your own greens (more on that later), adding them to your meals takes both forethought and discipline, i.e., you need to remember to buy some on Sunday, and eat them by Wednesday. It’s easy to skip the greens in our busy routines. Pre-prepared meals, whether an on-the-go sandwich or frozen mac-n-cheese, skew carb-heavy with few leafy greens in sight.
The perfunctory slice of iceberg lettuce on your burger or sub isn’t adding much in the way of nutrients. While watercress nabbed an amazing 100 out of 100, meaning it supplied 100% of the daily value of the measured nutrients per 100 calories, iceberg lettuce scored only 18.28.
Cultivating Watercress at Home
This perennial native to Asia, Europe and Northern Africa, hardy within USDA zones 3a-11b, is easily grown in soil with consistent moisture. Its favored location is at a pond edge in dappled shade. They like a richer soil so a higher-nitrogen fertilizer may help it keep producing new leaves. Protected from freezing temperatures, you may be able to harvest it year-round outdoors in Seattle. In fact, while not declared a noxious weed, it has been on the Monitor List of Washington’s Noxious Weed Board since 2012.
To give watercress the water it wants, some create mini ponds in 5-gallon buckets. It can also be grown inside. You can root mature plants from the farmer’s market in a jar with water or grow them from seed as microgreens to boost your winter nutrition. The leaves can turn bitter after flowering, so it’s best to snip flowers as they appear.
Erica Browne Grivas
Runners-upIn order, the next most nutritious plants, also greens, were Chinese cabbage (all subspecies of Brassica rapa including Napa, bok choy/pak choi, and Tatsoi) with a score of 91.99, Chard with 89.27, Beet greens with 87.08, and Popeye’s go-to Spinach, with 86.43.
According to a report on the findings in “Food and Wine,” these pack a wallop of vitamins A, E, K, and C, as well as essential minerals like calcium, magnesium, and iron. Interestingly, baby bok choy has more nutrition relative to standard bok choy.
All of these are considered “cool season” annual vegetables in the outdoor garden, meaning they prefer growing in early spring or fall. High temperatures will often scorch the leaves or make them bolt prematurely. Shade them with frost cloth if an inconvenient heat wave is approaching.
Indoors, they are all easily grown as microgreens, which concentrate even more nutrients in the seedling stage, making them great additions to sandwiches, soups, salads and smoothies.
These five greens may deliver the biggest nutritional bang per portion, but don’t discount the plants with lower scores. Kale, which has quite a good PR campaign going, despite its bitter taste and tough leaves, only earned 49.07 – just above dandelion greens.
There are some great foods on this list that didn’t make the grade as a “powerhouse fruit or vegetable” (PFV) but offer many other benefits, from fiber to amino acids and micronutrients. For instance, the allium family, including garlic, onion, and leeks, are known as beneficial prebiotics (fiber feeding helpful probiotic microorganisms in your gut). Also, among crucifers, broccoli provides a lot more fiber than watercress.
Roughly speaking, within the nutritional rainbow, the study notes that greens (both cruciferous and leafy) scored higher than orange/yellows and berries.
Among the few fruits studied, tomato (botanically some fruit) scored highest at 20.37, followed by lemon, strawberry, orange, lime, pink grapefruit, blackberry and white grapefruit (the lowest of all the foods studied) at 10.47. Raspberry, tangerine, blueberry, and cranberry scored below “powerhouse” level.
The U.S. Department of Agriculture recommends a goal of three to five servings of vegetables and two to four of fruit daily. For a balanced diet (and gut), eat your rainbow, but remember the greens.
Learn more:
The full CDC Study https://www.cdc.gov/pcd/issues/2014/13_0390.htm#table2_down
Growing watercress: https://farmplasticsupply.com/blog/how-to-grow-watercress-indoors-and-outdoors?srsltid=AfmBOoqHv9N9Zwjdj0cddfr5O5FvZbbzsoffnsdmKt6b1NMO1h0Yl1Yz
https://www.foodandwine.com/most-nutritious-vegetables-cdc-report-8727630
https://www.nwcb.wa.gov/weeds/watercress
https://www.myplate.gov/eat-healthy/vegetables