Kale has been hyped as the most nutrient-dense food you can buy in the produce department. But the Centers for Disease Control and Prevention has published a report called Defining Powerhouse Fruits and Vegetables (PFV): A Nutrient Density Approach that ranks it only number 15. It's still pretty potent, but that means there are 14 other superfoods you can add to your diet for more variety and an even bigger nutritional punch.

Watercress is a leader in the veggie superfood arena.
Photo credit: Shutterstock

"National nutrition guidelines emphasize consumption of powerhouse fruits and vegetables (PFV), foods most strongly associated with reduced chronic disease risk; yet efforts to define PFV are lacking," said the study's introduction. "This study developed and validated a classification scheme defining PFV as foods providing, on average, 10% or more daily value per 100 kcal of 17 qualifying nutrients. Of 47 foods studied, 41 satisfied the powerhouse criterion and were more nutrient-dense than were non-PFV, providing preliminary evidence of the validity of the classification scheme. The proposed classification scheme is offered as a tool for nutrition education and dietary guidance."

The study looks at green leafy, yellow/orange, citrus and cruciferous items as well as berries and alliums (garlic, onions etc.), based on scientific literature and consumer guidelines touting them as reducing the risk of chronic diseases and conditions such as cancer, heart disease, hypertension and inflammation. It found that all but six—raspberry, tangerine, cranberry, garlic, onion and blueberry—satisfied the VFV criterion. The average score was 32.23.

"Items in cruciferous (watercress, Chinese cabbage, collard green, kale, arugula) and green leafy (chard, beet green, spinach, chicory, leaf lettuce) groups were concentrated in the top half of the distribution of scores whereas items belonging to yellow/orange (carrot, tomato, winter squash, sweet potato), allium (scallion, leek), citrus (lemon, orange, lime, grapefruit) and berry (strawberry, blackberry) groups were concentrated in the bottom half."

And the winner is .... watercress, with a score of 100 (actually higher but the researcher capped the scores at 100.) It's not just easy to add a handful to that salad (and you'll get the most from its nutrients if you eat it raw), it's easy and quick to grow yourself so you've always got some fresh leaves on hand.

Rounding out the top five are Chinese cabbage (91.99), chard (89/27), beet greens (87.08) and spinach (86.43). Leaf lettuce and chicory scored 73.36 and 70.73 respectively, followed by parsley at 65.59, and romaine lettuce (63.48), a trio of popular soul-food greens—collard (62.49), turnip (62.12) and mustard (61.39)—and endive (60.44). Chives come in at 54.80, a notch above kale, which snags a healthy score of 49.07.

That doesn't mean, however, that those foods scoring lower don't provide benefits in specific areas, bringing particular nutrients to the mix. What is does mean is that vegetables clustered in the top half of the chart would make a heck of a healthy salad and could bring some variety as well as a mix of health-boosting vitamins and minerals to your salad bowl. Instead of going straight for the trendy kale—still a nutritious superfood choice—try them all and maybe discover some new favorites.

YOU MIGHT ALSO LIKE

Top 10 Superfoods of 2014

Kale is King: 5 Reasons You Should Eat It

25 Vegan Sources of Calcium