Sorry nutricionados: Science says that romaine beats kale.
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There are many things to be cautious of when it comes to your diet, one of which is the culture surrounding dietary nutrition. Fads emerge and fade away like trends in music, fiercely defended and rarely supported by hard evidence. Studies are published as often as they’re debunked, and the food industry itself markets itself accordingly, using whatever trendy new buzzword is likely to attract increasingly health-conscious consumers.
That's not to say that all research regarding dietary health is bunk. However, as a consumer, you should be skeptical of everything you’re told—especially if it comes from the industry itself.
This study, credibly conducted by scientists at William Paterson University and published by the CDC, reveals the foods with the highest density of critical nutrients. Researchers analyzed 47 fruits and vegetables and ranked them on a 100-point scale according to their content of 17 ingredients: potassium, fiber, protein, calcium, iron, thiamin, riboflavin, niacin, folate, zinc, and vitamins A, B6, B12, C, D, E, and K. Just forty-one items satisfied researchers’ “powerhouse” qualifications. And the top ones may surprise you, especially if you’re a kale evangelist.
Of the top five items on the list, all but one (spinach) are about as foreign to my diet as Martian sand. Another surprise (depending on your nutritional ignorance) is the supremacy of leafy greens—even romaine lettuce—over pretty much every “superfood” cited by food marketers. Yes, lettuce is more nutrient-dense than sweet potato (No. 40), blackberries (No. 38), and blueberries (not even included). Fruits in general were buried in the list—the highest being the red pepper (a vegetable for culinary purposes). Also: no garlic? I’ve been told that stuff is miraculous!
But even this list should be viewed with a healthy dose of skepticism. It is not a be-all-and-end-all guide to the healthiest foods on the planet, and researchers acknowledge this much. For example, phytochemicals—nutrients with disease-preventing properties—are rich in many fruits (including berries, citrus, garlic, and onions), but were not considered in the powerhouse list because of a lack of uniform data on intake recommendations.
There is plenty to be learned when it comes to nutrition, especially at the individual level, but I think it’s safe to say we can all eat a bit more watercress. Now if I only knew what to do with it.
Hero image: Wikimedia Commons, "Nillerdk" (CC BY 3.0)
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