Greens rank high on list of ‘powerhouse’ produce

A study published in the Centers for Disease Control & Prevention’s Preventing Chronic Disease uses a classification scheme to define “powerhouse” fruits and vegetables.

June 11, 2014

Powerhouse fruits and vegetables (PFV), foods most strongly associated with reduced chronic disease risk, are described as green leafy, yellow/orange, citrus, and cruciferous items, but a clear definition of PFV is lacking. A study published in the Centers for Disease Control & Prevention’s Preventing Chronic Disease uses a classification scheme to define “powerhouse” fruits and vegetables.

The researchers 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. The 17 nutrients are: potassium, fiber, protein, calcium, iron, thiamin, riboflavin, niacin, folate, zinc, and vitamins A, B6, B12, C, D, E, and K.

The researchers first generated a tentative list of PFV consisting of green leafy, yellow/orange, citrus, and cruciferous items on the basis of scientific literature and consumer guidelines. Berry fruits and allium vegetables were added in light of their associations with reduced risks for cardiovascular and neurodegenerative diseases and some cancers. For each, information was collected in February 2014 on amounts of the 17 nutrients and kilocalories per 100 g of food. Because preparation methods can alter the nutrient content of foods, nutrient data were for the items in raw form. Secondly, a nutrient density score was calculated for each food.

The researchers found that of 47 foods studied, all but six (raspberry, tangerine, cranberry, garlic, onion, and blueberry) satisfied the powerhouse criterion. Nutrient density scores ranged from 10.47 to 122.68 (median score = 32.23) and were moderately correlated with powerhouse group. The classification scheme was robust with respect to nutrients protective against chronic disease (97% of foods classified as PFV were separately classified as such on the basis of eight nutrients protective against cancer and heart disease).

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.

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