Powerhouse Rankings: Watercress Tops List, Blueberries Missing
According to a new study that focuses on nutrients, watercress, chinese cabbage and chard tops the list of foods that gives the most nutrients per bite, while some of the most talked about plant foods in health – such as blueberries – didn’t make the list.
The study, published in Preventing Chronic Disease, sought to rank how 47 fruits and vegetables stack up as nutrient “powerhouses.” Eating more of these fruits and veggies, notes the study, is one approach linked to reduced risk of chronic diseases, which includes cancer. AICR research links numerous fruits and vegetables, along with other plant foods, to lower cancer risk.
For the study, the author identified the powerhouses foods based on 17 nutrients, all vital for good health. The nutrients she looked at included vitamins, minerals, protein and fiber. Because there are no clear measures of many phytochemicals, the study did not include phytochemical content when ranking. Each fruit and vegetable is packed with hundreds of phytochemicals, many that show cancer-fighting properties in lab studies.
For the food to qualify as a powerhouse, every 100 calories of that food had to provide on average at least 10% of the daily value of the nutrients. That cut out six foods: raspberry, tangerine, cranberry, garlic, onion, and blueberries. Then the study calculated a nutrient content score for each food, based partly on its nutrients and its calorie density. The calorie density is how many calories are in a certain weight of food, in this case it was 100 grams.
Cruciferous and green leafy vegetables tended towards the top of the list, with watercress scoring a perfect 100. Berries and citrus fruits ranked lower; grapefruit, blackberries and sweet potatoes sat at the bottom of the rankings. For the bottom dwelling fruits and vegetables and those that didn’t even make the list, not having phytochemical content to include is the primary reason, according to the study author.
Source: Di Noia J. Defining Powerhouse Fruits and Vegetables: A Nutrient Density Approach. Prev Chronic Dis 2014;11:130390.