The most frequently eaten fruit and vegetables are not the best choices in terms of content of phytonutrients, US researchers have found.
The researchers analysed data from US health surveys of people's dietary habits to examine sources of phytonutrients and found that for 10 of the 14 phytonutrients studied, a single food type accounted for two-thirds or more of an individual's consumption. It made no difference whether or not a person consumed a high level or a low level of fruit and vegetables.
The most common food sources for five key phytonutrients were: carrots (beta-carotene), oranges/orange juice (beta-cryptoxanthin), spinach (lutein/zeaxanthin), strawberries (ellagic acid) and mustard (isothiocyanates).
However, the researchers found that there were better food sources of these phytonutrients available: sweet potatoes (nearly double the beta-carotene of carrots), papaya (15 times more beta-cryptoxanthin than oranges), kale (three times more lutein/zeaxanthin than spinach), raspberries (three times more ellagic acid than strawberries), and watercress (one cup contains as much isothiocyanate as four teaspoonfuls of mustard).
Study leader Keith Randolph, technology strategist for the supplement company Nutrilite, said: "These data highlight the importance of not only the quantity but also the significant impact the quality and variety of the fruits and vegetables you eat can have on your health."
He recommended that people tried to maximise their phytonutrient intake by varying the fruits and vegetables they consume and by focusing on foods that have a higher concentration of certain phytonutrients.