Strawberries This may sound a bit strange, but fruits and vegetables grown in adverse weather conditions or insect attacks may be healthier for you, as these plants release more flavonoid antioxidants. The amount of flavonoids – antioxidants found in fruits, nuts and vegetables linked to disease prevention – depends on how much stress the plant has endured.

In its most comprehensive study yet on the healthy compounds, the US Department of Agriculture suggests that certain varieties of fruits, nuts and veggies contain more antioxidants than others.

And flavonoid content varies widely between individual samples. For example, a market may display a tub full of red delicious apples, but flavonoid levels in each individual apple may vary, reports ABC online.

The research shows that the difference may be due to stress, which appears to increase the healthful properties of produce. Nutritionist David Haytowitz, one of the study’s authors, says that taxing conditions, such as those created by more natural farming methods, appear to force plants to release greater amounts of flavonoids and other beneficial compounds.

“Insect attacks and weather conditions can be stressful to plants,” he says. “Even harvest times are important, as early morning harvests are less stressful than those conducted around noon, since the midday sun adds to a plant’s stress.”

Such factors may explain why one flavonoid varied from 31 to 114 milligrams in 100 gram samples of the same variety of sweet red cherry.

Another factor is colour, which is chemically linked to many antioxidants. Raw blueberries, blackberries, cranberries and strawberries all ranked very high for several flavonoids that have been shown to reduce inflammation and to rid the body of damaging free radicals.

“We are interested, because they may help to prevent coronary vascular disease, cancer and other diseases,” says Haytowitz, who adds that colour does not always indicate antioxidant content.

“Green tea and green leafy vegetables happen to be high in flavonoids, but that is not related to their colour, which comes from chlorophyll,” he says.

Bananas ranked high for compounds called flavan-3-ols, even though the flesh of this fruit is creamy white.

Among other fruits, red delicious apples with peel, golden delicious apples with peel, Fuji apples and gala apples with peel all ranked high, as did other tested apples.