Total antioxidants in edible plants

The following is a summary of a study by a Norwegian group who looked at antioxidant levels in edible plant parts, including 19 cereals, 11 roots and tubers, 31 vegetables, 24 fruits, 19 berries, 10 pulses and 4 dried fruits (Halvorsen et al, Journal of  Nutrition (2002) 132: 461–471).   They found that fruits are by far the richest sources of these valuable phytochemicals.  Generally, berry fruit are the stars, and when added to other fruits in their average national diet they accounted for more than 70% of total antioxidants consumed.

A predominantly plant-based diet reduces the risk for development of several chronic diseases.  It is often assumed that antioxidants contribute to this protection, but results from intervention trials with single antioxidants administered as supplements quite consistently do not support any benefit.

Because dietary plants contain several hundred different antioxidants, it would be useful to know their total concentration in individual species as this might assist identification of the  most beneficial dietary plants.  We have assessed total antioxidants in a variety of dietary plants used worldwide, including various fruits, berries, vegetables, cereals, nuts and pulses.  When possible, we analysed three or more samples of dietary plants from three different geographic regions in the world.  Our results demonstrated that there is more than a 1000-fold difference among total antioxidants in various dietary plants.  Plants that contain most antioxidants include members of several families, such as Rosaceae (dog rose, sour cherry, blackberry, strawberry, raspberry), Empetraceae (crowberry), Ericaceae (blueberry), Grossulariaceae (black currant), Juglandaceae (walnut), Asteraceae (sunflower seed), Punicaceae (pomegranate) and Zingiberaceae (ginger).

In the average Norwegian diet, fruits, berries and cereals contributed 43.6%, 27.1% and 11.7%, respectively, of the total intake of plant antioxidants.  Vegetables contributed only 8.9%.  The data presented here will facilitate future research into the nutritional role of the combined effect of antioxidants in dietary plants.

Government and medical authorities recommend we eat more fruit and vegetables.  In addition to the above study, others have also found that fruits on average have several times the antioxidant levels of veges and similar healthy fibre content.  Some of the qualities of fruits that promote their consumption are their delightful tastes and flavours, their convenience with little or no preparation necessary for eating fresh, and their nutritional benefits for the health conscious. Although they may cost more than veges, you can offset or even eliminate such differences by growing your own,   Then you can indulge in your favourite treats knowing you’re eating a nutrient dense food that’s good for you, rather than the numerous culinary alternatives that have been refined over generations to be irresistible but are all too often unhealthy.