However, it is worth highlighting that all foods show some natural variation in nutrient levels, which
depend on many different factors. For example, the soil, climate, crop variety and degree of ripeness all
affect the nutrient content of fruit and vegetables. The degree of freshness, storage conditions and
processing conditions will also have an effect on the nutrient composition of the fi nal product.
Therefore it can be very diffi cult to design studies to demonstrate nutritional differences between
organic and non-organic foods per se that control for all other factors adequately. The following is an
overview of some of the studies that have been carried out comparing the nutrient content of organic
and conventionally produced foods. There have been a small number of review papers published in this
area and the fi ndings of these have been highlighted. Fruit, vegetables and cereal foods The fi ndings
from a number of reviews of the literature indicate that there are no signifi cant differences between
organic and non-organic cereals, potatoes and vegetables in the levels of many nutrients (including
vitamin A, betacarotene, B vitamins, minerals and trace elements). However, there is moderately strong
and consistent evidence for higher levels of vitamin C in organically produced potatoes. Around half of
all studies looking at vegetables have also found higher levels of vitamin C in organically grown
vegetables, particularly leafy vegetables. Higher nitrate levels have also been found in conventionally
