Is antioxidant plasma status in humans a consequence of the antioxidant food content influence?

BACKGROUND: A constantly growing part of consumers considers the organic foods healthier than the conventional foods. However, so far few nutritional intervention studies in humans are available on the comparison of organic and conventional food products. OBJECTIVE: The aim of the present work was to compare the total antioxidant activity of organic versus conventional fruits (apples, pears, red oranges, lemons, strawberries and bananas), vegetables (lettuces, tomatoes, onions, garlics, carrots, beans, potatoes, celeries, peas, courgettes and zucchinies), red wine and milk. DESIGN: The oxygen radical absorbing capacity (ORAC) procedure was used to determine both the antioxidant activity of food from organic or conventional origin, and the human plasma antioxidant capacity. Ten Caucasian Italian men, aged 30-65 years, were recruited. The subjects were healthy, according to the clinical examination and the disease history, none smoked or took any drug. Anthropometric parameters of all the participants were measured. RESULTS: The ORAC values of most part of organic foods, i.e. fruits, vegetables as well as red wine and milk were significantly (p < 0.005) higher than those of the conventional homologues. Three organic foods, i.e. pears (-25%) (p < 0.01), lettuces (-20%) (p < 0.01), and tomatoes salsas (-4%) showed ORAC values lower than the conventional homologues. After the consumption of 14 days Mediterranean organic diet a significant (p < 0.005) increase (21%) of the human plasma total antioxidant capacity was observed. CONCLUSIONS: Our results clearly show that the organic food products have an higher total antioxidant activity and bioactivity than the conventional foods. The results could be used in public health campaign to increase the consumption of products able to provide a significant health protection and prevention of chronic diseases.