Lycopene, found in tomatoes and other red fruits vegetables, is one of the most potent antioxidants in the carotenoid family and is used as an ingredient in both functional foods and dietary supplements.
A Finnish study, published in Diabetes Care (2004 Vol. 27, pp.362-366) reported that people who had high dietary intake of antioxidants and carotenoids were 40 per cent less likely to develop type-2 diabetes. However, this study linked the benfits to the carotenoid beta-cryptoxanthin, found in citrus fruits.
An estimated 19 million people are affected by diabetes in the EU 25, equal to four per cent of the total population. This figure is projected to increase to 26 million by 2030.
The new study, published in the March edition of the Journal of Nutrition (Vol. 136, pp. 696-689), reports the effects of dietary intake of lycopene and lycopene-containing food on the development of type-2 diabetes.
The large prospective cohort study analysed 35,783 women over the age of 45 with no known history of cardiovascular disease (CVD), cancer or diabetes at baseline. Intake of lycopene was quantified using a 131-item food frequency questionnaire.
After an average 10 years of follow-up, only 1544 cases of type-2 diabetes had been diagnosed.
"Our study found little evidence for an association between dietary intake of lycopene or lycopene-containing foods and the risk of type-2 diabetes," wrote lead-author Lu Wang, from the Brigham and Women's Hospital in Boston.
When the researchers adjusted the data for age, total energy intake, body mass index, and other known diabetes risks, they found no statistical difference between eating less than 1.5 servings of lycopene-containing food and more than 10 servings per week.
The risk factors for the lowest intake of lycopene (less than 1.5 servings per week) was 1.03, while he risk factor for the highest intake of lycopene (more than 10 servings per week) was 1.04.
US researchers recently claimed that too many antioxidants in the diet could actually increase the risk of diabetes (Proceedings of the National Academy of Sciences, 2004 Vol. 101, pp. 8852-8857).
Several studies have linked higher intake of lycopene with lower risks of heart disease and prostate cancer, while an animal study recently reported that lycopene could protect against emphysema.