Are tomato lycopenes beneficial?
Q - What is the evidence for the benefits of lycopenes found in tomatoes? What other fruits and vegetables contain them and is there is a 'recommended dose'?
A - Lycopenes belong to a group of compounds called carotenoids. In recent years more attention has been paid to the potential antioxidant properties of these compounds in regard to decreasing risk of cancer and certain chronic diseases.
The majority of evidence on lycopenes surrounds work done in the prevention of prostate cancer. This research has shown that the growth of cancer cell lines in vitro has been inhibited following administration of lycopenes from tomatoes. Some studies have shown levels of lycopene in human blood and tissue to be inversely related to rates of cervical and prostate cancer.
Tomato paste, tomato sauces used in pizza, tomato ketchup and canned whole tomatoes all contain between 11-33mg lycopene/100g product. Tomato juice from fresh tomatoes contains closer to 8mg/100g. It is known that lycopene is concentrated in the skin therefore peeling reduces the lycopene content of the whole tomato.
There is currently no recommended dose for lycopenes. Foods high in carotenoids include corn, green beans, pumpkin, carrots, cauliflower, broccoli, orange, peach, apple, vegetable juice and tomato sauce.
Moderate alterations in the diet can lead to increased plasma levels, however this requires continued consumption of these foods to maintain newly acquired levels.
Dr Amanda Patterson and
Dr Sharon Croxford are lecturers in nutrition and dietetics at
Kings College London