Humans don't get all the benefit from raw tomatoes
Auckland 17 April 2009
Antioxidant lycopene not released during digestion.
Eating a raw tomato may not be the best way to release all its healthy antioxidants into the body.
Research by Plant & Food Research, in collaboration with Lincoln University, has shown that lycopene, an antioxidant found in high levels in tomatoes, is only released in small amounts when digested by humans.
Scientists used a model of the digestive tract, simulating the activity of the human stomach and small intestine, to measure the amount of lycopene and other antioxidants released from tomatoes during typical digestive conditions. The study found that although around 75% of the total antioxidants were released, this included only 4% of the lycopene found in the raw tomato.
“Tomatoes are the richest source of lycopene in the human diet, as well as containing other antioxidants essential for health,” says nutritional biochemist Carolyn Lister. “However, the human digestive tract is not able to release the majority of lycopene from raw tomatoes, so only a small amount would be made available for the body to use.
“Processing tomatoes has been shown to make lycopene more bioavailable, so as well as eating raw tomatoes for their nutritional value, we should eat tomato sauces to get the goodness of the lycopene.”
Plant & Food Research’s Vital Vegetables® programme will continue to focus on increasing the supply of bioavailable lycopene to consumers, starting with high-lycopene tomato varieties.
The research is published in the International Journal of Food Sciences and Nutrition. It was supported by a New Zealand Official Development Assistance Doctoral Fellowship to Ramandeep Toor, for PhD research in conjunction with Lincoln University.
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