Bioavailability of tomato polyphenols is enhanced by processing and fat addition: Evidence from a randomized feeding trial

SCOPE

Tomato contains a variety of phenolics associated with health-promoting properties. However, the effects of processing and the addition of oil during tomato sauce preparation on microbial metabolism of phenolics in the small intestine are still unclear.

METHODS AND RESULTS

An open, controlled, randomized, and crossover feeding trial with 40 healthy volunteers was carried out to analyze the metabolites in plasma and urine after the consumption of tomato and tomato sauces, with tomato sauce enriched with refined olive oil (ROOE) and without refined olive oil (oil-free: OF). Ten phenolics in plasma and 93 metabolites in urine were quantified. Processing tomatoes into sauce enhanced the bioavailability of flavanones, flavanols, and some hydroxycinnamic acids, as reflected by the increase in the area under the plasma concentration versus time curve. An increase in their plasma half-life was also observed, particularly after ingestion of ROOE, possibly favored by enterohepatic circulation. A wide variety of gut microbial metabolites was also detected, namely flavanones, hydroxycinnamic acids, flavonols, hydroxyphenylpropanoic acids, hydroxyphenylacetic acids, and hydroxybenzoic acids.

CONCLUSIONS

Flavanones and flavonols in ROOE presented higher bioavailability, suggesting that the processing undergone by the raw tomato improved their absorption.

[Dietary interview: a useful tool for data collection]

Dietary interview is a very useful tool in the process of evaluating the nutritional state of a person and, of course, in the process of dietary counseling, particularly in the case of patients suffering from chronic conditions. The complexity of gathering information at individual or population level requires different models of questionnaires and tools to enhance the identification of the data collected. The current paper is based on the consensus document about dietary interview, made by a working group created during the 1st Meeting of the Spanish Dietitians' and Nutritionists' Association held in Barcelona 2002.