The protective effect of tomato ketchup consumption on inflammation induced ex-vivo in human blood

The consumption of tomatoes and tomato products has been associated with a
lower risk of developing cardiovascular disease and some types of cancer.
Tomatoes and tomato products provide a good source of antioxidants (lipophilic
and hydrophilic). Important tomato antioxidants are lycopene, α-tocopherol and
ascorbic acid. It has been reported that these antioxidants in isolated form
exert directly or indirectly anti-inflammatory effects in vitro.. Studies with
tomatoes or tomato products reported that the observed anti-inflammatory
effects could not be caused by only a single antioxidant. It was suggested that
these effects were due to the combination of antioxidants.
Since, however the relevance of the observed anti-inflammatory effects for
humans is entirely unknown the present pilot study aims to assess the acute
effects of a single tomato ketchup consumption on ex-vivo elicited inflammation
in a small group of healthy subjects

The objectives of the study are to investigate the acute effects of a single
consumption of tomato ketchup on ex-vivo elicited inflammation (release of the
cytokines TNF-α, IL-8 and IL-10 upon LPS stimulation), chemotaxis of monocytes
ex-vivo and on plasma concentrations of lycopene, its stereoisomers, α-
tocopherol and ascorbic acid, in healthy subjects.

The study is designed as a placebo-controlled cross-over trial. After a 3-days
run-in period of a diet low in antioxidants, the study parameters will be
measured on test day 1 upon a standardized control meal (i.e. the placebo meal)
and on test day 2 upon the consumption of 200 g tomato ketchup. For every
subject the study lasts in total 5 days.

3 Day Run-in period
During the 3-days-run-in period the subjects are instructed to avoid
consumption of tomatoes and tomato products, seeds and nuts, egg yolk, all
other fruits and vegetables, herbs, spices, ready meals and antioxidant
supplements or beverages high in antioxidants (e.g. tea, coffee, chocolate,
fruit juices, red wine, beer). Subjects are allowed to eat peeled potatoes,
white bread, white pasta, white rice, meat, fish, egg whites, cheese,
unflavored yogurt, salt, and pepper. The subjects are allowed to drink ad
libitum water, semi-skimmed, or skimmed milk. A similar run-in procedure has
been used successfully in a previous study to achieve a low antioxidant
background diet and did not cause any adverse effects. Subjects are asked to
record their food intake during the run-in period.
On the evening prior to test day 1 (third day of the run-in period) and in the
evening of test day 1, the subjects receive a standardized diner . The portion
will be 750 g and supplies 5820 kJ (1390 kcal).
After blood collection on test day 1 a standardized lunch will be provided
which consists of 2 white bread rolls, with cheese and meat products and 250 g
skimmed yoghurt, which will approximately supply 2060 kJ (492 kcal).
During both test days, the subjects are allowed to drink water ad libitum.


Test day 1
On test day 1, all subjects consume a placebo meal with 200 g white cooked
rice and a self prepared vinaigrette. The placebo meal consists of
approximately 2060 kJ (492 kcal). The vinaigrette is composed in order to
provide the same amounts of macronutrients and caloric value as the tomato
ketchup while being free of any antioxidants. The ingredients of the
vinaigrette are commercially available at the supermarket.
In the morning of test day 1 the vinaigrette will be freshly prepared by the
project leader (M. Hazewindus)

Test day 2
On test day 2 the subjects will consume 200 g tomato ketchup with 200 g white
cooked rice, which will supply approximately 2043 kJ (488 kcal). The tomato
ketchup is commercially available.

Subjects will not have a benefit of a participation in the study.


After signing of the informed consent form, subjects will receive the dietary
instructions for the 3 day run-in period, a study diary and 1 standardized
dinner for the third evening of the run-in period prior to test day 1. After
22.00 h on the evenings before test day 1 and 2, the subjects are not allowed
to eat and drink, with the exception of water. At both test days the subjects
will be expected at 7.30 h at the Department of Toxicology at the University of
Maastricht, where they will receive the placebo meal (test day 1) or the tomato
ketchup meal (test day 2). After consumption of the meal the subjects are free
to move within the department. At 14.30 h the subjects are expected back for
blood collection in a room being suitable for this purpose. In total 27 ml
blood will be collected. This volume of blood is needed to determine the
cytokine release upon ex-vivo stimulation with LPS (ca. 10 ml), to assess the
chemotaxis of monocytes ex-vivo (ca. 10 ml) and to measure the plasma
concentration of lycopene, its stereoisomer*s, α-tocopherol and ascorbic acid
by means of HPLC (ca. 5 ml). On test day 1 directly after the blood collection,
the subjects receive a standardized lunch which they can immedialty consume.
Moreover, they are provided with a second standardized dinner, which they can
take home and consume in the evening.

The risk being associated with the blood collection of 27 ml on 2 consecutive
days is negligible. Subjects are required to follow a diet low in antioxidants
for 3 days. A comparable approach has been applied in a previous study and did
not cause any adverse effects. The tomato ketchup is commercially available and
is safe for human consumption.