The effect of fruit and fruit juice on plasma total antioxidant capacity

The positive health effect of fruit and vegetables has been attributed to its
antioxidant content. Several intervention studies have shown that the
consumption of fruit and vegetables is able to increase the total antioxidant
capacity of plasma. The chronic intake of dietary antioxidants from fruit and
vegetables decreases oxidative damage to key structures in the body, including
lipids, proteins, and DNA.
Public campaigns have been launched to increase the consumption of fruits and
vegetables. In the Netherlands, the aim of the public campaign is to increase
the consumption to 2 pieces of fruit (* 200 gram) and 200 gram vegetables per
day in adults. Unfortunately, the average consumption of fruits and vegetables
is much lower. Beverages containing fruit and vegetables have been developed to
increase this intake. It is not yet clear if the consumption of these beverages
have comparable beneficial health effects as the consumption of fruit and
vegetables.

The aim of the present study is to compare the effect of consumption of a fruit
beverage on plasma antioxidant capacity with that of the consumption of fruit.

Cross-over, randomised design. Wash-out period of one week.

Consumption of fruit juice, apples and a salad of mixed fruit.

Each volunteer will participate in the study on three separate occasions (each
test will take approximately 6 and a half hour). Blood will be drawn at
different time points via a catheter (in total 75 ml per testday). Participants
are asked to consume a standardised meal the evening before each of the three
testdays. Volunteers are instructed not to consume any antioxidant supplements
or beverages containing high amounts of antioxidants or antioxidant rich food
for 3 days before each of the three trials. Subjects are asked to record their
food intake for 3 days before each of the three trials.
There are no risks involved in the participation of the study apart from the
limited risk associated with blood sampling. The fruit beverage is commercially
available and is consumed in an amount that is considered to be safe. The
consumption of apples and the salad of mixed fruit is safe. The fruit beverage
and the fruits are consumed once at the beginning of the testday.