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Processing and Bioavailability (WG2) page 61
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a ‘gross’ plasma response. Even comparative studies of two sources of the same carotenoid
within a single individual may not be valid. This is because the AUC after a carotenoid dose
may not be linear (i.e. a dose twice the size of another dose may not produce an AUC twice as
large). The equation of the dose response curve needs to be obtained. In addition, it is not
known if attenuated delivery or absorption caused by different physical characteristics of the
meal can effect the AUC.
Table 7 summarises recent studies on the intestinal absorption of lycopene using a single
dose.
Table 7. Human studies on the intestinal absorption of lycopene using a single dose
Dosage Matrix Result Reference
12 mg, single dose · Tomato juice (180 ml) No effect Brown et al.,
1989
16.5 mg, single dose · Tomato purée (60 g/d)
· Tomatoes (300 g/d)
23 mg, single dose · Tomato paste (40 g)
· Tomatoes (400 g)
Lycopene better
available from purée
Lycopene in chylomicrons
after tomato
paste ↑
Porrini et al.,
1998
Gärtner et al.,
1997
Chronic dosing
Chronic dosing with supplements or foods (Micozzi et al., 1992) needs to be carried out
until the plasma concentration reaches a plateau. This normally takes a period of weeks when
supplementing with dietary achievable amounts (15 mg/d) and may increase the plasma
concentration of β-carotene up to 10-fold, with other common carotenoids, particularly
lycopene, showing smaller increases. Again, absolute absorption cannot be measured but the
data may allow comparisons between isolated compounds and foods, and between different
foods. Dose response should also be considered (see acute dose AUC). Decay curves of
falling plasma concentration of carotenoids, when supplementation is discontinued, may also
provide some data on the half life of the body carotenoid pool (Dimitrov et al., 1988, Micozzi
et al., 1992).
Table 8 summarises recent studies on the intestinal absorption of lycopene using multiple
doses.