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Observational epidemiological surveys (WG 3) page 78
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6-1-2 Folates
The most interesting aspect with regards to folates is their possible interaction with alcohol
with regard to colon cancer (Freundheim et al., 1991; Giovanucci et al., 1995; Baron et al.,
1998) and breast cancer risks (Zhang et al., 1999-b; Rohan et al., 2000;). In all studies, folates
decreased the risk of cancers mainly in association with high levels of folate intake. The
inteference between folate metabolism and alcohol in the liver could explain this interaction.
6-2 Cardio-vascular diseases
6-2-1Phenolics
Three of the 4 prospective studies reported (Hertog et al., 1995; Knekt et al., 1996; Yochum
et al., 1999; Yochum et al., 2000) showed that flavonols decrease cardio-vascular risk. But
again the studies mainly relied on quercetin and kaempferol, the main sources being apple,
onions and tea. In England, no protection was found (Hertog et al., 1997), maybe because of
the widespread habit to add milk in the tea?
6-2-2 Folates
Beside their effect on neural tube defect, folates appear to be important in the prevention of
vascular diseases via the synthetic pathway of methionine: If there is a deficit in folates, there
is no synthesis of methionine and homocysteine accumulates. This compound is likely to be a
risk factor for vascular diseases as demonstrated by several studies (Stamfer et al., 1992;
Rimm et al., 1993; Alfthan at al, 1997);
6-2-3 Potassium
The anti-hypertensive property of this mineral is well known and demonstrated by
observational and intervention assays (reviewed in Corpet and Gerber, 1997).
6-3 Conclusion
The importance of other micro-compounds in the protective effect conferred by tomatoes
deserves further investigation. Tomatoes have the advantage to provide all these compounds,
except α-carotene and β-cryptoxanthine, and lycopene in addition. One might argue that the
quantities are generally smaller, but, as shown on table 43, because the tomato consumption is
large and widespread, the contribution of tomato in these microcompouds is sizable.
Table 43. Contributions of various vegetables in various nutrients as % of the total intake for
a Southern French population.
lycop. β− α− β- luteine vit vit folate Querc. Lignan
car car cryptox. C E s