Agriculture Reference
In-Depth Information
It has been speculated for some time that antioxidant vitamins would be par-
ticularly effective against prostrate cancer because it has a high prevalence, long
latency, endocrine dependency, and reliable serum markers (prostate-specific anti-
gen). Oxidative stress over prolonged periods has been associated with several types
of cancer, such as prostrate cancer. Antioxidants can reduce oxidative stress if and
when they reach the target tissues. Therefore, diets rich in antioxidants may offer
some protection from cancers that are initiated by long-term oxidative stress. Many
dietary factors have been related to prostrate cancer, such as dietary fat, cooked
meat, micronutrients and vitamins (carotenoids, retinoids, and vitamins C, D, and
E), and fruit and vegetable intake. There are clear trends that suggest positive effects,
but more data are needed according to Schmid et al. (2007).
Ruano-Ravina et al. (2006) reviewed the relationship between lung cancer and
antioxidant vitamins and addressed the mechanisms by which these nutrients might
be exercising their activity. While tobacco use was a leading cause of lung cancer,
the authors concluded that overall diet was also an important factor, but antioxidant
vitamins demonstrated no clear protective effect.
C
a r o t e in o i D is
Vitamin A conferred no protective effect; however, the provitamin A carote-
noids lutein, zeaxanthin, lycopene, and α-carotene displayed limited protection.
β-Cryptoxanthin showed a more consistent protective effect. Ruano-Ravine et al.
(2006) pointed out that dose response studies are needed, and it is also clear that
bioavailability is a question with the carotenoids.
Lycopene has been purported to have many health benefits. There are hundreds of
carotenoids in the diet, and while lycopene is the most abundant, other carotenoids
may have interesting activities. Supplementation of lycopene in foods to produce
“functional foods” may not be necessary, particularly if appropriate levels of fruits
and vegetables are consumed. Lycopene's potential benefits, its availability, and the
role of carotenoids in health and disease states, focusing on the metabolism of the
carotenoids, have been extensively reviewed (Bruno and Wildman, 2001; Faulks and
Southon, 2001; Bruno et al., 2007).
P
h e n of L i C
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in t i o x i D a in t s
Currently, there is enormous interest in the many functional properties of plant-
based phenolic compounds. As shown in Figure 13.1, phenolics encompass a wide
range of phytochemicals, ranging from relatively simple phenolic acids to flavonoids
to complex anthocyanins and tannins.
Epidemiology studies claimed a range of health benefits associated with tea con-
sumption, and consumption of red wine, which is rich in phenolics, has been associ-
ated with the French paradox. The French diet is rich in fat, particularly saturated fat,
yet the incidence of heart disease is much lower than seen in other countries where
similar diets are consumed. Because the French consume higher amounts of red
wine, it has been proposed that the red wine phenolic compounds prevent some of the
adverse effects associated with high-fat diets. Dubick and Omaye (2007) reviewed
