More on raw vs cooked:
http://cebp.aacrjournals.org/cgi/content/full/13/9/1422
Abstract:
This review of the medical literature from 1994 to 2003 summarizes the
relationship between raw and cooked vegetables and cancer risk and examines
whether they may affect cancer risk differently. Twenty-eight studies
examined the relationship between raw and cooked vegetables and risk for
various cancers. Twenty-one studies assessed raw, but not cooked, vegetables
and cancer risk. The majority of these assessed risk of oral, pharyngeal,
laryngeal, esophageal, lung, gastric, and colorectal cancers. Most showed
that vegetables, raw or cooked, were inversely related to these cancers.
However, more consistent results were found for oral, pharyngeal, laryngeal,
esophageal, and gastric cancers. Nine of the 11 studies of raw and cooked
vegetables showed statistically significant inverse relationships of these
cancers with raw vegetables, but only 4 with cooked vegetables. The few
studies of breast, lung, and colorectal cancers also suggested an inverse
relationship with both raw and cooked vegetables, but these results were
less consistent. In the two studies of prostate cancer, there was no
association with either raw or cooked vegetables. One of two bladder cancer
studies found an inverse relationship with cooked, but not raw, vegetables.
Possible mechanisms by which cooking affects the relationship between
vegetables and cancer risk include changes in availability of some
nutrients, destruction of digestive enzymes, and alteration of the structure
and digestibility of food. Both raw and cooked vegetable consumption are
inversely related to epithelial cancers, particularly those of the upper
gastrointestinal tract, and possibly breast cancer; however, these
relationships may be stronger for raw vegetables than cooked vegetables.
[...]
Conclusion:
It is clear from this review that both raw and cooked vegetables are
inversely related to several epithelial cancers, particularly those of the
upper gastrointestinal tract, and possibly to breast cancer. Although more
of the studies showed a statistically significant inverse relationship
between raw vegetables and cancer than either cooked or total vegetables,
the literature is too varied to compare definitively. Studies on diet and
cancer need to differentiate between raw and cooked vegetables in their
methods of food recall and in their analyses. In addition, more consistency
is needed regarding the types of vegetables assessed in each category. In
the meantime, the public should be encouraged to increase their vegetable
intake and to consider eating some of them raw.
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