world cancer report - iarc

Fig. 2.53 Fruit consumption is associated with reduced risk of cancer (according to results of meta-analyses). Findings are essentially similar for vegetable consumption.
Salt and salt-preserved foods
Consumption of salt added to food and
salt-preserved foods has been investigated
mainly in relation to cancers of the
stomach, colorectum and nasopharynx.
Several studies conducted in Europe,
South America and Eastern Asia have
reported increased relative risks of stomach
cancer in relation to the consumption
of salt and salt-preserved foods, particularly
in populations with high stomach
cancer incidence and high salt intake (Fig.
2.54). Salted, smoked, pickled and preserved
food (rich in salt, nitrite and preformed
N-nitroso compounds) are associated
with increased risk of gastric cancer.
Such high salt intake, together with
Helicobacter pylori infection, may contribute
to the development of atrophic
gastritis, and hence gastric cancer.
Domestic refrigeration and reduced salt
consumption are likely to have contributed
to the observed decreased stomach
cancer incidence in developed countries
during the 20th century [5].
Consumption of Chinese-style salted fish
has been specifically associated with
increased risk of nasopharyngeal cancer
in South-East Asia [6], whereas European-
style salted fish (e.g. anchovies and
salmon) has not been found to be associated
with any increase in cancer risk.
Several biological mechanisms have been
proposed to explain the association
between Chinese-style salted fish and
nasopharyngeal cancer, including partial
fermentation and nitrosamine formation.
The relationship of salt and salt-preserved
foods with colorectal cancer seems to be
of a different nature. Firstly, it has been
observed particularly in Western populations
and secondly, it mainly involves
foods such as cooked and raw ham, various
types of salami, European-style charcuterie,
bacon and other salt-preserved
pork (see next section).
Meat
Epidemiological studies on meat consumption
and cancer risk support the
existence of a specific association with
colorectal cancer risk (Figs. 2.57, 2.58).
This association, however, seems to have
been found more consistently for consumption
of red meat (beef, lamb and
pork) and processed meat (ham, salami,
bacon and other charcuterie) for which
consumption of 80 g per day may increase
colorectal cancer risk by 25 and 67%,
respectively [7].
Several biological mechanisms have been
investigated which could explain the possible
effect of meat consumption on
colorectal carcinogenesis. These include
the influence of meat and/or fat consumption
on the production and metabolism
of bile salts and bile acids by gut flora
[8]. Other hypotheses concern the potential
carcinogenic effect of certain compounds
that can be formed in meat during
cooking, such as heterocyclic amines [9]
and polycyclic aromatic hydrocarbons or
as a consequence of preserved meat processing
(nitrates and nitrites) or endointestinal
metabolism (various N-nitroso
compounds) (Food contaminants, p43).
Protein, carbohydrates and fat
The results of epidemiological studies on
macro-nutrients (for example, proportion
of total diet as protein) have so far been
much less consistent in establishing an
associated risk of cancer that those on
foods. No clear risk patterns have
emerged for consumption of protein.
Some studies on oesophageal cancer in
populations with high alcohol intake found
Diet and nutrition
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