1. APPLE AND HUMAN
HEALTH
Dr. Waqas Ahmed Awan

4. Is there a nutritional difference
between red and green apples

5.  The link between plant bioactives and human
health is highly complex and includes a wide
array of non-nutritional secondary metabolites,
including the three major classes:
 Polyphenols
 Terpenoids
 Nitrogen-containing compounds, such as alkaloids

6.  In a comprehensive study of 10,000
individuals conducted in Finland, only one of
the food types considered, apple, was
associated with a positive reduction in the
incidence of nearly all the chronic diseases
reported

7.  Much of the research has been conducted on
polyphenol absorption, metabolism or
degradation and it has been shown to mainly
occur in the small intestine and colon
 For apple, which has many bioactive
compounds and is a rich source of sometimes
hard to characterize polyphenols,
elucidating bioavailability can be highly
complex

8.  Each bioactive may have a different potential
for bioavailability according to its source. For
example, a study measuring plasma
concentrations of quercetin in healthy
individuals showed that the bioavailability of
apple quercetin was just 30% that of onion

9. Antioxidant activity of apple and apple
products
 A common theme for the putative health
benefits of fruit, including apple, is the
evidence for antioxidant activity.
Epidemiological studies have linked apple
consumption with a reduction in the risk of
chronic diseases such as cancer,
cardiovascular diseases (CVD), asthma and
diabetes
 the level of total phenolics in fruit does
appear to be correlated with antioxidant

10.  In terms of tissue type, apple peel contains a
significantly greater concentration of
phytochemicals than apple flesh (cortex) and
has a corresponding greater effect on
antioxidant capacity
 In rats, intervention with apple juice induced
higher levels of antioxidant response element
genes

11.  A comparison of apple, peach and pear found
that apple, particularly apple peel, was
significantly higher in bioactive compounds
and was the most effective at raising
antioxidant capacity in rats fed

12. Apple and Cancer
 The relationship between apple consumption
and decreased risks of developing chronic
diseases has been well reviewed, particularly
with reference to cancer
 From a number of fruits tested in in vitro trials,
apple was the second most effective bioactive
in antiproliferation and antioxidant activity
(shown as a bioactivity index) after cranberry

13.  Many studies conclude that flavonoids are the
most likely bioactive in cancer prevention,
other apple secondary metabolites, such as
triperpenoids (e.g. ursolic acid), have also
been implicated as antiproliferation agents

14. Cardiovascular disease and
Apple
 A large survey of some 40 000 women showed
that apple consumption lowered the risk of
CVD disease by up to 22%
 The mechanism of this association is still not
understood, although it seems that apples’
bioactives may exert some effect on blood
pressure and blood lipids

15. Diabetes and Apple
 A Finnish study showed an association
between a lower risk of type 2 diabetes and
apple consumption, with quercetin showing the
highest association of all the flavonoids tested
 Anthocyanins have been associated with a
lower risk of type 2 diabetes

16.  Conversely, a study into the incidence of type
2 diabetes in postmenopausal women found
no association between apple and incidence
rate, or for any of the flavonoids considered

17. Asthma and Apple
 Interestingly, one report showed a lower
incidence of asthma symptoms amongst five-
year-old children whose mothers had
consumed apples during pregnancy,
suggesting some protection for infants from
maternal apple consumption
 However, the specific apple bioactives
responsible for this association are not yet
known

18. Cognitive processes and Apple
 Combating age-related cognitive decline and
neurodegeneration is of increasing importance
to societies with lengthening life spans
 The effects of flavanols, flavanones and
anthocyanins from fruit have all been
implicated in neural protection

19. Gastrointestinal health and
Apple
 Studies have shown that anthocyanin-rich
extracts in the diet of rats increased total faecal
mass and moisture
 This increase would reduce endogenous
tumour-promoting compounds in the colon
 In particular, faecal bile acids, which are known
to promote colon cancer in rodent models
(Magnuson et al., 1993) were significantly
reduced.

20.  These results may be due
 to modulation of the gut microbiota, changing levels of the overall bacterial
population or the
 levels of individual bacterial species. In studies using bioactive extracts and in vitro
model gut
 systems it has been shown, for example, that both flavanols and anthocyanins can
modulate
 bacterial metabolism (Tzounis et al., 2008; Hidalgo et al., 2012), to a greater or
lesser extent
 depending on the food matrix presented (Aprikian et al., 2003; Bazzocco et al.,
2008), so it
 is quite possible that a phenolic-rich whole fruit such as apple may exert similar
modulation.
 The composition of microbiota in the human gut influences the incidence of disease
and
 general gut health and is largely determined by the complex interaction of
gastrointestinal
 Microbiota
 In effect, this could account for increased faecal output where
 Health Properties of Apple and Pear 93
 these apple-derived bioactives are acting in a prebiotic manner. Previous studies