23
Common Functional Foods
Mechanism of Action Effects Side Effects
Green tea (not extract)
Contains caffeine as
well as epicatechin,
epicatechin gallate,
and epigallocatechin
gallate (EGCG).
While they may
have antioxidant
effects, it is unclear
that the catechin
component of green
tea contributes to
weight loss beyond
the caffeine.
Meta-analyses
suggest minor weight
reduction.
Caffeine side effects
include anxiety,
tremors, cardiac
dysrhythmias.
Catechins may cause
indigestion and
constipation. Green
tea extract is an
important cause of
liver injury.
Green coffee and extract
Green coffee contains
less caffeine than
black coffee but also
contains chlorogenic
acid, which may
have peroxisome
proliferator-activated
receptor alpha activity.
Isolated studies
suggest minor weight
reduction with green
coffee extract.
Caffeine side effects
include anxiety,
tremors, cardiac
dysrhythmias.
Catechins may cause
indigestion and
constipation.
Phytoestrogens
Plant-derived
substances with
potential estrogenic
effects (isoflavones,
flavones, and
coumestans) are often
found in soy products.
If soy-based foods
are substituted for
higher fat, higher
calorie foods, this may
promote minor weight
reduction. Animal
studies suggest
some phytoestrogens
are associated with
decreased lipogenesis.
Mild nausea, bloating,
constipation.
In women,
phytoestrogens may
disrupt endogenous
hormone levels and
ovulatory cycle. In
men, typical doses
are unlikely to cause
feminization. Should
be used with caution
in women who are
pregnant, nursing, or
attempting to become
pregnant.
(cont'd)
