|
Involvement
in Gene Regulation and Cell Proliferation
*Transcription
factors are proteins that bind to DNA near its start site or "regulatory
region" where it begins to transcribe a gene.
They regulate gene expression by either facilitating or inhibiting the
enzyme RNA polymerase
in the initiation and maintenance of transcription. Certain micronutrients
such as folic acid, zinc, vitamin A, vitamin
D, vitamin C, and vitamin E, bind to their
specific nuclear receptor proteins and act as or activate transcription
factors to mediate gene expression in the regulation of cell
proliferation within the cell cycle (Kim
YI, 2005, Kato
S, 2000, Maden
M, 2000, de
Nigris F, 2000, Meier
CA, 1997, Slansky
JE, 1996, Sullivan
TA, 1994, Hashimoto
Y, 1991).
Types of Transcription
Factors
*Some of these regulating proteins (transcription
factors) act as "tumor suppressor genes"
as they have the ability to suppress uncontrolled cell proliferation, an
event that is central to the development of cancer. The tumor suppressor
gene
p53, a transcription factor considered to
be the most frequently mutated gene in human cancer, blocks cell cycle
progression (cell division) and induces apoptosis
(cell death). In this way p53 suppresses tumor growth (Werner
H, 1996). Zinc molecules form zinc
finger proteins that act
to stabilize the shape of p53, keeping it
from being mutated so that it can function fully (Kihara
C, 2000). Retinoic acid, an active form of vitamin
A, also stimulates p53 activity as well as
the transcription factor and tumor suppressor gene Rb
(retinoblastoma protein or p105) (Um
SJ, 2000), Other transcription factors (eg: Fos and Jun)
stimulate gene expression in key protein molecules (eg: interluekin-2
secreted
by activated T-cells) involved in proper cell-mediated
immune response. Still others are involved
in stimulating the development of certain embryonic organs such as WT-1
which initiates the formation of the gonads and kidneys in the fetus (Gilbert
SF, 1997).
Importance
of Diet
*It
is important that the human body receive an abundance of fresh,
raw fruits and vegetables, and whole grains
on a daily basis in order to have an adequate supply of micronutrients
to function in the control of cell proliferation and differentiation.
Ongoing research continues to support the hypothesis that dietary factors
significantly influence the incidence of human malignancies and disease
(Weisburger
JH, 2001 &
2000, Otsuka
M, 2000, Willett
WC, 1999). Leading health authorities are urging all people
to increase their consumption of fresh fruits and vegetables and whole
grains in order to strengthen their resistance to chronic diseases, yet
many are not complying with this recommendation (Cerully
JL, 2006, Cavadini
C, 2000, Torres MP, 2000).
Decline of the Human Diet
*In
recent years, American diets, as well as others such as in the United Kingdom
and Australia, have deteriorated, particularly among adolescents,
with carbonated soft drinks replacing juices and milk, and high fat red
meats and salty french fries replacing fish and green/orange vegetables.
Very few diets in the modern world contain the recommended
five daily servings of fruits and vegetables,
especially raw and unprocessed. Daily fruit and vegetable consumption
among children and adolescents often falls well
below five servings (Magarey
A, 2001, Cavadini
C, 2000). Intake of whole
grain foods, which are also rich sources of
antioxidant and B vitamins, has also been found to be lacking in the American
diet. On average, Americans consume only one
serving or less per day of whole-grains, far
below the FDA's daily recommendation of three
servings Slavin
JL, 2001). Most diets studied in developed countries,
especially those of the elderly, women, and
youth, have been found to be deficient in
at least calcium, zinc, folic acid, iron,
vitamin A, vitamin E, and vitamin C (Fenech
M. 2001, Marshall
TA, 2001, Stang
J, 2000, Giddens
JB, 2000). The typical modern diet is not only devoid
of essential micronutrients, but also contains potentially harmful chemicals
such as pesticides, preservatives, hormones, antibiotics, and other drugs
that in themselves require additional micronutrients in order to be broken
down and disposed of effectively. The modern
human diet in general has declined significantly from that of early man
where wild game,
fish, and uncultivated
plant foods high in phytochemicals and micronutrients were the main constituents.
Our
genome, however, remains essentially unchanged, requiring this ancestral
diet or these elements in the same ratio to
promote health and prevent disease
(Eaton
SB, 2000). If current dietary trends continue, particularly
among our youth, researchers predict the health of future generations will
most likely be seriously compromised (Cavadini
C, 2000).
The Need for a Dietary
Micronutrient Upgrade
*Mortality
statistics from the WHO database covering the period of 1960 to 1990 support
only one diet, the traditional Greek Mediterranean
diet, high in antioxidants from such foods
as olive oil, fruits, vegetables, and wild plants, as a diet that is beneficial
to health and longevity (Trichopoulou
A, 2000, Trichopoulou
A, 2003). It has been roughly estimated that up to 25%
of colorectal cancers, about 15% of the breast cancers, and about 10% of
prostate, pancreas, and endometrial cancers could be prevented if developed
Western countries shifted to the traditional healthy Mediterranean diet
(Trichopoulou
A, 2000). A daily multiple
vitamin/mineral supplement provides an essential
safeguard against cancer and various diseases, especially in individuals
on the typical modern-day cooked and processed, high fat Western diet. |
