Source for below
article : Grant & Associates Health Research
A study published this week in Anticancer Research confirms that solar UVB
irradiance is associated with reduced risk of 16 sites of cancer,
apparently through production of vitamin D.
A study published this week in Anticancer Research confirms that solar
UVB irradiance is associated with reduced risk of 16 sites of cancer,
apparently through production of vitamin D.
These cancers include 6 sites of gastrointestinal cancers, 3 cancers of
female sites, 3 urogenital cancers, 2 types of lymphomas, and 2 upper
aerodigestive tract cancers.
The analysis examined age-adjusted mortality rate data from 49 states
plus the District of Columbia for two periods: 1950-69 and 1970-94.
Other cancer risk-modifying factors were included in the analysis.
“This study provides important additional support for the vitamin D
-cancer hypothesis” according to William Grant. This new study shows
that the approach used, a statistical comparison of cancer mortality
rates by state according to several cancer risk factors, is likely to be
reliable since the results for known factors other than UVB agreed well
with the results in the literature.
"In addition, the new study replicates many of the links between higher
levels of vitamin D and lower risk of cancer that were identified in
earlier studies that had less control for risk factors other than
vitamin D or UVB deficiency."
“The mechanisms whereby vitamin D reduces the risk of cancer are well
known, and include effects on intercellular adhesion, apoptosis
(programmed cellular death), the inhibition of angiogenesis around
tumors, and the inhibition of metastasis.”
According to co-author Cedric Garland, Dr.P.H., “Enhancing vitamin D
status appears to be the single most important single simple thing that
people can do to reduce their risk of cancer, apart from avoiding
tobacco and moderation in intake of alcohol."
"While solar ultraviolet B is not always available or convenient for
synthesis of vitamin D and entails a possible small increase in risk of
nonmelanoma skin cancer, vitamin D supplements are readily available and
nontoxic in the preventive range of 1,000-1,500 IU/day.”
Other recent studies recently found that it takes 1000 to 1500
International Units (I.U.) of vitamin D per day to reduce the risk of
cancer incidence and death by 30-50%. Dietary sources provide only 250
to 300 I.U. per day.
People with fair skin living in the sunnier regions of the country can
make 1500 I.U. of vitamin D in about 20 minutes near solar noon with
10-20% of their body exposed, i.e., arms and back in women and back or
chest in men.
Those with darker skin require 2-4 times as much time or body exposed
for the same vitamin D production. This may help explain why black
Americans have higher cancer incidence and mortality rates than white
Americans, which was described recently in the Journal of the National
Medical Association.
Cedric Garland added, “Briefly exposing a large enough area of skin for
adequate vitamin D synthesis is more effective than increasing the
amount of time spent in the sun. Protracted exposures to the sun are
counterproductive after the 20-30 minutes at most when vitamin D
synthesis for the day is complete. People of all ages should wear a hat
whenever spending more than a few minutes in the sun, and should spend
the time walking or otherwise in motion.”
William Grant added “The public receives a steady barrage of public
service messages to avoid the sun and wear sunscreens in order to reduce
the risk of skin cancer and melanoma. Unfortunately, such messages do
not mention that these risks are counterbalanced to a substantial degree
by the advantages of producing vitamin D from solar UVB irradiance.
Insufficient UVB irradiance and vitamin D costs society about 10 times
what excess solar UVB does, and excess UVB irradiance is not required
for optimal vitamin D production.” Cedric Garland said “vitamin D in the
appropriate dose is giving society new hope in the fight to prevent
cancer.”
