Vitamin C works against cancer (but maybe not the way you thought)

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Life Extension Update Exclusive

Vitamin C works against cancer (but maybe not the way you thought)

 

Researchers from Johns Hopkins report in the September, 2007 issue of

the journal Cancer Cell that vitamin C can indeed help prevent cancer as

has been claimed for years by a number of scientists including Linus

Pauling, but it appears to do so in a different manner than that which

earlier researchers proposed. While it had been believed that the well

known antioxidant property of vitamin C prevented cancer by protecting

DNA from free radical damage, the latest research unveils a new

mechanism: that of preventing the ability of a tumor to grow in a

reduced oxygen environment.

 

Johns Hopkins professor of medicine and oncology Chi Dang, MD, PhD and

his associates tested the ability of vitamin C as well as

N-acetyl-cysteine, another antioxidant, in mice implanted with human

lymphoma or liver cancer cells, both of which produce a high number of

free radicals. Control groups of mice implanted with the cancers

received no antioxidant supplementation.

 

When the researchers examined DNA from the mice that did not receive

antioxidant treatment, a lack of significant damage was observed.

" Clearly, if DNA damage was not in play as a cause of the cancer, then

whatever the antioxidants were doing to help was also not related to DNA

damage, " lead author Ping Gao, PhD, said of the finding.

 

The team found that a protein known as hypoxia-induced factor (HIF-1),

which is dependent upon free radicals, was diminished in

antioxidant-treated animals. The protein enables tumors to survive in

the low oxygen environment of rapidly growing tumors. " When a cell lacks

oxygen, HIF-1 helps it compensate, " Dr Dang explained. " HIF-1 helps an

oxygen-starved cell convert sugar to energy without using oxygen and

also initiates the construction of new blood vessels to bring in a fresh

oxygen supply. "

 

The finding was verified by the engineering of cancer cells to contain a

variant of HIF-1 that was not dependent upon free radicals. Antioxidants

proved to be powerless against these cancerous cells.

 

" The potential anticancer benefits of antioxidants have been the driving

force for many clinical and preclinical studies, " Dr Dang noted. " By

uncovering the mechanism behind antioxidants, we are now better suited

to maximize their therapeutic use. "

 

" Once again, this work demonstrates the irreplaceable value of letting

researchers follow their scientific noses wherever it leads them, " he

added.

 

Health Concern

Complementary alternative cancer therapies

 

Vitamin A derivatives, known as retinoids, protect against the

development of various cancers, including those of the skin, breast, and

lung (Clarke N et al 2004; Khera P et al 2005). Dietary supplementation

with synthetic vitamin A for 12 months in liver cancer survivors

prevented recurrence of this cancer (Takai K et al 2005). In addition to

preventing cancer, vitamin A derivatives have been used to cure acute

promyelocytic leukemia (Clarke N et al 2004).

 

Vitamin C. Long-term human studies have shown that vitamin C dietary

supplements, when used in conjunction with other antioxidants, can

reduce the risk of developing cancer (Hercberg S et al 2004). Similar

results were found for cancers of the prostate (Meyer F et al 2005) and

lung (Mooney LA et al 2005; Wright ME et al 2004).

 

Clinical studies have shown that vitamin E can reduce the risk of

prostate and lung cancers, particularly when used in combination with

selenium supplements (Helzlsouer KJ et al 2000; Woodson K et al 1999).

Regular and long-term (over 10 years) use of vitamin E reduces the risk

of death from bladder cancer (Jacobs EJ et al 2002). Similarly, the use

of vitamin E supplements for longer than three years slightly reduces

the risk of recurrence among breast cancer survivors (Fleischauer AT et

al 2003).

 

http://www.lef.org/protocols/cancer/

alternative_cancer_therapies_01.htm