|
LE Magazine September
2002
Thiol Nutrients...
And the use of curcumin as an adjuvant cancer therapy
Q In the note at the end of your most
recent article on curcumin (July 2002, p.26), you stated:
"Cancer patients using curcumin may want to avoid high doses
of thiol nutrients… because these nutrients might
interfere with curcumin's PKC inhibiting effects in actively
growing cancer." I have been taking both curcumin and thiols
for adjuvant cancer therapy. What should I do?
A Thiols are certain
sulfur-related compounds that boost glutathione levels inside
cells. Examples of thiol supplements are N-acetylcysteine and
lipoic acid. Both are powerful antioxidants. Curcumin, a
supplement from the root of a ginger-like plant, is also a
potent antioxidant. In addition, it possesses many important
anti-cancer effects. One of curcumin’s known molecular
properties is inhibiting the growth of tumors by blocking an
enzyme known as PKC (protein kinase C) [Carcinogenesis
1993;14:857-61].
The problem with taking curcumin and thiols together for
cancer treatment is that thiols can interfere with
curcumin’s ability to block PKC. However, the extent of
the effect, and the type of cells in which the interference
happens, are an unknown. In addition, there are many forms of
PKC, and it’s not clear which form of PKC curcumin
inhibits and under what conditions. To be on the safe side,
our recommendation is to avoid “high doses” of
thiols when taking curcumin for cancer adjuvant therapy. By
high doses, we mean taking a wide variety of thiols and/or a
higher-than-what-is-stated-on-the-label of any one thiol
[Free Radic Biol Med
2001;31:670-8].
It should be noted that the problem might not be unique to
curcumin. Ellagic acid is another antioxidant (from berries)
that inhibits PKC. In a study from the University of Southern
California, thiols and vitamin C impeded its blockage of the
enzyme. Again, however, this does not mean that these
supplements will impede each other in any particular type of
cancer cells—more research will have to be done. We only
want to make people aware that the possibility exists [Proc Annu Meet Am Assoc Cancer Res
1997;38:A1395].
In addition to promoting cell growth, signals sent through
PKC participate in the initiation of cell death known as
apoptosis—the destruction of abnormal cells. But the
process is extremely complex and curcumin’s effects are
not completely understood. Does this mean that thiols might
impede curcumin’s apoptotic effect, too? There is no good
indication of it in literature at this time. In addition, it
was recently discovered that curcumin causes apoptosis in a
novel way that does not involve PKC [Exp Cell Res 1999;
249:299-307].
In sum, it is not clear whether the potential weakening of
effects of thiols and possibly other antioxidants on
curcumin’s anti-cancer effects is important in the long
run or not. But for adjuvant cancer therapy, we recommend
erring on the side of caution and avoiding high intakes of
thiol nutrients. For prevention, the story is different. Here,
curcumin works through many different processes that do not
rely on PKC.
Q I am a very healthy 35-year-old male who
became aware of your great organization through some friends.
In reading your magazine and other literature, I am fascinated
by many of the products and their potential to help me stay
relatively young and healthy. How do I determine what products
my body needs?
A The Foundation’s Prevention Protocol
includes a list of the top 12 supplements that a healthy adult
may want to consider using to help prevent age-related
diseases. If you want to further fine-tune your supplemental
regime, the “Male Panel” blood test profile offered
by Life Extension’s blood testing service can provide
critical information about what supplements will be of help to
you. For example, high homocysteine levels exhibit no
symptoms, yet can predispose you to heart disease. Only the
proper blood tests can determine what your levels are or how
much of homocysteine-lowering supplements you may need. To
inquire about Life Extension’s blood testing service,
call 1-800-208-3444.
Q I wanted to take DHEA but my doctor says
that because I have Chronic Fatigue Syndrome (CFS), DHEA won't
follow the correct pathways in my body and it will not get
absorbed. Is that correct?
A DHEA is readily absorbed,
especially when taken with some dietary fat (or fatty acid
supplements), but its does follow slightly different hormonal
pathways depending on the individual. In some people, DHEA
will elevate estrogen levels, while others will see a higher
testosterone level. The best way of ascertaining how DHEA
functions in your body is to test your blood for free
testosterone, estradiol and DHEA about six weeks after you
initiate DHEA supplementation. This blood test will also
indicate whether you need to increase or decrease your DHEA
dosage. While each person has a different hormone response to
DHEA, we are not aware of any studies indicating that this
pathway would be altered because of a certain illness or
disorder. DHEA supplementation might benefit those with CFS.
Studies show that DHEA-S levels were significantly lower in
those with CFS compared to healthy people [J Affect Disord 1999
Jul;54(1-2):129-37]. Other studies indicate that a deficiency
of DHEA-S in patients with CFS may also be related to the
neuropsychiatric symptoms [Int J
Mol Med 1998 Jan;1(1):143-6].
Q How much deprenyl should I take daily for
life extension and can I combine it with 20 mg of Prozac
daily?
A The general recommended
dosage for deprenyl for life extension is 5 mg twice a week.
Deprenyl is a selective, irreversible inhibitor of monoamine
oxidase B (MAO-B), and Prozac is a serotonin selective
reuptake inhibitor (SSRI). While you should consult your
physician before combining the two drugs, the very low dose of
deprenyl needed for potential life extension purposes (10 mg
each week) may not interact adversely with Prozac.
Parkinson’s patients who take 5 mg to 10 mg of deprenyl a
day have been warned of potential harmful interactions if they
take SSRI drugs like Prozac, Zoloft and Paxil. In fact, the
package insert for deprenyl specifically warns that people
contemplating deprenyl should discontinue the SSRI for at
least 14 days before initiating deprenyl. This warning,
however, is based on a daily dose of 5 mg to 10 mg of
deprenyl, whereas the dose of deprenyl being used for life
extension purposes is only 5 mg to 10 mg a week. We are not
aware of any adverse reports from people taking very low dose
deprenyl (10 mg a week) along with SSRI drugs like Prozac, but
there have been no published studies that address this
complicated issue.
Q What is the difference between Acetyl
l-carnitine and l-carnitine?
A Acetyl-l-carnitine is the
acetyl ester of the amino acid l-carnitine. Acetyl-l-carnitine
is absorbed into the bloodstream more efficiently than
l-carnitine, passes more easily through cell membranes and is
utilized more efficiently in the mitochondria of the cell.
Q I have read that high fructose from corn
syrup can cause hardening of the arteries and cross linking of
the skin. Is this accurate?
A Overconsumption of high
glycemic foods can cause excess production of insulin and can
contribute to chronic inflammation and glycation. Glycation is
the binding of a protein molecule to a glucose molecule
resulting in the formation of damaged, non-functioning
structures. Many age-related diseases such as arterial
stiffening, cataract and neurological impairment are at least
partially attributable to glycation. Taking supplements like
Carnosine or Chronoforte can help reduce glycation. Since the
intake of high-glycemic foods like fructose induces a sharp
insulin spike, and chronic high insulin levels
(hyperinsulinemia) is associated with increased risk of artery
diseases, reducing intake of foods that state "high fructose
from corn syrup" is a good idea. Many people tend to overlook
the value of moderation.
Back to
the Magazine Forum
|