Pectin is a constituent found in many plants, especially edible fruits. It
is most familiar to the North American consumer as a supermarket substance
used in the making of jellies and puddings. In conventional medicine it is
found in the useful over-the-counter remedy, Kaopectate®, and less
conventionally as a treatment for elevated cholesterol and diabetes.
Scientifically, pectin can be described as a complex polysaccharide which
functions as the intracellular "cement" in the cell walls of all fruits and
vegetables. An orange rind, for example, contains about 30 percent pectin.
One would hardly expect this common compound to convey any miraculous health
benefits.
Recently, however, Michigan scientists have been studying the effects of
plain citrus pectin (CP) as well as a chemically modified citrus pectin (MCP)
on the spread of cancer in various experimental systems. In the early 1990s,
they looked at MCP's impact on the ability of melanoma (deadly skin cancer)
cells to invade and form colonies in the lungs of rats.
"Injection of MCP significantly decreased B16-F1 experimental metastasis"
by more than 90 percent, according to David Platt and Avraham Raz of the
Michigan Cancer Foundation, Detroit, writing in the Journal of the National
Cancer Institute (1992;84:438-442).
In March 1995, another report by Dr. Kenneth J. Pienta and colleagues at
Wayne State University and the University of Michigan appeared as a featured
article in the same government-published journal. It reported on the value
of MCP in the prevention of metastases in prostate cancer in mice. Once again,
the results showed that MCP was a "potent inhibitor of spontaneous prostate
carcinoma metastasis in the Copenhagen rat."
BENEFITS IN PROSTATE CANCER
Prostate cancer is the most common cancer diagnosed in U.S. men. There are
about 244,000 new cases every year, and 40,000 deaths. About 50 percent of
these men have disease that has or will metastasize, usually to the skeletal
system. And, according to the JNCI article, "at present, there is no effective
curative therapy and very little palliative therapy for patients with metastatic
disease." New treatments are desperately needed.
This process of metastasis is complicated, but at several points involves
interactions with cell-surface proteins that bind to carbohydrates. Some
of these proteins are called galectins. In a prior experiment, when cancer
cells were treated with an anti-galectin compound, lung metastases were inhibited
(Cancer Res 1986; 46:5270-5275) A correlation has also been found between
the amount of galectin on a cancer cell and the stage of the tumor in human
colorectal, gastric [stomach], and papillary thyroid tumors (Oncogene
1992;7:2507-2511 and Cancer Res 1991;51:387-393 and Int J Cancer 1994;56:
474-480).
In 1992 it was further shown that modified citrus pectin (MCP) could interfere
with the interactions that were controlled by galectin between cells (JNCI
1992;84:438-442). So clearly, MCP is a promising agent.
In the Michigan experiment it was found that when rats were injected with
one million prostate cancer cells, 15 out of 16 developed lung metastases
after 30 days. (The sixteenth had lymph node metastases.) But when the rats
were given a 1.0 percent solution of MCP in their drinking water, 9 out of
16 had either no metastases or statistically significant reductions in size
and number of their metastases. It is important to note that MCP had no effect
on the growth of the primary tumors. Nor did it have any effect on blood
vessel formation in tumors.
Logically, the authors conclude that MCP acts as a "cytostatic" or
"antiadhesive agent" in the early stages of metastasis rather than as a treatment
for established primary tumor or metastatic growths. It is not cytotoxic:
put into a Petri dish with human prostate cancer cells it has no effect on
their growth.
When will MCP be made available to patients? A technique for manufacturing
MCP was first published in 1960 (Arch Biochem Biophys 90:46-49). To our knowledge
this remains in the public domain. However, recently the giant Hercules firm
of Wilmington, DE announced a deal to develop MCP as a cancer medicine, along
with the aforementioned Michigan scientists. So theoretically MCP may have
a commercial future as a prescription drug. (Allow us to express our doubts:
any use patent will probably be too weak and the manufacturing technique
too generally known to offer the company much protection in the marketplace;
also, the developers may be astonished to learn how little interest there
will be among the purveyors of toxic chemotherapy in any non-toxic agent
like MCP, which are seen as unfairly competitive with highly toxic agents.)
Recently, a source of MCP for today's consumer has come to light. In mid-1995,
a pharmaceutical researcher in California started making MCP for three friends
with prostate cancer. Word spread. He believes that the optimum dosage is
five grams—or one rounded teaspoon—consumed three times per day.
This can be added to hot water or added to a blendered energy drink It is
now available from Klabin Marketing, 2067 Broadway, New York, NY 10023, phone:
212-877-3632. The cost is about $140 for a months' supply.
There are no reports of pectin or MCP being harmful to anyone. Certainly
pectin is something most of us inadvertently consume every day. The California
scientist I referred to has tested MCP on himself and on several coworkers
and found that at this dose the level of galacturonic acid (a breakdown product
of pectin) was indeed elevated in the blood serum. He says this may show
that enough MCP is getting into the bloodstream to bind to the surface receptors
of cancer cells—which is exactly what you want the pectin to do.
Bear in mind that we have been discussing animal results, which may or may
not correlate with human clinical results. (The entire field of chemotherapy
was founded on exactly such animal studies.)
The presence of galectin-3 on human prostate cancer cells is certainly a
powerful hint that MCP will work in humans as it does in rats.
Who might take it? The obvious first choice would be men who have been diagnosed
with prostate cancers, whether operated on or not, that have not yet
metastasized. Another possibility would be men with very small bone or lung
metastases or men with elevated PSAs. As to other cancers, it seems likely
that some patients, male or female, with melanoma that has not yet metastasized
might also profit.
But it's not a sure thing, only a reasonable hunch, that in cases where preventing
the occurrence of metastases is a major consideration (as in almost all
cases of early stage prostate cancer) taking MCP seems like a relatively
harmless and inexpensive way of increasing one's odds.
