The health-enhancing properties of citrus fruits have been known for centuries. In 1593, Great Britain’s Sir Richard Hawkins suggested that something in lemons and oranges prevented the scurvy that bedeviled sailors on long voyages. That medicinal ingredient was identified as vitamin C in the 1920s, and since then we have learned that citrus fruits contain many other vitamins, minerals, and heath-enhancing substances. One of these is the pectin found in the fruit’s rinds. A soluble fiber, pectin is known to help counteract diarrhea and reduce cholesterol levels.1 But its effects are limited to the intestinal tract, as it is not readily absorbed into the bloodstream.
Medical researchers recently have learned how to “chop” citrus pectin into smaller “pieces,” and to subtly change its structure to make it much more absorbable. And they have discovered that once in the bloodstream, this modified citrus pectin, known as MCP, may help combat cancer and rid the body of certain toxic substances. It also may reduce several forms of blood cholesterol better than “regular” pectin.
MCP for Prostate Cancer
Prostate cancer is among the most frightening diagnoses a man can receive. Many men are not even aware they have a prostate—the small gland wrapped around the urethra, just below the bladder—until they have pain or difficulty with urination or ejaculation. If they are “lucky,” they will be told that they have an enlarged or inflamed prostate. If they are unlucky, the diagnosis may be prostate cancer. According to the American Cancer Society, more than 220,000 men received this diagnosis in 2003, and close to 29,000 died of the disease. It is the second most common form of cancer in men (after skin cancer), and the second most deadly (after lung cancer). One in six men will develop prostate cancer during his lifetime, and 1 in 32 will die of it.2
Physicians have a variety of treatments for prostate cancer, ranging from drugs that block the male sex hormones that “feed” the cancer, to surgeries that excise the diseased tissues, to radiation designed to destroy the cancer cells. These cancer-fighting medicines and other techniques are improving, and if the cancer is caught while it is still in the prostate or nearby, the odds of survival are good. But if the cancer has spread, there is only one chance in three that a man will survive five years past the diagnosis, no matter what treatment his doctor offers.2
Theories on the nature of cancer are evolving. Scientists used to think cancer cells were individual actors, and that even a single cell escaping from the main tumor would likely start a new colony elsewhere in the body. But now we are learning that cancer is more of a “group activity.” Just as a platoon of soldiers is more powerful than a single rifleman, cancer cells are more dangerous when they assemble and clump together. To do this, they must communicate with and bind to one another. That cell-to-cell interaction is made possible by special molecules that sit on the outer surfaces of the cancer cells. For certain types of cancer cells—such as breast, colon, melanoma, lymphoma, and prostate cells—one group of these “interaction molecules” is called the galectins. And one of these, known as galectin-3, plays a key role in the spread, or metastasis, of cancer. There appears to be more galectin-3 on metastatic cells than on the original tumor cells.3,4 And with certain types of cancer, the more advanced the cancer stage, the more galectin-3 is found.4 With more galectin-3 available, cancer cells find it easier to bind to one another or to stick to noncancerous tissues elsewhere in the body. Indeed, it seems as though galectin-3 and other interaction molecules prepare the way for cancer to grow and spread.
Galectins and other interaction molecules work like a car’s key and ignition. Only the correct key will fit into the ignition and activate the engine. Some other keys will fit, but they will not be quite right—they will only jam the ignition and prevent it from working. So it is with the interaction molecules that sit on the outer surfaces of cancer cells. Think of them as being the “molecular ignition” to the cancer cells. The right “molecular keys” will slip in, “turn on” the cells, and allow them to perform their deadly actions. But several “almost-right” molecular keys, similar to the real thing but not quite the right shape, will jam the molecular ignition. A jammed ignition is a bad thing in a car, but it can be a good thing in a cancer cell, which we do not want to “turn on.” We want the molecular ignition to jam up so the cancer cells cannot clump together or stick to healthy tissues.
Where cancer is concerned, a broken ignition is good, and it appears that modified citrus pectin can break it. Not literally, of course. Instead, MCP is like an imperfect version of the molecular key. It fits into the ignition and jams it, preventing the right key from getting in. In other words, it gums up the works. With their molecular ignitions jammed, cancer cells find it harder to stick to other cancer cells or to healthy tissues. In short, they are rendered less likely to metastasize.
Research on MCP vs. Cancer
Dr. Kenneth Pienta and his team published in the Journal of the National Cancer Institute the results of the first study on oral modified citrus pectin.5 For this study, prostate cancer cells were implanted in laboratory animals. Half of the animals were given water with MCP added, half drank regular water. The cancer spread to the lungs of 93% of the animals that drank regular water, compared to only 50% of those given the water containing MCP. This study showed that not only was the cancer less likely to spread in those taking MCP, but also that if it did spread, it established smaller colonies.
In 1999, researchers examined the effects of MCP on prostate cancer in humans.6 Seven men suffering from the disease who had not been helped by conventional treatment were given 15 grams of a modified citrus pectin called Pecta-Sol® every day for three months or longer. The researchers looked at the effects of Pecta-Sol® on a measurement called the PSA doubling time.
PSA, or prostate specific antigen, is a substance produced by the prostate. It is easy to measure in the blood. A healthy prostate manufactures relatively little PSA: a standard blood test will find less—often much less—than 2.0 ng/ml in the blood of a healthy man. When prostate cancer develops, PSA begins to rise. Depending on one’s age, levels between approximately 2.5 and 6.5 should be considered suspect, and anything above that should be considered alarming.
Besides looking at the absolute PSA reading, researchers also watch the PSA doubling time, or the amount of time it takes the PSA level to jump, for example, from 2 to 4, or from 4 to 8. The faster the rate of doubling, the more dangerous the situation. PSA doubling time is considered an important tool for tracking the growth of prostate cancer. Slowing the doubling time is a positive sign. Stopping the increase in PSA altogether is an even better sign, and a falling PSA level is the best sign of all.
The results for the seven men in the 1999 study were very encouraging. Four of the seven enjoyed a positive response—that is, it took significantly longer for their PSA levels to double. For a fifth man, it took slightly longer for the level to double, and in a sixth, the PSA remained about the same, which raised the possibility that his cancer did not progress at all. This small preliminary study suggested that modified citrus pectin does indeed “gum up the works” on prostate cancer cells, slowing the rate at which the cancer grows or spreads.
MCP was put to the test again in a 2003 study.7 Ten men with prostate cancer, all of whom had undergone standard treatment but had not been cured, were used to test the efficacy of the MCP called Pecta-Sol®. Each participant had “low but progressively rising PSA levels.” Each was given 14.4 grams of Pecta-Sol® daily. A year later, seven of the 10 recorded a statistically significant slowing of their PSA doubling time. This is a positive result, for as the researchers point out, “Intuitively, it seems that increasing the time it takes for the PSA to double, if sustained, would mean that the cancer progression would be slower and would conceivably result in a prolongation of life.”
Data from the Pecta-Sol® prostate cancer studies produced another interesting finding: in a few men, the PSA level dropped. This may have been a random occurrence, or the MCP may have triggered it. Isaac Eliaz, MD, one of the researchers, notes that until recently it was thought that modified citrus pectin works by “gumming up the works” on the surface of cancer cells, preventing the galectins from helping the cells link up with other cancer cells or with healthy tissues.8 If that were the case, one would expect the PSA to climb more slowly or to stop rising altogether when MCP is administered. But one would not expect MCP to make the PSA drop. Only a cancer-killing agent—one that destroys cancer cells and stops them from producing PSA—should do that. Could modified citrus pectin be a cancer killer?
If so, it might be through its effects on galactin-3. Galactin-3 may do more than just help cancer cells interact—it may also play a role in angiogenesis, or the growth of new blood vessels needed to feed tumors. Like other body cells and tissues, cancer cells and tumors need plenty of fresh blood. To ensure that they get it, they secrete substances that force the body to construct new blood vessels for their use. It is as though cancer hijacks the body’s internal “road-building” machinery and forces it to build blood vessels exactly where it needs them.
If galactin-3 is indeed involved in this process, then modified citrus pectin, which interferes with galactin-3, might be a cancer killer. By interfering with galactin-3 and preventing the building of new blood vessels, it could literally cause the cancer cells to starve to death. This hypothesis is supported by the results of a 2002 study published in the Journal of the National Cancer Institute, in which researchers found that MCP does reduce angiogenesis.9
“Strangling” cancerous tissues by preventing them from getting an adequate supply of blood means that modified citrus pectin could be useful in treating cancers other than prostate. Indeed, Dr. Eliaz notes, “It is important to emphasize that the benefits of MCP and the galectin-3 mechanism of action are not specific to prostate cancer, but apply to a wide variety of cancers such as breast, colon, melanoma, ovarian, lung, nasopharyngeal, leukemias, glioblastomas, and others.”
More and larger studies are needed before definite conclusions can be drawn. But the early evidence strongly suggests that modified citrus pectin helps to keep prostate cancer and other cancer cells from joining together and from sticking to healthy tissues. This makes it a potentially powerful weapon in the fight against prostate cancer and other forms of cancer.