Dr. Moshe Shike is an attending physician at Memorial Sloan-Kettering Cancer Center and a professor of medicine at Cornell University Medical College. He is the director of the Cancer Prevention and Wellness Program at MSKCC. A gastroenterologist, Dr. Shike conducts research on nutrition in cancer, and has been examining the role of diet and specific dietary factors on various stages of cancer development. Discovery Health interviewed Dr. Shike about gastrointestinal diseases and the role nutrition plays in causing and treating them.
Q: Dr. Shike, what is diverticulosis?
A: Diverticulosis is a very common problem. It occurs when the wall of the colon has little pouches that protrude, creating little pockets or inlets along it. Diverticulosis makes the colon look much like a map of the coast of Norway with all the fiords. It is usually associated with constipation and vague discomfort.
In extremely rare cases, diverticulosis causes what is known as diverticulitis. This condition is very rare. When diverticulitis happens, there is a severe inflammation and sometimes a micro-perforation in the wall of the colon and an abscess. This disorder has to be treated by a physician and fairly quickly, because if it is allowed to go [undetected], it can cause major infection inside the abdomen. But the overwhelming majority of people with diverticulosis experience only problems like slight discomfort, constipation and some excess gas in the colon.
The best way that we know of to treat such symptoms is to increase fiber in the diet. So we suggest that patients with diverticulosis consume adequate amounts of fiber, 25 to 35 grams of fiber a day.
This disorder is in no way associated with cancer of the colon. Some people think that having diverticulosis may increase their chances of getting colon cancer, but it does not. Now, of course a lot of people who develop colon cancer have diverticulosis and vice versa, but diverticulosis itself does not predispose a person to colon cancer.
Q: At what age does diverticulosis typically occur?
A: Diverticulosis starts in middle age, and as people age it becomes more common. Usually with advancing age, we see it spreading throughout the colon. In most people, it is confined to the area toward the end of the colon. But in some people we see these little pouches throughout the colon.
Q: Should people with diverticulosis avoid things like seeds and corn on the cob that can get stuck in the pockets?
A: This is a commonly held belief. It is amazing how many people think that this is the case. But there is no evidence whatsoever that avoiding seeds or corn will improve this disorder, or that eating these things will cause any problems. So we don't suggest this as a part of a dietary restriction. We see a lot of people whose diet is heavily restricted because of this belief, and it's not justified, as there is no evidence that seeds or corn will aggravate their problem.
Procedures for Extreme Cases
Q: In extreme cases of inflammatory bowel diseases, or IBDs, such as Crohn's disease, sometimes part of the colon needs to be removed. Can you discuss these types of procedures, and then how people go on living their lives once part of the colon has been removed?
A: The gastrointestinal tract is very long, and there is a lot of reserve capacity. Some people have disease in part of the gut or intestinal tract, and sometimes part of the tract has to be removed by a surgeon. Now, the removal of part of the intestinal tract does not necessarily result in severe problems. Let's go over some parts that are commonly resected.
People who have cancer of the stomach will have their stomach - or part of it - taken out. Usually when this happens, it is important to pay attention to their nutritional state and to their diet. A lot of people who have this resection lose weight because they tend to eat less. That's due to the absence of the reservoir of the stomach. Therefore, people who've had part of their stomach removed should consult with a dietitian in order to choose the right foods and the right pattern of eating.
In this kind of situation, we suggest people eat small meals and eat frequently, because they don't have the reservoir to eat a large meal. It is also important to consult a dietitian, because people who have a complete resection of the stomach cannot absorb vitamin B12 and may need to receive B12 injections on a regular basis.
Now, if we move on to resections of the small intestines - as happens in people with Crohn's disease - the small intestine is very long, about 15 feet. You can remove large parts of the small intestine, and people can still have enough surface to absorb the food they need. Again, it is important in cases of resection of the small intestine that patients confer with a dietitian to get advice on proper foods and to guard against deficiencies that can arise because of these resections.
For instance, resection of the very end of the small intestine - the part called the terminal illium - may result in diarrhea. It may also result in lack of absorption of vitamin B12. By consulting with a dietitian or with a physician who has knowledge in nutrition, a lot of the problems that can arise from this [type of] resection can be addressed.
People who have severe Crohn's disease or another inflammatory bowel disease called ulcerative colitis, in which there is also a lot of inflammation and ulceration in the colon, may undergo a resection of the colon. One can live perfectly well without a colon. Initially there is a lot of diarrhea, but as time goes by the diarrhea can subside.
In centers where colon-resection surgery is frequently performed, the level of technical sophistication is very high. Surgeons can attach the small intestines to the area of the very end of the rectum, the anal area, and preserve the sphincter, giving people control over their bowel movements and eliminating the need to have a bag, which is a frightening concept for many people. In certain cases a bag is unavoidable, but these are a very small minority.
Treating GI Disorders
Q: Can you comment on another inflammatory bowel disease, ulcerative colitis?
A: Ulcerative colitis is another inflammatory disease of the intestines, which affects the colon. It can affect other organs in the body, but primarily affects the colon, not the small intestine. In this disease, there is ulceration of the lining of the colon, called the mucosa, and these ulcerations and inflammation cause bleeding, diarrhea and pain. There is an effective medical therapy to quiet down the disease.
Ulcerative colitis cannot be cured, and even when it subsides due to medications, it usually comes back sometime later. If the disease is serious and does not respond to treatment, the colon will start to dilate, and there is a risk that it will perforate. In extreme cases, the colon is taken out.
Although there is no dietary therapy for this kind of disorder, it is important for people with ulcerative colitis to maintain proper nutrition. However, when patients are taking medicine for severe inflammation, they often don't feel like eating and can find it difficult to maintain good eating habits. But diet does not cure, nor does it affect, the course of the disease itself.
Q: As a medical practitioner, what is your view on alternative therapies for GI disorders?
A: Gastrointestinal disorders must be treated by means and methods that have been fully investigated and proven to be helpful and not cause excess damage. A lot of the so-called alternative or complementary medicine methods have not been adequately researched, and thus we do not know their impact or potential damage. For instance, a lot of people take herbs, but we don't know what they do in the body. We don't know the nature of these herbs, and a lot of people have gastrointestinal problems from these herbs that they don't associate with them.
There are other practices such as taking coffee enemas, or other enemas containing all kinds of things, that supposedly cleanse the body. You cannot. There is no such thing as cleansing the body. In the normal course of eating and absorption, stool is eliminated. Enemas with coffee or other materials are not going to cleanse the body. The stool has to come out, and the way it should come out is by regulating bowel movements, by following an appropriate diet and - in extreme cases - by taking an enema. But putting all kinds of materials into an enema does not necessarily help, and sometimes it can be harmful.
Q: What about things like acupuncture, reflexology, Yoga or raw food diets?
A: Acupuncture, reflexology and raw foods have not been proven to be helpful against gastrointestinal disorders. Now, we should not confuse the issue of feeling well by doing something with curing or controlling a disease. For instance, a lot of people like to have a massage. It makes them feel good, it may make them feel relaxed, but that does not cure gastrointestinal diseases or any other diseases. And this confusion has to be avoided, because we're seeing people who are relying on these highly questionable and potentially harmful therapies instead of following the appropriate medical treatments.
Medical Advancements and Prevention
Q: Would you comment on recent advancements in medical procedures?
A: One of the major developments occurring in the field is imaging of the colon. For instance, there is now what is called virtual colonoscopy, where the entire colon can be visualized by means of a CAT scan. We do not know yet the full utilization of this method because it is still under research. There are also new methods of using laser therapy and other therapies to prevent damage to the esophagus from acid, and changes in the cells that eventually can lead to cancer.
Major developments have also happened in our understanding of ulcers. Now that we know the major cause of ulcers is bacteria, we can treat the bacteria and thus eliminate the underlying cause of ulcers in many people. There is also improved understanding of how the gastrointestinal tract contracts, and moves food through the intestines. This is important because eventually it will lead to a better understanding of irritable bowel syndrome (IBS) and hopefully to better therapy.
Q: What can Americans do to ensure that they have a healthy digestive system? What's the best dietary advice you can give?
A: Since the gastrointestinal tract's main function is to take food, break it down and absorb it, let's talk a little bit about what's the best food to put into the gastrointestinal tract.
There has been tremendous research done on what a healthy diet is. This is a very complex area. But a healthy diet has been found to prevent heart disease, lower blood pressure, decrease the risk of certain cancers and maintain general health. There are four principles of a healthy diet: 1) Avoid consuming too many calories, which results in weight gain and obesity; 2) Cut fat intake to no more than 20 percent of total calories; 3) Consume adequate amounts of fruits and vegetables; and 4) Make sure that there is an adequate amount of fiber in the diet.
Let's elaborate a little bit on these four principles. First of all, people should not overeat. Overeating makes you feel full, creates a lot of gastrointestinal symptoms and, of course, is the underlying cause for obesity, which is a major health problem. So everybody should define the number of calories they need in order to maintain a healthy weight, and try to stick to them by having a reasonable eating plan and not overeating.
With regard to how much fat one should consume, numerous studies have shown that diets containing about 20 percent of total calories in the form of fat are healthiest.
The third principle is fruits and vegetables. Clearly, Americans do not eat an adequate amount of fruits and vegetables. Fruits and vegetables are sources of many compounds that can maintain health. We recommend that the average person consume at least five to eight servings of fruits and vegetables a day. The average American eats about half the recommended amount.
The average American also consumes only half the recommended amount of fiber. A typical American diet includes about 12 to 14 grams daily, and we recommend that about 25 to 35 grams of fiber be consumed.