Diseases with Indeterminate Risk
Unfortunately, a precise risk score cannot be formulated for every nutritionally related disease; but we can, sometimes, define certain genetic and lifestyle characteristics that predispose us to a particular disease. If these predispositions raise our risk score above a certain level, we must consider modifying our diet. If our risk score is very low, dietary modification is not necessary. The major diseases discussed in the preceding chapters are fairly predictable.
With some diseases, we know there is an association with diet, but we do not know enough to develop a risk profile. For example, diverticulosis relates to a low-fiber diet; but we are not able to separate people at high risk from those at low risk. Any recommendations for diseases within this category will apply to the general public. They will depend on the prevalence of the disease and our own dietary practices.
To illustrate, suppose a disease affects 20 percent of the population; you have one chance in five of developing it. If your diet puts you in the susceptible category, you may need to change it. By contrast, suppose the disease in question has an incidence of one percent or less. Your chances for getting it are less than one in a hundred. You may elect not to change your diet. Not only will the incidence of the disease influence your choice, but its severity is also important. You may elect to take a one-in-a-hundred chance for one disease, but not for another.
In this chapter we will discuss some serious diseases for which a risk profile cannot be defined. We will define the disease and outline its prevalence. Then, we will identify dietary practices associated with it. If you have these eating habits, you may want to change them. For anyone who elects to make a change, we will describe the best way to accomplish it.
The gastrointestinal tract is divided into four discrete regions. The esophagus is the tube passing from the mouth through the thorax and diaphragm to the stomach. It is a tunnel through which the food is helped along by muscular contractions that propel it in the right direction. The stomach mixes the food with fluids that begin the process of digestion. The small intestine is a long, narrow, coiled tube in which most digestion and absorption takes place. The large intestine is a short, wide tube in which water is re-absorbed and the undigested food is processed for excretion. Disease that occurs anywhere along this lengthy tract will often call for a change in diet. The type and consistency of the food passing through the digestive system may alter its condition. In addition, certain diseases within the gastrointestinal tract, particularly in the small intestine, may affect digestion or absorption of specific nutrients, and thereby necessitate a change in diet or the use of a supplement. In this chapter, we will not discuss this type of disease. Although diet is part of the treatment, sometimes the major part, it is not the cause of the disease. Anyone with this type of condition should be under a physician’s care.
Some diseases of the gastrointestinal tract, particularly of the large intestine, may be caused by improper diet over a long period of time. To understand how diet may cause these diseases, consider what happens to the residue of our food as it traverses the large intestine. Very little absorption or digestion takes place after the food enters the large intestine. It is simply prepared for excretion. The consistency of the residue and the amount of pressure that must be generated to expel this material depends to a large extent on the composition of the undigested residue reaching the large intestine. When we eat, we consume certain complex carbohydrates that our gastrointestinal systems are unable to digest. These pass intact through the entire system and reach the large intestine in virtually the same condition as when eaten. These undigested complex carbohydrates are called fiber. Fiber comes from cereal brans and various fruits and vegetables. While there are many different types of fiber, they all have one property in common: they trap water.
We’ve learned that different kinds of fiber help prevent different kinds of illnesses. There are actually two types of fiber: soluble and insoluble.
As their names suggest, soluble fiber dissolves in water, but insoluble doesn’t. Most plant foods contain both kinds of fiber, but they usually have more of one type than the other. Both soluble and insoluble fiber fill you up, but each one has specific benefits.
Soluble fiber, the kind that will dissolve, helps you feel full and also helps lower your cholesterol and your blood sugar. Soluble fiber is believed to lower cholesterol by linking up with bile acids, which are made from cholesterol stored in the liver, and escorting them out of the body. But the bile-acid supply must be replenished, and this calls for more cholesterol, thus lowering the cholesterol circulating in the blood. Soluble fiber also slows down the body’s absorption of carbohydrates, thus restricting dramatic highs and lows in blood sugar.
The best food sources of soluble fiber are apples, barley, beans, carrots, grapefruit, oats, oranges, peas, rice bran, and strawberries. Some breakfast cereals are rich suppliers of soluble fiber, which will help to lower your cholesterol. Select from a wide variety of cereals that contain large amounts of oat and rice bran, two very effective cholesterol-lowering agents. University of Maryland researchers have found, in fact, that the soluble fiber in oat bran is just as effective in lowering cholesterol and far less expensive than some of the commonly used cholesterol-lowering drugs are.
Insoluble fiber, which won’t dissolve, comes from the outer, hard shell of grains, and some is also found in most fruits and vegetables. It will help you to feel full and has the added benefit of helping to regulate your bowels by bulking up stools. Insoluble fiber is also believed to help prevent certain forms of cancer, most notably colon/rectal cancer.
This is the kind of fiber you probably know of as the wheat bran in bran muffins and raisin bran cereal. Other excellent sources of insoluble fiber are celery, corn bran, green beans, green leafy vegetables, potato skins, and whole grains.
Increasing the amount of fiber in our diet gets more water into materials passing through the large intestines. The more water, the softer the material and, ultimately, the softer the stool. Thus, one way to prevent constipation (or, for that matter, treat constipation) is to consume a high-fiber diet. Constipation can be a serious problem, particularly for older people. By creating a softer stool, a high-fiber diet will affect the large intestine in two ways. First, it will reduce the amount of pressure necessary to move the stool along for excretion. Second, a high-fiber diet moves the contents of the large intestine more rapidly and generates less pressure.
The large intestine is a muscular tube with an inside lining of specialized cells. Normally there are stronger and weaker areas in the tube. If very high pressure is constantly generated upon the walls of the tube, some areas will balloon and form small outpouchings, called diverticuli. If many outpouchings form, we call the condition diverticulosis. This disorder is common in older people. Twenty percent or more of people over sixty-five may have diverticulosis. High pressure over a long time causes the problem. Occasionally food or other debris within the large intestine gets trapped inside one or more of these diverticuli. This creates conditions that favor infection. The diverticuli become inflamed. When this happens, we term the condition diverticulitis. That is a painful and serious condition, and it demands immediate medical attention. We don’t know what makes one person more susceptible than another to getting diverticuli. Perhaps minute differences in the nature of the intestinal wall itself cause them. We do know, however, that increasing the amount of fiber in the diet reduces the risk of diverticulosis, and its most serious consequence—diverticulitis.
Should you go on a higher-fiber diet? That depends on how much fiber you are consuming. Table 21 (page 121) lists foods that are high in fiber. How often do you eat these foods? Usually, natural foods are higher in fiber than processed foods, and plant foods are higher in fiber than animal foods. Thus, the closer you are to being a vegetarian, the higher the fiber content of your diet.
Before you decide whether you need more fiber, you should consider another disease that may relate to a low-fiber diet. This disease is much less common than diverticulosis but much more serious: cancer of the colon. It is the second property of fiber in the diet that appears to provide some protection against cancer of the colon.
The more fiber in the diet, the faster the intestinal contents move, and the less chance they have to come in contact with the intestinal wall. If there are substances within the stool that can induce cancer, the exposure time to such substances is shorter on a high-fiber diet. Whether such substances are present in the contents of the large intestine appears also in part to depend on the nature of our diet. The higher its fat content, the higher the risk for colon cancer. Thus, the best type of diet to reduce our risk for colon cancer is one high in fiber and low in fat. The primary sources of fat in our diets are meat and dairy products. These foods are also low in fiber. Increasing the amount of fiber in our diet will almost automatically decrease the amount of fat.
We can summarize the arguments for a high-fiber diet as follows:
It will keep the stool soft and help prevent constipation.
It will keep the pressure inside the large intestine low and reduce the risk of diverticulosis.
It will move the contents of the large intestine more rapidly, reducing contact time with the intestinal wall. And it will almost always decrease the amount of fat in the diet, thereby reducing the potential carcinogen content of the stool.
How do we know if our diet contains enough fiber? The average American consumes about 12 grams of fiber per day. The optimal amount is believed to be between 20 and 30 grams. Look at Table 21. Add up the amount of fiber that you consume on an average day. Try to increase your consumption of high-fiber foods to approach 30 grams. You may find that the quantity of food required to increase the fiber is so high that you can’t eat it all. In that case, you may need to cut back more on some of the high-fat foods to make room for them.
It seems ludicrous to suggest that anyone take fiber supplements, but many people do. Maybe they have to restrict their calorie intake to the extent that they feel they cannot consume enough bulky vegetables without giving up too many of the delicious and satisfying animal products. (No foods of animal origin contain fiber!). There are some good supplements to be found in drug stores and elsewhere that were intended to control constipation, but if you think you need them because your diet is too low in fiber, some of them could serve equally well as dietary supplements. There is concern that supplemental fiber may decrease absorption of certain vitamins and minerals. So a multiple vitamin-mineral supplement may be advisable for anyone who takes fiber supplements for prolonged periods of time. Also, if you use any of the powdered fiber supplements, be sure to consume them with plenty of water.
If you make this type of change, do it gradually. If you suddenly take in much more fiber than you are used to, you may feel bloated and suffer from gas pains. Your gastrointestinal tract needs to adapt to the higher-fiber content of the foods. Make the change over several weeks, progressively increasing your fiber intake by small amounts each day.
One of the great fears of getting old is the prospect of losing one’s teeth. One out of every five of our older population has lost all teeth. There is increasing evidence that faulty nutrition plays some role in causing this problem. In early life, diet affects dental caries; in later life, it is related to periodontal disease.
There is no doubt that dental caries are related to diet. Specifically, there is a strong association between the amount of refined sugar we consume and the incidence of dental caries. To understand the nature of this relationship, let us examine how cavities occur.
The mouth is normally a breeding ground for millions of bacteria. The conditions within the mouth, as well as the food eaten, favor the growth of certain types of bacteria. Some of these organisms break down simple sugars, such as sucrose (ordinary refined sugar), to a number of products, including organic acids. They also use these sugars to construct a hard substance, called dental plaque, which adheres to the teeth. Thus, a diet high in simple sugar favors the growth of bacteria that require simple sugars to multiply. These bacteria, in turn, metabolize the simple sugar in a way that releases products that cause dental caries.
The bacteria secrete substances that form plaque. The plaque adheres to the teeth, and the bacteria beneath it are sheltered from your toothbrush. These bacteria continue to break down the simple sugar and in the process secrete organic acids that erode tooth enamel. Soon, a cavity appears which, under the constant exposure to these acids, gets deeper and deeper, finally invading the pulp of the tooth. So far, we have discussed two factors involved in the production of dental caries: sugar and bacteria. A third element must also be considered—the hardness of the tooth enamel itself.
The harder the enamel, the more resistant it will be to the acid secretions of the sugar-metabolizing bacteria. How hard a tooth becomes also depends, to some extent, on diet. Enamel, like bone, depends on calcium for its hardness. Unlike bone, however, enamel is not a calcium reservoir (except under extreme circumstances). Once formed, it holds on to its calcium. Thus, the crucial time for determining the hardness of the teeth is during early childhood when the teeth are forming.
Some studies shown that a diet poor in calcium will result in poor enamel formation and in teeth that are very prone to cavities. It is important, therefore, that the diet of every young child be adequate in calcium. The time to begin is at birth. Breast milk is rich in calcium, in a form easily absorbed by the infant. If your infant is bottle-fed, use a formula that is as close as possible, in composition, to breast milk. After the child is a year old, whole milk becomes the best source of calcium. Low-fat or skim milk can replace whole milk at about eighteen months of age, if you are concerned about fat. Dairy products will continue to be the major source of dietary calcium throughout childhood, but as the child grows older, other foods can contribute significant amounts of it. See Table 26 in Chapter 8 for foods that are rich in calcium. Remember, too much phosphorus will reduce calcium absorption. This is a particular problem in children. Many soft drinks contain significant amounts of phosphorus. Read the label. Phosphoric acid means phosphorus. Substitute a drink devoid of phosphoric acid.
Another very important nutrient in determining the hardness of teeth is fluoride, particularly during the early development of the teeth. Fluoride promotes calcium deposition, and ensures that it is firmly bound in the enamel. Fluoride is found in minute amounts in some foods and in some water supplies. In the United States, many localities have added fluoride to their water. Others have not. There is no question that the addition of fluoride to water supplies has reduced the incidence of dental caries. Yet, many areas are still reluctant to fluoridate their water, because of possible unknown side effects which, supposedly, could manifest themselves after long-term. Many households now use bottled water from which all minerals, including fluoride, have been removed. Some of us have installed filters in our home water supply to remove undesirable odors, or potential hazards. Some of these filters will remove fluorides. To date, we have not seen any long-term hazards from fluoridated water, and there is no valid theoretical reason to avoid it.
Breast milk does not contain significant amounts of fluoride. Therefore, breast-fed babies should be supplemented with fluoride. Fluoride is not added to infant formula. Therefore, if you use powdered formulas and the water in your area is not fluoridated, your infant should be supplemented. Fluoride taken in small quantities into the body will get into the teeth only during the first year or so of life. However, larger quantities applied to the teeth are effective throughout childhood. Therefore, we recommend fluoride toothpaste for all children.
To protect your youngster’s teeth, then, the diet must be low in refined sugar, high in calcium, and low in phosphorus, and (during the first year of your child’s life) with fluoride added to it either directly or through the water supply. Yet, this type of diet is not enough. The form of the sugar in food may be even more important than the quantity of sugar consumed. If the sugar is in a form that sticks to the teeth, such as chewing gum, caramels, candy bars, etc., it is much more harmful than a form that quickly clears the mouth. Therefore, you must pay attention to how you consume your sugar, not just to how much you eat. If it is a sticky type (as in raisins, fruit rolls, and sometimes bread—as well as candies and other “sweets”) then it is a good idea to brush your teeth after eating it.
The main points to remember in protecting ourselves and our youngsters from dental caries are:
Brush often to reduce the bacterial count.
Reduce the intake of refined sugar.
Reduce the amount of sugar in a sticky form (and brush after you eat it).
Consume an adequate supply of calcium.
Reduce your phosphorus intake, particularly at the same time as you consume your calcium.
Give your infant a fluoride supplement in the first year of life if you breast-feed or if the water supply in your area is not fluoridated.
Brush with a fluoridated toothpaste.
Periodontal disease occurs in later life and doesn’t directly affect the teeth, but the gums and the bones into which the teeth are anchored. If left untreated, periodontal disease can lead first to a loosening of teeth and then to their loss. Periodontal disease is the major cause of tooth loss in older people, and it is the primary reason that such a high percentage of older people are toothless.
The cause or causes of periodontal disease are not clearly understood. Chronic infection of the gums is one aspect. Erosion of the jawbones is another. Which comes first is not clear. Our best judgment is that usually the chronic infection leads to bone erosion. However, it is possible that sometimes the reverse is true. The erosion that occurs in the bones of the jaw is similar to that seen in osteoporosis. However, the risks associated with osteoporosis do not apply to periodontal disease. It is not more frequent in women. It has no relation to menopause, and it does not respond to hormone therapy. Thus, we cannot predict who will be at high risk for it.
Good oral hygiene is very important in preventing periodontal disease. Frequent brushing, the use of mouthwashes, and dental flossing all contribute to the control of chronic infection of the gums. Regular dental examinations will allow treatment to start early enough to control the infection before too much bone erosion has taken place.
Beyond this, there is a role for diet. As with the other bones of the body, the mandible and the maxilla (the two jawbones) participate in the regulation of body calcium. During early life, calcium deposits in these bones. In later life, calcium loss occurs. When more calcium is deposited in these bones during the formative years, more can be lost in later life without seriously affecting bone structure. Thus, the same dietary principles that we discussed for osteoporosis are important in periodontal disease. Unlike osteoporosis, however, there is evidence that sometimes periodontal disease can be reversed by calcium supplementation. Although this approach does not always work, it is worth trying. There is little or no risk to taking a calcium supplement. The potential benefits may be great. The dosage should be between 500 and 1,000 mg daily in the form of calcium carbonate, calcium gluconate, or any non-phosphorus-containing calcium salt.
Suppose your risk for all the diseases we have discussed is low. There are still reasons to consider changing your diet somewhat. That you are at low risk at any given time does not mean that you will remain at low risk for all time. Certain risk factors do not change—your gender, your race, your family history. Others can change rapidly and sometimes dramatically. Suppose you have a serum cholesterol level of 160 and no other major risk factors for atherosclerosis. A year later you check your cholesterol level and it is 180. Your risk is higher, and the trend is in the wrong direction. Should you alter your diet and increase your activity? If your diet is high in fat and if your lifestyle is sedentary, the answer is yes. It is this changeability of risks combined with our inability to define specific risk factors in other diseases that has prompted some experts to taker a more global approach.
Prestigious authorities have called for all Americans to change their diets. Their argument is that these changes will not harm us and will surely benefit some of us. There are several reasons to refute this argument. First, it discourages us from taking responsibility for a major part of our future health. Everyone should determine his or her own risk for those diseases in which such a determination is possible. If our risk is high, then certain changes in our diet may be needed. If our risk is low, we must determine at regular intervals whether that risk has changed. This is our own responsibility. Second, not everyone needs to change his or her diet even if risk cannot be established. Only those whose diet is poor in one respect or another need make specific changes. If you are a saltaholic, you should lower your salt intake. If your diet is high in fat, you should avoid certain fatty foods. If you take in very little calcium or iron or zinc, you should take measures to correct the deficiency. While all these recommendations are appropriate for many people, they are not necessary for all people. Examine your own dietary pattern and then look at the recommendations. Make up your own mind about what needs modification and how best to modify it. The recommended guidelines include:
Consuming the number of calories necessary to achieve and maintain ideal weight
Consuming no more than 30 percent of those calories in the form of fat
Keeping your salt (sodium) intake moderate
Consuming about 55 percent or slightly more of our calories as carbohydrate, with no more than 10 percent as simple sugar
Eating abundant quantities of foods containing dietary fiber while including whole grain breads and cereals in place of refined ones
Do these suggestions look familiar? Some or all of these guidelines were designed for lowering our risk to one or a combination of diseases. Even if your risk is low, they are worth considering if your present diet differs greatly. However, if you do decide to start one or more of these changes, be careful not to unbalance your diet and increase your risk for certain diseases. The woman who decides that she is taking in too much fat, particularly saturated fat, and cuts out all dairy products may induce a calcium deficiency. If she relies heavily on the newly available “fat free” products, she may not get enough vitamin E (a nutrient necessary for healthy skin, for protection of our lungs from environmental pollutants, etc.). Similarly, if she decides to cut out all meats, she may induce an iron deficiency. Unless the diet one is accustomed to is grossly abnormal, radical changes should be avoided, particularly for those at low risk. Any needed changes should be made in a manner that will insure a balanced nutrient intake.
Finally, the first guideline in the list may not be appropriate for many people. In order to achieve and maintain ideal weight, they may have to struggle constantly with calories, thereby increasing their risk for other deficiencies. Perhaps a weight that is 105 percent of your ideal would be easier to achieve and maintain. As we have seen, it is just as healthy and may keep you from constantly dieting.
In order for anyone to change his dietary pattern, adequate food choices must be available. While the United States has the most abundant food supply in the world, our food choices have been not always been adequate in nutrient content. It is still not easy to lower our salt intake significantly. Of course, if you salt your food heavily you can stop. What about the foods themselves? Until recently, as their convenience went up, so did their salt content. TV dinners, canned foods, smoked or pickled foods were usually high in salt. Going on a moderately salt-restricted diet meant a major change in lifestyle. It was difficult to eat in most restaurants or to take out food or snacks. Not so many years ago, this was true regarding dietary fat. Today, however, there are many alternatives: margarine, safflower, canola or corn oil, skim milk, fat-free or low-fat cheese, etc. We now have many fat-free and low-fat foods on our grocery shelves!
These foods did not appear spontaneously, but because the public demanded them. It is the same with low-salt foods; and we now see a wide variety of high-fiber foods, whole-grain products, and foods rich in calcium, zinc, iron, and folic acid. Increasingly, foods are being sold for the nutrients they contain—diet sodas for their low calories, salmon and sardines for their high-calcium content, skinless chicken for its low-fat content, vegetables that are high in fiber, low-salt spaghetti sauce, and low-fat (or fat free) ice cream. Given the incentive of potentially large profits, the American food industry is extremely innovative.
The more this trend continues, the easier it will be to alter our diets when we need to. Therefore, as more people participate in these dietary changes, the more choices become available. Those at high risk for certain diseases can make dietary changes more easily. As the buying habits of the public move in the direction of healthy dietary practices, it will be easier for all of us to alter our diets when necessary. Beyond that, as more and more products become available, more and more people may find they like them. Our eating patterns may totally change. Diet may no longer be a major risk factor for certain serious diseases.
After you have thoroughly evaluated your own health profile, determine whether you need any changes in your diet and lifestyle. If so, decide which plan (or combination of plans) is best for you and your loved ones; and try to motivate yourself and others to develop such a plan and stick with it.
You may ask, “How do I motivate myself to adhere to such a plan?” Here is one strategy that has worked for many individuals, and it may work for you:
Make a list of your strongest desires, regardless of whether you expect them to materialize and no matter how attainable they look on paper. Carry the list with you and add to it any new desires that occur to you. Then, by the process of elimination, decide what you want most. The things you do not truly want will make you drowsy or bored when you think about them. You’ll find yourself going to the refrigerator for a snack or something to drink. The things you really want will make you forget about bodily comforts, big meals, or something to drink.
When you concentrate on things you truly, deeply, desperately want, you will forget the clock, creature comforts, vacations, and the nonessentials of life. If you truly want something, your subconscious will furnish you with ample reasons and full power for doing it. Watch your memory in connection with anything you think you want. If you keep forgetting dates, appointments, or tasks related to what you think you want, you don’t really have the desire for it. When you have arrived at an awareness of just what you really truly want most, you will find that you must make yourself healthier and more attractive in order to achieve these goals.
Keep your conscious mind on the things you really, truly want to accomplish, and your subconscious mind will guide you to the reasons for achieving them.
Do not adopt measures that may help you in your short term goals—such as losing five pounds to get into your favorite nightgown for the annual ball, but which will damage your health for your long term goals. And don’t forget that professionals, in addition to your physician, in several medical and paramedical disciplines (psychology, nutrition, physical therapy, etc.) are trained and experienced in guiding persons such as yourself over (or around) the barriers which you will encounter. Do not hesitate to ask for their assistance. There are also several support groups that offer valuable assistance to persons or families with specific health problems; and don’t be surprised if you get a tremendous amount of support from your own loved ones. Perhaps, because you share so many genetic and environmental risk factors, your health profiles have many similarities; and, when one person in a family chooses to adopt a new nutritional health regimen, there is a direct spin-off.
The importance of diet and lifestyle becomes more evident to other members. The whole unit begins to improve its eating patterns, and everyone in the household begins to eat in a manner that is closer to the recommended diet. Soon it becomes obvious that these changes are neither difficult nor unpleasant. Often the new experiences are more enjoyable than the old. The principles of good nutrition are particularly important to young people because it is they who will set future trends. They will soon be starting their own families and determining their children’s eating patterns.