Food and You
Dallas E. Boggs, PhD
Common Sense about Food
Common Sense about Food
THE PRECEDING CHAPTERS present an outline of the science of nutrition; but, even in this abbreviated form, it was necessary to include a great number of technical matters that, for many readers, are interesting details of a large picture; but it is often difficult for the non‑technical reader to remember or implement the facts. Applied nutrition is practiced by dietitians as a profession—and by housewives by force of circumstance. Many among the latter group might welcome information that would be useful in solving the difficult problems that daily beset the "family expert" in nutrition. The individual who eats most of his meals in restaurants also might welcome a few tips about using the scientific data. In addition, we all need an expression of the "common sense" of the subject of food and its relation to personal nutrition. The USDA provides excellent guidelines for applying these principles.
Man is well suited to a diet that includes a large variety of foods that may be selected from both plant and animal sources, and we are quite adaptable to the extremes of our environments. Consequently, we live in all parts of the globe. In the tropics, where plants grow in abundance, man's sustenance may come wholly from fruits and vegetables. In the Arctic, on the other hand, his diet, for long periods of time, may consist only of meat and fat. These extremes present certain problems in nutrition. The tropical diet may often contain too little protein of high quality--while the Arctic diet is likely to be deficient in some of the vitamins and minerals. Added to the geographic limitations on the type of food avaiable, there are those imposed by custom, cussedness and crackpots.
Food Fads and Fancies
The dietary customs of a people often have their origins in the taboos of religion, old wives' tales and other forms of prejudice. Generally, the practical outcome of such influence is to prohibit the eating of certain foods that are either alleged to be unhealthful, or provoke the wrath of superior authority upon a hungry and hapless transgressor. The writer is unaware of a single food taboo of this type that makes any sense when compared with well controlled scientific studies.
Feeding the world is at best a difficult and precarious job. It is time for the mystical and sentimental obstacles to its accomplishment to be removed to make way for a rational attitude based solely on the facts of science. It may be considered axiomatic that a well‑fed world population is a prerequisite for world peace. A chronically hungry man is incapable of entertaining high ideals and unable, as well as unwilling, to engage in their defense. The half‑starved man is always a complaisant coworker of evil political leaders that thrive on strife. The demoralizing effects of an inadequate diet have been known, in a limited way, for ages; but during wars they are emphasized on a colossal scale—with gruesome and unforgettable realities; and it may be added that coercion by hunger does not vanish from the earth when the shooting stops.
Pure cussedness in regard to food habits is found in some individuals of all nations. There is little hope of changing the feeding habits of the present generation of such characters. They are often people who grew up subsisting on limited fare in a provincial environment. To them, any departure from old habits is as painful as mild cerebration about them—and, hence, is avoided like poison. The net result of denying oneself of all new adventures in eating is a lifelong continuation of a stereotyped pattern of food habits—reminiscent of the bovine complacency about rumination. The boy who learns to hate spinach will, of course, grow to manhood without it; and he continues to hate spinach. This sort of thing makes him a nuisance to his family and friends and deprives him of the benefit to be derived from a perfectly good food. A distaste for spinach is taken simply as an example of food aversions that have no rational basis—that example might equally well involve noodles, okra or peppers.
Food aversions and other strange habits are passed on from parents to children without conscious effort. A child is quick to see whether his parents themselves eat the foods that they insist are essential for his well being. He also interprets, with consummate and exasperating skill, the innuendos uttered by his elders about certain items that are on the menu. Children may develop queer ideas about a given food because their mothers are constantly nagging them about it. If a child is not ill, his hunger recurs frequently and with physiological regularity. Satisfaction of this hunger with a nutritious diet is enough to insure normal growth and development. A child, like an adult, may have experiences that rob him temporarily of his normal craving for food; and, under such circumstances, it is stupid to insist that he eat his usual hearty meal. If left to his own devices, and when there is no illness, he will easily make up the temporary deficit at the next meal. Furthermore, if left alone, the child will not subsequently associate a certain meal or type of food with maternal heckling. Instilling in the child an unbiased attitude toward food selection is a worthwhile goal for any parent; and, in fact, it may be considered an important first step in achieving the open mind in other matters.
Crackpots in nutrition are perennial. They cherish bizarre ideas about food and frequently display missionary zeal in spreading their notions abroad. Their fundamental fault is a lack of precise knowledge of the facts of nutrition. For instance, at one time there was a craze for unrefined sugar, which was supposed to be a "health food." It may very well possess some qualities superior to the refined product. The people who indulged in this food fad, however, did not have any clear idea about the nature of the magic nutrient alleged to be present in the unrefined sugar. The only concrete evidence of a difference between this and the refined product was the little pile of dirt that remained undissolved in the bottom of the coffee cup.
After a popular lecture on nutrition, the writer was informed by a man in the audience that he had cured his arthritis by drinking a daily dose of onion juice. This conclusion was probably the result of the common fallacy of associating two simultaneous events as cause and effect. The subsidence of this man's arthritic pains might have occurred spontaneously, with nothing whatever to do with the drinking of onion juice. The writer does not deny that this natural product may have some valuable nutritional properties, but they can only be discovered by carefully controlled studies involving many cases. The arthritic man who attributed his improved condition to the virtues of the onion simply fell into the error of drawing sweeping conclusions on the basis of insufficient evidence. Fortunately this man did not have a press agent and his idea did not spread beyond his immediate circle of friends. The uncritical acceptance of this type of idea can be as harmful as the mania for patent medicines.
Some food fads and fancies gain a wide though transient acceptance because somebody stands to make some money out of the vogue of the moment. Food products are highly advertised by every possible means; and claims are made that are later refuted or shown to be half truths. It may be recalled how bran was publicized as a means of "keeping regular"; the producers of this product failed to point out that bran is highly irritating to some people and that a large amount of roughage in the human diet results in excessive losses of nitrogen in the feces. This loss must be replaced from the supply of dietary protein.
A large dose of lemon juice was recommended at one time as an early morning cocktail, also for the purpose of "keeping regular". (An investigation of the national craze for mild catharsis should be an interesting project for the psychiatrists.) It was soon discovered that people who regularly took their cocktail of lemon juice, following the well advertised directions, found that their teeth were being dissolved by the rather strong acids that occur naturally in the lemon. Lemons and lemon juice are good foods; but they must be used in moderation. Bran and lemon juice are only two examples among dozens that could be mentioned.
When the consumer is constantly bombarded by extravagant claims for this or that food, it behooves him to become well informed and to adopt a highly critical attitude toward all such propaganda. An advertisement may claim that a particular product furnishes more vitamins, more protein, more "quick energy" or more iron without bothering to state the standard comparison. “More than what?”, is the important question. Almost anything edible contains more "quick energy" than wood shavings; but such direct comparisons are rare.
The Basic Seven Food Groups
Foods differ widely in their content of various nutrients. Eggs contain more protein than potatoes; milk furnishes more calcium than meat; and butter and margarine provide more fat than other foods. The body's daily dietary needs are usually stated as so many grams of protein, fat, carbohydrate, minerals and vitamins and not in terms of specific foods such as meat, potatoes and bread. In making up a diet, however, one must deal with foods and not with the pure foodstuffs. As an aid to diet planning and to insure an adequate intake of all the foodstuffs, the common foods have been arranged in the following seven groups:
( 1 ) Green and yellow vegetables. Lettuce, spinach, other "greens," carrots and sweet potatoes are common examples of this group. They constitute the chief dietary source of carotene, the plant pigment which the body converts to vitamin A. This food group also supplies significant amounts of vitamin C, thiamine, riboflavin, iron and calcium.
( 2 ) Oranges, grapefruit and tomatoes. The foods in this group are the richest sources of ascorbic acid or vitamin C. Tomatoes and tomato juice also contain considerable amounts of carotene, the precursor of vitamin A.
( 3 ) Potatoes, other vegetables and fruits. Potatoes contribute calories in the form of starch but they also are an important source of vitamin C. The percentage of vitamin C in the potato is quite small but potatoes are eaten in such large quantities that they may furnish as much as one fourth to one third of the daily vitamin C requirement. Potatoes are also a fair source of thiamine, niacin and iron.
All types of vegetables and fruits contain some crude fiber or roughage. This is not a nutrient in the usual sense because it cannot be digested or absorbed in the intestine. It is essential, however, to include in the normal diet a certain amount of fill or ballast in order to maintain proper tone and motility in the muscles of the gastro‑intestinal tract. The stream in the alimentary canal tends to become sluggish without the presence of some roughage. Highly refined and concentrated foods do not contain enough bulk to cause the comfortable distention of the stomach which is an important feature of a satisfying meal. A diet will not be entirely satisfactory, even if it supplies all of the nutrients, unless it fills the "cavity" that is sensed by the hungry man.
( 4 ) Milk and milk products, exclusive of butter, are the outstanding sources of calcium. In addition to this important mineral element, milk and its products furnish proteins of high biological value, phosphorus, vitamin A, riboflavin and thiamine. Milk is of course a necessity for the proper growth and development of a child or other young mammal. Normal rapid bone formation is impossible without an adequate supply of calcium and phosphorus, and both of these are abundantly supplied by milk. Before a child is born the pregnant woman must furnish everything needed for its development. It is almost a necessity, therefore, to include milk products in her diet in order to meet the demands of the developing child, especially for calcium. Milk is equally important for the woman who nurses her baby because the production of her milk makes large demands on the body stores of calcium. There is an honest difference of opinion among nutrition authorities regarding the necessity for large quantities of milk in the diet of non‑pregnant or non‑lactating adult women and adult men. Man is the only mammal that continues to drink milk after reaching maturity. It is a habit recently acquired and is most common in the United States. In some countries, the majority of the people cannot digest lactose (milk sugar) due to loss (after four years of age) of the enzyme that splits it into the simple sugars galactose and glucose.
It is a popular misconception that premium priced milks are nutritionally superior to the ordinary product. The higher price is charged to pay for a slight increase in butter fat. The butter fat in milk contributes some calories and contains most of the vitamin A; butter fat does not contribute any calcium or protein, which are the most important nutrients in milk. As a matter of fact, when economy is necessary, it is much wiser to invest in skim milk than to spend the extra money for a small amount of butter fat. Much is made of the "golden color" of certain milks but all this means is that certain breeds of cattle have difficulty in converting the plant pigment carotene, which is orange yellow, into vitamin A, which is colorless. The pale milk from certain cows may be just as good nutritionally as the "golden yellow" milk that is so highly advertised.
( 5 ) Meat, poultry, fish and eggs constitute the group of foods that are rich in proteins. On an equal weight basis these animal proteins are all superior to the vegetable proteins in biological value. Besides protein, the animal foods in this group furnish significant amounts of phosphorus, iron, thiamine, riboflavin and niacin. They also contribute a large share of the daily calories, but this is due in part to their fat content.
It is quite possible to have an adequate diet without meat, but a meatless diet is considered rather dull by most people. In this regard, it is interesting and significant that vegetarians often go to great lengths to make their main dishes look and taste like meat. Man is an omnivorous animal (that is, one adapted to eat both animal and vegetable foods); and it seems only sensible to recognize this fact, and to live accordingly and enjoy life. It is good health insurance to include one or two servings daily of some kind of animal protein.
( 6 ) Bread, flour and cereals as a group supply a number of nutrients in low concentration but the consumption of these foods is so great that they are an important source of proteins, B complex vitamins, and mineral salts. The starch content is high so that this group of foods also contributes a fair share of the daily calorie requirement. Cereals and cereal products generally are relatively inexpensive; thus, they usually account for a very important part of low cost dietaries. It is possible to devise an adequate diet that contains a great deal of the cereal group of foods, but it must be wisely supplemented with foods from the other groups.
Cereal proteins generally rank below the animal proteins; and, hence, it is advisable to include some meat, eggs and milk to enhance the value of the cereal proteins. Likewise, Vitamins A and C are almost absent in the cereals; so it is necessary to provide vegetables and especially the green and yellow varieties in the daily menu. It is good sense to regard the cereal group of foods as the expansible portion of a dietary--that is, the one that can be increased or diminished according to the caloric needs of the individual. A laboring man can have the same basic diet as the sedentary office worker; but he will find it necessary for him to eat much more bread and other cereal products in order to provide the extra fuel needed for active muscles.
( 7 ) Butter and fortified margarine are the fats most commonly found in the average diet. In addition to their contribution of vitamin A and calories they furnish "satiety value" in a diet. This refers to the sensation of satisfaction associated with the eating of certain types of meals. "Satiety value" is probably connected with the fact that fats tend to prevent too rapid emptying of the stomach and hence the onset of the next hunger pain is delayed. A diet low in fat is not only rather tasteless, but it fails to satisfy the person who eats it; it does not "stick to the ribs."
The producers and distributors of butter and margarine carried on a propaganda war for many years during which scientific investigations failed to show significant differences between the nutritive values of these two table fats. But, in this instance, the ''crackpots" won the war. We did not anticipate the harmful effects of the trans-fatty-acids that are incidental ingredients of partially-hydrogenated fats. Also, butter contains more unsaturated fatty acids than margarine; and, in the summer, the vitamin A value of butter may be higher than margarine fortified with vitamin A (1,500 international units per pound). In the winter, however, when dairy cows do not have access to green feed, the vitamin A value of butter may be very low.
The person who is living on a limited food budget, and who finds it difficult to taste any difference between butter and margarine, can use fortified margarine with reasonable confidence that his food fat requirements will be met. The gourmet who has an unlimited food budget will, of course, use only butter in the preparation of his food.
However, revelations that partially hydrogenated fats (including margarines) contain trans fatty acids, which increase production of "bad" cholesterol and decrease "good" cholesterol in the body, have shed new light on this issue; and we are now inclined to suggest that everybody should limit the use of margarines containing trans fatty acids. The food industry is changing the products that they put on the market to eliminate the trans fats.
The necessity for variety in the food supply is quite obvious. The brief discussion of the seven basic food groups is intended to emphasize this point. The average healthy person's nutritional needs will be satisfied if he eats at least one serving from each of the seven basic food groups every day. Following the guidelines of the USDA, as illustrated by the USDA Food Plate would be even better. Variety is obtained in the same kinds of food by obtaining them from different sections of the country; the progress in transportation of perishable foods makes this possible. Fruits and vegetables raised on the West coast will differ from such products raised in the East because the soils and climate are different. It is folly to say that one is better than the other because the western product, for example, may excel in vitamin content--but the eastern product may be superior in minerals.
The Importance of Cooking
It is proper to call attention to the importance of the fine art of cooking. It has been stated elsewhere in this book that the finest foods can be ruined in the kitchen. Improper storage, too much heat, too much water, prolonged soaking and discarding the cooking water are only a few of the malpractices of the casual cook. Aside from the actual destruction and waste of nutrients, poor cooking usually results in food which has no appeal to the appetite. An astonishing number of people seem to be completely insensitive to the rank negligence so evident in the preparation of the food that they eat. The housewife has a great responsibility in preparing properly the food for her family; and her family members should express their appreciation frequently and encourage her to greater perfection in her art. Poor cooking is not confined to the home; hundreds of restaurants ought to be closed because through careless kitchen practice they are squandering the nation's food supply. In the opinion of the writer it is preferable to go hungry than to submit to the insult of an atrociously prepared meal.
Safety of our Food Supply
Over the past 50 years, the U.S. has reduced by roughly half the death and illness from food-borne disease. Yet 325,000 Americans are still hospitalized and 5,000 die each year from contaminated food. Food safety is of utmost importance in our modern system of farming and distribution because contamination from one grower can cause nationwide outbreaks of vicious foodborne illness. Irradition of food, a process that propels gamma rays into meat, poultry and produce in order to kill most insects and bacteria is one answer to the problem. It is similar to milk pasteurization, and the American Medical Association, the Centers for Disease Control (CDC), the Food and Drug Administration and the World Health Organization have all certified that a big reduction in disease could result from irradiating foods.
Today only about 1% of our meat and produce is irradiated, though the technology was invented here. Such nations as India, Mexico and Thailand are starting to irradiate most of the food they export to the U.S., which means that produce from abroad could be safer than that grown here.
If even 50% of meat and poultry consumed in the United States were irradiated, the potential impact on foodborne disease would be a reduction in 900,000 cases, and 350 deaths. Food irradiation is a logical next step to reducing the burden of food borne diseases in the United States.
Most of the fresh-cut (minimally processed) fruits and vegetables can tolerate a radiation of 1.0 kGy, a dose that potentially inactivates 99.999% of E. coll.
The safety of irradiated foods is well established through many toxicological studies. No other food technology has gone through more safety tests than food irradiation. An overwhelming body of scientific evidence demonstrates that irradiation does not harm the nutritional value of food, nor does it make the food unsafe to eat.
The Food and Drug Administration bears some of the blame for bending to political pressure and slowing the spread of food irradiation. The food processing industry requested permission to apply irradiation to enhance the safety of produce in 1999, but seven years later the agency still hasn’t approved this “food additive.” The FDA does allow irradiation for meat, but it requires warning labels that send a message to consumers that eating such beef or chicken is risky. It would be wiser to require that meats and produce that aren't irradiated have a safety warning label. Those are the potentially unsafe foods.
In conclusion, good nutrition is not achieved by chance. The prime requirement is some accurate information on the subject. The object of this book is to provide at least an introduction to the normal processes of the digestion and utilization of food, the foodstuffs required for health, the foods that contain them, and the necessity and wisdom of handling and preparing foods with care.
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