Nutrition - Carbohydrates, Sugars And Starches
( Originally Published 1954 )
All natural foods consist of a certain proportion of sugars and starches. Almost every fruit contains sugar. Every vegetable contains starch or sugar. There are a number of familiar foodstuffs which contain high amounts of sugar or starch.
In the digestive process, starches and compound sugars are changed into a simple form of sugar called dextrose, in which form the blood absorbs it. The blood is the transport medium for carrying dextrose to all parts of the body, as energy is used in every activity of its cells, and carbohydrates are the most effective source of energy for the various bodily activities.
Every muscular action, every glandular function, every function of the nervous system, depends on the metabolism, or burning, of dextrose. This carbon compound burns more readily and easily than fats. In other words, it furnishes energy to the body more readily, as it is oxidized or broken down with the help of less oxygen than is required for the oxidation or metabolism of fat.
To prevent wasteful burning, so to speak, of this readily burn-able nutriment, dextrose, the body has an interesting provision for rapidly transforming the surplus into a more stable compound, called glycogen. Glycogen is stored within the cells of the body, and it is readily converted back into dextrose, as the system requires it. The liver and muscles store about 80 per cent of the glycogen; the bones, nerves, and other tissues about 20 per cent (Sherman).
There are other interesting uses for which the body's organic activities call upon dextrose. For our purposes it is important to bear in mind (1) the best possible sources of starches and sugars to give dextrose to the body; (2) the correct amount to avoid both any deficiency that might result in starvation, or an excessive supply that might result in numerous forms of disease.
The inflammatory diseases of the breathing tract, of the nose, sinuses, throat, and bronchi, are due in a large measure to excessive eating.- of sugar and starch or carbohydrate foods. Many of the disease affections of the stomach and intestines are due to excessive sugar and starch eating.
Dr. Kellogg, in his excellent work The New Dietetics, quotes numerous authorities who demonstrated on laboratory subjects that common table sugar, or refined sucrose, is an irritant to the mucous membrane of the stomach. This form of irritation may produce inflammation. In fact, inflammation, acute and chronic, is the most common form of disease.
The excessive use of sugar, such as is very prevalent in America, causes irritation and weakening of the mucous membranes of the body. Excessive carbohydrates cause excessive chemical wastes from their metabolism. These waste by-products are eliminated as rapidly as possible from the system, but before being eliminated, they combine with the alkaline or the acid-neutralizing minerals of the blood and tissues and are carried out as excretions from the system. This very often results in alkaline mineral deficiencies. People who eat lots of starches and sugars, and not enough leafy vegetables and fruits, rob their teeth, bones, and blood of a certain percentage of their minerals.
Dental decay is now recognized more and more as being caused by faulty diet. And faulty diet is the prevalent diet that the majority of the people of this country generally subsist upon. Sugar is used in numerous forms in this country. And starches find their way on the dining table in more than one form at each meal.
The new knowledge of food chemistry and of correct body nutrition teaches that carbohydrates are needed in lesser quantities than is generally consumed. And a better choice of sugars and starches can be made than has heretofore been made available by the industrial food providers. With our modern knowledge of foods and how they behave in the body, we may be able to work out a number of scientific guiding principles on how to eat correctly. In the discussion that follows, the important principles on the selection of starches and sugars are pointed out.
Physically hard-working people with good digestive systems can usually take care of a large amount of starchy foods. People with poor digestive ability, even though they may be hard workers, cannot digest much starch. They must get their carbohydrates for the various bodily functions from the simpler foods, the fruits, honey, and sweet root vegetables.
Sedentary workers, who exercise little after their daily work, need very little starch- If they have good digestive and assimilative abilities, they may put on surplus flesh and fat, and may develop diseases to which the fat are predisposed. Those of sedentary occupation who are below par in digestive and assimilative abilities suffer discomforts which are often agonizing when they overeat on starches and on cane sugar.
A generally applicable rule on the amount of carbohydrate which may be eaten with comfort is the following: When you feel heavy, sleepy, or fatigued after a meal containing starch, you should reduce the quantity of future starch feeding. This rule will be workable only with people who do not take stimulating beverages, such as coffee and tea with their meals. These drugs, like any other drug, mask the real sense of the body's condition.
Good fresh air for respiration is always necessary as an aid to normal digestion and assimilation. No undue mental or physical strain should be permitted, as strains interfere with proper digestion and metabolism in those who are debilitated. When the body is in good health and well adapted to surrounding conditions, it can tolerate carbohydrate foods with a maximum of comfort.
Some of the newer-school nutritionists are recommending a very small starch ration. For example, Dr. J. H. Tilden held the view that people over 85 years of age should not eat any starch, or should eat very little of it. The very strong and physically hard-working of any age can take care of more starchy food than people with digestive limitations.
Most of the foods essential to health, the fruits and vegetables, contain carbohydrates easier to digest than any of the grain or legume starches. Most people in the best of health may depend with safety upon the carbohydrates found in the roots, subacid fruits and non-starchy vegetables, those vegetables that ripen above the ground.
Unfortunately, the right kinds of sweets rarely find their way to the consumer, in the civilized world. Most confections and pastries are prepared with white refined cane sugar. This sugar is lacking in many of the elements which are contained in natural sugars, such as honey or maple sap or unpurified brown sugar.
Inflammatory diseases of the breathing and digestive systems are common among young children, because refined sugar is extravagantly used in their feeding. Many diseases of adults often develop because of excessive consumption of sugar. A desire for sweets, "the sweet tooth" so common among modern people, is a cultivated taste. Many primitive people, who never tasted sugar, reject it with dislike after a first taste.
Since civilized people have already cultivated the taste for sweets, a choice should be made from the syrup of maple, honey, dates, figs, ripe persimmons and the sweet root vegetables. When energy is quickly needed by the body, a teaspoon or two of honey in a glass of hot water, with a little fruit juice, will quickly yield sustaining energy to the body. Honey is to be preferred to table sugar (cane or beet sugar) be-cause ordinary table sugar, even the unrefined brown, is a compound sugar and it takes longer to digest and absorb than do the sugars of fruit or honey.
A growing number of people are learning the truth about the sugar question, and the business world is far-sighted enough to offer various sweet preparations with honey and other wholesome sweets instead of white sugar.
I here it may be stressed that brown sugar is as objectionable as the refined white product, being equally injurious to the digestive system. The only difference is that brown sugar contains a certain amount of mineral matter, while the white sugar is purified carbohydrate containing no minerals. Brown sugar, or sucrose, may predispose the mucous membranes to inflammation the same as white, because it is equally hard to digest.
A number of practical points will be made on the important and numerous staples, the starchy foods, the breads and the cereals, the dry beans, peas, and lentils. As they are eaten by vast numbers of people of the world, they are not all purified and devitalized. These foods contain 60 per cent or more of starch, 10 per cent protein, some fat, some minerals and a variable percentage of water.
The white potato is the least starchy of all the starch foods. It contains only about 20 per cent starch and 2 per cent protein, also valuable alkaline mineral matter. In order to get all the good there is in this food, the potato must be baked or steamed in the skin. Most of its protein and minerals are concentrated next to the skin.
Carbohydrate digestion is quite complex, involving the transformation of the starch grains into a series of intermediate products of less and less complexity, until the state of soluble sugar (dextrose) is reached, in which form it can be absorbed via the tiny blood vessel surfaces (intestinal villi) in the small intestine.
The saliva in the mouth is the first chemical which starts the digestive process of starch. Therefore it is necessary to insalivate properly and masticate even soft starches.
Soft starches such as porridge will obviously not incorporate as much saliva as stale or toasted bread, because it is overmoist to begin with. Moist food:, are not efficient stimulators of the salivary glands. Stale bread, being dry, absorbs a considerable amount of saliva and therefore is more easily digested than fresh, soft bread.
Any starch eaten should be masticated until its taste has turned somewhat sweet. At this stage starch has undergone the chemical change to dextrin.
Dextrin is an intermediate product between starch and a compound sugar (disaccharide) called maltose. Browned crusts of bread, and toasted bread which is subjected to slow heat until it browns gradually, consist mostly of dextrin. Oven heat has a chemical effect on starch, simplifying its structure.
This is worth knowing when it is a question of feeding individuals with poor digestion. The simpler their food is chemically, the better they will fare. Toasted bread is known to be easier to digest than fresh soft bread, because the heat of toasting converts the starch into dextrin.
The action of saliva on starch continues even when the food has been swallowed and is in the stomach. However, this valuable step is lost by faulty eating.
People generally eat too many other foods with starch—meat, eggs, fish, etc. Protein has a stimulating effect on the stomach, causing it to pour out certain digestive chemicals (hydrochloric acid and pepsin) which tend to destroy the chemical potency of saliva. Moreover when starch is present in the stomach at the same time as protein, it mechanically absorbs the pepsin which is needed for protein digestion.
Fortunately, nature made ample provision for adequate digestion of all foods. The small intestine and its accessory digestive glands (pancreas and liver) produce very powerful chemicals which, in a vigorously healthy body, are able to complete the work of digestion. Disease of the stomach and intestines is so common because these organs are strained with overwork by too much eating, and by eating too many food mixtures, such as starch, protein and sugar all at the same meal. When sugar (sucrose) is eaten together with starch, fermentation instead of proper digestion often results.
When all is normal with the process of starch digestion, the dextrin stage is followed by maltose. Maltose divides readily into dextrose by further action of the digestive chemicals in the small intestine.
Maltose is not only produced in the normal digestive process of starch but it is also produced by commercial methods. Vast quantities of the cereal barley and other starches are used for the manufacture of maltose sugar. Maltose is used in the manufacture of beer and for infant-feeding formulas.
Maltose is prepared in combination with dextrin commercially on a very large scale for infant feeding. This carbohydrate combination is generally added to milk, because milk sugar (lactose) does not digest very easily but undergoes a change into lactic acid by fermentation in the intestine.
This lactic acid has a useful function in the digestive tract. It helps to prevent abnormal chemical changes of putrefaction of protein by its antiseptic action on the colon bacilli. The bacilli are either greatly weakened or killed by lactic acid. Maltose and dextrin are carbohydrates which the infant's digestive system is able to handle more efficiently than starch.
As already pointed out, maltose is used commercially for fermentation into alcoholic beverages. A similar phenomenon may also take place in the human infant's laboratory-that is, in its digestive tract—when it is overfed! Since stomach and intestinal disease is so very common in infancy, even though such disease can readily be corrected by reducing the food intake, it can be seen that overfeeding is largely responsible.
A very serious objection to commercial dextri-maltose is that it is purified carbohydrate, lacking in vital elements. Honey, which is composed of fruit sugar (fructose) and grape sugar (dextrose) requiring no further digestion, can be used with greater satisfaction in infant feeding. Honey also contains valuable minerals and vitamins, which dextri-maltose lacks. Savages and barbarians often raise healthier babies (when they have the wisdom not to overfeed them) than do civilized people.
When maltose undergoes normal digestion, it changes into dextrose. In this form it is ready for absorption into the blood. Dextrose is also called "grape sugar" because a large proportion of this type of sugar is found in grapes.
Another sugar called levulose (invert sugar or fruit sugar or fructose) is abundant in nature. The fruits, particularly, contain fructose in combination with dextrose. When table sugar (sucrose) digests normally in the alimentary tract, it breaks down into dextrose and fructose.The latter, before it can be absorbed by and utilized in the blood, is converted into dextrose. This change takes place in the liver.
All these points about the digestion of carbohydrates are given because they help one to understand how necessary it is to take care of this most complex, vital, yet self-managed laboratory—the alimentary tract.
To many people, eating is a sensuous pleasure. Gluttony is ram-pant because false notions are built up about food. Proper selection of food is an applied science and art which men and women must learn.
Nature forms complex and integrated plant compounds. The simple sugars, dextrose and levulose, are generally found in young plants, fruits and vegetables. As plants become mature their simple sugars turn into disaccharides like sucrose in beets and carrots, or like starch in mature potatoes, wheat, peas, and other grains. These last-named foods contain simple sugar in their unripe states. Everyone is familiar with fresh green peas, for example. They are sweet because the carbohydrates within them is a sugar. When mature, they are more or less starchy.
Another interesting provision of nature, in furnishing an abundance of foods for man and animals, can be seen in her way of producing certain foods which may be picked in their unripe state and kept stored for out-of-season periods. Winter apples, pears, bananas, persimmons, tomatoes, avocados, and numerous other fruits and vegetables may be picked before they are fully ripened. This makes it possible not only to store foods, but also helps in transportation from places where they grow in overabundance to regions which are less favored by nature.
The argument one often hears advanced, that all foods should be eaten when fully ripened on the plant, is not altogether valid. Storage-ripened persimmons, pears, peaches, melons and avocados have excel-lent food value. Moreover, we, in temperate regions, can hardly get those foods transported in their ripened state.
It seems natural for some foods to ripen after they are picked be-cause they change from a raw, objectionable taste and consistency into sweet and luscious foods within a certain period of storage. Their elements are transformed from crudeness to wholesome matureness. Examples are the banana, persimmon, avocado, etc.