Vitamin C

MARY L. DODDS.

THE conquest of scurvy is a land- mark in the dramatic story of nutrition. Scurvy once was common during famines and wars and among sailors who ate little except bread and salt meat on long voyages.

Scurvy brings debility, skin degeneration, spongy gums, hemorrhages in body tissues, and sometimes death.

People recognized the symptoms readily enough and concluded that scurvy and diet were related somehow. Naval physicians conducted thorough investigations of causes and the remedies. They learned that eating fresh fruit, especially citrus fruits, and some vegetables can prevent scurvy. The British Navy in 1795 ordered all its ships to carry supplies of lemons or limes.

It took a long time to establish that the effective substance is vitamin C. The way it performs its work is still mysterious.

Charles G. King, then at the University of Pittsburgh and later director of the Nutrition Foundation, and a graduate student, William Waugh, isolated vitamin C from lemons in 1932.

They identified it as the antiscorbutic scurvy preventing vitamin.

Hungarian scientists had isolated it 4 years earlier, but they did not recognize it as the scurvy- preventing vitamin, because its striking chemical properties were of greater interest to them.

The vitamin was officially named "ascorbic acid" to indicate its anti-scorbutic function.

Its chemical activity may account for its mystifying qualities. It reacts readily under so many circumstances that one is tempted to connect its chemical versatility with its antiscorbutic function although several compounds have the same chemical properties but little or no antiscorbutic potency.

Its chemical structure is quite simple. Its behavior as a chemical is well known. Relatively satisfactory methods have been developed for determining it. Scientists have analyzed endless biological materials to see if it exists in them.

Vitamin C occurs in animals and vegetables extensively but haphazardly. Fresh raw fruit and vegetables contain it, yet few animals need it. People, monkeys, and guinea pigs get it from sources outside their bodies. Other species make their own.

Some vitamins exist in several forms, but vitamin C occurs naturally in only one. It exists in two states of oxidation.

Closely related forms have been synthesized but are not known to occur in nature. A few of them have slight antiscorbutic activity. Other vitamins, especially those of the B family, carry on their biological duties in combination with partners and become coenzymes, but whether vitamin C does so has not been proved.

People, monkeys, and guinea pigs show similar signs of physical deterioration when they are deprived of it.

Recovery follows the same pattern when vitamin C is given them. The evidences of its function may be observed, but the manner in which it functions remained a secret in 1959.

Vitamin C is the same chemical compound whether it is isolated from foods or is synthesized and sold as pills or capsules.

It is known as L-ascorbic acid in the reduced form and as L-dehydroascorbic acid in the oxidized form.

Chemical pictures or formulas of these two forms can be found in any standard textbook on physiology, such as Practical Physiological Chemistry, by Philip B. Hawk, Bernard L. Oser, and William H. Summerson.

The chemical makeup is related to the hexose sugars. These sugars have a backbone of six carbon atoms firmly joined to each other rather like vertebras. On the side these carbons are joined to oxygen and hydrogen. Vitamin C has this form, too, but between the second and third carbons there is a double bond, which means chemically that this backbone is not so firm as that of the hexose sugars. These two carbons in vitamin C are free to make changes.

The hydrogen atoms at this point are especially at liberty to wander off, and they have a high preference for any oxygen that may be about. It is when these two hydrogens have left that the vitamin becomes known as L-dehydroascorbic acid. This feature makes it an extremely changeable chemical in solution, and the ability to drop off the two hydrogens is one of its outstanding features.

Outside the body, in solution, this compelling chemical action takes place easily the characteristic that is the basis of a number of the analytical methods in use for ascorbic acid.

This chemical activity of vitamin C suggests possible ways in which it may enter into the chemical activities in the living organism.

Glucose, an important hexose sugar in metabolism, is a more stable chemical than vitamin C, although in some ways it resembles it in structure. Glucose is easily stored in the body, and it divides into successively smaller molecules that provide energy during breakdown by well-established routes.

In human beings, ascorbic acid chemically fragile though it may be sidesteps vigorous activity, and any excess not needed for its specific function is eliminated in the urine without being changed.

SCURVY now is uncommon in the United States. Nearly all of us get some vitamin C in our food. Infants on formula feeding who get no supplementary vitamin C will develop scurvy. Old people, especially those who live alone on restricted food intakes because they are poor, cannot go to a food market, or are indifferent, may show scorbutic signs. Some diets in institutions are low in fresh fruit and vegetables, and inmates who spend many years in them may show symptoms of scurvy.

Symptoms differ in infants and adults because of the added stress put on the organism by growth.

The normal newborn infant has stores of ascorbic acid adequate to prevent development of scurvy for about 5 months. The breast-fed baby normally gets enough for protection until he begins to eat a variety of foods. Deficiency is rare in children more than 15 months old. Infantile scurvy will develop in 3 months or more after breast feeding is stopped if no antiscorbutic is given either as a food or a supplement.

The most marked symptoms are found in growing bones. Bones may form improperly because the intercellular cementing substance or supporting tissue is missing and mineralization is faulty. Even though the minerals are available, they are disarranged and cannot form normal bones.

Areas at the ends of the bone shafts are especially affected. The soft tissue about the joints swells and is tender. The difficulty tends to be more severe in the legs than in the arms. Walking and sitting become painful, and the child lies on his back to avoid the pain involved in moving his legs.

The front ends of the ribs are sore. Breathing may be difficult. The ribs may be beaded. The child cries when handled or even approached, because he expects pain. If there are teeth, the gums may bleed. Changes in the soft tissues are less common in infants than in adults.

The staff of Vanderbilt University Medical School Hospital worked with deficiency diseases and their diagnoses for many years.

Dr. Calvin Woodruff of that staff reviewed a 28-year record (1926-1954) of 103 cases of infantile scurvy treated there. In an article in the Journal of the American Medical Association for June 2, 1956, he reported that in all cases scurvy resulted because of long periods of feeding when there was no ascorbic acid or negligible amounts of it in the diet. The disease was reversed in 3 to 4 days when even small amounts of ascorbic acid were supplied as foods or in capsules.

His record showed that infantile scurvy is not frequent but it also showed that there should be no scurvy at all, because it is so easy to supply the vitamin C a baby needs.

The soft tissues of adults who have scurvy are the site of the most evident signs of the deficiency. The cementing material is missing, and the cells literally seem to fall apart. The gums become sore, swollen, spongy, bleed readily, and are easily infected. In extreme cases, the teeth may loosen. This condition is known as gingivitis. The skin is thickened and scaled in spots. Small hemorrhages due to weakness of blood vessels form at the hair follicles; they appear where there is pressure, even as slight a pressure as the binding of clothes. These signs appear first on the legs and thighs. Large discolored patches form as blood leakages continue. A feeling of general weakness and a complaint of breathlessness are common. Anemia may occur because of loss of blood as the capillaries break. Resistance to infection is reduced. Wounds do not heal. Old wounds break open.

As with infants, the healing process is dramatically rapid once a supply of vitamin C is given.

SIGNS OF SCURVY now seen are less drastic.

Borderline cases are hard to diagnose by any of the classical symptoms, because weariness may result for many reasons, gums may be infected even when intakes of vitamin C are high, and anemias may have many causes. Unless there is other proof, we can rely on no single symptom to indicate a deficiency of vitamin C.

The amount of ascorbic acid suggested for a person is based on a great deal of research. Vitamins perform their work in unbelievably small amounts. The measures used for them have a strange sound as compared to usual commercial units such as ounces, pounds, and quarts. It may help in appreciating the powerful activity of vitamins to compare the units used in their measurement with the more ordinary units.

A sweetpotato furnishes about 35 milligrams of ascorbic acid for every 100 grams eaten. That means there are 35 parts of ascorbic acid for every million parts of sweetpotato. A sweetpotato of modest size weighs about 200 grams, or a little less than one-half pound.

One hundred milligrams of ascorbic acid eaten each day is a generous supply. For a person weighing 132 pounds, this will be about 1 part of the vitamin to 10 million parts of the body. The content of vitamin C in the blood is considered good if there is 1 part in a million ( 1.0 milligram per 100 milliliters). One hundred milliliters is close to one-tenth of a quart.

The authorities who have interpreted research and set the goals for the amounts of vitamin C intake by people have had different objectives requirement and recommendation.

The requirement is estimated to be the intake that is adequate to prevent scurvy.

The recommendation is set to provide certain benefits, over and above the prevention of scurvy, such as averting gum disorders and favoring resistance to infections.