Scarcity of Vitamin D in the Diet and Other Obstructive Factors

By  S. M. WENGER, B. S., and R. L. HOESLY, B. A. of  The Wisconsin Alumni Research Foundation

Any extensive review of the literature on nutrition rarely fails to impress the reader with the fact that –the average diet is almost devoid of Vitamin D –the nutrient which is primarily responsible for bone and tooth structure.

Of all deficiency diseases, particularly those of children, rickets, due to a lack of Vitamin D, has been one of the most troublesome. In discussing deficiency diseases as whole, the late Dr. C. U. Moore said, “The faces of children are as the open pages of a book upon which are recorded their dietetic histories. There are certain tell-tale evidences of unbalanced dietaries that are almost always visible in the face, form, disposition, and habits of the innocent victims.”

And well phrased is his thought when we realize that unfortunately the results of these deficiencies are so often not obvious until a long period of time has elapsed. Hence prevention is greatly to be preferred over cure.

Moore further commented that “in the poorer sections of our cities, one expects to meet the little under fed members of the ignorant and poverty-stricken households. However, the sadder story lies in the fact that, not alone among the poor and foreign families are these under nourished and improperly fed children; they appear almost equally often in well-educated and well-to do families.


Dr. Moore’s comment merely helps to definitely establish the difference between the under-nourished and the malnourished child. In the former the dietary fault is largely a quantitative one but in the latter the dietary fault is largely a qualitative one. And quality is more essential than quantity as far as proper nutrition is concerned.

The goal is optimal nutrition as defined by Sherman is as follows: “Foods should be so chosen that the health and efficiency of the individual shall be served in the highest degree, and at the same time it should be used with such regard to the economics of food supply that the possibility of optimal nutrition shall be brought within the reach of a steadily increasing proportion of the population, and shall finally be the birthright of all.”

While the lack of vitamins is the cause of so many deficiency diseases, it is interesting to note that if given a well-balanced, averages, mixed diet, one is able to secure all of the essential factors except Vitamin D.

In our two previous articles we have cited studies which clearly indicate the necessity for the inclusion of Vitamin D in the diet in order to realize optimum health. We have cited many studies which point definitely to the relationship of Vitamin D to rickets as well as its relationship to dental caries, and have shown how the lack of this important vitamin handicaps the normal growth and health of two of the most important foundations of a healthy being –the bones and the teeth.

Lack of Vitamin D in Diet Widely Recognized

In 1935 Dr. Joseph Coffin in a paper entitled The Lack of Vitamin D in Common Foods began his article with the statement, “There is very little Vitamin D in common foods.” Scott in a paper which appeared in the Archives of Physical Therapy in March of 1937 substantiates this statement by declaring, “Ordinary foods used in our homes are singularly deficient in Vitamin D.” Branion, Drake and Tisdall likewise stated that “Most foods ordinarily consumed are devoid of Vitamin D.” In an earlier study, Branion also stated that “Vitamin D, the anti-rachitic factor, is not so generally found in foodstuffs as are the other vitamins. It is most likely to be deficient in the usual dietaries.”

So few foods contain even traces of Vitamin D that Mary Swartz Rose does not even list it in the tables given in her Laboratory Handbook for Dietetics. She explains this omission when she says, “Most foods contain relatively little Vitamin D.”

In a miscellaneous publication of the United States Department of Agriculture, table 3, which is a digest of quantitative values for the Vitamin A, B, C, D and G content of foods, 120 differently-grouped foods are listed. Of these, only 7 are shown to contain any amounts of Vitamin D. Four of these are clams, oysters, livers and cod liver oil, which are seldom used in the average daily diet.

Lack of Vitamin D Shown in Dentist’s Dietetic Survey

This dental bytes journal has established a Dietetic Service to which Dentists were invited to send menus of patients whose diets, as a result of dental findings, needed correction.

Over a thousand diet analyses have been submitted and the general findings reveal that a large percentage of people are not consuming sufficient amounts of the food factors necessary for the growth and maintenance of healthy tooth structure.

The most common deficiency was shown to be Vitamin D. 78 per cent of the diets were lacking in this factor. Diets were more often deficient in Vitamin D than any of the other vitamins. Vitamin C, which is important in the health of the gums, was deficient in 30 per cent in only 11 per cent .

Calcium and phosphorus –the minerals needed to build strong teeth and bones –were found to be deficient in 60 and 49 per cent respectively.

It is interesting to note Gutman’s version of the physiological action of Vitamin D at this point. He states, “The physiological action of Vitamin D in the organism is concerned with the very important function of calcium-phosphorus metabolism. In general the vitamin affects the retention and concentration of these minerals in the body with their higher content deposition in bones and teeth. It is assumed that Vitamin D assists in more complete absorption of the calcium and phosphorus from the intestinal tract and that it decreases their excretion, thus favoring their deposition in bones and teeth, where mostly demanded.

Lack of Vitamin D Causes Faulty Calcium-Phosphorus Metabolism

In view of Gutman’s statement, confirmed by scientific research and referred to in our previous article, it is logical to assume that while some diets are deficient in calcium and phosphorus intake, others are lacking in Vitamin D, essential to the adequate retention of these mineral elements.

This scarcity problem becomes exceedingly important when one realizes that over 90 per cent of the American people suffer from dental caries and that the principal causative factors, according to many investigators, are inadequate intake of calcium and phosphorus, and insufficient Vitamin D to enable the body to utilize these minerals.

As preventive measures Gutman suggests that, “In our country especially, where the condition of the teeth of a great number of children is sadly deplorable, the scientific nutrition of infants and children during their temporary and permanent dentition periods is of utmost importance.”

Dr. E. V. McCollum has stated that “The deficiency of Vitamin D may be the most important dietetic deficiency in the world today.”

Factors Obstructing Sun’s Supply of Vitamin D

Mankind’s normal source of Vitamin D should be from the sun and undoubtedly primitive man gained his Vitamin D by sun exposure. Unfortunately, however, civilization has robbed man of his birthright.

Unfortunately, however, as light passes through the layers of air laden with clouds, fog, dust of the smoke of cities, much of the ultra-violet portion is filtered out and by the time the sunlight actually reaches the body, it contains very little ultra-violet

In this connection Scott points out that “The city dwellers are denied most of the effect of the life-giving orb. Tenement dwellers in city slums, or those living in richly equipped apartment buildings are alike shut off from the direct rays of the sun. The Gold Coast, or Park Avenue dweller, is no better off than the inmate of the East Side, for a pall of smoke, soot, dust and grime hangs almost constantly over our large urban communities.”

Atmospheric Pollution a Barricade to Vitamin D

A study on the atmospheric pollution was made by the United States Public Health Service in 14 of the largest cities of this country. The cities included, Baltimore, Boston, Buffalo, Chicago, Cleveland, Detroit, Los Angeles, New Orleans, New York, Philadelphia, Pittsburgh, St. Louis, San Francisco and Washington.

The results of this study divided the 14 cities into three groups, according to the degree of their atmos-cities within groups is alphabetical, not according to the degree of atmospheric pollution.

First Group
St. Louis

Second Group
New Orleans
New York

Third Group
Lost Angeles
San Francisco

If a combination of the degree atmospheric pollution for all cities, during the winter months, was set at 100, the degree of atmospheric pollution in the first group was 137; in the second, 97; and in the third, 56.

In this study it was also found that atmospheric pollution is greatest in winter, reaching a maximum in December. The winter months showed about twice as much pollution as the summer months.

In this connection it is interesting to note a study by Hugh M. Barrett in which he exposed albino rats, fed on a rickets-producing diets, to the ultra-violet rays of a quartz mercury arc. The rays from this arc were to transverse a box, glazed top and bottom with vita-glass –into which known concentrations of smoke were introduced. In addition a control group given no irradiation, and a third group irradiated through a smokeless chamber, were used.

Smoke Absorbs Ultra-Violet Rays

His conclusions indicated that smoke in concentrations ordinarily occurring in urban atmospheres possesses the power to absorb anti-rachitic rays to such an extent that their power to prevent rickets in rats is considerably diminished.

These conclusions were made after the assumption that a layer of smoke above a city extends to 1000 feet and Barrett had estimated that each cc. contained 750 particles. The dust counts made later in various centers indicated the presence of from 200 to 25,000 particles per cc.

In a similar study Knudson found that 15 minutes daily exposure to June and July sunshine in Albany, New York, was insufficient to prevent the developments of rickets in albino rats. And that 270 minutes daily in mid-winter was not quite pro-phylactic. Knudson further concluded that “if we take the relationship between cure and prevention of rickets of 4:1 observed with G. E. sunlamp, CX lamps and summer sunlight, then it would theoretically require about one thousand and 80 minutes per day of mid-winter sunshine to cure rickets in rats. This amount of radiation it would, of course, be impossible to obtain.”

Tisdall and Brown in Toronto found that there was a definite but slight antirachitic effect of sunshine during the winter months and that it increased approximately 8 times in the spring months.

McCollum comments on this problem when he states that “In temperate regions, especially in cities where smoke screens cut the active rays of light and where infants and children wear heavy clothing and remain in doors most of the time during the colder months, sunlight is not effective as an anti-rachitic agent and Vitamin D should be provided.”

Seasonal Variations of Sunlight Large

Seasonal variations of sunshine are another factor to be considered. Laurens shows that the sunlight on December 15 contains only12 per cent or one-eight as much ultra-violet as the sunlight of June 15. Accordingly by September there is only 43.3 per cent as much ultra-violet as there was on June 15. And by March 15, it has increased to only 38.8 per cent of the June 15th amount.

Aldrich maintains that “it is undoubtedly true that in all temperate climates Vitamin D should be administered routinely to children as exposure of the skin to ultra-violet light is usually insufficient to permit of normal absorption of the vitamin.”

Window Glass Another Barrier

Mothers often erroneously concluded that allowing the baby or their children to bask in the sunshine behind a glass window provides sufficient Vitamin D. Unfortunately, however, the ultra-violet rays of the sun cannot penetrate window glass. Consequently no Vitamin D is received in that manner. Scott commenting on this obstructive factor says, “Many think that if they let the sunshine into their homes through an abundance  of window glass, they are getting all the benefits of light. While this is true with visible light, window glass, plate or otherwise, is as impenetrable to the invisible ultra-violet ray as a brick wall.”

Sherman likewise states, “It is now known that the effective wave lengths (ultra-violet) do not pass through ordinary window glass.”

Tisdall and Brown tested the anti-rachitic value of the sun’s rays through various special window glasses. They selected three glasses which, according to the claims of the manufacturer’s, would transmit ultra-violet rays. Their conclusions indicated that the “anti-rachitic effect of the sun’s rays through these three makes of glass if from 25 to 50 per cent of the anti-rachitic effect obtained without the use of glass.” They further concluded that the use of these types of glass during the winter months is of little value but that their use from the first of March is justified.

Unfortunately, however, glass of this type is expensive. Scott points this out when he says, “Hospitals install expensive quartz windows in their  solaria at enormous cost, but such a procedure is beyond the reach of even the well-to-do.”

Shade and Clothes also Obstruct Beneficial Rays

In addition to the aforementioned obstructive factors, the average person spends comparatively little time in the direct rays of the sun. According to statistics the ultra-violet rays of the sun are strongest and most effective at noon in mid-summer when people ordinarily seek the shade of trees and buildings.

The beneficial ultra-violet rays are further obstructed by all clothing –even the thinnest of garments prevents the sun’s ultra-violet from making contact with the skin.

Edible Vitamin D Sources Limited

We have dealt at length with the subject of the relative deficiency of Vitamin D in foods, and have also pointed out the obstructive factors which make it impossible to gain Vitamin D from the sun, the natural source.

As we have stated, few foods contain Vitamin D. Some do!

Fish liver oils are potent sources of Vitamin D. For centuries cod liver oil has been known to be effective in the treatment of rickets and is recognized as a good source of Vitamin D. Moore stated that “salmon oil is even more potent as a source of Vitamin D than cod liver oil and is less disagreeable taste.

Schlutz comments in his discussion that “The Liver oil and body oil of certain species of fish are highly active.” Scott has stated that, “Sardines and salmon have some Vitamin D, but where salt water fish have an appreciable amount of this vitamin, it is generally concentrated in the liver.”

In any discussion on Vitamin D, egg yolk will be mentioned as the most potent natural food source of Vitamin D. But Coffin states that in order to secure enough Vitamin D from egg yolk to equal 50 Steenbock units, it would be necessary to eat from 4 to 25 eggs per day.

Tisdall likewise states, “Egg is the only food commonly used which contains appreciable amounts of Vitamin D.” He concludes that “even so, additional Vitamin D should be given as our observations have shown that 14 egg yolks are required to furnish the Vitamin D equivalent of 1 teaspoon of cod liver oil.

Traces of Vitamin D are also found in butter and natural milk but they are so slight and variable as to render them unreliable as a source of Vitamin D for preventing rickets or dental caries.

Science Comes to the Rescue

Fortunately for mankind, however, scientific investigators have found that any substance containing the pro-vitamin D, upon exposure to ultra-violet rays, can be enriched with Vitamin D.

Schlutz in his discussion on Vitamin D declared, “The discovery that certain parts of the solar spectrum have the photodynamic action of activating certain organic substances in the plant and animal kingdom and of giving them Vitamin D characteristics is one of the Great Biologic discoveries of the age.” He further states that “this very important vitamin is available, the, to man in various ways and its rather limited distribution in a natural state is counterbalanced by the ingenuity of the research laboratory in liberating it and making it available in practically unlimited amounts from sources totally unsuspected or un-thought of only a few years ago.”

“Less than a Decade has passed,” says Friedman, “since the first efforts toward augmenting the natural Vitamin D content of milk were initiated. During those few years great strides have been made in both the comparatively simple problem of providing what is now termed Vitamin D milk and in a more complex one of determining to what physical and physiochemical changes this addition to our anti-rachitic armament owes its potency.”

Teeth Reflect Improvement

Roberts says that improvement in nutrition is reflected in physical signs, one of the most striking of which is the condition of the teeth.

It is pertinent in this connection to note Robert’s quotation of the advance made by investigators showing the importance of Vitamin D in relation to dental caries. She points out that, “Evidence has been forthcoming from numerous sources –notably from Mellanby in England; Boyd, Drain and Nelson at Iowa City and Bunting and Collaborators at Ann Arbor –that dental caries may actually be arrested in children by merely fortifying the dietary with the essential foods.”

That the addition of Vitamin D to the diet is a problem in which every physician and dentist is extremely interested is further voiced in an editorial which appeared in the Lancet in which a committee dental diseases appointed by the Medical Research Council in England stated, “Investigations show conclusively that a relatively high Vitamin D content of the food can do much to diminish the incidence of caries if the vitamin is given during the development of the teeth. That a beneficial effect may be obtained if the vitamin is given at a fairly late stage of development.”

The difficulty, in fact the futility, of attempting to obtain sufficient Vitamin D from the ordinary diet or from sunlight becomes apparent from a review of the literature.

But scientific resourcefulness has led to the discovery of methods for incorporating this important nutrient in foods and to thus make it available to mankind.

The importance of this development and the sources through which Vitamin D is now available will be discussed at length in the next and last of this series of articles.

Madison, Wisconsin.



1 Moore, C. Ulysses, Nutrition of Mother and Child, J. B. Lippincott Company, 1935.

2 Sherman, Henry C., Chemistry of Food and Nutrition, Fifth Edition, The Macmillan Company, 1937.

3 Wenger, S. M., Hoesly, R. L., Factors in the Cause and Prevention of Dental Caries, Nutrition and Dental Health, 4:6-11, January, 1938. Also Vitamin D, Calcium and Phosphorus in the Prenatal Diet, February 1938.

4 Coffin, Joseph, The Lack of Vitamin D in Common Foods, J. Am. Diet. Assoc., 11:119-127, July 1935.

5 Scott, H. T., Light and Its Application to the Irradiation of Foods, Arch. Phys. Therapy, X-ray, Radium, 18:154-61, March 1937.

6 Branion, H. D., Drake, T.G.H., Tisdall, F. F., Vitamin D Content of Egg Yolk, Canadian Meg. Assoc. Jrl., 32:9-12, Janury 1935.

7 Branion, H. D., The Vitamin D Content of Eggs, Canadian Pub. Health Jrl., 25:171-174, April 1934.

8 Rose, Mary Swartz, A Laboratory Handbook for Dietetics, Fourth Edition, p. 6, The Macmillan Company, New York, 1937.

9 Daniel, E. P., Munsell, H. E., Vitamin Content of Foods, Misc. Pub. U.S.D.A. No. 275, p. 134-136, June 1937.

10 Editorial, Nutrition and Dental Health, 4:4-5, January 1938.

11 Gutman, Jacob, Modern Views on Vitamins and Treatment of Nutritional Disorders –Vitamin D, Medical Record, 146:179-181, August 18, 1937.

12 McCollum, E. V., Quoted in Arnold Nicholson’s article, Sunshine in Milk, Country Gentleman, February 1935.

13 Ives. James E. at al, Atmospheric Pollution of American Cities for the Years 1931-1933, p. 72, U.S. Public Health Bulletin No. 224, March 1936.

14 Barrett, Hugh M., Antirachitic Effect of Ultra-Violet Radiation Transmitted by a Smoky Atmosphere, Journal of Indus. Hygiene, 17:199-216, September 1935.

15 Knudson, Arthur, Ricket –Comparative Value of Several Light Sources for Cure and Prevention, Am. Jrl. Dis. Child., 44:531-541, September 1932.

16 Tisdall, F. F., Brown, Alan, Seasonal Variations, of the Antirachitic Effect of Sunshines, Am. Jrl. Dis. Child., 34:721-736, November 1927.

17 McCollum, E. V., Recent Advances in Nutritional Research, J. Mich. Med. Soc., 36:211-227, April 1937.

18 Laurens, Henry, Physiological Effects of Radiant Energy, p. 44, The Chemical Catalogue Co., New York, 1933.

19. Aldrich, C. A., The Use of Vitamins in Children’s Diet, M. Clin. No. America, 21:63-74, January 1937.

20 Tisdall, F. F., Brown, Alan, Anti-rachitic Value of the Sun’s Rays Through Various Special Window Glasses, Am. Jrl. Dis. Child., 34:742-752, November 1927.

21 Schlutz, Frederick W., The Clinical Significance of Vitamin D in Infancy and Childhood, The Vitamins- A symposium of A.M.A. articles, 1932.

22. Tisdall, Frederick F., Preventin of Dental Caries and Improvement of Health by Dietary Means, Pennsylvania Medical Journal, December 1935.

23. Friedman, S., Vitamin D Milk, Journal of Pediatrics, 4:678-692, May 1934.

24 Roberts, Lydia J., Nutrition Work with Children, University of Chicago Press, Chicago, Illinois, 1935.

25 Editorial, The Relation of Diet to Dental Caries, Lancet, 2:280-282, August 1, 1936.


Dr. George M. Wishart of the University of Glasgow states in an article appearing in the British Dental Journal that “since much of our food calcium is of organic nature, is the question whether organic calcium, such as the calcium caseinogenate of milk, is better absorbed than inorganic salts. Sherman and Hawley have emphasized very strongly the favorable utilization of milk calcium. They fed children first with a liberal supply of milk and then with half that amount plus vegetables equivalent in calcium content to the other half. The all-milk regime showed a much superior degree of storage. This much-quoted experiment has frequently been criticized, and others appear to have been successful in obtaining satisfactory storage with carefully selected vegetables diets, especially if orange-juice, which has a favorable action on calcium absorption, be added.”

“Be that as it may, leaving all questions of relative facility of absorption aside, there is no doubt that quantitatively milk and milk products are the richest natural food source of calcium. that is shown in the accompanying table.