The Newer Knowledge of Nutrition

The Newer Knowledge of Nutrition: The Use of Food for the Preservation of Vitality and Health

PREFACE

The need for knowledge of nutrition was never
greater than at the present time when so large a
part of the energies of the people of Europe and
America are absorbed in the activities of war. The
demoralization of agriculture over wide areas, to-
gether with the shortage of tonnage for the trans-
portation of food, have reduced the food supply of
a number of nations to the danger point, and have
cut off in great measure the opportunity for securing
the variety which exists in normal times.

The investigations of the last few years have,
fortunately, led to great advancement in our knowl-
edge of what constitutes an adequate diet. Such
knowledge can, if rightly applied, greatly assist in
enabling us to make use of our food supply in a
manner which will avoid mistakes sufficiently serious
to become reflected in a lowering of our standard
of public health. It seems certain that pellagra is
the sequel to the adherence to a faulty diet for such
a period as to materially reduce the powers of re-
sistance of the body to infection, and reasons are
presented in support of the view that there is a

vi PREFACE

much closer relationship between the character of
the diet and the incidence of tuberculosis than has
hitherto been believed. This view is offered in the
present discussion as an invitation to criticism, in
the hope that new data either in support or refuta-
tion of its validity will be presented. If it shall be
definitely proven that faulty diet is the chief factor
in the etiology of this disease, and that pellagra,
is, as the Thompson-McFadden Commission, Jobling
and Peterson and others believe, caused by infection,
it will establish that, as the author suggests, large
groups of people are at the present time making
serious errors in the selection of foods. Regardless
of the outcome of future studies relating to the im-
portance of diet to the etiology of these diseases, a
non-technical presentation of the kinds of combina-
tions of our natural foods which induce good or
faulty nutrition in animals, should be of service in
showing the inadequacy of the practice, which is
still in vogue, of regarding calories as the factor of
prime importance in the planning of the diet.

From the data discussed in the following pages it
will be evident that the idea that freedom of choice,
and variety of food sources for the diet will prevent
any faults in the diet from becoming serious, is no
longer tenable, especially if one is willing to admit

PREFACE vii

the existence of many degrees of gradation of mal-
nutrition, not recognizable except in their effects on
the individual over a long period of time. The
author recently enjoyed with a friend, a dinner
which consisted of steak, bread made without milk,
butter, potatoes, peas, gravy, a flavored gelatin
dessert and coffee. The meal was appetizing and
satisfying, but such a diet of seeds, tubers and meat
would not promote health in an experimental animal
over a very long period.

The literature which has a bearing on the applica-
tion of modern research to the practical problems
of human nutrition has become somewhat extensive
and is scattered in technical journals, and is not
readily accessible, or easy to read in proper sequence.
During the present year the author had the pleasure
of presenting an interpretation of this literature in
the Thomas Clarence Cutter Lectures at the Harvard
Medical School. Believing that the publication of
these lectures would serve to answer many of the
questions which have been asked in numerous letters
from the public, they have been edited and presented
in their present form.

It is a pleasure to acknowledge the author's in-
debtedness to those who have assisted in carrying
out the experimental work which made possible the

viii PREFACE

discussion of nutrition offered in this book. Nearly
three thousand feeding experiments varying in length
from six weeks to four years have been observed.
Special appreciation should be accorded to Miss
Marguerite Davis who assisted with the early work,
in the first two years of which no interpretation of
the cause of success or failure of our experimental
animals was possible, and to Miss Nina Simmonds
and Miss Helen T. Parsons for their keen interest
and never-failing loyalty to the work.

Elmer Verner McCollum

The Johns Hopkins University
School of Hygiene and Public Health,
Baltimore, Md.

CONTENTS

CHAPTER • PAGE

I. The Biological Method for the Analysis of a
Food-stuff 1

II. Experimental Scurvy and the Dietary Properties

of Vegetables 34

III. The Vegetarian Diet 53

IV. The Foods of Animal Origin 69

V. The Diseases Referable to Faulty Diet, or the

So-called "Deficiency Diseases" 83

VI. The Nursing Mother as a Factor of Safety in the

Nutrition of the Suckling 116

VII. Practical Considerations which Should Guide in

the Planning of the Diet 130

Introduction to the Legends to the Charts . . . 154

Bibliography 191

Index 197

THE NEWER KNOWLEDGE OF NUTRITION

Share this with your friends