XV. DEFENSES AGAINST ENVIRONMENTAL DEFICIENCIES AND EXCESSES

The earlier part of this course has concerned itself with a consid-
eration of the mechanical, physical, chemical, and micro-organismal causes
of ill health. Science has also demonstrated that we have another great
group of causes: sickness, inefficiency, and death. They may be broadly
classified as environmental excesses and deficiencies.

These excesses and deficiencies play an important part in our levels
of health. One might consider them from a chronological point of view on
account of their peculiar effects on every age group.

(a) Pre-natal (d) Maturity
(b) Infaney and pre-school (e) Old age
(c) School or college

The time at our disposal will permit only a consideration of the prin-
ciples involved in the health effects of excesses and deficiencies,

Food Excesses and Deficiencies

No argument is needed to establish the fact that food is one of the
prime essentials of life. The difficulty is to convince the average in-
dividual that we have sufficient scientific knowledge to prove that more
than instinct, taste and the subjective sensation of satisfaction of hun-
ger are necessary to insure the individual an adequate diet and to protect
him against food excesses and insure him against food deficiencies,

Food Deficiencies

From our studies of normal nutrition, we learned that the amount of
food taken in by the individual should be adapted to his age, body weight,
and degree of activity. Further, that this intake should be distributed
properly among proteins, fats, and carbohydrates with an insurance of se-
curing sufficient vitamins and inorganic salts.

If we are to plan successful defensive hygiene of foods, we must know
the correct amounts and distribution of food elements and understand the
Signs of deficiency of each group.

(a) Protein (c) Carbohydrates (e) Water
{(b) Fats (d) Vitamins (f) Inorganic salts

Food Excesses

It is impossible to judge exactly whether an individual is taking
food in excess without a careful study and expert examination. It is
doubtful wisdom to take the unreliable testimony of the feelings and the
scales, It seems almost uncecessary to mention that we should be able to
recognize the signs of excesses of:

(a) Water (c) Fats (e) Inorganic salts
(vo) Proteins (d) Carbohydrates