Vitamin deficiency; causes, treatment

What Is Meant by the Term Vitamin Deficiency?

Because the gross functional and morphological changes caused by deprivation of the vitamins were the source of their discovery as important nutrients, these signs have become the focus of attention for many with interests in human and/or veterinary health. Indeed, freedom from clinical diseases caused by insufficient vitamin nutriture has generally been used as the main criterion by which vitamin requirements have been defined. The expression vitamin deficiency therefore simply refers to the basic condition of hypovitaminosis. Vitamin deficiency is distinct from but underlies the various biochemical changes, physiological and/or functional impairments, or other overt disease signs by which the need for a vitamin is defined. A vitamin deficiency is the shortage of supply of a vitamin relative to its needs by a particular organism.

Vitamin A


Many Organ Systems Can Be Affected by

Vitamin Deficiencies

Every organ system of the body can be the target of a vitamin deficiency. Some vitamin deficiencies affect certain organs preferentially (e.g., vitamin D deficiency chiefly affects calcified tissues); others affect several or many organs in various ways. Because the diagnosis of a vitamin deficiency involves its differentiation from other potential causes of similar clinical signs, it is useful to consider the various morphologic lesions caused by vitamin deficiencies from an organ system perspective. After all, anatomical and/or functional changes in organs are the initial presentations of deficiencies of each of the vitamins.

THE MANY CAUSES OF VITAMIN

DEFICIENCIES

Primary and Secondary Causes of Vitamin

Deficiencies

The balance of vitamin supply and need for a particular individual at a given point in time is called vitamin status.

Reductions in vitamin status can be produced either by reductions in effective vitamin supply or by increases in effective vitamin need. Vitamin deficiency occurs when vitamin status is reduced to the point of having metabolic impact (i.e., stage II); if not corrected, continued reductions in vitamin status lead inevitably to the observable stages of vitamin deficiency (stages III and IV), at which serious clinical and morphological changes can become manifest. When these changes occur as a result of the failure to ingest a vitamin in sufficient amounts to meet physiological needs, the condition is called a primary deficiency. When these changes come about as a result of the failure to absorb or otherwise utilize a vitamin owing to an environmental condition or physiological state, and not to insufficient consumption of the vitamin, the condition is called a secondary deficiency.

The two fundamental ways in which vitamin deficiencies can be caused are:

Primary deficiencies … involve failures to ingest a vitamin in sufficient amounts to meet physiological needs.

Secondary deficiencies … involve failures to absorb or otherwise utilize a vitamin post-absorptively.

Potential Causes of Vitamin Deficiencies in

Humans

Primary deficiencies have psychosocial and technological

causes:

Poor food habits

Poverty (i.e., low food-purchasing power)

Ignorance (i.e., lack of sound nutrition information)

Lack of total food (e.g., crop failure)

Lack of vitamin-rich foods (e.g., consumption of highly refined foods)

Vitamin destruction (e.g., during storage, processing, and/or cooking)

Anorexia (e.g., homebound elderly, infirm, dental problems)

Food taboos and fads (e.g., fasting, avoidance of certain foods)

Apathy (lack of incentive to prepare adequate meals).

Secondary deficiencies have biological causes:

Poor digestion (e.g., achlorhydria – absence of stomach acid)

Malabsorption (impaired intestinal absorption of

nutrients; e.g., as a result of diarrhea, intestinal infection, parasites, pancreatitis)

Impaired metabolic utilization (e.g., certain drug therapies)

Increased metabolic need (e.g., pregnancy, lactation, rapid growth, infection, nutrient imbalance)

Increased vitamin excretion (e.g., diuresis, lactation, excessive sweating).

High-Risk Groups for Vitamin Deficiencies

Pregnant women

Infants and young children

Elderly people

Poor (food-insecure) people

People with intestinal parasites or infections

Dieters

Smokers.

REFERENCE

The Vitamins

Fourth Edition

Gerald F. Combs, Jr

Professor Emeritus

Cornell University

Ithaca, NY

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