Epidemiologia

Nutricional epidemiology

The field of nutricional epidemiology. Has developed from interest in the concept that aspectos of diet may influence the occurrence of human disease

It has used Basic epidemiology methods. For more than 200 years to identify Essentials nutrients. Lind 1753 (scurvy) Vit. C

Goldvereger (1964) pelagra

Deficiency epidemiological Studies confronts. The primary focus of contemporary nutricional epidemiology.

The major disease of western civilization. Heart disease, cancer, diabetes.

Unlike nutricional deficiencias these diseases almost always have multiple causes:

Diet, genetic, occupational, psicosocial behavioral.

These conditions are not reversible. And may result from excessive as well as insufficient intake of dietary factors.

The tradicional methods of nutritionist

Animal experimentation, Basic biochemistry, metabolic studies.

Contribute substantially but do not address directly the realtion between diet and occurrence of mayor disease.

Although epidemiologic effort originally concentrated on infectious deseases. Contemporary epidemiologist are accustomed to the study.

Diseases with low frequency. Long latency periods. Multiple causes.

Although epidemiology is logically equipped to address the dietary causes. The complex natura of diet, has posed a difficult Challenge to this dicipline.

A lot of information on literature. Example cigarette smoking. Easy to get quantitive information

With few exceptions: all individuals are exponed to fat, fiber, vit A.

Diet:

No characterized as presento or absent. They are continuous variables, with limited range of variation.

Individuals are generally not aware of the content of the foods taht they eat. Therefore the consumption of nutrients is usually determined indirectly based on report or on biochemical measurements.

The most serious limitation to research in nutricional epidemiology. Has been the lack of practice methods to measure diet.

In Studies with thousands of subjects the diestary method must be not only reasoblable achúrate but also relatively inexpensive. The diets of persons within one country are too homogeneous to detect relationships with disease.

Relationship between dietary lipids, serum, colesterol and coronary heart disease. Not correlation between intake of these lipids and serum colesterol was found in many cross-sectional Studies.

Many investigators concluye that the measurement of diet is anaccurate. Aggected by genetic factors (hupercholesterolemia). Physical activity.

Epidemiologic Approaches to diet and disease.

Correlation Studies (ecologic). Diseases rates vs per capita consumption of specific dietary factors.

Meat intake and incidente of colon cancer. In US individuals consume between 25% and 45% of their calories from fat.

The diestary infromation based on:

Disappearence data. Food produced plus imported. Minus food exported. Minus food fed to animals.

Countries with low incidente of colon cancer tend to be economically underdeveloped. Correlation betewwn gross nacional product and colon cancer r=.77 males, .69 females.

Primary problems with these Studies: confounding factors, ecological fallacies. Many potencial determinants of the disease other tan diet. Genetic, lifestyle.

Special exposure groups. Groups that consume unsusual diets. Provide an additional opportunity to learn about. The relation of dietary favtors and disease.

These groups are often defined by religious or ethnic characteristics. Seven day adventistis (vegetarian). Colon

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