Diet Evaluation. A Guide to Planning a Healthy Diet PDF
Preview Diet Evaluation. A Guide to Planning a Healthy Diet
Diet Evaluation A Guide to Planning a Healthy Diet G. Richard Jansen, Patricia A. Kendall, and Coerene M. Jansen Department of Food Science and Human Nutrition Colorado State University Fort Collins, Colorado Academic Press, Inc. Harcourt Brace Jovanovich, Publishers San Diego New York Boston London Sydney Tokyo Boston This book is printed on acid-free paper. @ Copyright © 1990 by Academic Press, Inc. All Rights Reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photo copy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agri culture, Kenneth R. Bolen, director of Cooperative Extension, Colo rado State University, Fort Collins, Colorado. Cooperative Extension programs are available to all without discrimination. To simplify technical terminology, trade names of products and equipment occa sionally will be used. No endorsement of products named is in tended nor is criticism implied of products not mentioned. Academic Press, Inc. San Diego, California 92101 United Kingdom Edition published by Academic Press Limited 24-28 Oval Road, London NW1 7DX Library of Congress Cataloging-in-Publication Data Jansen, G. Richard. Diet evaluation : a guide to planning a healthy diet / G. Richard Jansen, Patricia A. Kendall, and Coerene Jansen, p. cm. Includes bibliographical references. ISBN 0-12-380215-6 (alk. paper) 1. Dietetics. I. Kendall, Patricia A. (Patricia Ann), Date. II. Jansen, Coerene. III. Title. [DNLM: 1. Diet-handbooks. 2. Nutritional Requirements- -handbooks. QU39J35d] RM216.J355 1990 613.2-dc20 DNLM/DLC for Library of Congress 90-179 CIP Printed in the United States of America 90 91 92 93 9 8 7 6 5 4 3 2 1 Introduction Americans have a high degree of interest in nutrition, especially the role of nutrition in health promotion and disease prevention. Nutrition is a popular topic in newspapers, magazines, and on talk shows. Impor tant government reports are coming out on a regular basis, and re search papers on the subject often are reported on television before the scientific journal even arrives at college and university libraries around the country. Unfortunately, much information provided to the public is unreli able and not based on scientific knowledge. Adding to the confusion are legitimate differences of opinion among well-informed scientists. The purpose of this Guide is to provide, in concise form, the current state of knowledge about diet and health along with an accurate and convenient way to assess the nutritional adequacy of individual and family diets. There are two basic approaches to dietary guidance: Food groups and nutrients. A number of food group approaches have been recom mended. The basic four food group plan, in which foods are grouped as meats and meat alternatives, dairy products, breads and cereals, and fruits and vegetables, is one such system. Consuming a variety of foods within all food groups is good advice. Recently a fifth group of foods of very low nutrient value, such as candy, soft drinks, and alcoholic bev erages, has been added as a group of foods to restrict. The food group approach is designed to assure nutritional adequacy, particularly for protein, vitamins, and minerals. It does not address nutritional excesses, especially of calories, fat, and cholesterol. In addi tion, many foods are mixtures of food ingredients and are not ex clusively contained in one food group or another, making evaluation by food groups difficult. This Diet Guide uses the "nutritional shares'' concept which is a nutrient approach to diet evaluation and menu planning. This method, to be described below, helps individuals evaluate their diet in terms of individual nutrients and helps control nutritional excesses appropri ately while assuring nutritional adequacy. In addition, it helps the reader better understand food composition and the nutritional value of individual foods. ι Nutritional Standards and Guidelines In order to use a nutrient approach in diet evaluation, an appropriate nutritional standard is needed. Since the 1940s, the Food and Nutrition Board of the National Academy of Sciences has published recom mended dietary allowances (RDA) for key nutrients approximately every 5 years. According to the ninth edition published in 1980, "Rec ommended Dietary Allowances (RDA) are the levels of intake of essen tial nutrients considered, in the judgment of the Committee on Di etary Allowances of the Food and Nutrition Board on the basis of available scientific knowledge, to be adequate to meet the known nu tritional needs of practically all healthy persons/' The tenth edition, which should have been published in 1986, was held up for several years because of controversy within the scientific community and the National Academy of Sciences. It was released in 1989 and is used in this Diet Guide. Recommended dietary allowances which vary by age, sex, and reproductive status for women have been established for ener gy (calories), protein, 11 vitamins, and 7 minerals. In addition, estimat ed "safe and adequate" levels have been established for two vitamins and five trace elements. Estimated "minimum requirements" have been set for the electrolytes sodium, potassium, and chloride. The scientific information on which these "estimated" levels are based is not as complete as that for the RDA nutrients. Not to be confused with the "RDAs" are the "U.S. RDAs." These are based on the 1968 version of the Recommended Dietary Allowances (seventh edition) and were established by the Food and Drug Admin istration (FDA) for nutritional labeling of food. Food labeling regula tions are currently undergoing extensive review in Congress as well as within the FDA. Since the 1977 report on "Dietary Goals for the United States" by the United States Senate Select Committee on Nutrition and Human Needs, increasing attention has been directed to the role of nutrition in health promotion and disease prevention. Current concerns are di rected toward the role of all nutrients in growth and good health and the role of such nutrients as fat, cholesterol, carbohydrate, and dietary fiber in chronic diseases such as obesity, heart disease, diabetes, and cancer. These are nutrients for which no RDAs have been established or, in fact, can be established. Both quantitative and nonquantitative approaches have been applied to dietary guidance to reduce risk of chronic disease. The "Dietary Guidelines for Americans," established collaboratively by the United States Department of Agriculture (USDA) and the United States De partment of Health and Human Services (USDHHS) provide a non- Nutritional Standards and Guidelines 3 quantitative approach to health promotion/disease prevention. The Dietary Guidelines recommend less consumption of fat, saturated fat, cholesterol, refined sugar, and salt, in the context of a varied diet bal anced among the four food groups with increased emphasis on whole grain cereals, legumes, fruits, and vegetables to provide more dietary fiber. These guidelines do not indicate how much less fat or how much more fiber is desirable, primarily because the committee that estab lished these guidelines either couldn't agree on quantitative guidelines or the need for such guidelines for the general public. In contrast to the "Dietary Guidelines for Americans/' the National Cholesterol Education Program, American Heart Association, Ameri can Diabetes Association, the Surgeon General, the National Cancer Institute, and the National Academy of Sciences all have established quantitative guidelines. For the most part, these guidelines all are con sistent with the "Dietary Goals for the United States" established in 1977. They recommend consuming no more than 30% of calories as total fat with equal proportions of saturated, monounsaturated, and polyunsaturated fatty acids, less than 300 mg of dietary cholesterol per day, and approximately 5 g of salt per day. This Diet Guide provides a method for planning and evaluating menus to meet these quantitative goals and remain adequate in essential nutrients. Who Are Guidelines For? The major causes of death in the United States today are heart disease and cancer, with obesity, diabetes, and hypertension being important contributing factors. Since 1977 when the report "Dietary Goals for the United States" was issued by the United States Senate Select Com mittee on Nutrition and Human Needs, there have been many govern ment and private reports that have made dietary recommendations to promote health and prevent disease. Although they vary slightly, there is general agreement on major recommendations. In food terms, it is generally recommended that the consumption of whole-grain breads and cereals, fruits, and vegetables be increased and that lower fat selec tions of dairy foods, meat, poultry, and fish be served. A diet as described above often is referred to as a "prudent" diet. There is good agreement among most nutrition experts that individu als at increased risk of heart disease for whatever reason are advised to consume a prudent diet. What is not yet agreed on is whether everyone should follow these dietary recommendations. This is because our un derstanding of the causes of heart disease and cancer as well as our understanding of the role of diet in the initiation and development of these diseases is incomplete. This Diet Guide is based on the concept that the purpose of nutrition education is to provide consumers with objective information so they can make better and more informed decisions. Food choices are a mat ter of individual choice. Individuals need to understand what is known and not known about the role of diet and other important risk factors related to health promotion and disease prevention, assess their own situation, and then act accordingly. One individual at low known risk of heart disease may elect to consume a prudent diet to reduce known and unknown risks even further. However, this same individual may as a matter of choice engage in technical rock climbing for challenge and personal enjoyment. Another individual, also at low known risk for heart disease, may not engage in rock climbing because the risk of injury is high, but not feel the need to consume a diet reduced in fat and cholesterol and high in dietary fiber to further reduce health risks. This Diet Guide is thus designed to help consumers make better and more informed decisions on diet and to assist those interested in mov ing toward a prudent diet do so effectively without sacrificing nutri tional quality. 4 Basis of Diet Guide We have seen that nutritional guidelines are expressed in a variety of ways. Grams, international units, milligrams, and micrograms are used to express the daily need for essential nutrients such as protein, vitamins, and minerals. In contrast, quantitative guidelines for such nutrients as carbohydrate and fat are expressed as percentages of food energy consumed. In the face of this complexity, many individuals are content to follow the dietary guidelines in food terms, that is, use the time-tested food group approach. This Diet Guide follows a nutrient approach and is designed for individuals that have a higher degree of interest in the relationship between nutrition and health and who are interested in learning more about the nutritional value of food. The Diet Guide reduces complex ity in the expression of nutritional requirements and guidelines by expressing both in terms of "nutritional shares." This concept was developed over 60 years ago by Mary Swartz Rose, a very perceptive nutritionist. Very simply, her idea was to express nutritional content not as grams or milligrams, but rather in terms of the number of shares a food supplied of the daily need for a particular nutrient. At the time, daily requirements had been established for few nutrients, and little knowledge about nutrients in food was available. Today, however, the advent of the high-speed computer combined with our knowledge of nutritional requirements and food composition makes it possible to use the nutritional share concept in evaluating diets and planning menus. In this Diet Guide, the nutritional values of over 2000 individual foods are expressed in nutritional shares, called nutri-units (See Table 1 and the table of Nutrient Nutri-Unit values for Foods and Beverages on page 61). Twenty nutri-units of each nutrient provide a 2000-kcal diet, rich in complex carbohydrates and dietary fiber, controlled in fat, saturated fat, sugar, cholesterol and sodium, and adequate in 8 indica tor vitamins and minerals. One nutri-unit of food energy equals 100 kcal. For those nutrients expressed as percentages of food energy, nutri-units are calculated such that when they equal calorie shares, the diet is suitably controlled in restricted nutrients. Thus, a 2700-kcal diet would meet the prudent diet guidelines if it supplied 27 calorie nutri-units and no more than 27 nutri-units of fat, saturated fat, polyunsaturated fat, and sugar. Sim ilarly, the guideline for an 1800-kcal prudent diet would be 18-calorie nutri-units and 18 nutri-units of fat, saturated fat, polyunsaturated fat, and sugar. Dietary fiber goals also are set equal to calorie goals, such that 10 g of 5 6 Diet Evaluation: A Guide to Planning a Healthy Diet Table 1 Nutrient Standards for the Diet Guide Nutrient 1 Nutri-unit 20 Nutri-units Basis of standard Kilocalories 100 2000 23- to 50-year-old woman Protein 3.25 g 65 g 13% of total calories Carbohydrates 14.25 g 285 g 57% of total calories Dietary fiber ig 20 g 10 g/1000 kcal Sugars 5g 100 g 20% of total calories Fats 3.3 g 66 g 30% of total calories Saturated fat 1.1 g 22 g 10% of total calories Polyunsaturated fat 11 g 22 g 10% of total calories Cholesterol 15 mg 300 mg Prudent guidelines Sodium 100 mg 2000 mg Prudent guidelines Vitamin A 250 IU 5000 IU 100% of U.S. RDA Vitamin C 3 mg 60 mg 100% of U.S. RDA Thiamin 0.075 mg 1.5 mg 100% of U.S. RDA Riboflavin 0.085 mg 1.7 mg 100% of U.S. RDA Vitamin B 0.1 mg 2.0 mg 100% of U.S. RDA 6 Calcium 50 mg 1000 mg 100% of U.S. RDA Iron 0.9 mg 18 mg 100% of U.S. RDA Zinc 0.75 mg 15 mg 100% of U.S. RDA dietary fiber is recommended per 1000 kcal. This allows for a diet generous in dietary fiber, but not so overly high that it interferes with mineral bioavailability. Cholesterol and sodium standards are set independent of calorie level. Twenty nutri-units of cholesterol provides 300 mg cholesterol and 20 nutri-units of sodium, 2000 mg sodium. Consuming less than 20 nutri-units of each of these will meet the prudent diet guidelines for all diets. Dietary evaluation of eight indicator vitamins and minerals (vitamin A, vitamin C, thiamin, riboflavin, vitamin B , calcium, iron, and zinc) 6 is also included. These were chosen as representative of the 40 to 50 essential nutrients and the 4 major food groups. When these eight nutrients are provided through traditional nonfortified foods, other nu trients provided by the major food groups also are likely to be present. For example, vitamins A, C, and B represent nutrients provided by the 6 Fruit and Vegetable group; thiamin, vitamin B , iron, and zinc, the 6 Meat, Poultry, Fish, and Beans group and the Bread and Cereal group; and calcium and riboflavin, the Milk and Cheese group. For each, 20 nutri-units provides 100% of the U.S. RDA. The U.S. RDAs were de veloped for use with nutrition labeling to represent the amounts of protein and certain vitamins and minerals needed to meet the daily needs of most healthy adults and children over age four. For most nutrients, the U.S. RDA is set equal to the amount recommended for those individuals with the greatest need. Thus, the recommendations frequently are higher than the needs of many people. Table 2 is a chart for setting nutri-unit goals for these nutrients according to recommen dations for age and sex. It is not intended that this quantitative approach to menu planning and evaluation be used routinely. However, it is suggested that if used occasionally but regularly, it would offer a number of advantages. r^. Η -o CO —< gl z 5 s ó •sO m un un LD ON S I .2 ß χι -3 2 Η fi OÍ <fl ß q cS —ι es es cS cS « ß α O vO vO £ 1 < o ¿4 o ^cScSrrjcScScScScScScS 2 s 43 3 υ O ce 3 en 2 S ce — i •8 'S 1 OS O o t "fl w TD O £ * £ o -£ ^ O o .g 3 -S o ü =5 o T3 2 .2 8ao8Ou8->8008\08\e8oc8Sc8Sc8Sc8SO88\ <O 8*m8 m cá ° -Hcscs<r3cscscscscscscs-H+ + + ·§ o Q ^ O U ·§ Ü « 'S Ο τ}- 00 O TtQOTtO _ . «» ¿ ω D η 7 7 Η i 7 7 Í 1 S ca ^ -Η CS Η- ι ^ 8 S OO β μ·ÖΗ Β « 3 OS Μ .¿ α SS ö o, d ° 2 ecj eö « 5? C Η Q ζ! OH ^ 8 Diet Evaluation: A Guide to Planning a Healthy Diet First, following the guidelines makes sure that a diet is suitably controlled in calories, fat, and cholesterol, and at the same time con tains generous quantities of required nutrients such as protein, vi tamins, and minerals. This is important since concern about control ling sodium could compromise calcium intake, and concern about saturated fat consumption could result in an inadequate intake of iron. Another advantage of this nutrient approach is that it helps the user obtain a better understanding of food composition. This makes it pos sible to make better food choices in the future even without extensive dietary analysis. In understanding the nutritional value of individual foods two aspects are important. One is the amounts of nutrients supplied by a food per serving. The other is the level of nutrients supplied by the food relative to food energy, the index of nutritional quality (INQ). The food composi tion information in this diet guide provides direct information on the nutrient levels per serving in all foods listed. In addition, the INQ can be simply calculated for each nutrient in each food by dividing the number of nutri-units for a given nutrient by the number of calorie nutri-units in the food. The next section of this diet guide shows how to use this nutritional shares system to evaluate your diet and plan menus, and also how to incorporate information from food labels into the menu planning pro cess.
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