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With an understanding of nutrition, you can make healthy choices in your daily life and provide others with accurate information in your professional career. Score: 4. This text includes 20 chapters beginning with core nutrition topics; such as, diet planning, macronutrients, vitamins and minerals, and following with chapters on diet and health, fitness, life span nutrition, food safety, and world hunger. With its focus on Australia and New Zealand, the text incorporates current nutrition guidelines, recommendations and public health nutrition issues relevant to those studying and working in nutrition in this region of the world.

A thorough introductory guide, this market-leading text equips students with the knowledge and skills required to optimise health and wellbeing. The text begins with core nutrition topics, such as diet planning, macronutrients, vitamins and minerals, and follows with chapters on diet and health, fitness, life span nutrition and food safety.

People may buy vegetables from local farmers to save the fuel and environmental costs of foods shipped from far away. They may also select foods packaged in containers that can be reused or recycled. To contributions are called functional foods. These foods must also taste good—as good as the traditional choices.

A person selects foods for a variety of reasons. Biologically speaking, people eat to receive nourishment. Do you ever think of yourself as a biological being made of carefully arranged atoms, molecules, cells, tissues, and organs?

Are you aware of the activity going on within your body phytochemicals FIE-toe-KEM-ih-cals : nonnutrient compounds found in plant-derived foods that have biological activity in the body. The atoms, molecules, and cells of your body continuously move and change, even though the structures of your tissues and organs and your external appearance remain relatively constant.

Your skin, which has covered you since your birth, is replaced entirely by new cells every 7 years. The fat beneath your skin is not the same fat that was there a year ago. Your oldest red blood cell is only days old, and the entire lining of your digestive tract is renewed every 3 to 5 days. Foods bring pleasure—and nutrients. Nutrients in Foods and in the Body Amazingly, our bodies can derive all the energy, structural materials, and regulating agents we need from the foods we eat.

This section introduces the nutrients that foods deliver and shows how they participate in the dynamic processes that keep people alive and well. Nutrient Composition of the Body A chemical analysis of your body would show that it is made of materials similar to those found in foods see Figure FIGURE Body Composition of Healthy-Weight Men and Women The human body is made of compounds similar to those found in foods—mostly water 60 percent and some fat 13 to 21 percent for young men, 23 to 31 percent for young women , with carbohydrate, protein, vitamins, minerals, and other minor constituents making up the remainder.

Chapter 8 describes the health hazards of too little or too much body fat. The energy in food is chemical energy. The body can convert this chemical energy to mechanical, electrical, or heat energy. Nutrients may also reduce the risks of some diseases. The remaining pounds are mostly protein, carbohydrate, and the major minerals of the bones.

Vitamins, other minerals, and incidental extras constitute a fraction of a pound. Chemical Composition of Nutrients The simplest of the nutrients are the min- erals. Each mineral is a chemical element; its atoms are all alike. As a result, its identity never changes.

For example, iron may have different electrical charges, but the individual iron atoms remain the same when they are in a food, when a person eats the food, when the iron becomes part of a red blood cell, when the cell is broken down, and when the iron is lost from the body by excretion. The next simplest nutrient is water, a compound made of two elements—hydrogen and oxygen. Minerals and water are inorganic nutrients, which means they do not contain carbon.

The other four classes of nutrients carbohydrates, lipids, proteins, and vitamins are more complex. In addition to hydrogen and oxygen, they all contain carbon, an element found in all living things. As Chapter 19 explains, organic farming refers to growing crops and raising livestock according to standards set by the U. Protein and some vitamins also contain nitrogen and may contain other elements such as sulfur as well see Table Essential Nutrients The body can make some nutrients, but it cannot make all of them.

The nutrients that foods must supply are essential nutrients. The Energy-Yielding Nutrients: Carbohydrate, Fat, and Protein In the body, three organic nutrients can be used to provide energy: carbohydrate, fat, and protein.

Energy Measured in kCalories The energy released from carbohydrate, fat, and protein can be measured in calories—tiny units of energy so small that a single apple provides tens of thousands of them. About 40 nutrients are currently known to be essential for human beings.

In contrast, vitamins and minerals are micronutrients, required only in small amounts milligrams or micrograms daily.

Food energy is measured in kilocalories calories equal 1 kilocalorie , abbreviated kcalories or kcal. To convert kcalories to kilojoules, multiply by 4. Through such experiences, a person can become familiar with a measure without having to do any conversions. In addition to using metric measures, the SI establishes common units of measurement. For example, the SI unit for measuring food energy is the joule not the kcalorie. A joule is the amount of energy expended when 1 kilogram is moved 1 meter by a force of 1 newton.

The joule is thus a measure of work energy, whereas the kcalorie is a measure of heat energy. To convert energy measures from kcalories to kilojoules, multiply by 4. For additional practice log on to www. Volume: Liters L A liter of liquid is approximately one U. Four liters are only about 5 percent more than a gallon. TRY Convert your body weight from pounds to kilograms and your height from inches to centimeters.

Then add the results together. Knowing that this snack provides 47 percent of its kcalories from fat alerts a person to the need to make lower-fat selections at other times that day.

TRY Calculate the energy available from a bean burrito with cheese 55 grams car- IT bohydrate, 15 grams protein, and 12 grams fat. Determine the percentage of kcalories from each of the energy nutrients.

Energy from Foods The amount of energy a food provides depends on how much carbohydrate, fat, and protein it contains. Because fat provides more energy per gram, it has a greater energy density than either carbohydrate or protein. Figure p. Alcohol, however, is not considered a nutrient. Unlike the essential nutrients, alcohol does not sustain life. In fact, it interferes with the growth, maintenance, and repair of the body. Its only common characteristic with nutrients is that it yields energy 7 kcalories per gram when metabolized in the body.

Most foods contain all three energy-yielding nutrients, as well as vitamins, minerals, water, and other substances. For example, meat contains water, fat, vitamins, and minerals as well as protein. Bread contains water, a trace of fat, a little protein, and some vitamins and minerals in addition to its carbohydrate.

Only a few foods are exceptions to this rule—the common ones being sugar pure carbohydrate and oil essentially pure fat. Energy in the Body The body uses the energy-yielding nutrients to fuel all its activities. As the bonds break, they release energy. Thus the energy from food supports every activity from quiet thought to vigorous sports. Both of these breakfast options provide kcalories, but the cereal with milk, fruit salad, scrambled egg, turkey sausage, and toast with jam offers three times as much food as the doughnuts based on weight ; it has a lower energy density than the doughnuts.

Selecting a variety of foods also helps to ensure nutrient adequacy. If the body does not use these nutrients to fuel its current activities, it converts them into storage compounds such as body fat to be used between meals and overnight when fresh energy supplies run low.

If more energy is consumed than expended, the result is an increase in energy stores and weight gain. Similarly, if less energy is consumed than expended, the result is a decrease in energy stores and weight loss. When consumed in excess of energy needs, alcohol, too, can be converted to body fat and stored. Highlight 7 describes the effects of alcohol on health and nutrition. Proteins are found in structures such as the muscles and skin and help to regulate activities such as digestion and energy metabolism.

Chapter 6 presents a full discussion on proteins. The Vitamins The vitamins are also organic, but they do not provide energy. Instead, they facilitate the release of energy from carbohydrate, fat, and protein and participate in numerous other activities throughout the body. Each of the 13 vitamins has its own special roles to play.

When you cut yourself, one vitamin helps stop the bleeding and another helps repair the skin. Vitamins busily help replace old red blood cells and the lining of the digestive tract. Almost every action in the body requires the assistance of vitamins. The fat-soluble vitamins are vitamins A, D, E, and K. The watersoluble vitamins are the subject of Chapter 10 and the fat-soluble vitamins, of Chapter This is why the body handles them carefully and why nutrition-wise cooks do, too.

The strategies of cooking vegetables at moderate temperatures for short times and using small amounts of water help to preserve the vitamins. The Minerals In the body, some minerals are put together in orderly arrays in such structures as bones and teeth. Whatever their roles, minerals do not yield energy. Only 16 minerals are known to be essential in human nutrition. Still other minerals, such as lead, are environmental contaminants that displace the nutrient minerals from their workplaces in the body, disrupting body functions.

The problems caused by contaminant minerals are described in Chapter Because minerals are inorganic, they are indestructible and need not be handled with the special care that vitamins require. It participates in many metabolic reactions and supplies the medium for transporting vital materials to cells and carrying waste products away from them. Water is discussed fully in Chapter 12, but it is mentioned in every chapter. Energy is measured in kcalories. Vitamins, minerals, and water facilitate a variety of activities in the body.

Without exaggeration, nutrients provide the physical and metabolic basis for nearly all that we are and all that we do. The next section introduces the science of nutrition with emphasis on the research methods scientists have used in uncovering the wonders of nutrition.

Its foundation depends on several other sciences, including biology, biochemistry, and physiology. And it is currently experiencing a tremendous growth spurt as scientists apply knowledge gained from sequencing the human genome.

Chapters 12 and 13 are devoted to the major and trace minerals, respectively. Some minerals are essential nutrients required in small amounts by the body for health. The study of genomes is called genomics. Thus the sequence begins anew, and research continues in a somewhat cyclical way.

Develop a theory that integrates conclusions with those from numerous other studies. Epidemiological studies include cross-sectional, casecontrol, and cohort see Figure Laboratory-based studies are often conducted in test tubes in vitro or on animals. Because each type of study has strengths and weaknesses, some provide stronger evidence than others see Table Some examples of various types of research designs are presented in Figure p.

In attempting to discover whether a nutrient relieves symptoms or cures a disease, researchers deliberately manipulate one variable for example, the amount of vitamin C in the diet and measure any observed changes perhaps the number of colds. As much as possible, all other conditions are held constant. The following paragraphs illustrate how this is accomplished.

Controls In studies examining the effectiveness of vitamin C, researchers typi- cally divide the subjects into two groups. One group the experimental group receives a vitamin C supplement, and the other the control group does not. Researchers observe both groups to determine whether one group has fewer, milder, or shorter colds than the other. The following discussion describes some of the pitfalls inherent in an experiment of this kind and ways to avoid them.

In sorting subjects into two groups, researchers must ensure that each person has an equal chance of being assigned to either the experimental group or the control group. Ideally, the control group receives a placebo while the experimental group receives a real treatment. If A increases as B increases, or if A decreases as B decreases, the correlation is positive. This does not mean that A causes B or vice versa. If A increases as B decreases, or if A decreases as B increases, the correlation is negative.

This does not mean that A prevents B or vice versa. Some third factor may account for both A and B. The experimental group receives the real treatment. Blood cholesterol Researchers compare people who do and do not have a given condition such as a disease, closely matching them in age, gender, and other key variables so that differences in other factors will stand out. These differences may account for the condition in the group that has it. Many people in the Mediterranean region drink more wine, eat more fat from olive oil, and yet have a lower incidence of heart disease than northern Europeans and North Americans.

Researchers analyze data collected from a selected group of people a cohort at intervals over a certain period of time. Data collected periodically over the past several decades from over people randomly selected from the town of Framingham, Massachusetts, in have revealed that the risk of heart attack increases as blood cholesterol increases. People with goiter lack iodine in their diets.

Such studies test possible disease causes and treatments in a laboratory where all conditions can be controlled. Mice fed a high-fat diet eat less food than mice given a lower-fat diet, so they receive the same number of kcalories—but the mice eating the fat-rich diet become severely obese.

These trials help determine the effectiveness of such interventions on the development or prevention of disease. Heart disease risk factors improve when men receive fresh-squeezed orange juice daily for two months compared with those on a diet low in vitamin C—even when both groups follow a diet high in saturated fat.

Importantly, the two groups of people must be similar and must have the same track record with respect to colds to rule out the possibility that observed differences in the rate, severity, or duration of colds might have occurred anyway. In experiments involving a nutrient, the diets of both groups must also be similar, especially with respect to the nutrient being studied. Statistical methods are used to determine whether differences between groups of various sizes support a hypothesis.

Placebos If people who take vitamin C for colds believe it will cure them, their chances of recovery may improve. This phenomenon, the result of expectations, is known as the placebo effect. Severity of symptoms is often a subjective measure, and people who believe they are receiving treatment may report less-severe symptoms. One way experimenters control for the placebo effect is to give pills to all participants.

Those in the experimental group, for example, receive pills containing vitamin C, and those in the control group receive a placebo—pills of similar appearance and taste containing an inactive ingredient.

This way, the expectations of both groups will be equal. It is not necessary to convince all subjects that they are receiving vitamin C, but the extent of belief or unbelief must be the same in both groups. A study conducted under these conditions is called a blind experiment—that is, the subjects do not know are blind to whether they are members of the experimental group receiving treatment or the control group receiving the placebo.

Double Blind When both the subjects and the researchers do not know which subjects are in which group, the study is called a double-blind experiment.

To prevent such bias, the pills are coded by a third party, who does not reveal to the experimenters which subjects are in which group until all results have been recorded.

Scientists must be cautious about drawing any conclusions until they have accumulated a body of evidence from multiple studies that have used various types of research designs.

Correlations and Causes Researchers often examine the relationships between two or more variables—for example, daily vitamin C intake and the number of colds or the duration and severity of cold symptoms. Importantly, researchers must be able to observe, measure, or verify the variables selected. Findings sometimes suggest no correlation between variables regardless of the amount of vitamin C consumed, the number of colds remains the same.

Correlational evidence proves only that variables are associated, not that one is the cause of the other. People often jump to conclusions when they notice correlations, but their conclusions are often wrong.

This raises an important point regarding information found on the Internet: much gets published without the rigorous scrutiny of peer review. Highlight 1 offers guidance in determining whether website information is reliable. Table describes the parts of a typical research article. The abstract provides a brief overview of the article. The introduction clearly states the purpose of the current study.

A comprehensive review of the literature reveals all that science has uncovered on the subject to date. Usually, they answer a few questions and raise several more. Highlight 5 provides a detailed look at how dietary fat recommendations have evolved over the past several decades as researchers have uncovered the relationships between the various kinds of fat and their roles in supporting or harming health.

In designing their studies, researchers randomly assign control and experimental groups, seek large sample sizes, provide placebos, and remain blind to treatments. Such research has laid the foundation for quantifying how much of each nutrient the body needs. These recommendations apply to healthy people and may not be appropriate for people with diseases that increase or decrease nutrient needs.

The committee selects a different criterion for each nutrient based on its roles in supporting various activities in the body and in reducing disease risks. Their names make sense when you learn their purposes. The text discusses three of these people—A, B, and C. Some people require only a small amount of nutrient X and some require a lot. Most people, however, fall somewhere in the middle. For this reason, the committee clusters its recommendations for people into groups based on age and gender.

Even so, the exact requirements for people of the same age and gender are likely to be different. For example, person A might need 40 units of a particular nutrient each day; person B might need 35; and person C, Looking at enough people might reveal that their individual requirements fall into a symmetrical distribution, with most near the midpoint and only a few at the extremes see the left side of Figure In Figure , the Estimated Average Requirement is shown as 45 units.

Recommended Dietary Allowance RDA : the average daily amount of a nutrient considered adequate to meet the known nutrient needs of practically all healthy people; a goal for dietary intake by individuals. Recommendations are therefore set high enough above the Estimated Average Requirement to meet the needs of most healthy people.

Small amounts above the daily requirement do no harm, whereas amounts below the requirement may lead to health problems. In this example, a reasonable RDA might be 63 units a day see the right side of Figure Such a point can be calculated mathematically so that it covers about 98 percent of a population. Almost everybody—including person C whose needs were higher than the average—would be covered if they met this dietary goal.

Although both the RDA and the AI serve as nutrient intake goals for individuals, their differences are noteworthy. The percentage of people covered by an AI is unknown; an AI is expected to exceed average requirements, but it may cover more or fewer people than an RDA would cover if an RDA could be determined.

Both of these recommendations are high enough to provide reserves in times of short-term dietary inadequacies, but not so high as to approach toxicity. Nutrient intakes above or below this range may be equally harmful. Nevertheless, it is probably best not to exceed these recommendations by very much or very often. Individual tolerances for high doses of nutrients vary, and somewhere above the recommended intake is a point beyond which a nutrient is likely to become toxic.

Later chapters discuss the dangers associated with excessively high intakes of vitamins and minerals, and the inside front cover p. C presents tables of upper levels for selected nutrients. Excess energy cannot be readily excreted and is eventually stored as body fat. Balance is key to the energy recommendation. Enough energy is needed to sustain a healthy and active life, but too much energy can lead to weight gain and obesity.

Because any amount in excess of energy needs will result in weight gain, no upper level for energy has been determined. Each of these three energy-yielding nutrients contributes to the total energy intake, and those contributions vary in relation to one another. Tolerable Upper Intake Level UL : the maximum daily amount of a nutrient that appears safe for most healthy people and beyond which there is an increased risk of adverse health effects.

Estimated Energy Requirement EER : the average dietary energy intake that maintains energy balance and good health in a person of a given age, gender, weight, height, and level of physical activity. Acceptable Macronutrient Distribution Ranges AMDR : ranges of intakes for the energy nutrients that provide adequate energy and nutrients and reduce the risk of chronic diseases.

See Highlight 1 for more on what constitutes a nutrition expert. Estimates of adequate energy and nutrient intakes apply to healthy people. They need to be adjusted for malnourished people or those with medical problems who may require supplemented or restricted dietary intakes. Recommendations are not minimum requirements, nor are they necessarily optimal intakes for all individuals.

Most nutrient goals are intended to be met through diets composed of a variety of foods whenever possible. Because foods contain mixtures of nutrients and nonnutrients, they deliver more than just those nutrients covered by the recommendations.

Excess intakes of vitamins and minerals are unlikely when they come from foods rather than dietary supplements. Recommendations apply to average daily intakes. Each of the DRI categories serves a unique purpose. For example, the Estimated Average Requirements are most appropriately used to develop and evaluate nutrition programs for groups such as schoolchildren or military personnel. Tolerable Upper Intake Levels serve as a reminder to keep nutrient intakes below amounts that increase the risk of toxicity—not a common problem when nutrients derive from foods, but a real possibility for some nutrients if supplements are used regularly.

With these understandings, professionals can use the DRI for a variety of purposes. Comparing Nutrient Recommendations At least 40 different nations and international organizations have published nutrient standards similar to those used in the United States and Canada.

The Dietary Reference Intakes DRI are a set of nutrient intake values that can be used to plan and evaluate diets for healthy people.

The Recommended Dietary Allowance RDA is based on the Estimated Average Requirement and establishes a goal for dietary intake that will meet the needs of almost all healthy people. With an excess of energy, the person may become obese and vulnerable to diseases associated with overnutrition such as heart disease and diabetes.

Similarly, over time, regular intakes in excess of needs may also have adverse effects. Malnutrition symptoms—such as diarrhea, skin rashes, and fatigue—are easy to miss because they resemble the symptoms of other diseases.

But a person who has learned how to use assessment techniques to detect malnutrition can identify when these conditions are caused by poor nutrition and can recommend steps to correct it. This discussion presents the basics of nutrition assessment; many more details are offered in later chapters and in Appendix E.

To take a diet history, the assessor collects data about the foods a person eats. The data may be collected by recording the foods the person has eaten over a period of 24 hours, 3 days, or a week or more or by asking what foods the person typically eats and how much of each. To determine the amounts of nutrients consumed, the assessor usually enters the foods and their portion sizes into a computer using a diet analysis program.

This step can also be done manually by looking up each food in a table of food composition such as Appendix H in this book. The assessor then compares the calculated nutrient intakes with the DRI to determine the probability of adequacy see Figure Anthropometric Measurements A second tech- nique that may help to reveal nutrition problems is taking anthropometric measurements such as those of height and weight.

Chapter 8 presents information on body weight and its standards, and Appendix E includes growth charts for children. Physical Examinations A third nutrition assessment technique is a physical examination looking for clues to poor nutrition status.

Visual inspection of the anthropometric AN-throw-poe-MET-rick : relating to measurement of the physical characteristics of the body, such as height and weight. However, outward signs of sickness need not appear before a person takes corrective measures.

Laboratory tests can help determine nutrient status in the early stages. Laboratory tests are most useful in uncovering early signs of malnutrition before symptoms appear. Next, the body begins to use up its stores of iron. We hope that this book serves you well. Understanding Nutrition presents the core information of an introductory nutrition course. The Chapters Chapter 1 begins by exploring why we eat the foods we do and continues with a brief overview of the nutrients, the science of nutrition, recommended nutrient intakes, assessment, and important relationships between diet and health.

Chapter 2 describes the diet-planning principles and food guides used to create diets that support good health and includes instructions on how to read a food label. In Chapter 3 readers follow the journey of digestion and absorption as the body breaks down foods into nutrients.

Understanding Nutrition is a quite lengthy book. It contains more than thousand pages. The nutrition book is also available in 13th edition. There are twenty full length chapters in the book.

Like the book personal nutrition, this book also encircles all the major aspects of human nutrition. The book supplies whole apparatus for planning a healthy diet. Nutrients are studied in detail.