chapter 1 nuitrition 310

Nutrition

The study of how food and its components affect growth and development, metabolism, health and disease, and mental and physical performance.

Nutrients

Substances that elicit a biochemical or physiological function in the body.

Sports nutrition

A specialty discipline that merges nutrition and sports science research to develop nutrition guidelines for physique changes, optimal training, performance, and recovery.

Digestion

The process of breaking food down so its components can be used by the body.

Absorption

The process by which nutrients move from the digestive tract into the body.

Metabolism

The body's processes that use and transform nutrients.

Transportation

The movement of nutrients and other substances throughout the body.

Storage

The body's process of storing nutrients or energy for later use.

Elimination

The removal of waste products from the body.

Carbohydrate

Molecules built of carbon, hydrogen, and oxygen with the general formula (CH2O)n.

Glucose

A monosaccharide and major carbohydrate used as an energy source.

Fructose

A monosaccharide carbohydrate.

Galactose

A monosaccharide carbohydrate.

Disaccharides

Carbohydrates made of two monosaccharides.

Maltose

A disaccharide carbohydrate.

Sucrose

A disaccharide carbohydrate.

Lactose

A disaccharide carbohydrate.

Polysaccharides

Complex carbohydrates made of many sugar units.

Starch

A polysaccharide consisting of amylose and amylopectin.

Glycogen

A stored form of carbohydrate found primarily in the liver and muscle.

Fiber

A type of carbohydrate that can be classified as soluble or insoluble.

Insoluble fiber

Fiber that decreases the transit time of fecal matter through the intestines.

Soluble fiber

Fiber that can lower blood cholesterol concentrations and normalize blood glucose.

Short-chain fatty acids

End products produced when much soluble fiber is fermented by bacteria in the large intestine.

Lipids

Compounds that are soluble in organic solvents such as acetone, ether, and chloroform.

Simple lipids

One of the three main classes of lipids.

Compound lipids

One of the three main classes of lipids.

Derived lipids

One of the three main classes of lipids.

Oils

Lipids that are liquid at room temperature.

Fats

Lipids that are solid at room temperature.

Fat energy value

Fat provides 9 kcal of energy per gram.

Functions of fat

Fat provides energy, protects vital organs, helps transport fat-soluble vitamins and carotenoids, and contributes to cell membranes and hormone production.

Fat-soluble vitamins

Vitamins A, D, E, and K whose intake and transport depend on dietary fat.

Phospholipids

Important constituents of cell membranes.

Cholesterol

An important component of cell membranes and a precursor for bile and steroid hormones.

Steroid hormones

Hormones such as testosterone, estrogen, and cortisol that are produced using cholesterol as a precursor.

Linoleic acid

A fatty acid that plays an important role in the formation of eicosanoids.

Protein

A nutrient that provides structure to cells and is involved in enzymes and many other biological functions.

Amino acids

The building blocks of all proteins.

Essential amino acids

Nine amino acids that cannot be synthesized by the human body and must be obtained from food.

Peptide bonds

Bonds that connect amino acids to each other in a protein.

Complete proteins

Proteins that contain all the essential amino acids; also called high-quality proteins.

Incomplete proteins

Proteins that are deficient in one or more essential amino acids; also called low-quality proteins.

Protein intake

Recommended protein intakes vary worldwide between 0.8 and 1.2 g/kg body weight.

Enzymes

Proteins that increase the rate of metabolic reactions.

Water

An extremely important nutrient that makes up about 60% of the adult body by weight.

Intracellular water

Water found inside cells; approximately two-thirds of total body water.

Extracellular fluid

Water found outside cells, including blood plasma, lymph, cerebrospinal fluid, interstitial fluid, urine, and fluid in joints and eyes.

Functions of water

Water transports nutrients, protects and lubricates tissues, regulates body temperature, participates in biochemical reactions, transports oxygen and waste products, and helps eliminate waste.

Alcohol

Ethanol consumed as a beverage that provides 7 kcal/g but is not essential in the diet.

Alcohol and exercise

Alcohol can slow recovery processes after exercise and should not be part of a serious athlete's diet during training and competition.

Micronutrients

Vitamins, minerals, and trace elements that have many biological functions.

Vitamins

Organic compounds that are essential for many metabolic processes.

Minerals

Inorganic compounds that serve important biological functions.

Trace elements

Inorganic micronutrients required by the body in small amounts.

Fat-soluble vitamins

Vitamins A, D, E, and K.

Water-soluble vitamins

Vitamins that dissolve in water rather than fat.

Vitamin D exception

Vitamin D can be synthesized from sunlight.

Vitamin K exception

Vitamin K can be synthesized by bacteria in the intestine.

Functions of vitamins and minerals

They regulate and link energy-release processes, act as cofactors in chemical reactions, and help maintain homeostasis.

Phytonutrients

Organic components of plants that may promote human health but are not essential nutrients.

Carotenoids

Common class of phytonutrients that can have antioxidant and anti-inflammatory effects.

Polyphenols

Common class of phytonutrients that can have antioxidant and anti-inflammatory effects.

Essential nutrients

Nutrients that cannot be synthesized in the body and must be obtained from the diet for growth, health, and survival.

Nonessential nutrients

Nutrients that can be synthesized within the body from precursors.

Conditionally essential nutrients

Nutrients that are normally nonessential but become essential under certain conditions when the body cannot synthesize enough.

Dietary Reference Intake (DRI)

A framework for current nutrient intake recommendations.

Estimated Average Requirement (EAR)

The nutrient intake estimated to meet the requirement of half of the healthy people in a group.

Purpose of EAR

EARs are used to assess nutritional adequacy of population groups and to calculate RDAs.

Acceptable Macronutrient Distribution Range (AMDR)

The range of intake for carbohydrate, fat, or protein associated with reduced risk of chronic disease while providing essential nutrients.

Risk of being outside the AMDR

Intake outside the AMDR may increase the risk of chronic disease and insufficient intake of essential nutrients.

Recommended Dietary Allowance (RDA)

The recommended daily intake intended to serve as a goal for individuals.

RDA factors

RDA recommendations vary according to age, sex, pregnancy, and lactation.

Factors affecting nutrient needs

Stress, disease, injuries, and total energy expenditure, including training, can influence nutrient needs.

Adequate Intake (AI)

A recommended daily intake level used when an RDA cannot be determined.

Basis of AI

AI is based on an observed or experimentally determined approximation of nutrient intake for healthy people.

Tolerable Upper Intake Level (UL)

The highest daily nutrient intake level likely to pose no risk of adverse health effects to almost all individuals in the general population.

Risk above UL

As nutrient intake increases above the UL, the risk of adverse effects increases.

Daily Values (DV)

Reference values used on food labels to represent recommended nutrient intake levels.

Reference Daily Intake (RDI)

The reference used for essential vitamins and minerals that makes up most Daily Values.

Daily Reference Value (DRV)

A standard for protein and dietary components that have no RDA or other established nutrient standard.

Percent Daily Value (% DV)

The percentage of the RDI or DRV available in a single serving of food.

Dietary intake analysis

The process of measuring dietary intake to assess diet adequacy, investigate health problems, and evaluate nutrition education or intervention programs.

3-day dietary survey

A method used to measure dietary intake by recording food consumption over three days.

7-day dietary survey

A method used to measure dietary intake by recording food consumption over seven days.

24-hour recall

A dietary assessment method in which food and beverage intake from the previous 24 hours is reported.

Food Frequency Questionnaire

A dietary assessment method used to measure how frequently foods are consumed.

Importance of nutrition in sport

The amount, composition, and timing of food intake can profoundly affect sports performance.

Nutrition and athletic potential

A good diet will not make an average athlete elite, but a poor diet can prevent an elite athlete from reaching their performance potential.

Nutrition and recovery

Well-chosen nutrition strategies can enhance an athlete's well-being, performance, and recovery.