Chap018

Nutrition

The study of nutrients and how the body uses them.

Nutrients

Chemicals from the environment that organisms need for survival, used to supply energy and building blocks for the body.

Macronutrients

Nutrients required in large quantities, such as carbohydrates, lipids, and proteins, that provide energy.

Micronutrients

Nutrients required in small amounts, such as vitamins and minerals, that help extract energy from macronutrients.

Essential nutrients

Nutrients that the body cannot synthesize or cannot synthesize in sufficient quantity and must be obtained from the diet.

Calories

Units of heat used to express the amount of energy in foods.

Carbohydrates

Organic compounds, such as sugars and starches, that provide energy for cellular processes.

Polysaccharides

Complex carbohydrates, such as starch from plant foods and glycogen from meats.

Disaccharides

Double sugars, such as milk sugar, cane sugar, beet sugar, and molasses.

Monosaccharides

Single sugars, such as those found in honey and fruits.

Cellulose

A complex carbohydrate abundant in food that provides fiber but is not digested.

Glucose

The most common cellular fuel oxidized in glycolysis, obtained from the breakdown of carbohydrates.

Glycogen

A storage form of glucose, stored in the liver and muscle cells.

Lipogenesis

The process of converting excess glucose into fats and storing them in adipose tissue.

Gluconeogenesis

The conversion of noncarbohydrates (amino acids, glycerol) into glucose for cells that require glucose as an energy source.

Lipids

Organic compounds that include fats, oils, phospholipids, and cholesterol, which supply energy and serve as building blocks for structures such as cell membranes.

Triglycerides

Composed of glycerol and three fatty acids, the most common dietary lipids.

Saturated fats

Found mainly in foods of animal origin and associated with an increased risk of cardiovascular disease.

Unsaturated fats

Found in seeds, nuts, and plant oils, containing one or more double bonds between carbon atoms.

Cholesterol

Abundant in the liver and egg yolk, found in whole milk, butter, cheese, and meats, but not in foods of plant origin.1. Lipoproteins:Proteins that combine with lipids and are classified based on density, used in lipid transport to specific target cells.

VLDLs (very low density lipoproteins)

Lipoproteins with high triglyceride content.

LDLs (low density lipoproteins)

Lipoproteins with high cholesterol content.

HDLs (high density lipoproteins)

Lipoproteins with high protein content.

Cholesterol

Produced by the liver, released into the blood, can be used to make bile salts and excreted in bile.

Adipose tissue

Stores and releases triglycerides as needed.

Monounsaturated fats

Healthier fats found in avocados and olives.

Saturated fats

Less healthy fats found in butter and lard.

Proteins

Consist of chains of amino acids and have many functions, including building new proteins and supplying energy.

Amino acids

The building blocks of proteins.

Essential amino acids

Amino acids that cannot be synthesized by the body and must be obtained from the diet.

Non-essential amino acids

Amino acids that can be synthesized by the body.

Complete proteins

Proteins that contain adequate amounts of essential amino acids for good health.

Incomplete proteins

Proteins that do not contain adequate amounts of essential amino acids.

Nitrogen balance

The state in which the amount of nitrogen taken in equals the amount excreted, indicating a balance in protein intake and utilization.1. Protein Requirements:Proteins provide essential amino acids, nitrogen, and other elements for producing non-essential amino acids and certain non-protein nitrogenous substances.

Dietary protein intake

The amount of protein recommended to be consumed daily, typically 10% of a person's diet (0.8 g/kg of body weight, or 0.4 g/lb. of body weight).

Deficiency of protein

Leads to tissue wasting and a decline in plasma proteins, resulting in decreased plasma osmotic pressure and nutritional edema.

Carbohydrate

Primarily sourced from starch and sugars in foods of plant origin, used for energy production, stored as glycogen, and converted to fats. Excesses can lead to obesity and dental caries, while deficiencies can cause metabolic acidosis.

Lipid

Found in meats, eggs, milk, lard, and plant oils, used for energy production, production of triglycerides, phospholipids, lipoproteins, and cholesterol. Excesses can lead to obesity and increased risk of heart disease, while deficiencies can cause weight loss and skin lesions.

Protein

Found in meats, cheese, nuts, milk, eggs, cereals, and legumes, used for building cell structure, functioning as enzymes or hormones, and various physiological processes. Excesses can lead to obesity, while deficiencies can cause extreme weight loss, wasting, anemia, and growth retardation.

Energy Expenditures

Carbohydrates, fats, and proteins supply energy for metabolic processes. Deficiencies can lead to consumption of structural molecules, while excesses can lead to obesity.

Calorie

The amount of potential energy a food contains, measured in units of heat. Carbohydrates and proteins contain 4.1 Calories/gram, while lipids contain 9.5 Calories/gram.

Basal Metabolic Rate (BMR)

The rate at which the body expends energy under basal conditions, mainly reflecting energy needed to support organ activities. BMR varies with gender, body size, body temperature, and thyroid hormone activity.

Energy Balance

Exists when caloric intake from food equals caloric output from BMR and muscular activities. Positive energy balance leads to weight gain, while negative energy balance leads to weight loss.

Desirable Weight

Difficult to determine, but Body Mass Index (BMI) is used to assess weight, taking height into consideration. BMI classifies a person as underweight, normal weight, overweight, or obese.1. Body Mass Index (BMI):A chart that measures a person's body fat based on their height and weight.

Obesity

A condition characterized by having excess body fat, which increases the risk of various health problems.

Type 2 diabetes

A chronic condition that affects the way the body metabolizes sugar, resulting in high blood sugar levels.

Digestive disorders

Conditions that affect the normal functioning of the digestive system, such as irritable bowel syndrome or gastroesophageal reflux disease.

Heart disease

A range of conditions that affect the heart, including coronary artery disease and heart failure.

Kidney failure

A condition in which the kidneys are unable to filter waste products from the blood effectively.

Hypertension

High blood pressure, which can increase the risk of heart disease and stroke.

Stroke

A medical emergency that occurs when blood flow to the brain is interrupted, leading to brain damage.

Heredity

The passing of traits or characteristics from parents to offspring through genes.

Environment

The surroundings or conditions in which a person lives, which can influence their health and well-being.

Hunger

The physiological sensation of needing to eat.

Satiety

The feeling of fullness and satisfaction after eating.

Hypothalamus

A region of the brain that plays a crucial role in regulating appetite and other bodily functions.

Insulin

A hormone produced by the pancreas that helps regulate blood sugar levels.

Adipocytes

Fat cells that store energy in the form of fat.

Glucose

A type of sugar that serves as the primary source of energy for the body's cells.

Glycogen

A form of stored glucose that can be used for energy when needed.

Leptin

A hormone produced by fat cells that helps regulate appetite and energy balance.

Neuropeptide Y

A neurotransmitter in the hypothalamus that stimulates appetite.

Ghrelin

A hormone produced by the stomach that stimulates appetite.

Bariatric surgery

Surgical procedures used to treat obesity by reducing the size of the stomach or bypassing a portion of the digestive system.

Vitamins

Organic compounds that are essential for normal metabolic processes and cannot be synthesized in adequate amounts by the body.

Fat-soluble vitamins

Vitamins A, D, E, and K that dissolve in fats and are stored in various tissues.

Water-soluble vitamins

B vitamins and vitamin C that dissolve in water and are not stored in the body.

Fallacy

A false belief or misconception.

Varied diet

A diet that includes a wide variety of different foods.

Vitamin supplements

Pills or capsules containing concentrated amounts of vitamins.

Carbohydrates

A macronutrient that provides energy to the body, found in foods like bread, pasta, and fruits.

Fats

A macronutrient that provides energy and helps with the absorption of fat-soluble vitamins, found in foods like oils, butter, and nuts.

Proteins

A macronutrient that is essential for building and repairing tissues, found in foods like meat, fish, and beans.1. Fat-Soluble Vitamins:Vitamins that are soluble in fat and are stored in the body's fatty tissues.

Vitamin A

A fat-soluble vitamin that is necessary for the synthesis of visual pigments, mucoproteins, and mucopolysaccharides, as well as for the normal development of bones and teeth.

Vitamin D

A fat-soluble vitamin that promotes the absorption of calcium and phosphorus and is important for the development of teeth and bones.

Vitamin E

A fat-soluble vitamin that acts as an antioxidant and helps prevent the oxidation of other vitamins and fatty acids.

Vitamin K

A fat-soluble vitamin that is required for the synthesis of prothrombin, which is involved in blood clotting.

Water-Soluble Vitamins

Vitamins that are soluble in water and are not stored in the body, so they need to be consumed regularly.

Vitamin B complex

A group of B vitamins that are usually found together in the same foods and are essential for normal cellular metabolism.

Thiamine (Vitamin B1)

A water-soluble vitamin that is part of a coenzyme required for the oxidation of carbohydrates and ribose synthesis.

Riboflavin (Vitamin B2)

A water-soluble vitamin that is part of enzymes and coenzymes required for the oxidation of glucose and fatty acids and cellular growth.

Niacin (Vitamin B3)

A water-soluble vitamin that is part of coenzymes required for the oxidation of glucose and synthesis of proteins, fats, and nucleic acids.

Pantothenic acid (Vitamin B5)

A water-soluble vitamin that is part of coenzyme A required for the oxidation of carbohydrates and fats.

Vitamin B6

A water-soluble vitamin that is a coenzyme required for the synthesis of proteins, amino acids, and nucleic acids.

RDA

Recommended Daily Allowance, the amount of a nutrient that is considered sufficient to meet the dietary needs of most healthy individuals.1. Biotin (Vitamin B7):Stable to heat, acids, and light; destroyed by oxidation and bases. Coenzyme required for metabolism of amino acids and fatty acids and for nucleic acid synthesis.

Folacin (Vitamin B9, Folic acid)

Occurs in several forms; destroyed by oxidation in an acid environment or by heat in an alkaline environment; stored in liver where it is converted into folinic acid. Coenzyme required for metabolism of certain amino acids and for DNA synthesis; promotes production of normal red blood cells.

Cyanocobalamin (Vitamin B12)

Complex, cobalt-containing compound; stable to heat; inactivated by light, strong acids, and strong bases; absorption regulated by intrinsic factor from gastric glands; stored in liver. Part of coenzyme required for synthesis of nucleic acids and for metabolism of carbohydrates; plays role in myelin synthesis; required for normal red blood cell production.

Ascorbic acid (Vitamin C)

Chemically similar to monosaccharides; stable in acids but destroyed by oxidation, heat, light, and bases. Required for collagen production, conversion of folacin to folinic acid, and metabolism of certain amino acids; promotes absorption of iron and synthesis of hormones from cholesterol.

Minerals

Inorganic elements required in metabolism. Usually extracted from the soil by plants. Obtained from plant foods or animals that have eaten plants.

Major Minerals

Calcium, Phosphorus, Potassium, Sulfur, Sodium, Chlorine, Magnesium. Ca and P account for nearly 75% of the mineral elements of the body by weight.

Calcium (Ca)

Mostly in the inorganic salts of bones and teeth. Structure of bones and teeth; essential for neurotransmitter release, muscle fiber contraction, the cardiac action potential, and blood coagulation; activates certain enzymes.

Phosphorus (P)

Mostly in the inorganic salts of bones and teeth. Structure of bones and teeth; component of nearly all metabolic reactions; in nucleic acids, many proteins, some enzymes, and some vitamins; in cell membrane, ATP, and phosphates of body fluids.

Potassium (K)

Widely distributed; tends to be concentrated inside cells. Helps maintain intracellular osmotic pressure and regulate pH; required for impulse conduction in neurons.1. Major Minerals:Essential minerals required in larger amounts by the body, including sulfur, sodium, chlorine, and magnesium.

Sulfur (S)

Widely distributed in the body and essential for certain amino acids, thiamine, insulin, and other compounds.

Sodium (Na)

Found mostly in extracellular fluids and plays a role in maintaining osmotic pressure, regulating water movement, and impulse conduction in neurons.

Chlorine (Cl)

Closely associated with sodium and helps maintain osmotic pressure, regulate pH, and aid in electrolyte balance.

Magnesium (Mg)

Abundant in bones and involved in metabolic reactions that produce ATP and breakdown of ATP to ADP.

Trace Elements

Essential minerals found in minute amounts in the body, including iron, manganese, copper, iodine, cobalt, zinc, fluorine, selenium, and chromium.

Iron (Fe)

Primarily found in blood and important for hemoglobin synthesis and vitamin A synthesis.

Manganese (Mn)

Concentrated in liver, kidneys, and pancreas and required for fatty acid synthesis and normal nervous system functioning.