• Specific biochemical substances used by the body for growth, development, activity, reproduction, lactation, health maintenance, & recovery from illness or injury.
• Metabolic processes involved in these functions are complex
• Nutrient needs change throughout the life cycle in response to changes in body size, activity growth, development, & state of health.

• Either they aren't sysnthesized in the body or are made in insufficient amts. Must be provided in the diet or through supplements.
• Supply energy and build tissue such as: carbohydrates, lipids, proteins are referred to as macronutrients.
• Micronutrients: vitamins & minerals-required in smaller amts to regulate and control body processes.

• Don't have to be supplied through dietary sources because they either aren't required for body functioning or are synthesized in the body in adequate amts.
• Some nutrients can be converted to others in the body. Ex: the body converts excess carbohydrates & protein into fat & stores them as triglycerides.

Of the 6 classes of nutrients, 3 supply energy:

3 are needed to regulate body processes:

• Supplies Energy: carbohydrates, lipids, protein
• Regulates body processess: Vitamins, mineral, water

• Measured in the form of kilocalories, commonly abbreviated as Calories, or cal.
• Only carbohydrates, lipids, and proteins provide energy.
• Vitamins & minerals, needed for the metabolism of energy, don't provide calories.
• Energy is used to carry on any kind of activity, whether voluntary or involuntary.

• The sum of all the calories used to perform physical activity, maintain basal metabolism, & digest, absorb, & metabolize food.
• Daily energy intake is equal to total daily energy expenditure, weight will remain stable.
• energy intake is less than the energy expended, the person's weight will decrease.
• Energy intake exceeds energy expenditure, weight increases

• The energy required to carry on the involuntary activities of the body at rest- the energy needed to sustain the metabolic activites of cells & tissues.
• These activites include actions such as maintaining body temp & muscle tone, producing & releasing secretions, propelling food through the GI tract, inflating the lungs, & contracting the heart muscle.

• Males have a higher BMR due to larger muscle mass.
• BMR is abt 1 cal/kg of body weight per hour for men 
• BMR is about 0.9 cal/kg of body weight per hour for women
• Factors that increase BMR: Growth, infections, fever, emotional tension, extreme environmental temperatures, elevated levels of certain hormones
• Factors that decrease BMR: Aging, prolonged fasting, and sleep

Ideal Body Weight (IBW)

(Healthy Body Weight)

• An estimate of optimal weight for optimal health.
• General guideline: Rule of Thumb method- determines ideal weight based on height.
• Method can result in unrealistically low figures for adults who are very short or very tall.

• Most preferred method to establish ideal body weight include BMI (adults & children) & measurement of waist circumference (adults).
• A ratio of weight (kg) to height (meters).
• A reliable indicator of total body fat stores in general population. Doesn't differentiate according to gender.

Body Mass Index (BMI)

Cont.

• Provides an estimation of relative risk for diseases such as heart disease, diabetes, & hypertension.
• It's important to note the BMI may not be accurate for ppl such as athletes, w/ a large muscle mass, or ppl w/ edema or dehydration, & older persons & others who have lost muscle mass.
• BMI below 18.5= Underweight/ 25-29.9= Overweight/ 30 or greater= obesity/ 40 or greater= extreme obesity.

BMI

Significant weight change:

• Determined by how much weight is lost per unit of time.

• Measured by placing a measuring tape snugly ard the waist at the level of the umbilcus. Measure abdominal fat.
• Where excess body fat is deposited is thought to be an important & reliable indicator of risk for disease, such as type 2 diabetes, dyslipidemia, hypertension, & cardiovascular disease.
• Risk increase w/ waist measurment of over 40inches in men & 35inches in women. 

Carbohydrates

(Sugars & starches)

• Classified as simple or complex sugars
• Organic compounds composed of carbon, hydrogen, oxygen.
• Serve as the structural framework of plants. The only animal source of carbohydrates in the diet is lactose, or "milk sugar"
• Easy to produce and store, making them the most abundant & least expensive source of calories in the diet worldwide..
• In countries where grains are the dietary staple, carbohydrates may contribute as much as 90% of total calories.

• The # of molecules w/in the structure determines the classfication of carbohydrates. Classified as simple (monosaccharide & disaccharide) or complex (polysaccharide) sugars.
• More easily digested & quickly than protein & lipids.
• 90% intake is digested. % decreases as fiber intakes increases
• All carbs are converted to glucose for transport through the blood or for use as energy. Glucose is an efficient fuel that certain tissues (CNS) rely on almost for energy.
• Cells oxidize glucose to provide energy, CO2, and H2O.
• Unlike lipds & protein-glucose in burn efficiently & completely & doesn't leave a toxic product for the kidneys to excrete.

• Fuction: supply energy
• Recommended dietary allowance (RDA): refers to recommendations for average daily amts that healthy population groups should consume over time.
• 50 to 100 g of carbohydrates are needed daily to prevent ketosis (an abnormal accumulation of ketone bodies that's frequently associated w/ acidosis)
• Recommends that carbs provide 45%-65% of total cals, mostly in the form of complex carbohydrates.

• A vital component of every living cell.
• Proteins made by combining 22 basic bldg blocks known as amino acids. Although amino acids, like carbohydrates, contain carbon, H, O2, they differ in that amino acids also contain N.
• Required for the formation of all body structures, including genes, enzymes, muscle, bone matrix, skin, & blood.

• Labeled complete (high quality) or incomplete (low quality), based on their amino acid composition. Complete proteins: contain sufficient amts & proportions of the essential amino acids to support growth. Incomplete proteins: deficient in one or more essential amino acids.
• Animal proteins (eggs, dairy products, meats)-Complete
• Plant proteins (grains, legumes, vegetables)-Incomplete (Exception-soy, plant protein that's considered complete)

Classification & Metabolism of Proteins:

Cont.

• Protein tissues-constant state of flux.
• Tissues are continously being broken down (catabolism) & replaced (anabolism).
• Nitrogen balance, a comparison b/t catabolism & anabolism,, can be measured by comparing N intake (Protein intake) & N excretion (N lost in urine,urea,feces,hair,nails,skin)
• Positive N Balance: occurs when N intake is greater than excretion. Ex. during periods of growth, pregnancy, lactation, recovery from illnesss.
• Negative N Balance: Occurs when more N is excreted than ingested. Occurs in situations such as starvation & catabolism that STAT follows surgery,illness,trauma,stress

• N shows amt of protein
• To maintain body tissues that break down from normal wear & tear & to support the growth of new tissue.
• Energy must be used to excrete the N. Like carbohydrates, protein consumed in excess of need can be converted to & stored as fat.
• RDA for adults is 0.8 g/kg of body weight
• Protein intake 10% to 20% total calorie intake

• (Lipids)-insoluble in H2O & blood.
• Like carbohydrates, they are composed of carbon, H, & O2.
• 95% of lipids in the diet are in the form of triglycerides, the predominant form of fat in food & the major storage form of fat in the body.

• Contain mixtures of saturated & unsaturated fatty acids.
• Saturated fats contain more H than unsaturated fats.
• Animal fats-saturated & have a solid consistency at room temp.
• Vegetable fats-unsaturated, remain liquid at room temp, referred to as oils.
• Saturated fats raise cholesterol level. Unsaturated fats lower cholesterol level.
• Trans Fat: when manufacturers partially hydrogenate liquid oils, they become more solid & more stable. Trans fat raises cholesterol.

Classification & Metabolism of Fats:

Cont.

• Cholesterol: fatlike substance found only in animal products. Not an essential nutrient; the body make sufficient amts. Its an important component in cell membranes & is especially abundant in bran & nerve cells. Its also used to synthesize bile acids & is a precursor of the steroid hormones & vit D.
• To help lower cholesterol levels, researchers recommend limiting cholesterol intake, eating less fat-especially saturated & trans fat-eating more unsaturated fat, & increasing fiber intake, which increases fecal excretion of cholesterol. Fat digestion occurs largely in the small intestine.

• The most concentrated source of energy.
• Body fat aids in the absorption of fat-soluble vits & provides insulation, structure, & temp control.
• RDA not established
• should be no more than 20% to 35% total calorie intake

Carbohydrates

(Simple sugars & starch)

• Sources: Fruits, vegtables, grains, peas, beans, milk (lactose), sugars
• Function: provide energy, spare protein, prevent ketosis
• Significance: Provide abt 46% if cals in amerian diet. Low carbohydrate intake can cause ketosis; high simple sugar intake increases the risk for dental caries. Are nondigestible; therefore, are excreted. Help relieves constipation. Excess intake can cause gas, diarrhea, distention. Helps improve glucose tolerance in diabetics.

• Sources: milk & milk products, meat, poultry, fish, eggs, dried peas & beans, nuts
• Function: Tissue growth & repair. Component of body framework. Component of body fluids. Helps regulate fluid balance through oncotic pressure. Helps regulate acid-base balance. Detoxifies harmful substances. Forms antibodies. Transports fats & other substances through the blood. Provides energy when carbohydrate intake is inadequate.
• Significance: Experts recommend that we eat less animal protein & more veg protein. Protein deficiency: edema, retarted growth & maturation, muscle wasting, changes in hair & skin, permanent damage to physical/mental development (children), diarrhea, malabsorption.

• Sources: butter, oils, margarine, lard, salt pork, salad dressings, bacon, whole milk & whole milk products, high-fat meats, Nuts
• Functions: provides energy, provides structure, insulates body, cushions internal organs, necessary for the absorption of fat-soluble vitamins.
• Significance: High fat diets increase the risk for heart disease & obesity & are correlated w/ an increased risk for colon & breast cancers.

• Organic compounds needed by the body in small amts. Active in the form of coenzymes. 
• Needed for the metabolism of carbohydrates, proteins, fats.
• Essential in diet because most aren't syntesized in the body or are made in insufficent quantities.
• Fresh foods are higher in vits than processed foods because they are destroyed by light, heat, air, & during preparation.

Vitamins

Classified as either water soluble or fat soluble:

• Water Soluble vitamins: vit C & B complex vits (ascorbic acid, thiamin, riboflavin, niacin, phyridoxine, folate,). Absorbed through intestinal wall directly into bloodstream
• Because water soluble vits aren't stored, amts consumed in excess of need are excreted in the urine.
• Fat soluble vitamins: vits A, D, E, K absorbed w/ fat into the lymphatic circulation. Like fat, they must be attached to a protein to be transported through the blood.
• Body stores excesses of fat soluble vits in liver & adipose tissue. 
• Excessive intake of vit A & D=toxic

Water Soluble Vitamins

Vitamin C:

• Sources: citrus fruits, broccoli, green pepper, strawberries, greens
• Functions: Collagen formation, antioxidant, enhances iron absorption.
• Deficiency: scurvy, hemorrhaging, delayed wound healing
• Excess: hot flashes, headache, diarrhea

Water soluble vitamins

Vitamin B Complex: Thiamin:

• Sources: pork, liver, whole & enrinched grains, legumes
• Function: Coenzyme in key reactions that produce energy from glucose
• Deficiency: Beriberi, mental confusion, fatigue
• Excess: none known

Water soluble vitamins

Vitamin B Complex: Riboflavin:

• Sources: milk, organ meats, enriched grains, greens
• Function: carbohydrate, protein, & fat metabolism
• Deficiency: Dermatitis, glossitis, photophobia
• Excess: none known

Water soluble vitamins

Vitamin B Complex: Niacin:

• Sources: kidney, grains, lean meat, nuts
• Function: carbohydrate, protein, & fat metabolism
• Deficiency: pellagra, dermatitis
• Excess: flushing & itching, nausea, vomiting, liver damage

• Water soluble vitamins

Vitamin B Complex: B6 (Pyridoxine):

• Sources: yeast, banana, cataloupe, broccoli, spinach
• Function: coenzyme in protein, fat, carbohydrate metabolism
• Deficiency: Microcytic anemia, CNS problems
• Excess: Difficulty walkiing, numbness of feet & hands

Water soluble vitamins

Vitamin B Complex: Folate:

• Sources: green leafy vegetables, liver
• Function: RNA & DNA synthesis, formation & maturation of RBC
• Deficiency: Macrocytic anemia: fatigue, weakness, pallor
• Excess: none known

Water soluble vitamins

Vitamin B Complex: B12 (cyanocobalamin)

• Sources: animal products: organ meats, seafood
• Function: coenzyme in protein, metabolism & formation of heme portion of hemoglobin.
• Deficiency: Pernicious anemia (B12 deficiency related to impaired absorption due to lack of intrinsic factor)
• excess: none known

Water soluble vitamins

Vitamin B Complex: Pantothenic Acid:

• Sources: widespread in foods; meat, poultry, fish, whole grain cereals
• Function: carbohydrate, protein, & fat metabolism
• Deficiency: none known
• Excess: none known

Water soluble vitamins

Vitamin B Complex: Biotin:

• Sources: liver, yolk
• Function: carbohydrate, protein, & fat metabolism
• Deficiency: rare; dry skin, anorexia, fatigue
• Excess: none known

Fat Soluble Vitamin

Vitamin A:

• Sources: liver, carrots, egg yolk, fortified milk.
• Function: visual acuity in dim light, formation & maintenance of skin & mucous membranes; immune function
• Deficiency: night blindness, rough skin, bone growth ceases
• Excess: anorexia, loss of hair, bone pain, vomiting, birth defects during pregnancy

Fat Soluble Vitamin

• Sources: sunlight, fortified milk, fish liver oils
• Function: calcium & phosphorus metabolism, stimulates calcium absorption
• Deficiency: retarted bone growth, bone malformation
• Excess: excessive calcification of bones, renal calculi, nausea, headache

Fat Soluble Vitamin

• Sources: vegetable oils, wheat germ, whole grain products
• Function: antioxidant, protects vit A, heme synthesis
• Deficiency: increased RBC hemolysis & macrocytic anemia in premature infants
• Excess: relatively nontoxic, although large doses can cause fatigue, diarrhea, & enhance action of anticoagulant meds.

Fat Soluble Vitamin

• Sources: dark, green leafy vegetables; synthesized in intestines from gut bacteria
• Functions: syntesis of certain proteins necessary for blood clotting.
• Deficiency: hemorrhagic disease of newborn, delayed blood clotting
• Excess: hemolytic anemia & liver damage w/ synthetic vit k

• Inorganic elements found in all body fluids & tissues in the form of salts (sodium chloride) or combine w/ organic compounds (iron in hemoglobin). 
• Some minerals function to provide structure w/in body, whereas others help regulate body processes.
• Elements that aren't broken down or rearranged in the body, but are contained in the ash that remains after digestion.
• Not commonly destroyed by food processing.

• (bulk minerals): needed by the body in amt greater than 100mg/day
• Includes calcium, phosphorus (phosphates), sulfur (sulfate), Na, chloride, K, & magnesium.

• (Trace elements) Needed by the body in amts less than 100mg/day. 
• Include iron, zinc, magnesium, chromium, copper, molybdenum, selenium, fluoride, iodine

• Major body constituent present in every body cell, H2O accounts for b/t 50% & 60% of the adult's total weight. Infants have proportionately more H2O accounting for body weight.
• Two-thirds of body water is contained within the cells (ICF)
• Remainder of body water is ECF, body fluids (plasma, interstitial fluid)
• Total body H2O & ECF decreases w/ age; ICF increases w/ an increase in body mass.

Water

Cont.

• More vital to life than food because it provides the fluid medium necessary for all chemical reactions, it participates in many reactions, & it's not stored in the body.
• Acts as a solvent that dissolved many solutes, thereby aiding in digestion, absorption, circulation, & excretion.
• Helps to regulate body temp.
• As a lubricant, H2O is needed both for mucous secretions & for mvmt b/t joints.
• Produced through the metabolism of carbohydrates, proteins, lipids.
• Water intake of 2,000-3,000mL/day for adults.

• Physiologic and physical factors
• --Stage of development, state of health, medications
• Physical, sociocultural, and psychosocial factors influencing food choices
• --Economics, culture, religion, tradition, education, politics, social status, food ideology

• Periods of intense growth & development, such as during infancy, adolescence, pregnancy, laction-cause an increase in nutrient needs. 
• Nurtrient needs stabilize during adulthood, although older ppl may need more or less of some nutrients. 
• Age influences not only nutrient requirements, but also food intake.

• (Birth-1yr): most rapid period of growth.
• Birth weight doubles in 4-6months & triples by 1 yr of age.
• Lenght increases 50% in the 1st yr.
• Nurtitional needs per unit of body weight are greater than at any other time in the life cycle.
• Breastfeeding is recommended as the major source of nutrition for the 1st 6-12 months of life.
• By 1 yr of age, the infant typically is eating table food. Iron fortified food are recommended.

• (3-5yrs) During this stage, growth rate slows. 
• Mobility, autonomy, & coordination increase, as do muscle mass & bone density.
• Lang skill improve & develops attitudes towards food.
• Can feed themselves, verbalize food likes & dislikes, & ocaisoinally use food to manipulate their parents.
• Inappropriate use of food (punish, reward, bribe) may lead to inapproprate food attitudes.

• (6-12yrs) Has an uneven, individualized, sometimes erratic growth pattern
• Permanent teeth erupt as the digestive system matures.
• Body accumulates reserves in preparation for the upcoming adolescent growth spurt
• Parent's role as the primary regulator of food intake diminishes, & advertising has more of an impact on the child's food choices.

• A period of rapid, physical, emotional, social, & sexual maturation. 
• Girsl begin menstruation & experience fat deposition. Males experience an increase in muscle mass, lean body tissue, & bones.
• Nutritional problems worsen during adolesence.
• Anorexia nervosa & Bulimia may develop.
• Often eat food rapidly, leading to overconsumption before satiety is experienced.

• Growth ceases
• marked by a decline in the BMR w/ each decade
• nurtritonal needs level off in adulthood, & fewer calories are required because of the decrease in BMR.

• Because of decrease in BMR & physical activity & loss of lean body mass, energy expenditure decreases.
• loss of taste b/t sweet & salty begins b/t 55-59yrs, but discrimination b/t bitter & sour remains intact.
• sensation of thirst decreases.
• Social isolation, poor self esteem, loss of independence may affect nutritinal intake negatively
• Caloric needs of the body decrease.
• Needs for nutrients increases or stays the same.
• Fiber & fluid intake can relieve constipation.

• Men: larger muscle mass translates into higher caloric & protein requirements (slightly highe needs for vit B that metabolizes cals & protein) because muscle mass is more metabolically active than adipose tissue.
• Women have more adipose tissue.

• alteration in nutrient requirements that results from illness & trauma varies w/ the intensity & duration of the stress. (Fever increases the need for cals & H2O)
• Trauma, like major surgery, burns, crush injuries is followed by hormonal changes that profoundly affect the body's use of nutrients.

• Can alter body's use of nutrients. 
• B vitamins increase because they are used to metabolize alcohol.
• Liver damage has profound effects on the body's nutrient metabolism & requirements
• Toxic effect of alcohol on the intestinal mucosa interferes w/ normal nutrient absorption; thus, requirements increase as the efficiency of absorption decreases.

• Nutrient absorption may be altered by drugs that change the pH of the the GI tract, increase GI motility, damage the intestinal mucosa, or bind w/ nutrients, rendering them unavailable to the body.
• Nutrient metabolism can be altered by drugs that act as nutrient antagonists, alter the enzyme systems that metabolize nutrients, or alter nutrient degradation.