Ch. 18 Nutrition

Nutrition

study of nutrients and how body uses them

Nutrients

chemicals from the environment that organisms need for survival; used to supply energy to fuel metabolic processes, and for building blocks for producing the molecules the body needs

Macronutrients

required in large quantities such as carbohydrates , lipids, proteins; provide energy

Micronutrients

required in small amounts such as vitamins and minerals; help extract energy from macronutrients

Essential nutrients

nutrients that the body cannot synthesize or cannot synthesize in sufficient quantities (must be obtained from the diet)

Calories

units of heat used to express amounts of energy in food

Carbohydrates

organic compounds such as sugars and starches that hold energy in chemical bonds that is used to power cellular processes

Polysaccharides

complex carbohydrates, such as starch from plant foods and glycogen from meats

Disaccharides (double sugars)

milk sugar, cane sugar, beet sugar molasses

Monosaccharides

simple sugars (honey, fruit)

Cellulose

complex carb abundant in our food; not digested, but provides fiber

Glucose

used as the most common cellular fuel oxidized in glycolysis

Excess glucose

converted into glycogen by glycogenesis and stored in liver and muscle cells

Glycogenolysis

breakdown of glycogen into glucose

Gluconeogenesis

conversion of noncarbohydrates into glucose, for cells that require glucose as energy source

Lipogenesis

the conversion of excess glucose into adipose

125 to 175 grams/day

About how much carbohydrates are needed daily?

200 to 300 grams/day

About how much carbohydrates are consumed in the US diet?

Lipids

organic compounds that include fats, oils, phospholipids, and cholesterol; supply energy for cellular processes serve as building blocks for structures such as cell membranes

Triglycerides

composed of glycerol and 3 fatty acids; found in plant based and animal based foods

Saturated fats

no double bonds between carbon atoms in fatty acids; found in animal foods like eggs, lard, milk

Unsaturated fats

contains one or more double bonds between carbon atoms; found in seeds, nuts, and plant oils; monounsaturated are healthiest

Cholesterol

abundant lipid in liver and egg yolk; some in whole milk, butter, cheese, and metal not found in foods of plant origin

Lipid use

supply energy, contain more than twice as much energy as carbs/proteins; is broken down to glycerol and fatty acids to release energy; can be used to synthesize storage fats in adipose tissue

Liver

converts fatty acids from one form to another; does NOT synthesize essential fatty acids

Lipoproteins

combination of lipids and proteins that are classified based on density

VLDLs (very low density lipoproteins)

type of lipoproteins that have a high triglyceride content

LDLs (low density lipoproteins)

type of lipoproteins that have high cholesterol content

HDLs (high density lipoproteins)

type of lipoproteins that have high protein content (good kind)

No more than 30% of daily calories

How much fat should be in a daily diet?

Proteins

long chains of amino acids that have many functions including building new proteins, enzymes, hormones, antibodies; can also be used as energy

Deamination

removal of the amino group from protein forming urea which is excreted in urine

Complete proteins

(high-quality proteins) contain adequate amounts of the essential amino acids for good health; found in meat, milk, and eggs

Incomplete proteins

(low-quality proteins) do not contain adequate amounts of essential amino acids; found in many plant proteins

Protein sources

meat, fish, poultry, cheese, nuts, milk, eggs, legumes

8

how many essential amino acids are there?

12

How many non essential amino acids are there?

Negative nitrogen balance

occurs due to starvation where nitrogen excretion exceeds dietary intake

Positive nitrogen balance

develops in growing children, pregnant women, or an athlete in training (protein being built into new tissue exceeds energy usage and excretion)

Protein requirements

no more than 30% of total daily calories from fat

Deficiency of proteins

leads to tissue wasting and a decline in plasma proteins (which results in decreased plasma osmotic pressure and nutritional edema)

TIMLKFWV

What are the 8 essential amino acids?

Arginine and Histidine

What two amino acids are essential in children?

Basal metabolic rate (BMR)

Rate at which body expends energy under basal conditions (awake and at rest, after overnight fasting, in comfy environment)

BMR varies with

gender, body size, body temperature, thyroid hormone activity

Energy is needed in body to

maintain BMR, support muscular activity, maintain body temp, and growth in children and pregnant women

Energy balance

exists when caloric intake from foods equals caloric output form BMR and muscular

Positive energy balance

state of balance when caloric intake exceeds output, tissues store excess nutrients, and weight gain occurs

Negative energy balance

state of balance when caloric expenditure exceeds intake, tissues are broken down for energy, and weight loss occurs

Body mass index (BMI)

consists of being underweight, normal weight, overweight, or obese

Overweight

exceeding desirable weight by 10% to 20%, or a BMI of 25 and 30

Obesity

exceeding desirable weight by >20%, or with a BMI over 30; excess adipose tissue

Obesity increases risk for

type 2 diabetes, digestive disorders, heart disease, kidney failure, hypertension, stroke, certain cancers

Appetite

drive that compels people to seek food; control center located in the hypothalamus

Insulin

Hormone secreted by the pancreas after eating; stimulates adipocytes to take up glucose and store fat, and other cells to take up glucose and store glycogen

Leptin

Hormone secreted by adipocytes while eating; acts on hypothalamus to suppress appetite, by inhibiting release of Neuropeptide Y

Neuropeptide Y

Neurotransmitter secreted by the hypothalamus in response to the hormone, grehlin; stimulates appetite

Ghrelin

Hormone secreted by the stomach; enhances appetite by causing secretion of Neuropeptide Y

Vitamins

organic compounds that are required in small amounts for normal metabolic processes; essential

Fat soluble vitamins

ADEK, vitamins that are resistant to heat

Know which are fat soluble, know their alternative names, food sources

Water soluble vitamins

B vitamins and vitamin C

B vitamins

essential for normal cellular metabolism; usually found in the same foods aka vitamin B complex

Vitamin A

An antioxidant necessary for synthesis of visual pigments, mucoproteins, and mucopolysaccharides; for normal development of bones and teeth; and for maintenance of epithelial cells

Vitamin D function

Promotes absorption of calcium and phosphorus; promotes development of teeth and bones

Vitamin E function

An antioxidant; prevents oxidation of vitamin A and polyunsaturated fatty acids; may help maintain stability of cell membranes

Vitamin K function

Required for synthesis of prothrombin, which functions in blood clotting

Vitamin A food source

Liver, fish, whole milk, butter, eggs, leafy green vegetables, yellow and orange vegetables and fruits 600 IU**

Vitamin D source

Produced in skin exposed to ultraviolet light; in milk, egg yolk, fish liver oils, fortified foods 400 IU

Vitamin E source

Oils from cereal seeds, salad oils, margarine, shortenings, fruits, nuts, and vegetables 30 IU

Vitamin K source

Leafy green vegetables, egg yolk, pork liver, soy oil, tomatoes, cauliflower 55 to 70 µg

Thiamine

Vitamin B 1 is also known as

Riboflavin

Vitamin B2 is also known as

Niacin, nicotinic acid

Vitamin B3 is also known as

Pantothenic acid

Vitamin B5 is also known as

Source of thiamine

Lean meats, liver, eggs, whole-grain cereals, leafy green vegetables, legumes; 1.2 mg

Source of riboflavin

Meats, dairy products, leafy green vegetables, wholegrain cereals; 1.3 mg

Source of niacin

Liver, lean meats, peanut butter, legumes; (14 mg for females 16 mg for males)

Source of Pantothenic acid

Meats, wholegrain cereals, legumes, milk, fruits, vegetables; 5 mg

Vitamin B6 source

Liver, meats, bananas, avocados, beans, peanuts, whole-grain cereals, egg yolk; 1.3 mg < 50 years, 1.7 mg > 50 years

Biotin

What is another name for vitamin B7?

Folacin, Folic acid

What is another name for vitamin B9

Cyanocobalamin

What is another name for vitamin B12?

Ascorbic acid

What is another name for vitamin C?

Sources of biotin (Vit. B7)

Liver, egg yolk, nuts, legumes, mushrooms; 0.3 mg

Sources of folacin (vitamin B9)

Liver, leafy green vegetables, wholegrain cereals, legumes; 0.4 mg

Sources of cyanocobalamin (B12)

Liver, meats, milk, cheese, eggs; 2.4 µg

Sources of vitamin C

Citrus fruits, tomatoes, leafy green vegetables;

Minerals

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

Mineral toxicity

can result from ingestion of too much of a mineral, or from overexposure to industrial pollutants, household chemicals, or certain drugs

4%

How much body weight is made up of minerals?

Major minerals

account for 0.05% or more of body weight; Ca, P, K, S, Na, Cl, Mg

Ca and P

What two minerals account for 75% of mineral elements

blood ions, electrolytes, organic molecules

Where can you find minerals?

Roles of minerals

partake in muscle contraction, nerve impulse conduction, blood coagulation, pH regulation

Trace minerals (microminerals)

Essential minerals found in minute amounts; each makes up less than 0.005% of body weight; Fe, Mn, Cu, I, Co, Zn, Fl, Se, Cr

Iron location

Primarily in blood; stored in liver, spleen, and bone marrow

Iron function

Part of hemoglobin molecule; assists in vitamin A synthesis; incorporated into a number of enzymes

Manganese location

Most concentrated in liver, kidneys, and pancreas

Manganese function

Part of enzymes required for fatty acid and cholesterol synthesis, urea formation, and normal functioning of the nervous system