Nutrition Flashcards
Main function of lipids
Other functions
Energy storage
Insulate and protect the body
Transport fat soluble vitamins
Provide flavor and satiety.
Lipid groups
Triglycerides
Phospholipids
Sterols
Essential fa - linoleic acid 18:2 and linolenic acid 18:3
Trans fatty acids
Associated with increased risk of cardiovascular disease
Occur naturally and as a result of food processing
Associated with elevated ldl and decreased hdl
Lipoproteins
Consists of proteins and phospholipids
How lipids are transported through the body
Act as emulsifiers so that fat and fat soluble substances can be transported in the blood
Bad cholesterol
LDL
Idl
Vldl
Chylomicron and cylomicron remnant
Good cholesterol
Hdl
What is a more important predictor of serum cholesterol
Dietary fat
Saturated fat is important
What contributes to serum triglyceride levels
Simple sugars and alcohol
How does the body use dietary fat
Dietary fat can be stored, used for energy or act as a precursor to other compounds
2 ways alcohol is metabolized into
Fatty acids
Co2 and h2o
Carbohydrates
Classified based on the number os saccharine units
Dietary fiber and human digestive enzymes
Fibers cannot be digested by human digestive enzymes.
Not absorbed
Helps maintain bowel health
Lowers serum cholesterol levels
Soluble dietary fiber
Forms a gel matrix in the GI tract - slow absorption of some substance.
Increases transit time
Examples of soluble dietary fiber
Pectin from apples Sweet potatoes Beans Oats Prunes
Insoluble dietary fiber
Decreases transit time
Can bind or complex with other compounds - not absorbed
Examples of insoluble dietary fiber
Lentils
Whole wheat bread
Avocado
Lactose intolerance
Occurs when an ind does not synthesize lactase or at least in significant amounts.
So microbiota takes care of it with some sad side effects.
Primary function of carbohydrates
Serve as source of energy which in turn spares protein and prevents ketosis
Endogenous source of body energy
Made by the body by gluconeogenesis or glycogenolydid
Exogenous source of body energy
Carbohydrate containing food
What does adequate carbohydrate intake do?
Necessary for normal fat metabolism and provides flavor and sweetness to food.
Normally acetyl coA combines with what to enter the cac
Oxaloacetate from glucose
What happens to the cac when glucose is not available
Incomplete combustion of fatty acids occurs and ketone bodies are formed.
(Fatty acids > acetyl CoA> acetoacetic acid> ketone bodied Bhydroxybutyric acid and a tone
Nutritional ketosis
Mild
Less than 50 g of cho
Complications include dehydration, electrolyte disturbances, hypoglycemia
No acidosis
Diabetic ketoacidosis
Severe Type 1 diabetes Insufficient insulin Can be life threatening Blood ph decreases as alkali reserves are depleted
Gluconeogenesis
Formation of glucose from non cho sources
Occurs in the liver and a little in kidney
Not glycolysis in reverse
Gluconeogenesis substrates
Lactic acid
Glycerol
Amino acids (ala pro ser)
Glycogenolysis
Breakdown of glycogen into glucose or glucose derivatives
Liver glycogenolysis vs muscle glycogenolysis
Liver - direct source of blood glucose
Muscle - indirect source of blood glucose
Liver cell glycogenolysis
Glycogen>g1p > g6p>glucose
Muscle cell glycogenolysis
Glycogen > g6p> lactic acid
Proteins
Polymers of aa joined by peptide bonds
Essential aa
Pro Val Thr Trp Ile Met His Ala Leu Lys
Semiessential / conditionally essential aa
Cys (met)
Tyr (phe)
Protein quality is determined by what
Types and amounts of amino acids it contains
Digestibility of protein.
Animal proteins
Tend to be complete proteins
Includes meat, poultry, fish, eggs, dairy products
Plant proteins
Tend to be incomplete (except soy and quinoa)
Grains, nuts, seeds, legumes, veggies
Primary function of proteins
Other functions
Tissue maintenance and growth Fluid balance Acid base balance Hormones and enzymes Immune funciton Gluconeogenesis
Protein needs measurement
0.8 G protein per kg healthy body weight
Total protein requirements deviations
Total protein per day is higher at older ages but protein per body weight is highest during the first year of life
What factors are important in determining protein needs
Health status of ind (malnourished? Other medical conditions?)
Medications (nutrient drug interactions, prednisone)
Vitamins
Organic compounds that cannot be synthesized by the body
Natural component of food
Water soluble vitamins
Vitamin c Vitamin b (1,2,6,12,folate, biotin etc)
Fat soluble vitamins
A
D
E
K
Why are some sign and symptoms of deficiency similar?
Interrelated nature of vitamins
Excretion of fat soluble vs water soluble bitamins
Water soluble vitamins are excreted more readily
Fat soluble are not readily excreted
Which vitamin can be stored
Fat soluble vitamins
Which type of vitamin does vitamin deficiency symptoms occur quickly
Water soluble
How are fat soluble vitamins handled
Similar to other fat soluble compounds
Absorbed along with dietary fat. Packaged with chylomicrons and transported by vldl and ldl
Where does vitamin d come from
Synthesized from cholesterol derivative
Vitamin k from
Synthesized by bacteria within gi tract
Niacin synthesized from
Trp
What causes vitamin loss
Food processing and preparation
Over cooking, cut up and exposed to air
Which type of vitamin is more likely to be toxic
Fat soluble vitamins
Especially from supplements.
Deficiency symptoms
Occur late in deficiency state
Subclinical deficiency
Occurs in early stages when few/no symptoms are observed
Assessment of body stores as measures of recent dietary intake are lacking.
Biomarkers of deficiency that occur prior to deficiency are limited and flawed
Groups considered at risk for micronutrient deficiency or toxicity
Elderly Babies and young ins Preggos Alcoholics Chronic health conditions - dialysis, malabsorption
Vitamin c deficiency disease
Scurvy
Vitamin d deficiency disease
Ricketts
Osteomalacia
Thiamin deficiency disease
Beri beri
Niacin deficiency disease
Pellagra
Why is assessing vitamin status challenging
Signs and symptoms similar for many vitamins
If deficient in one vitamin, likely to be deficient in serveral vitamins
Blood and tissue levels may be controlled by factors other than dietary intake
Niacin
Forms
Toxicity
Uses
Nicotinic acid and nicotinamide.
Nicotinic acid is associated with toxicity at high doses and lowers ldl - powerful drug
60 mg trp > 1 mg niacin
Deficiency of vitamin b6
Rare, but can occur when patient is on isoniazid
Isoniazid is used to treat tb.
Excess b6
Can lead to irreversible nerve damage
Long term use of 200mg/day to treat pms.
Folic acid / b12 deficiency
Result in macrocytic / megaloblastic anemia
And increased neural tube defects
Vitamin a deficiency
Most preventable form of blindness
Loss of sensitivity to green light> impairment to adapt to dim light > night blindness > complete blindness
Excessive vitamin a
Result in unbound vitamin a causing tissue damage
Chronic - death and other symptoms
Acute - death and other symptoms
Teratogenic - fetal malformations
Carotenoids
Not toxic for most people and some vitamin manufacturers use beta carotene in place of vitamin a.
Beta carotene is converted to vitamin a when needed.
Vitamin d synthesis
Cholesterol derivative
Requires 2 hydroxylation steps (in liver and kidney) to make vitd125 vitd125 = active form of vitamin d
Medical conditions at risk of vitamin d deficiency
Elderly - especially in northern climates or nursing homes
Kidney diseased
Liver diseased
Stomach, gallbladder, intestinal diseased
Vitamin e toxicity
Assumed to be least toxic of fat soluble vitamins. Toxic in high doses though
High douses can inhibit vitamin k metabolism> possible hemorrhage.
Vitamin k concerned people
Newborns, at risk for deficiency - no microbiota to create
Patients taking anticoagulants - nutrient drug interaction
How are minerals classified
Based on requirement
Macrominerals
More than 100 mg Ca Phos Mg N.A. K Cl
Trace mineral
Less than 100 mg/day
Fe An Cu We Cr I Man Fl Co
Fe mineral
Trace mineral
An mineral
Trace mineral
Ca mineral
Macromineral
K mineral
Macromineral
Mg mineral
Macromineral
N.A. mineral
Macromineral
Bioavailability
- Percent of consumed material that enters the body via the intenstinal absorptive cell
- Used for its intended purpose
Minerals 100% absorbed
N.A. K Cl We Mg
Absorption dependent factors
Solubility
Presence of compounds such as phytates and oxalates
Amount of element to be absorbed
Why are animal products usually the best sources of mineral
More concentrated
More bio available
Antioxidants
Natural/ synthetic compound readily oxidized and prevents the oxidation of another compound
Phytochemicals
Nonnutrient compounds found in plant foods that have biologic activity
Dietary supplement
Broad range considered food by fda, regulates differently than conventional food
Nutrient based approach diet
Type of approach would include the dris
Focuses on specific nutrient.
Food based diet approach
My plate
Focuses on food groups as means of evaluating dietary intake
My plate breakdown
1/2 fruits and veggies
1/4 grains (whole)
1/4 protein (lean)
Dairy foods are side items
Dash diet
For lowering bp
Low sodium
Emphasizes fruits and veggies
Low fat/non fat dairy products
Ada exchange plan
Diabetes
Organizes food into groups with each groups having similar kcal and macronutrient content based on serving size indicated.
Food labels tell you
Size of single serving
Kcals per serving
Key nutrients
List of ingredients
Medical nutrition therapy
Concerned with meeting nutritional needs of patients who require some type of diet modification as result of illness/disease.
Enteral nutrition
Method of providing nutrient solutions into a gi through tube
Can be placed in several different locations depending on functional gi status
Requires adequate absorptive capacity
Parenteral nutrition
Direct entry of nutrients into systemic circulation
Iv or tpn.
Appropriate when pt cannot be adequately nourished by oral or enteral feeding methods.
Gi tract not functional
Determining energy needs
Needs are based on energy expenditure and protein utilization.
Determining protein requirements
24 hr urinary urea nitrogen
Positive protein balance needed to restore protein stores
Dietary reference intake
Set of nutrient intake values for healthy people in us and canada
Used fo planning and assessing diets
Recommended dietary intake
Average daily amount of a nutrient considered adequate to meet known nutrient needs of practically all healthy people
Estimated average requirement
Average daily amount of nutrient that will maintain a specific biochemical or physiological funciton in half of they healthy people of a given age and gender.
Adequate intake
Average daily amount of a nutrient that appears to maintain a specified criterion
Tolerable upper limit
Max daily amount of nutrient that appears safe for most healthy people
Daily value
Reference values developed by fda specifically for use on food labels.
