Dietary Reference Intakes (DRI) 19/09/2007 15:00:00 ← Ch2 ← ← DRIs Replace and expand on the Recommended Dietary Aowance Intended to prevent nutritional deficiencies as well as reduce the risk of chronic diseases Specific for gender, age (infants to 70+ years), and pregnancy/lactation Consists of several types of reference intakes RDA – Recommended Dietary Allowance AI – Adequate Intake UL – Tolerable Upper Intake Level EER – Estimated Energy Requirement DV – Daily Value, for food labels (Not the same as the rest, RDA for worst case scenerio) RDA Average daily dietary intake level that is sufficient to meet the nutrient requirement of nearly all (97 – 98 percent) healthy individuals in a particular life stage and gender group o Not the minimum requrement o You can be below RDA and not have deficiency Developed to prevent nutrient deficiency diseases Age and gender specific Deficiency: intakes below 70% of RDA over and extended period o 2/3 of RDA is ok for a few days 1
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Dietary Reference Intakes (DRI) 9/19/07 10:00 AM
← Ch2
←← DRIs
Replace and expand on the Recommended Dietary Aowance
Intended to prevent nutritional deficiencies as well as reduce the
risk of chronic diseases
Specific for gender, age (infants to 70+ years), and
pregnancy/lactation
Consists of several types of reference intakes
RDA – Recommended Dietary Allowance
AI – Adequate Intake
UL – Tolerable Upper Intake Level
EER – Estimated Energy Requirement
DV – Daily Value, for food labels (Not the same as the rest, RDA for
worst case scenerio)
RDA
Average daily dietary intake level that is sufficient to meet the
nutrient requirement of nearly all (97 – 98 percent) healthy
individuals in a particular life stage and gender group
o Not the minimum requrement
o You can be below RDA and not have deficiency
Developed to prevent nutrient deficiency diseases
Age and gender specific
Deficiency: intakes below 70% of RDA over and extended period
o 2/3 of RDA is ok for a few days
1
Toxicity: intakes above 3 times RDA
Adequate Intake (AI)
Recommended intake value based on observed or experimentally
determined approximations or estimates of nutrient intake by a
group of healthy people
Used when an RDA cannot be determined
o Not as definitive as RDA; more research needed
← Tolerable Upper Intake Level (UL)
The highest level of daily nutrient intake that is likely to pose no
risk of adverse health effects for almost all individuals in the
general population. As intake increases above the UL, the potential
risk of adverse effects increases.
o Adverse effects over a long time of eating bad
← Estimated Energy Requirement (EER)
An estimate of the calorie needs of the average person based on
gender, age, height, weight, and physical activity level
o Energy = calories
← Range of Intake
Upper Level (UL) met or exceeded
RDA/AI/EER (good)
Deficient State
← Daily Value (DV)
Used on food labels (%DV)
Based on 2,000 kcal diet
Rough guide for comparing food nutrient content to requirements
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Vitamins: Fat Soluble (A, D, E, K) 9/19/07 10:00 AM
← What are Vitamins?
Essential organic compounds
o Essential – important to proper growth
o Organic - carbon
Needed in very small amounts
Do not provide energy
Function as coenzymes: B vitamins and vitamin K
o Work with enzymes
Fat soluble: vitamins A, D, E, and K
o Soluble in non polar things
Water soluble: B vitamins and vitamin C
o Soluble in polar things
← Why are they essential?
Vitamins either cannot be synthesized in the body or are not
synthesized in adequate amounts
o We are one of the few animals that do not make vitamin C
o We didn’t make some vitamins we needed as infants
Must be supplied in the diet
Exceptions: vitamins D, K, niacin, and biotin
Produce deficiency symptoms when missing from the diet
← Function of vitamins
Participate in energy-yielding reactions
3
Contribute to blood formation, clotting, bone health, protein
metabolism, antioxidant defense
← Sources and storage
Plant and animal foods in diet
Supplements
Fat-soluble vitamins (except vitamin K) are stored in body – not
readily excreted
o Hard to get deficiency
Water-soluble vitamins (except vitamins B6 and B12) are not stored –
readily excreted via urine
← Deficiency and toxicity
Deficiency: vitamin is lacking in the diet and the body stores are
depleted, loss of function
o Not often seen in our country
Toxicity: excessive intake can cause damage to the body
o Upper limit – line at where toxicity begins
← Toxicity
Fat-soluble vitamins accumulate in the body most readily and can
cause toxic effects (3x RDA for vitamin A-most extreme and easy to
overtake)
Water-soluble vitamins are toxic only in very large amounts (15-
100x RDA)
Toxicity most likely from supplementation
← Preservation of vitamins
Eat foods soon after harvesting
Tore properly (avoid heat, light, air)
o Cold/dark
Avoid excessive cooking
4
o Boiling in water causes vitamins to go into water
Frozen frouts and vegetables are as nutritious as fresh
← Absorption of fat-soluble vitamins (A, D, E, K)
Absorbed along with dietary fat
o Some drugs block absorption
Transported with fat through the bloodstream inside lipoproteins
Usually 40-90% of fat-soluble vitamins are absorbed
Fat malabsorption (diseases or weight loss during orlistat) may
cause deficiency
← Vitamin A
Found in several forms of foods
o carrots
Retinoids in foods of animal origin
Carotenoids (pigments) in vegetables, can be converted into
vitamin A
o Pre- or pro- vitamin A
Vitamin A Functions
o Promotes vision
Night blindness
o Promote growth, development, reproduction
o Prevents drying of the skin and eyes
Xerophthalmia (dry eye)
Need to maintain skin
5
o Promotes immune function and infection resistance
o Cardiovascular disease prevention
o Cancer prevention
o Acne medication (vitamin a derivatives)
Vitamin A recommendations
o Measured in Retinol Activity Equivalents (RAE) = vitamin A +
carotenoids (beta-carotene)
o RDA is 900 ug RAE for men, 700 ug RAE for women
o DV is 1000 ug RAE
o Average intakes in the us meet the RDA
o Much of vitamin A is stored in the liver
Vitamin A Deficiency
o Leading cause of preventable blindness in children
o Night blindness
o Xerophthalmia
o Dry skin
o Poor growth
Vitamin A Toxicity
o Highly toxic
o Enlarged liver
o Fetal malformations and spontaneous abortions (why
Accutane is not prescribed during pregnancy)
o Bone/muscle pain, fractures
6
o Headaches
o Hair loss
o Skin changes
o Eating polar bear liver – toxicity, makes person blind.
Vitamin A sources
o Yellow-orange vegetables (beta-carotene), dark green leafy
vegetables (lutein and zeaxanthin) and tomatoes (lycopene)
o Liver
o Fish oils
o Eggs
o Fortified milk and yogurt
← Vitamin D
Prohormone: activated by enzymes in the liver and kidneys
Derived from cholesterol (like a hormone
Synthesized from sunlight
80-100% of vitamin D needs can be provided by sunlight
Deficiency causes bone diseases
Functions
o Calcium metabolism and bone health
o Regulates absorption of calcium and phosperos from intake
o Regulates deposition of cacium in bones
o Influences cell development
7
o Immune function and cancer prevention
o Immune system modulator
Reccomendations
o 5 ug/day for adults under 51
o Sun
Deficiency
o Rickets, deficiency in children
Bowed legs
Rib “beads” at sternum
Slow growth
Bowed spine
o Osteonalacia – deficiency in adults
“soft bones”
bones lose minerals and become pourous
Toxicity
o Toxic in high amounts, especially for infants and children
o Over-absorption of calcium, calcium deposits in organs
o Weakness, appetite loss, diahrea, vomiting, mental
confustion, increased urine
Sources
o Fortified milk/milk products
o Fortified breakfast cereals
8
o Fish oils
o Sardines
o Salmon
o Sunlight
← Vitamin E
The fat soluble antioxidant vitamin
Protects unsaturated fats from oxidization
Donates electron to electron seeking compounds, “free radicals”
Found mostly in cell membranes
Improves vitamin A absorption
Recommendations
o 15 mg/day for adults
o many adults get recommended
Deficiency and toxicity
o Deficiency
Breakdown of cell membranes
Hemolytic anemia
Nerve degeneration
o Toxicity (not likely)
Muscle weakness
Headaches
9
Nausea
Inhibition of vitamin K metabolism
Sources
o Plant oils and products made from plant oils
o Green leafy vegetables
o Some fruits
o Nuts and seeds
o Fortified breakfast foods
← Vitamin K
Supplied by diet as well as intestinal bacteria
Synthesized by bacteria in the colon, 10% of Vitamin K needs
Functions
o Coenzyme with major role in coagulation process (blood
clotting)
o Activates proteins invoved in bone metabolism
Deficiency
o Hemorrhage
o Fractures
o Most at risk: patient with long standing fat malabsorption,
person taking antibiotics fro long periods, infants
Toxicity
o Unknown
Sources
o Green leafy vegetables
o Liver
o Broccoli
o Peas
o Green beans
o Fresh oils
o Meats
←
10
Water Soluble Vitamins 9/19/07 10:00 AM
← Water-Soluble Vitamins
11
Dissolve in water
Very little is stored in body
Excreted from body if consumed in excessive amounts
Include all essential B vitamins, Vitamin C, and choline (vitamin-like
compund)
Large amounts can be lost during cooking
← B Vitamin Functions
Coenzymes in energy metabolism
o Pathways used by carbohydrates (CHO), amino acids, and fats
Red Blood Cell formation and functions
Neurological function
Nearly 50-100% of B vitamins in the diet are absorbed
← Thiamin (B1)
Coenzyme form used in CHO metabolsm
Nerve function
RDA
o 1.1 to 1.2 mg/day
o most diets exceed RDA
Thiamin Deficiecy and Toxicity
o Deficiency
Beriberi
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Sinhalese: “I cannot, I cannot”
Dry: wasting, peralisys
Wet: edema, heart failure
Seen in areas where white rice is a staple
o Non-Toxic
Thiamin Sources
o Lean pork products
o Organ meats
o Whole and enriched grain products
o Dried beans
o Seeds
o Peanuts
o Peas
← Riboflavin
Coenzyme form participate in energy-yielding metabolic pathways
(aerobic energy)
RDA
o 1.1 to 1.3 mg/day
o nutrient-poor diets are usually low in riboflavin, i.e. alcoholics
Riboflavin deficiency and toxicity
o Deficiency
Cheilosis (cracking on outside of lips), angular stomaitis
(cracks or sores at corners of mouth, inflimation of
mouth and tounge, and dermatitis)
13
o Non-toxic
Sources
o Milk and milk products
Destroyed by light
o Enriched and whole grains
o Meat, liver, eggs, spinach, oysters
← Niacin
Coenzyme forms in energy metabolism
RDA
o 14 mg/day for women
o 16 mg/day for men
Deficiency and Toxicity
o Deficiency
Pellagra – 4 D’s
Dermatitis
Diarriha
Dementia
Death
o Toxicity with intakes >100 mg/day
Vasodilation, itching, headaches, flushing
Sources
14
o Poultry, beef, tuna, and other fish (high protein foods)
o Enrichd prducts
o Wheat bran
o Asparagus
o Peanuts
o Can be synthesized from tryptophan (essential amino acid)
← Vitamin B6
Coenzyme form
o Activates enzymes needed for metabolism of CHO, fat, and
protein
o Synthesizes non-essential amino acids
o Synthesizes neurotransmitters
o Synthesizes hemoglobin & WBC
o Role in homocysteine metabolism
o PROTIEN METABOLISM
RDA
o Avg daily intake is more than RDA
o Alcoholics at risk for deficiency
B6 Deficiency and Toxicity
o Deficiency
Irritability, nervousness, depression/moodiness,
vomiting, skin disorders, and impaired immune
response
o Toxicity >200 mg/day can lead to irreversible nerve damage
15
Risk with using megadoses to reduce the symptoms of
PMS
Sources
o Animal products
o Dairy products
o Bananas
o Potatoes
o Widely available
← Folate
Coenzymes help form DNA and metabolize various amino acids
Red blood cell formation and maturation
RDA
o 400 ug/day adults
o 600 ug/day pregnant women
Deficiency and Toxicity
o Deficiency
Results in neural tube defects in fetus
Results in megaloblastic anemia in adults (large
immature RBC in the blood, fewer mature RBC,
decreased ability to carry O2)
o Toxicity
Excess can mask B12 deficiency
Sources
o Foliage
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o Liver
o OJ
o Enriched products
o Grains, legumes
Heat and microwave can destroy some forms
← Vitamin B12
Coenzyme form
Role in folate metabolism
Maintaining myelin sheaths
o Transfer electrical pulse
RBC formation
RDA
o 2.4 mg/day for adults
o stored in liver
Absorption
o Requires a protein from salivary gland
o Requires stomach acid
o Requires intrinsic factor
Protein-like compund produced by the stomach that
enables B12 absorption
o Absorbed in the last part of small intestine
About 50% absorbed
17
Deficiency and Toxicity
o Deficiency
Pernicious anemia : (“deadly, fatal”) duue to lack of
intrinsic factor inability to absorb B12
Megaloblastic anemia
Nerve degerneration & peralysis
o Non-toxic
Sources
o ONLY in foods from ANIMAL SOURCES
o Animal products
o Organ meats
o Seafood
o Eggs, milk
o Hot dogs
o Synthesized by bacteria, fungi, and lower organism
← Pantothenic Acid
Coenzyme form essential for metabolism of CHO, fat, and protein
RDA
o 5 mg/day
Deficiency
o Rare, however usually in combination with other deficiencies
Toxicity unknown
18
Sources
o Found everywhere
o Wheat, milk, veggies, sunflower seeds, mushrooms, peanuts,
eggs
← Biotin
Coenzyme form aids in fat and CHO metabolism
Helps break down certain amino acids
RDA
o 30 ug/day
Deficiency
o Rare. Scaly/inflamed skin, changes in tounge and lips,
decreased appetite, nausea/vomiting
Non-toxic
Sources
o Caluflower
o Egg yolk
o Peanuts, cheese
o Intestinal bacteria can synthesize and supply some biotin
o More than a dozen raw egg whites a day can cause absorption
to be inhibited
Vitamin C
Synthesis of callogen
o Makes up connective tissue
Iron absorption
19
Immune function
Antioxitant
RDA
o More for smokers
Deficiency of Vitamin C
o Scurvy: bleeding gums, pin-point hemorrhaging, poor wound
healing, wakness
Toxicity
o Stomach inflammation and diarrhea
Sources
o Citrus fruits
o Potatoes
o Green peppers
o Cauliflower
o Broccoli
o Strawberries
o Lettuce
o spinach
← Choline 8-3
Essential nutrient, however it is not considered a vitamin
All tissues contain choline
Precursor for acetylcholine (neurotransmitter)
20
Precursor for phospholipids
o Good for tying things together
RDA
o 425-550 mg/day for adults
← Choline Deficiency (never the right answer)
Deficiency
o Rare
Toxicity
o In high doses: associated with fishy body odor, vomiting,
salivation, sweating, hypotension, GI effects
← Choline Sources
Widely distributed in foods
Milk
Liver
Eggs
Peanuts
Lecithin added to foods
←
21
Major/Macro Minerals 9/19/07 10:00 AM
← Minerals
Various functions in the body
Do not provide energy
Major/macro minerals
Micro/trace minerals
Bioavailability depends on interactions with fiber, vitamins, and
other minerals
o Sometimes 10% absorbed
o Fiber keeps some from being absorbed
o Compete for absorption
Toxic in excessive amounts, especially trace minerals
← Major/Macro Minerals
Calcium (Ca)
Magnesium (Mg)
Sodium (Na)
Sodium (Na)
Chloride (Cl)
Potassium (K)
Phosphorus (P)
Sulfur (S)
← Calcium
99% in bones and teeth
22
makes up 40% of all the minerals present in the body
Functions
o Forming and maintaining bones
o Blood, nerve, muscles, and cells
RDA
o 1000 to 1200 mg/day for adults
o 1300 mg/day for children
o Avg intake is NOT enough
Absorption of calcium
o Normally 25% absorbed from food
o Vitamin D and acidic gut help absorption
o Absorbed in upper part of small intestine
o Absorption increased to 60% in time of need, i.e. pregnancy,
infancy
Decreased Absorption of Calcium
o High fiber intake
o Excess phosphorus
soda
o Vitamin D deficiency
o Polyphenols (tannins) in tea
o Diarrhea
o Aging
23
Calcium Deficiency
o Deficiency
Osteoporosis: loss of bone mass
Most at risk
Post-menopausal women
Slender, inactive women who smoke
Previntion
Build peak bone mass when young with
adequate calcium and vitamin D intake
Weight-bearing physical activity
o Calcium Toxicity
Not common
Risk of kidney stones and other problems
o Sources
Dairy products
Canned fish
Ca-fortified orange juice
Supplements
← Magnesium
60% is found/stored in the bones
Functions
o Bone formation
24
o Enzyme function
o Nerve and heart function
RDA
o 310-320 mg/day for women
o 400 to 420 mg/day for men
Deficiency
o Unlikely unless diurectic use or alcoholism
o Weakness, muscle pain, poor heart function
Toxicity
o Overuse of antacids, laxatives, or supplements
o Causes diarrhea and weakness in patients with kidney failure