Vitamins!!!
What are general characteristics of water-soluble vitamins vs. fat-soluble vitamins?
General Characteristics of Vitamins
• Small, organic compounds (contain carbon).
• Needed in small amounts (micrograms or milligrams).
• Usually obtained from food.
• Some are synthesized by the body.
o Vitamin D is made in skin from exposure to sunlight (UVB rays).
o Vitamin K is made by bacteria in GI tract.
• May be a precursor or provitamin.
o Example: Beta carotene is converted by the body into vitamin A.
• There are more than 1 form of some vitamins. Example: menaquinone and phylloquinone
are both active forms of vitamin K.
• Essential to life.
• Each has one or more specific functions.
• Regulate body processes; support growth.
• Do not provide energy (kcalories).
• Some are toxic in high doses (such as from megadoses from supplements).
o Examples: Vitamins A & D
• No perfect food contains all vitamins.
• Body can’t detect difference between synthetic and natural vitamins.
• Classified as fat soluble or water soluble
Absorption:
Water-soluble vitamins are absorbed from the GI tract directly into the bloodstream.
Fat soluble vitamins are absorbed with lipids into the lymph system before entering the bloodstream.
Excretion:
Excess water-soluble vitamins (or their metabolites) are excreted in the urine.
Fat soluble vitamins cannot be excreted in the urine, so excess amounts are stored in the body.
Storage:
Water-soluble vitamins are found in water in cells and fluids. They are not stored in large amounts (with the exception of vitamin B12).
Fat soluble vitamins are stored in the liver and fatty tissues.
Toxicity:
Fat Soluble vitamins can be toxic in high doses. This is especially true for vitamins A and D.
Some water-soluble vitamins can be also be toxic in very high amounts from supplements. Since excess fat-soluble vitamins can’t be excreted, there is a greater risk of toxicity from high doses of fat-soluble vitamins than from high doses of water-soluble vitamins.
Transport:
Water-soluble vitamins travel freely in the body and don’t require transport protein in the bloodstream.
Fat-soluble vitamins require transport proteins to travel in the bloodstream.
Thiamin
Thiamin ( B1)
Functions:
• Coenzyme in energy metabolism; essential in carbohydrate energy metabolism as part of the co-enzyme Thiamin Pyrophosphate (TPP)
• Essential for healthy nerve function
RDA:
• Women – 1.1 mg/day
• Men – 1.2 mg/day
Deficiency:
• Called Beriberi
• Symptoms include nerve damage, poor coordination, paralysis, loss of appetite, mental depression, and heart failure. Beriberi may be wet (with edema) or dry (no edema).
• Causes Wernicke-Korsakoff Syndrome in alcoholics.
Toxicity: No
Food Sources: Enriched grains, pork, fish, and legumes are good sources. There are small to moderate amounts in many foods, including whole grains, meats, and nuts.
Sodium
Sodium (Na+)
Extracellular Cation - Sodium is concentrated in extracellular fluid (outside cells).
Major Functions (Potassium also has these functions.)
• helps maintain fluid balance
• helps maintain acid-base balance
• helps send nerve impulses
• needed for muscle contraction
Sodium Recommendations
AI for sodium = 1,500 mg/day for adults aged 19 – 50 years
CDRR for sodium = 2,300 mg/day (to reduce chronic disease risk)
• It is recommended that we limit sodium to 2,300 mg/day to reduce risk for high blood
pressure, stroke, and heart disease.
• *This is the amount of sodium in one level teaspoon of salt!
A sodium intake of 1,500 mg to 2,300 mg/day is in the recommended range for healthy adults.
Sodium Deficiency
• Caused by excessive sodium losses (i.e., from illness or heavy sweating).
• Causes hyponatremia – low blood sodium
Sodium Excess
• Most Americans have diets high in sodium. The average sodium intake of American
adults is >3,400 mg/day.
• A high sodium diet is a risk factor for high blood pressure, stroke, heart disease, and
stomach cancer.
• A high sodium diet increases calcium excretion in urine (an osteoporosis risk factor).
Major Sodium Sources
According to the Centers for Disease Control (CDC), processed foods and restaurant foods are
the biggest sources of sodium for Americans. These account for 71% of the sodium in the
American Diet.
Tips for reducing Dietary Sodium
• Choose mainly whole foods that you cook yourself (whole foods are naturally low in
sodium).
o Good choices include fresh or frozen meats & seafood, whole grains, plain rice or
pasta that you cook yourself, and fresh or frozen fruits & vegetables.
• Make foods flavorful with herbs, spices, vinegars, oils, wine, pepper, or lemon juice
(rather than salt).
• Read food labels; choose lower sodium options.
• Avoid or limit high sodium processed foods: lunch meats, sausages, foods prepared in
brine (i.e., pickles, olives), high-sodium condiments & sauces, canned & instant soup, flavored rice & pasta mixes, salted snack foods, cheesy foods or processed cheese.
When are vitamin/mineral supplements needed?
when your doctor says so
What is the most common nutrient deficiency worldwide?
Which water-soluble vitamins are cofactors in energy metabolism reactions?
Thiamin, Riboflavin, Niacin, Biotin, Pantothenic Acid
Riboflavin
Riboflavin (B2)
Functions:
• Coenzyme in energy metabolism (FAD)
• Essential for DNA synthesis
• Needed for healthy skin and vision.
• Converts the amino acid tryptophan to niacin.
o Part of the coenzymes flavin monoucleotide (FMN) and flavin adenine dinucleotide
RDA:
• Women - 1.1 mg/day
• Men - 1.3 mg/day
Deficiency:
• Called Ariboflavinosis
• Symptoms include cheilosis (dry, red, cracked corners of mouth); glossitis (smooth red tongue); skin rash; eyes sensitive to light
Toxicity: No
Food Sources:
• Dairy is high in riboflavin and is the best riboflavin source for most Americans who consume dairy products.
• Meat, dark green vegetables, whole grains and enriched grains, mushrooms, and liver are additional good sources.
Potassium
Potassium (K+)
Intracellular Cation: Potassium is concentrated inside cells. Sodium-potassium pumps in cells
concentrate potassium inside cells and concentrate sodium outside of cells. This creates an
electrical potential that is important for enabling sodium and potassium to send nerve impulses
and to contract muscles.
Functions*
• helps maintain fluid balance
• helps maintain acid-base balance
• helps send nerve impulses
• needed for muscle contractions
*Sodium also has these functions.
Potassium Recommendations
AI – 2,600 mg/day for women
3,400 mg/day for men
• Notice that we should consume more potassium than sodium.
• A good potassium intake helps to control (reduce) blood pressure and lowers risk for
high blood pressure, heart disease, and stroke.
UL: No
Potassium Deficiency
• Increased blood pressure; increased risk for heart disease & stroke.
• Increased bone turnover (loss of calcium from bones)
• Kidney stones
• Irregular heartbeat and muscle weakness in severe deficiency
Potassium Toxicity
• Does not occur in healthy people from eating high potassium foods.
• Kidney failure is the major cause. Can also occur from potassium injections, high dose
potassium supplements, or certain medications.
• Causes nausea & vomiting, muscle weakness, irregular heartbeat. Possibly fatal.
Sources of Potassium
• Potassium is widespread in the food supply.
• Whole foods are the best sources: fruits, vegetables, meats, milk, legumes
• In general, ultra-processed foods are lower in potassium than whole foods.
• Examples of high potassium foods: potatoes, milk, yogurt, sweet potato, artichoke,
winter squash, soybeans, legumes, bananas, cantaloupe, salmon (not a complete list!).
• A good strategy to increase potassium is to eat more fruits, vegetables, and legumes,
and to choose more whole foods and fewer ultra-processed foods.
What can a consumer look for on the label of a vitamin or mineral supplement to choose a safe dose?
A consumer should look for the % Daily Value (%DV) and the amount of the nutrient per serving on the supplement label.
They should also check the Tolerable Upper Intake Level (UL) to avoid consuming excessive amounts.
Answer: Check the amount per serving and %DV on the label and make sure total intake does not exceed the UL.
What are phytochemicals? What types of foods provide phytochemicals? Name some health benefits of phytochemicals.
Phytochemicals are naturally occurring chemical compounds produced by plants. They aren't considered essential nutrients like vitamins and minerals, but many have beneficial effects on health.
What foods provide phytochemicals?
They are found primarily in plant foods, including:
Potential health benefits
Phytochemicals can have several beneficial effects, including:
Study tip:
Phytochemicals = plant compounds → fruits, vegetables, whole grains, legumes, nuts/seeds → antioxidant, anti-inflammatory, and other protective effects.
What are the names for the deficiency diseases for thiamin, niacin, and vitamin C?
Thiamin = Beriberi
Niacin= Pellagra (4 D's Diarrhea, Dermatitis, Dementia, Death)
Vit C = Scurvy
Niacin (B3)
Function:
• Coenzyme in many metabolic reactions (glucose, fat, & alcohol)
o Part of NAD (nicotinamide adenine dinucleotide)
o Part of NADP (nicotinamide adenine dinucleotide phosphate).
• Supports skin, nervous, and digestive systems.
Unique Property: The body synthesizes niacin from the essential amino acid tryptophan.
• 1 mg niacin = 60 mg dietary tryptophan
RDA:
• Women - 14 mg/day
• Men - 16 mg/day
Deficiency: Pellagra
• Causes the 4 “Ds” - diarrhea; dermatitis; dementia; death
Toxicity: Yes, especially nicotinic acid (from very high doses from supplements).
• Niacin flush; liver damage; impaired glucose tolerance ( blood sugar)
Food Sources: Meat, liver, poultry, seafood, and legumes; peanuts; whole grains, enriched grains;mushrooms, potatoes.
Magnesium
• Helps with energy metabolism
• Muscle and nerve function
• Bone formation
• Helps regulate blood glucose and blood pressure
Deficiency:
Muscle weakness/cramps
• Tremors
• Loss of appetite
• Abnormal heart rhythm in severe deficiency
Food Sources:
Nuts and seeds, whole grains, beans, spinach and other leafy greens, avocado, dark chocolate
Which of the six classes of nutrients is considered most essential/critical to your health?
Essential Nutrient – Water is an essential nutrient. It is the most important essential nutrient, because it is a large part of your body composition and you can’t live long without it.
Which water-soluble vitamin needs an “intrinsic factor” for absorption and why?
B12 (COBALAMIN) absorption in the small intestine requires Intrinsic Factor, a protein made by the stomach.
Without intrinsic factor, the body cannot efficiently absorb B12, which can lead to vitamin B12 deficiency.
B12
Cobalamin – Vitamin B12
Functions:
• DNA & RNA synthesis; new cell formation (notice folate also has this function)
o red blood cell formation
o growth
• Myelin synthesis – essential for normal nerve function
Absorption:
• HCL produced by stomach releases B12 from foods.
• B12 absorption in the small intestine requires Intrinsic Factor, a protein made by the stomach.
RDA: 2.4 ug/day for women and men
Deficiency:
• Cognitive impairment (an early symptom)
• Pernicious anemia (from lack of intrinsic factor)
• Macrocytic or megaloblastic anemia (large immature red blood cells)
• Permanent nerve damage; paralysis.
Risk Factors for B12 Deficiency: vegan diet*
, long-term use of heartburn medications, older
adults (50+ years), diabetic on Metformin, major stomach disease/surgery (i.e., bariatric surgery)
*Vegans should eat foods fortified with vitamin B12 or take a B12 supplement to avoid B12 deficiency.
Toxicity: No
Food Sources: Animal products and B-12 fortified foods and beverages only. Meat, poultry, seafood, eggs, and dairy products are good sources.
Calcium
• Builds and maintains bones and teeth
• Muscle contraction
• Nerve transmission
• Blood clotting
Deficeny:
• Weak/brittle bones
• Increased risk of osteoporosis
• Muscle cramps/spasms
Food:
Milk, yogurt, cheese, fortified plant milks, canned salmon/sardines with bones, tofu made with calcium, kale, bok choy
What is the AI for total water for healthy adults? How much water should healthy adults drink each day?
AI for Water – this is for total water (from fluids + foods) and is for healthy adults in normal
environmental conditions. This AI can be met by any type of beverage except alcohol.
• Women: 2.7 liters/day
• Men: 3.7 liters/day
How much to drink? Aim to drink 80% of your water AI from beverages:
• ~ 2 liters of fluid a day for women
What are major risk factors for developing a vitamin B12 deficiency?
Risk Factors for B12 Deficiency: vegan diet*
long-term use of heartburn medications,
olderadults (50+ years),
diabetic on Metformin,
major stomach disease/surgery (i.e., bariatric surgery)
*Vegans should eat foods fortified with vitamin B12 or take a B12 supplement to avoid B12 deficiency.
Toxicity: No
Food Sources: Animal products and B-12 fortified foods and beverages only. Meat, poultry, seafood, eggs, and dairy products are good sources.
B6
Pyridoxine, Pyridoxal, Pyridoxamine (3 forms)
Functions:
• Coenzyme in energy metabolism reactions; needed for amino acid and fatty acid metabolism and for protein synthesis
o Part of the coenzyme pyridoxamine phosphate (PMP)
o Part of the coenzyme pyridoxal phosphate (PLP)
• Essential for hemoglobin formation in red blood cells.
RDA: 1.3 mg - adults
UL: 100 mg daily for adults
Deficiency: microcytic hypochromic anemia (anemia with small red blood cells low in hemoglobin);
weakness, fatigue, growth failure, impaired motor function, convulsions, depression.
Toxic: Yes (from very high doses from supplements). Causes irreversible nerve damage. To avoid
toxicity, stay under the UL.
Food Sources: Widely distributed in foods. Good sources include chicken, meat, legumes, green leafy vegetables, potatoes, whole grains, bananas, watermelon.
What are functions of phosphorous? Is phosphorous an essential nutrient?
Phosphorus has several important functions in the body:
Yes. Phosphorus is an essential mineral, meaning your body needs it for normal growth and functioning but cannot produce enough on its own, so it must come from the diet.
Study answer:
Phosphorus is essential for bones/teeth, energy (ATP), DNA/RNA, cell membranes, and acid-base balance.
Be able to calculate someone’s recommended water intake if given their kcalorie requirement. Your textbook explains how much water is recommended for adults per kcalorie expended by the body.
Women: 2.7 liters/day
• Men: 3.7 liters/day
Textbook Recommendation: 1.0 – 1.5 ml of water per kcalorie expended. This is in line with the
AI recommendation for water.
This person should consume 1.0 – 1.5 ml of water for each calorie used by the body.
1.0 ml X 2,000 kcal = 2,000 ml
1.5 ml X 2,000 kcal = 3,000 ml
Answer: A person who uses 2,000 kcalories a day should drink 2,000 – 3,000 ml of
water/day. This equals 2 – 3 liters/day (equivalent to ~ 8 – 12 cups/day).
What compound produced by the stomach is essential for normal absorption of vitamin B12?
Intrinsic factor — a protein produced by the stomach’s parietal cells that is necessary for normal absorption of vitamin B12 in the small intestine.
Vitamin C
Ascorbic Acid – Vitamin C
Functions:
• collagen synthesis
• aids in wound healing (scar tissue is collagen)
• antioxidant
• supports immune function
• promotes absorption of non-heme iron (such as the iron from legumes, vegetables, nuts, seeds, and grains)
Note: Vitamin C does not prevent the common cold.
RDA:
75 mg/day - women
90 mg/day - men
+35 mg/day - smokers
UL: 2,000 mg/day
Deficiency:
• Called Scurvy
• Symptoms: bleeding gums, pinpoint hemorrhages, swollen painful joints, delayed wound healing, sudden death from massive internal bleeding (these are symptoms of inability to make collagen)
Toxicity: Nausea, vomiting, diarrhea, kidney stones, flare-up of gout in those who have gout
Sources: Fruits and vegetables. Many fruits and vegetables are good sources of vitamin C. A good strategy to meet your vitamin C needs is to eat your recommended servings of fruits and vegetables.
What important digestive compound in the stomach contains chloride? Is chloride an essential nutrient?
The important digestive compound in the stomach that contains chloride is hydrochloric acid (HCl).
Answer: Hydrochloric acid (HCl); yes, chloride is an essential nutrient.
What are major sources of water for the body, and how does the body lose water?
Three Main Sources of Water for Humans
• Beverages – provide about 80% of water consumed daily.
• Foods – an important water source. Foods provide ~20% of water consumed daily.
• Water of metabolism – water generated during metabolic reactions averages about 200-
300 ml a day. The body uses this water.
Water Losses from the Body
The body is continually losing water, and this water needs to be replaced to maintain good fluid
balance. Fluid losses occur from urine, perspiration, stools, and exhaled air.
Which 4 Vitamins are Fat Soluble
A
D
E
K
Folate
Folate and Folic Acid (B9)
Functions:
• DNA & RNA synthesis; cell division - new cell formation (notice B12 also has this function).
o red blood cell formation
o growth
• Activates B12
• Coenzyme forms are THF (tetrahydrofolate) & DHF (dihydrofolate)
RDA:
400 ug/day - women*
600 ug/day - men
600 ug/day - pregnancy
*It is important for women of childbearing age to consume the RDA for folate in case a pregnancy occurs, to prevent neural tube defects (such as Spina Bifida or anencephaly) in the fetus.
UL: 1,000 ug/day
Deficiency:
• Macrocytic or megaloblastic anemia (large immature red blood cells)
• Mental confusion, depression, GI deterioration.
• Neural tube defects such as Spina Bifida in the fetus can occur when the mother has folate deficiency early in pregnancy.
Toxicity: Masks early symptoms of vitamin B12 deficiency.
Food Sources: Fortified grains since 1996, green leafy vegetables, legumes, liver, asparagus, citrus fruits
What is osteoporosis?
What are risk factors for development of osteoporosis, and how can people reduce their risk for this disease?
Osteoporosis is a disease in which bones become less dense and weaker, making them more likely to fracture. It often develops gradually without obvious symptoms until a fracture occurs.
Risk factors that cannot be changed:
Risk factors that can be changed or managed:
Study answer:
Osteoporosis = weakened, low-density bones with increased fracture risk. Prevention focuses on adequate calcium/vitamin D, regular weight-bearing exercise, avoiding smoking/excessive alcohol, and maintaining good nutrition.
What are major symptoms of dehydration?
Water Deficiency – Dehydration
• Symptoms: Thirst, fatigue, weakness, loss of appetite, dry mouth, headache, irritability,
darker more concentrated urine, and muscle cramps are common symptoms. When 2%
or more of body weight is lost from water loss, exercise performance is impaired. Severe
dehydration can cause dizziness, impaired temperature regulation, confusion, rapid
heart rate, poor coordination, collapse, kidney failure, and death.
What is the major non-food source of vitamin D for humans?
Sunlight (UVB Rays)
Vitamin A
Vitamin A
Forms: There are three active forms in the body: retinal, retinol, and retinoic acid.
Precursor: Beta-carotene, an orange pigment found in deep green and deep orange fruits & vegetables; converted to retinol (an active form of vitamin A) in the intestine and liver.
Storage: Excess vitamin A is stored in the liver. Beta-carotene is stored in body fat, especially in fat just under the skin.
Major Functions:
• Promotes cell differentiation (specialization) – retinoic acid
• Needed for normal function of retina of eye & for night vision (retinal)
• Helps maintain health of cornea of eye.
• Needed to maintain healthy epithelial cells – skin, mucous membranes
• Beta-carotene is an antioxidant.
• Supports immunity.
• Needed for growth & reproduction; essential for fetal development.
• Helps in bone remodeling.
RDA for Vitamin A:
The RDA for vitamin A is in Retinol Activity Equivalents (RAE), which are determined as follows:
RAE (Retinol Activity Equivalent)
• 1 ug retinol = 1 RAE
• 12 ug beta-carotene = 1 RAE
• 24 ug other carotenes = 1 RAE
RDAs: 900 ug RAE/day for men
700 ug RAE/day for women
UL = 3,000 ug RAE /day or 10,000 IU/day from preformed vitamin A (not beta-carotene)DIT121_Ch.11_Lecture Notes_0126_17e 2
Sources of Vitamin A:
• Preformed Vitamin A (vitamin A in its active form): Liver, egg yolk, fortified milk, fortified butter, fish liver oils.
• Beta-carotene: Deep orange and deep green fruits and vegetables. Examples: carrots,
sweet potatoes, cantaloupe, papaya, mango, leafy greens, broccoli
Deficiency Symptoms:
• Night blindness (poor vision or inability to see in dim light)
• Xerosis – dry hard patches on cornea of eye
• Blindness (Xerophthalmia) – Vitamin A deficiency is a leading cause of preventable blindness in the world. This blindness is from damage to the cornea and is permanent.
• Keratinization – accumulation of the hard protein keratin in tissues (i.e. skin)
o Very rough bumpy skin
• Damage to epithelial cells; loss of cell integrity
• Impaired immunity; increased risk of illness & death from infection
• Poor growth in infants, children, and adolescent
Toxicity of Vitamin A:
Name: Hypervitaminosis A
Cause: Caused by overconsumption of preformed vitamin A (active vitamin A forms), not from
excess beta-carotene. Ten times the RDA is a potentially toxic dose.
Symptoms:
• Increased fracture risk
• Liver damage and liver failure
• Severe headache (from increased intracranial pressure)
• Birth defects, especially prior to 7th week pregnancy
o This is from high doses of preformed vitamin A from supplements, not from normal
amounts of vitamin A in foods. This is not caused by beta-carotene from fruits &
vegetables.
Effects of High Amounts of Beta-carotene
• Orange discoloration of skin (from beta-carotene stored in subcutaneous fat)
• Increased risk for lung cancer in smokers who take beta-carotene supplements
(however, consuming normal amounts of beta carotene from foods reduces lung cancer
risk in smokers).
What is the DASH diet? What foods are included? What is the purpose of this diet?
DASH stands for Dietary Approaches to Stop Hypertension. It is a healthy way of eating that is
effective in reducing blood pressure. It includes plenty of potassium, among other benefits. We
will cover the DASH diet in the next module. Here is a Description of the DASH Eating Plan from
the National Heart Lung and Blood Institute for those of you who would like a preview of DASH.
What are examples of healthy beverage choices? What kinds of beverages should we limit or avoid?
Water!
• Milk
• Fortified Dairy Substitutes
• 100% fruit juice (in moderation)
• 100% vegetable juice (in moderation)
• Coffee (in moderation, unsweetened)
• Tea (in moderation, unsweetened)
Notice sugar-sweetened beverages are not on this healthy beverage list! Sugar-sweetened
beverages include soft drinks, fruit punch, vitamin waters, sugar-sweetened lemonade, sugar-
sweetened teas & coffees, and sports drinks.
Water & Beverage Choices
• Alcohol – Alcohol is a diuretic (stimulates loss of body water in urine). Alcohol
suppresses release of antidiuretic hormone, which increases excretion of water in urine.
• Bottled Water vs. Tap Water – Both bottled water and tap water must meet the same
safety standards. Bottled water isn’t necessarily any healthier than tap water. Some of
the major brands of bottled water sold in the U.S. are municipal tap waters that have
been bottled. Bottled water and tap water are both healthy water sources. Tap water
has the advantage when it comes to sustainability and cost.
• Soft Water vs Hard Water – The terms soft water and hard water refer to the mineral
composition of the water. Hard water is higher in magnesium and calcium (and lower in
sodium) than soft water. Soft water is higher in sodium and/or potassium and lower in
calcium and magnesium than hard water. Hard water is better for health. Sodium in soft
water can contribute to hypertension. Magnesium and calcium in hard water may help
to reduce blood pressure and have other health benefits.
• Sports Drinks – provide glucose, sodium, and potassium to replace glucose and
electrolytes lost during exercise. Sports drinks are appropriate for people exercising
continually for 1 – 1½ hours or more or who are working for long periods of time in hot
environmental temperatures. Sports drinks are not a healthy beverage choice for
everyone. Most people don’t need extra sugar and sodium from sports drinks.
Which fat-soluble vitamin is made by bacteria in the GI tract (although we should still consume this vitamin in the diet too)?
Vitamin K
VITAMIN D
Vitamin D – Calciferol
Functions of Vitamin D:
• Needed for normal absorption of calcium and phosphorous; this makes vitamin D
essential for bone mineralization.
• Acts to release some calcium from bones when blood calcium drops; this helps to maintain
normal blood concentrations of calcium.
• Supports immunity; decreases inflammation.
• Essential for cell differentiation.
• Other possible functions.
Major Sources: Sun and Food
• Vitamin D Production in Skin – Sun is the #1 source of vitamin D for humans. Vitamin D3 is
made in the skin from exposure to UVB light from the sun. The UVB rays penetrate the skin
into the dermis layer, where a cholesterol compound is converted into cholecalciferol, a
form of vitamin D.
o Exposing the hands & face to the sun for 5-10 minutes 2-3X a week can meet
vitamin D needs.
• Types of Vitamin D from Foods
o D2 (ergocalciferol) from plants (such as sun-exposed mushrooms)
o D3 (cholecalciferol) from animals
Good food sources of vitamin D are outlined on p. 5 of these lecture notes.
Vitamin D Activation:
The vitamin D compounds produced by the skin and consumed in the diet must be activated by
the liver and kidneys. The liver does the first activation step (hydroxylation to form Calcidiol). The
kidneys do the second step, a hydroxylation to make the active form of vitamin D (Calcitriol). This
process is illustrated in Figure 11-8 in your textbook.
Vitamin D Deficiency:
• Rickets in infants and children
o Poor calcium & phosphorous absorption from vitamin D deficiency causes poor
bone mineralization. Bones remain soft and bend under the child’s weight.
o Symptoms include skeletal deformities such as bowed legs or knock-knees,
beaded ribs.
o Common worldwide.
• Osteomalacia in adults
o Poor calcium & phosphorous absorption from vitamin D deficiency causes poor
bone mineralization.
o Symptoms: Bones become soft, brittle, flexible, deformed; increased fracture
risk; may be painful.
Vitamin D and Osteoporosis: Vitamin D deficiency can be one of many factors that contributes
to osteoporosis (very low bone density) in the elderly. Osteoporosis and osteomalacia are
different conditions.
Risk Factors for Vitamin D Deficiency
• Lack of sun exposure (i.e., staying inside or out of the sun when outdoors; covering up
with clothing when outdoors, etc.)
• Living in a far northern or far southern latitude – sun too low in the sky in winter
months to stimulate vitamin D synthesis. This is the case for roughly the northern half of
the U.S. (above 40 degrees N latitude).
• Sunscreen use – proper use significantly reduces vitamin D synthesis (but protects skin
from sun damage and reduces risk for skin cancer).
• Darker skin. We all have skin pigment (melanin). Melanin blocks some of the UVB rays
Which major minerals affect blood pressure?
Which mineral should we limit to reduce our risk for high blood pressure?
Which minerals should we eat in recommended amounts from foods to help control blood pressure?
The major minerals that affect blood pressure are sodium, potassium, calcium, and magnesium.
Quick answer:
Who might benefit from sports drinks? Are sports drinks a healthy beverage choice for everyone?
Increased Fluid Needs: Illness, exercise, hot environmental temperatures, and breastfeeding
will increase fluid needs beyond the amounts shown above.
Sweat Rate for Athletes: Exercise can significantly increase fluid needs. Athletes are advised
to calculate their individual sweat rate (amount of water the body uses during a typical training
session or competition) to plan their hydration schedule to stay properly hydrated for exercise.
Sports Drinks – provide glucose, sodium, and potassium to replace glucose and
electrolytes lost during exercise. Sports drinks are appropriate for people exercising
continually for 1 – 1½ hours or more or who are working for long periods of time in hot
environmental temperatures. Sports drinks are not a healthy beverage choice for
everyone. Most people don’t need extra sugar and sodium from sports drinks.
Which fat-soluble vitamin is given by injection to newborns in the United States to promote normal blood clotting and to prevent dangerous bleeding?
In the U.S., newborns are injected with vitamin K at birth to promote
normal blood clotting. Newborns are at risk for vitamin K deficiency because they store little vitamin
K during gestation and because the gut hasn’t yet colonized with the bacteria that produce vitamin K.
VITAMIN E
Vitamin E
Active Form: Alpha-tocopherol
Function:
Vitamin E is a strong antioxidant. Antioxidants donate electrons to free radicals, which protects cells
from free radical damage. Free radicals are unstable molecules and atoms produced in the body
during metabolism.
Deficiency:
• Very rare, although most adults fall short of the RDA
• Erythrocyte hemolysis (RBC burst)
• Prolonged deficiency causes neuromuscular dysfunction (loss of muscle function; impaired
vision & speech)
Toxicity:
• Rare
• High levels (over 65 x the RDA) may interfere with vitamin K’s ability to clot blood.
• Some studies have found increased mortality risk from all causes from high dose vitamin E
supplementation.
RDA: 15 mg TE or 600 IU in adults
Upper Limit (UL): 1,000 mg/day
Good Sources of Vitamin E: Vegetable oils, nuts, and seeds are the best sources.
What is the DRI for sodium? What is the CDRR for sodium (to reduce disease risk)?
For adults, the current Dietary Reference Intakes (DRIs) for sodium are:
Answer:
DRI (AI): 1,500 mg/day
CDRR: 2,300 mg/day
A sodium intake of 1,500 mg to 2,300 mg/day is in the recommended range for healthy adults.
What effect does alcohol have on fluid balance?
• Alcohol – Alcohol is a diuretic (stimulates loss of body water in urine). Alcohol suppresses release of antidiuretic hormone, which increases excretion of water in urine.
Which vitamins are antioxidants?
Antioxidant Nutrients and Phytochemicals
• Antioxidant Vitamins: Beta-carotene, Vitamin C, Vitamin E
• Antioxidant Minerals: Selenium and zinc
• Antioxidant Phytochemicals
o Carotenoids (in many fruits and veg.)
o Polyphenols (many sources: berries, legumes, nuts, soy, tea, dark chocolate,
grapes, etc.)
o Lipoic Acid (broccoli, spinach, tomatoes, brussels sprouts, etc.)
Vitamin K
Vitamin K
Forms
• phylloquinone (K1) - plants
• menaquinone (K2) – made by gut bacteria; found in fermented foods
• menadione - a synthetic form (supplements)
Functions
• Needed for blood clotting – essential to make several blood clotting proteins
• Synthesis of a bone protein, osteocalcin
Deficiency
• Hemorrhage (bleeding from failure of blood to clot)
• Skeletal weakness
Treatment of Newborns: In the U.S., newborns are injected with vitamin K at birth to promote
normal blood clotting. Newborns are at risk for vitamin K deficiency because they store little vitamin
K during gestation and because the gut hasn’t yet colonized with the bacteria that produce vitamin
K.
AI: 90 ug women/120 ug men
UL: no (toxicity rare)
Sources:
• synthesized by bacteria in gut (although we still need vitamin K from food)
• milk, eggs, liver, vegetable oils, green leafy vegetables, cabbage, brussels sprouts,
broccoli; fermented foods (such as natto).
What foods contribute the majority of sodium we eat each day?
Fast foods/ restaurant/ processed
2 functions of selenium:
• Antioxidant
• Needed to make the thyroid hormone T3 (helps convert T4 to T3)
Rickets in children and infants
Adults get Osteomalacia
Risk Factors for Vitamin D Deficiency
• Lack of sun exposure (i.e., staying inside or out of the sun when outdoors; covering up
with clothing when outdoors, etc.)
• Living in a far northern or far southern latitude – sun too low in the sky in winter
months to stimulate vitamin D synthesis. This is the case for roughly the northern half of
the U.S. (above 40 degrees N latitude).
• Sunscreen use – proper use significantly reduces vitamin D synthesis (but protects skin
from sun damage and reduces risk for skin cancer).
• Darker skin. We all have skin pigment (melanin). Melanin blocks some of the UVB rays
from penetrating into the dermis layer of the skin. This reduces vitamin D synthesis in
skin but helps to protect the skin from sun damage. People with more heavily
pigmented skin will need longer sun exposure to meet their vitamin D needs than
people with less skin pigment.
• Aging – The elderly are at higher risk for vitamin D deficiency than younger adults.
o The skin of the elderly produces less vitamin D from sun exposure.
o It is common for the elderly to have reduced activation of vitamin D in the liver and
kidneys.
o Many elderly adults spend less time in the sun than younger adults.
• Diet low in vitamin D. This is very common. It is difficult to meet vitamin D
requirements from diet alone, as there are few good food sources.
Iron
Functions
• part of hemoglobin, the protein in red blood cells that transports oxygen to tissues
• part of myoglobin, a protein in muscles that delivers oxygen to muscles for muscle
contraction
• part of electron carriers in the electron transport chain (needed for ATP formation)
• supports immune system
• cofactor for serotonin, norepinephrine, and dopamine (neurotransmitter) synthesis
Major Types of Iron in Foods
Heme Iron – iron that is part of the hemoglobin molecule
• found in meats, poultry, seafood
• absorbed better than non-heme iron
Non-heme iron – iron in food that is not part of the hemoglobin molecule
• The iron in plant foods (fruits, veg., grains, legumes, nuts, seeds) is non-heme iron.
Meats also contain some non-heme iron.
• Non-heme iron is not absorbed as well as heme iron.
• Non-heme iron absorption can be increased by vitamin C and by eating a little meat, fish
or poultry at meals.
Important Concepts about Dietary Iron
• Iron consumption is linked to kcalorie intake. We obtain about 6-7 mg of iron for every
1,000 kcalories we eat from a mixed diet. This is why it is difficult for women of
childbearing age and pregnant women to meet their iron needs from diet alone.
• Diets high in empty calories (soft drinks, desserts, candy, low-nutrient snack foods) are
more likely to be low in dietary iron than well-balanced diets.
• Heme iron (from meats, poultry, fish) is absorbed better than non-heme iron (from
plants).
• Eating fruits and vegetables (which provide vitamin C) with meals & snacks can
significantly increase absorption of non-heme iron.
Practical Applications:
• Don’t take iron supplements with high calcium foods & beverages or with coffee or tea,
as these will significantly decrease iron absorption.
• Eat fruits & veg. with meals and snacks, as the vitamin C from these increases non-heme
iron absorption.
• Even a small amount of meat, fish, or poultry at a meal can increase absorption of non-
heme iron from plant foods (this is the MFP factor in the table above).
• Enjoy legumes, grains, nuts, and seeds in recommended amounts as part of your healthy
diet. While the phytates in these bind iron, we can still benefit from the many nutrient
contributions of these foods while maintaining good iron status. High dietary phytate
can contribute to iron deficiency when phytate intakes are high (very high fiber diet) and
diet quality is poor.
Iron Deficiency
Prevalence: Iron deficiency is the most common nutrient deficiency in the U.S. and in the
world.
Stages:
• 1st stage – iron stores are depleted
• 2nd stage – body increases transferrin (an iron transport protein)
• 3rd state – iron deficiency anemia
Major Symptoms:
• anemia – microcytic, hypochromic (anemia with small red blood cells low in iron)
• fatigue
• poor exercise tolerance
• impaired work performance & cognitive function
• impaired immunity – increased risk for infection
• concave nails
• feeling cold – inability to regulate body temperature
• pica – eating non-food substances (ice, clay, etc.)
Risk Factors for Iron Deficiency:
• Obesity
• Increased Need for Iron
o infancy
o childhood
o adolescence
o pregnancy
• Blood Loss
o donating blood; surgery; trauma
o menstruation
Iron Toxicity
• Causes:
o excessive iron intake (i.e., from supplements)
o hemochromatosis - a genetic condition that causes excessive iron absorption and
iron overload
o Excessive alcohol use increases risk for iron overload.
• Symptoms: GI distress (constipation, diarrhea, stomach pain), organ damage, death
Too much or too little iron can be harmful. Meet your RDA for iron but avoid high doses (above
the UL) unless prescribed by a doctor to treat iron deficiency or for medical therapy.
What affect does processing have on sodium content
In general, food processing tends to increase sodium and decrease potassium in foods.
Answer: Processed foods generally have more sodium and less potassium than their less-processed counterparts.
Which trace minerals are antioxidants:
What is beta-carotene, and why is it important in the diet? Which vitamin does the body produce from beta-carotene? What foods are good sources of beta-carotene?
Beta-carotene is a carotenoid pigment found in many colorful fruits and vegetables, especially orange, yellow, and dark-green foods.
It is important because:
In short: Beta-carotene is a provitamin A carotenoid that the body can use to make vitamin A.
Beta-carotene: Deep orange and deep green fruits and vegetables. Examples: carrots, sweet potatoes, cantaloupe, papaya, mango, leafy greens, broccoli
Effects of High Amounts of Beta-carotene
• Orange discoloration of skin (from beta-carotene stored in subcutaneous fat)
• Increased risk for lung cancer in smokers who take beta-carotene supplements
(however, consuming normal amounts of beta carotene from foods reduces lung cancer risk in smokers).
Iodine
Functions
• essential to make the thyroid hormones T3 and T4, which regulate basal metabolism.
The thyroid hormones are important for reproduction, growth, and more.
RDA: 150 ug/day – adults
UL: 1,100 ug/day - adults
Deficiency Symptoms
• Goiter – an enlarged thyroid gland (see Figure 13-10 in your textbook for a photo)
o Goiter was common in the U.S. before iodized salt became available.
• Cretenism – occurs when a pregnant woman is iodine deficient
o causes severe permanent cognitive impairment and growth retardation in the
fetus
Toxicity
• Goiter: Goiter can occur from too little or too much iodine.
Sources
• Iodized Salt is the most reliable source of iodine in the American food supply.
o Consumers have the choice of purchasing iodized or non-iodized salt.
o Salt in processed foods is not iodized. Restaurants may use iodized or non-
iodized salt.
• Seafood – iodine is abundant in the oceans.
• Seaweed
• Iodine amounts in plant foods (fruits, veg., grains, legumes, nuts, seeds) vary with the
iodine content of the soil. Crops grown in iodine-poor soil are low in iodine.
o Areas of the world with low soil iodine content include many mountainous
regions (Alps, Andes, Appalachians, Himalayas) and river valleys prone to
flooding. The Great Lakes region of the U.S. has low iodine soil content.
• Other possible sources:
o dairy products (from iodine disinfectant and iodine-containing medications given
to dairy cows)
o baked goods (iodine salts in dough conditioners).
What minerals are most important for bone and skeleton formation?
The minerals most important for bone and skeleton formation are:
Answer: Calcium and phosphorus are the two most important, with magnesium also playing an important supporting role.
What is the main function of chromium?
Enhances action of insulin; helps maintain glucose homeostasis
What 2 fat soluble vitamins are considered the most toxic in excessive amounts?
Zinc
ZINC
Functions
Zinc has too many functions to list here! Zinc is important for the function of more than 100
metalloenymes. Here are a few critical functions of zinc:
• essential for new cell formation – helps to stabilize DNA & RNA; needed for enzyme
systems for DNA & RNA formation and cell division
o growth & maturation
o wound healing
o fetal development
• needed for normal immune function
• antioxidant
• needed to make, store, and secrete insulin and for insulin signaling
• essential for normal taste sensitivity
• part of pancreatic digestive enzymes
• activates vitamin A in retina of eye and is essential for retinol binding protein (a transport
protein for vitamin A)
Zinc is Recycled: Enteropancreatic Circulation
The zinc excreted into the small intestine with digestive enzymes is reabsorbed into the body
and reused. This is called the enteropancreatic circulation of zinc.
RDA: 8 mg/day – women
11 mg/day – men
UL: 40 mg/day (adults)
Deficiency Symptoms
• stunted growth
• delayed sexual maturation
• impaired immune function – increased risk for infection & death from infection
• poor wound healing
• loss of taste
• eye & skin lesions
• hair loss
Toxicity Symptoms
• copper deficiency → anemia
o excess zinc interferes with copper absorption
• iron deficiency → anemia
o excess zinc reduces iron absorption
• impaired immunity
• low HDL (increases heart disease risk)
Zinc Sources
milk, and yogurt.
The best food sources are high protein foods such as beef, poultry, shellfish, legumes, nuts,
Zinc Absorption
• Zinc is absorbed better from animal products than from plant foods.
• Phytates in whole grains & legumes decrease zinc absorption.
o Recommended amounts of whole grains & legumes can be consumed in a
balanced diet without impairing zinc status.
Zinc Supplementation
• Zinc is sometimes prescribed by physicians for poor wound healing. Supplemental zinc
improves wound healing in people with zinc deficiency.
• Research studies have found that zinc lozenges (i.e., containing zinc acetate or zinc
gluconate) shorten the length of time people suffer from common cold symptoms.
o Use zinc lozenges only for the duration of cold symptoms and then stop to avoid zinc
toxicity.
o Nausea and bad taste reactions are side effects.
• Avoid doses above the UL.
What is the DRI for calcium for adults aged 19 – 50 years? How much milk would provide this much calcium?
For adults 19–50 years old, the DRI (RDA) for calcium is 1,000 mg/day.
Answer: 1,000 mg calcium/day, which is approximately 3⅓ cups of milk.
What factors enhance nonheme iron absorption from plants?
Don’t take iron supplements with high calcium foods & beverages or with coffee or tea, as these will significantly decrease iron absorption.
• Eat fruits & veg. with meals and snacks, as the vitamin C from these increases non-hemeiron absorption.
• Even a small amount of meat, fish, or poultry at a meal can increase absorption of non-heme iron from plant foods (this is the MFP factor in the table above).
• Enjoy legumes, grains, nuts, and seeds in recommended amounts as part of your healthy diet. While the phytates in these bind iron, we can still benefit from the many nutrient contributions of these foods while maintaining good iron status. High dietary phytate can contribute to iron deficiency when phytate intakes are high (very high fiber diet) and diet quality is poor.
How is vitamin/mineral toxicity most likely to occur?
Vitamin and mineral toxicity is most likely to occur from excessive use of dietary supplements, rather than from eating too much from normal foods.
Answer: Taking high doses of vitamin or mineral supplements, especially over long periods, can lead to toxicity.
Flouride
Fluoride
Fluoride is a trace mineral from soil and water.
Functions
• part of the crystalline structure of bones & teeth
o strengthens teeth
o helps prevent tooth decay
AI: 3 mg/day - women
4 mg/day - men
UL: 10 mg/day – adults
Deficiency: increased risk for tooth decay
Toxicity
• Fluorosis – pitting and staining of teeth
• Possible decreased IQ in children who consume high levels of fluoride (higher amounts
than allowed in fluoridated water in the U.S.)
• Skeletal fluorosis – damage to bones; uncommon; industrial contamination of the
environment from fluoride compounds is a cause
Main causes of fluorosis of teeth:
• swallowing fluoridated toothpaste or fluoridated mouthwash
• drinking well water high in fluoride (well water should be tested for fluoride content &
for contaminants)
Sources
• Fluoridated municipal tap water
o Water fluoridation is a local (city and county) decision.
o The majority of cities and counties in the U.S. have fluoridated water.
o The EPA regulates the fluoride content of municipal tap water (0.7 ppm).
• Tea: Tea leaves concentrate fluoride.
• Seafood
• Fluoridated toothpaste adds topical fluoride (to the surface of teeth).
American Dental Association Recommendations for Young Children (to prevent fluorosis)
• For children under 3: brush teeth with no more than a smear (the size of a grain of rice)
of fluoridated toothpaste.
• For children 3 – 6: use no more than a pea-sized amount of fluoridated toothpaste.
• Teach young children to spit out toothpaste.
How does oxalate (oxalic acid) affect calcium absorption? What foods are high in oxalate?
digestive tract, forming calcium oxalate, which is poorly absorbed.
Foods high in oxalate
Common high-oxalate foods include:
Key point: Not all calcium-rich foods are equally well absorbed. For example, spinach contains calcium, but its high oxalate content makes much of that calcium poorly bioavailable.
How do phytates affect iron & zinc absorption? Which foods are high in phytates?
Phytates (phytic acid) can decrease the absorption of iron and zinc by binding to these minerals in the digestive tract and forming compounds that are difficult for the body to absorb.
Foods high in phytates
Phytates are especially common in:
Study tip:
Phytates ↓ iron & zinc absorption. They are mainly found in whole grains, legumes, nuts, and seeds.