Nutrition 2351 Unit 3 (Baylor - Arnold)

What deficiency is associated with scurvy?

Vitamin C

What vitamin deficiency is associated with Beriben?

thiamin

Which vitamin deficiency is associated with Rickets?

Vitamin D

Are vitamins organic or inorganic?

organic

Are vitamins essential or nonessential?

essential

Are vitamins energy-yielding (produce ATP)?

no

Are vitamins water or fat soluble?

yes both

What is different between vitamins and macronutrients?

vitamins are each a singular unit with unique structure and function

What are characteristics of fat-soluble vitamins?

stored in liver and adipose, daily and weekly intakes can vary without an increase in risk of deficiency

What are characteristics of water-soluble vitamins?

not stored, need to be consumed regularly to prevent deficiency

Which vitamins are water soluble?

B vitamins and vitamin C

Which vitamins are fat soluble?

Vitamins A, D, E, K

Where are all vitamins absorbed?

the small intestine

Are water-soluble vitamins hydrophobic or hydrophilic?

hydrophobic

Are fat-soluble vitamins hydrophobic or hydrophilic?

hydrophilic

Where are water-soluble vitamins absorbed into?

the blood

Where are fat-soluble vitamins absorbed into?

lymph system

Which vitamins act as antioxidants?

vitamins C and E

Which vitamins play a role in blood clotting and red blood cell synthesis?

folate, B6, B12, K

Which vitamins play a role in bone health?

Vitamin A, C, D, and K

Which vitamins play a role in energy production?

biotin, niacin (B3), pantothenic acid, riboflavin (B2), thiamin (B1), B6, B12

Which vitamins play a role in growth and reproduction?

vitamins A and D

Which vitamins play a role in the immune system?

Vitamins A, C, and D

Which vitamins play a role in protein metabolism and synthesis?

Folate, B6, B12, C

Define bioavailability

the degree to which a nutrient is absorbed from foods and used in the body

What percent of nutrients in food is absorbed and used in the body?

40-90%

What are some factors affecting bioavailability?

food prep, food storage, efficiency of digestion and absorption, compromised GI tract, pregnancy, age, gender, what other foods are consumed at the same time

Define precursors

also known as provitamins, inactive vitamins found in some foods, converted to active form once inside the body

What is the process of general vitamin digestion?

chewing (mouth) breaks food into small particles helping to release vitamins, digestion (stomach) releases vitamins and some niacin is absorbed, bile released (gallbladder) which emulsifies fat to help absorb fat-soluble vitamins, digestive enzymes secreted (pancreas) to help release vitamins from food, (small intestine) fat-soluble vitamins incorporated into micelles and absorbed by simple diffusion to mucosal cells where they're packaged into chylomicrons, which enter the lymphatic system, (small intestine) water-soluble vitamins absorbed directly into the bloodstream but many depend on active transport or specific binding in the GI tract to be absorbed, bacteria (large intestine) synthesize small amounts of vitamins and some of those are absorbed

how do pepsin and HCl improve the bioavailability of vitamins?

release vitamins from food components

What carries fat-soluble vitamins to the brush border in the small intestine?

micelles

Are vitamins digested?

no

What are fat-soluble vitamins packaged in to travel through the lymph into the bloodstream?

chylomicrons

What do you need in your diet to be able to absorb fat-soluble vitamins?

dietary fat

When does produce start to lose its vitamins?

almost immediately after being harvested

What type of vitamins are the most stable in fruits and vegetables?

fat-soluble

What are factors that affect the stability of vitamins in fresh produce?

exposure to oxygen, exposure to uv light, water, changes in pH, heat

How do you most effectively cook vegetables in water?

add vegetables to a small amount of already boiling water

What methods of cooking are best to limit heat exposure for veggies?

microwaving or stir-frying instead of boiling or frying

Is fresh always better than frozen or canned fruits or vegetables?

no

Define fortification

the addition of nutrients to foods, gov't mandated and voluntary, one form of this is enrichment

Define enrichment

form of fortification

What does fortification do?

enhance nutrient quality, prevent deficiency leading to diseases, may (rarely) cause toxicity

Is spinach a good source of iron and calcium?

yes, but it also contains oxalates which bind to these vitamins so they are poorly absorbed

Can you boost the amount of iron you absorb by also consuming more vit C?

Yes, vitamin C does help your body absorb iron from

nonmeat sources, but only if these nutrients wind up in

your intestines at the same time, which usually means

they must be eaten at the same meal

What are free radicals?

unstable molecules with unpaired electrons created from metabolism, smoking, pollution, UV

What makes free radicals bad for the body?

damage DNA and body proteins, alter cell structure, induce oxidative stress, contribute to heart disease, cancer, aging, diabetes, Parkinson's, and Alzheimer's

What is oxidative stress?

when free radicals are produced in the body faster than they can be neutralized

How do antioxidants help with free radicals?

neutralize them by 'leading' an electron to stabilize damaged atoms

Define antioxidants

substances that neutralize harmful oxygen-containing free radicals that can cause cell damage

What are examples of antioxidants?

Vit E, C, selenium, phytonutrients (flavonoids and carotenoids)

What is preformed Vit A?

retinoids

What are sources of Vit A?

animal foods (liver, fish, dairy, eggs)

What are the types of Vit A used for?

retinal - vision

retinol - reproduction

retinoic acid - growth

retinyl ester - stored form in liver, found in food

What is Provitamin A?

precursor found in plants, only source of vit A for vegans, carotenoids (include beta-carotene)

What are the main functions of Vit A?

vision, protein synthesis, cell differentiation, gene expression, epithelial cell health, reproduction, bone health, immunity, antioxidants

What is the effect of Vit A on gene expression?

stimulates cell division and differentiation (specialization)

How does Vit A support vision?

key component of rhodopsin (visual protein complex of opsin and retinal that changes from cis to trans when hit by light detected in the eye to then send impulse to the brain that there is light), some rhodopsin is lost each cycle of light detection, so maintenance is needed to rebuild and keep vision good

What is vitamin A's role in epithelial cell health?

cilia and mucous production, allows new epithelial cells to be made (high turnover rate)

What is the early stage of vit A deficiency?

night blindness

What are the chronic conditions of vit A deficiency?

Xerophthalmia (dryness of cornea causing permanent damage and blindness), keratinization (epithelial cells secrete keratin instead of mucus = rough dry skin)

Why do we need so many veggies to get carotenoids?

absorption of carotenoids is not super efficient

What is required for vit A absorption?

fat -> adding dressing to salad

What is required for vit A transportation and metabolism?

zinc

What are characteristics of vit A toxicity?

hypervitaminosis A, can cause osteoporosis, bone fractures, birth defects in children of pregnant women with toxicity, can turn skin yellow (carrots)

What is the primary cause of vit A toxicity?

supplements, can be animal foods for pregnant women

What vitamin is called calciferol?

Vitamin D

What are the two inactive forms of Vitamin D and where are they found?

cholecalciferol D3 (animal foods, cholesterol, UV light)

ergocalciferol D2 (plant foods and dietary supplements)

Where is the majority of Vitamin D sotred?

in the bones

What percent of vitamin D is stored in the blood and why?

1% for nerve and muscle functioning

How is vitamin D conditionally essential?

inadequate sun exposure can make vitamin D essential

What organs activate vitamin D?

the kidneys and liver

What levels does vitamin D maintain in the blood?

calcium and phosphorous levels

What is the interaction between vitamin D and low calcium levels?

low blood calcium stimulates the parathyroid hormone, which stimulates the kidneys to activate more vitamin D

What role does vitamin D play in gene expression?

turns on genes for calcium absorption in intestines, turns on genes for bone breakdown in bones

What is the process of activating vitamin D from uv light exposure?

a vitamin D precursor is made into an inactive form of vitamin D in the skin

What is the fully activated form of vitamin D produced by the kidney?

calcitriol

What are the three ways that the release of parathyroid hormone increases the concentration of calcium in the blood?

pulls calcium from bones, decreases loss of calcium in urine (kidneys), and enhances absorption of calcium (intestine)

Define prohormone

precursor to hormones

What does vitamin D act as in relation to hormones?

a prohormone (precursor)

What percent of calcium is absorbed when an individual is low in vitamin D?

only 10-15%

What is the role of vitamin D in cell growth and differentiation?

regulation, higher prevalence of certain cancers in sun-poor regions, deficiency ca decrease proliferation of healthy cells and allow cancer cells to thrive

What sun exposure is thought to be sufficient for vitamin D?

10-20 minutes 2-3 times per week

What are the dietary needs of vitamin D for adults and children?

15ug for both adults and children

What are good food sources of vitamin D?

fatty fish, fortified dairy, fortified soymilk, egg yolk, some mushrooms, fortified cereals (not a lot of foods naturally have high amounts of vitamin D)

What groups of people are especially at risk for vitamin D deficiency?

vegans, people who avoid dairy, dark skin, little sun exposure

What is vitamin D deficiency in children?

rickets

What are the causes of Rickets?

decreased milk consumption, fear of skin cancer from sun exposure, and air pollution

What is vitamin D deficiency in adults?

osteomalacia and osteoporosis

What other diseases are associated with vitamin D deficiency?

cancer, hypertension (hbp), autoimmune disease (T1D), kidney disease, T2D, cardiovascular disease, fatigue, depression

What are symptoms of vitamin D toxicity?

loss of appetite, nausea, vomiting, constipation

What can overuse of vitamin D supplements lead to?

hypervitaminosis which causes hypercalcemia

What is hypercalcemia?

can cause damaging calcium deposits in kidneys, lungs, blood vessels, and heart

What can cause vitamin D toxicity?

rarely caused by food intake or overexposure to the sun, supplements can do it, also cod liver oil

What are the fat soluble vitamins?

A, D, E, K

What is the most active form of vitamin E in the body?

alpha-tocopherol

What are the general functions of vitamin E?

antioxidant, anticoagulant

What is the role of vitamin E as an antioxidant?

protects cell membranes of RBC, WBC, nerve cells, lung cells, lipids in lipoproteins, decreases oxidation of LDL, decreases inflammation and foam cell formation

What is the role of vitamin E as an anticoagulant?

inhibits platelets from clumping together, reduces plaque buildup, reduced risk of heart attack, unclear if supplements also hold this property

What are some food sources of vitamin E?

vegetable oils, nuts, seeds, avocado, green veggies, wheat germ, fortified cereal