Quiz 7 (Ch 10.5 & some of ch 11) Flashcards
phytochemicals
phyto = plant
protects plants from UV, microbes, and oxidation
also protects humans
not considered to be a nutrient
present naturally in coffee fruits, vegetables, spices and beer
phytochemicals reduce the risk of ……
CVD cancer diabetes Alzheimer's disease cataracts age-related functional decline
functions of phytochemicals
reduces inflammation
enhances enzyme activity that detoxifies carcinogens/protects against cancer
enhance immune function: antibacterial/antiviral
reduce cardiovascular disease
anti-obesity
recent discoveries about phytochemicals
phytochemicals interact with each other in body synergistically
interact with macronutrients and vitamins and minerals
can act in different ways under different circumstances in the body
phytochemical supplements
protective in lower doses commonly provided by foods, but may have toxic effects as supplements
avoid phytochemical supplements
phytochemical supplements
protective in lower doses commonly provided by foods, but may have toxic effects as supplements
avoid phytochemical supplements
no RDA for phytochemicals; synergistic effects make establishing RDA difficult
Consume a plant-based diet/as many whole foods as possible
functional foods
provide health benefits beyond basic nutrition
include fortified, enriched, or enhanced foods, and dietary supplements
may contain naturally occurring phytochemicals and helpful bacteria
are functional foods safe?
FDA has no official definition or regulatory category for functional foods
regulated in the same way as conventional foods
“functional” ingredient added to a food must be generally recognized as safe
are functional foods effective?
claims of health benefits from the manufacturers
designer yogurts
probiotics (beneficial bacteria)
no national standards for identifying level of active bacteria in foods or supplements
prebiotics (fiber) promote friendly bacteria
what are Bones
living organs that contain bone tissue, arteries, veins, cartilage, and connective tissue
blood vessels supply nutrients to bone to support its activites
Bones provide …….
strength and flexibility
contains about 65% minerals, providing the hardness of bone
contains 35% organic structures for strength, durability, and flexibility
collagen
fibrous protein in bone tissue
hydroxyapatitie
mineral crystals around collagen designed to bear weight
cortical bone
compact bone
80% of the skeleton
outer surface of bone
trabecular bone
spongy bone
20% of skeleton
inside of bones (scaffolding)
faster turnover rate (sensitive to hormonal changes and nutritional deficiencies)
functions of bone
structure and support (protects vital organs, physical support for organs and body segments, support for muscles that allow movement)
metabolic processes of bones
act as a storage reservoir for many minerals
when need be body can draw calcium, phosphorus, fluoride, as a result can reduce bone mass
most of the blood cells needed by our bodies are produced in the bone marrow
bone growth
increase in bone size
on average, completed by the completion of height (after puberty)
bone modeling
shaping of bone
completed by early childhood
exercise and overweight increase thickness
bone remodeling
recycling of bone tissue maintains high integrity of bone replaces old bone with new bone to maintain mineral balance involves bone resorption and formation occurs predominantly during adulthood
bone density
compactness
peak bone density
the highest achieved bone mineral density, based on individual’s genetic potential
factors associated with low peak bone density
late pubertal age in boys late onset of menstruation in girls inadequate calcium intake low body weight physical inactivity during the pubertal years
resorption
surface of bones is broken down by osteoclasts
exceeds new bone formation after age 50: density begins to decrease
osteoclasts
cells that erode the surface of bones
formation
new bone matrix formed by osteoblasts
synthesize new bone matrix by laying down collagen-containing component of bone
osteoblasts
bone builders
dual energy x-ray absorptiometry (DXA)
measures bone density
results are compared with average peak bone density of 30-year-old healthy adult known as the T-Score
t-score
used to assess a person’s risk for fracture and diagnose osteoporosis
recommended for postmenopausal women
classification for bone health
normal bone t-score between +1 and -1
osteopenia t-score between -1 and -2.5
osteoporosis t-score more negative than -2.5
nutrients for bone health (6)
calcium (most recognized nutrient associated with bone health) vitamin D vitamin K Phosphorus Magnesium Fluoride
functions of calcium
provides structure for bones and teeth assists with acid-base balance transmission of nerve impulses assists in muscle contraction maintains healthy blood pressure initiates blood clotting regulates hormones and enzymes
calcium absorption
enhanced in an acidic environment
requires 1,25-dihydroxyvitamin D
calcium intake
RDA varies w/ age and gender (1,000 mg to 1,300mg/day)
UL: 2,500mg
bioavailability
the degree and rate at which a substance is absorbed into a living system or is made available at the site of physiological activity
depends on individual’s age and calcium need, dietary calcium and vitamin D, and binding factors
sources of calcium
excellent sources include milk products
green leafy vegetables (kale, collard greens, broccoli – all of those are low in oxalate)
fortified foods (orange juice, soy milk)
fish with edible bones
excess dietary calcium
excreted in the urine
mineral imbalances from supplements
hypercalcemia (high blood calcium)
hypercalcemia
caused by cancer or parathyroid hormone (PTH) overproduction
symptoms: fatigue, appetite loss, constipation, mental confusion, calcium deposits in soft tissues
calcium deficiency
osteoporosis from long-term calcium deficiency
hypocalcemia (low blood calcium)
hypocalcemia
caused by kidney disease, Vitamin D deficiency, or diseases that inhibit the production of PTH
symptoms: muscle spasms and convulsions
vitamin D
fat soluble
excess stored in adipose tissue and liver
can be synthesized in the body from exposure to UV rays from the sun
Considered a hormone: synthesized in one location and regulates activities in other parts of the body
functions of vitamin D
regulates blood calcium levels (regulates calcium and phosphorus absorption from the small intestine)
stimulates osteoclasts when calcium is needed elsewhere
required for bone calcification
factors influencing vitamin D synthesis (sunlight)
Time: sunny days, 9AM-3PM
Season: inadequate sun in the winter
Latitude: more than 40N or more than 40S
factors influencing vitamin D synthesis – darker skin
more melanin pigment
reduces the penetration of sunlight
factors influencing vitamin D synthesis – age
older than 65
decreased capacity to synthesize vitamin D from the sun
factors influencing vitamin D synthesis – obesity
lower circulating vitamin D levels
vitamin D adequacy
RDA:
19-50 yr old 5 micrograms/day
51-70 10 micrograms/day
>70 15 micrograms/day
sources of Vitamin D
egocalciferol (D2) – plants, supplements
cholecalciferol (D3) – animal foods, sun
cholecalciferol (D3) – animal foods, sun
most foods naturally contain little Vitamin D
mostly obtained from fortified foods (e.g. milk)
high amounts: cod liver oil, fatty fish (salmon, mackerel, and sardines)
vegetarians not consuming milk products may receive vitamin D from the sun, fortified soy or cereal products, or supplements
vitamin D toxicity and deficiency
toxicity: hypercalcemia
deficiency: loss of bone mass, Rickets (children), osteomalacia (adults)
medications that alter Vitamin D metabolism and activity
glucocorticoids
phenobarbital
Vitamin K
fat soluble vitamin stored in the liver
phylloquinone: plant form
menaquinone: animal form (by bacteria in the large intestine)
functions of vitamin K
coenzyme for formation of specific proteins
blood coagulation and bone metabolism
bone metabolism: coenzyme “Gla” protein production
osteocalcin
secreted by osteoblasts (bone remodeling)
matrix gla protein
in protein matrix of bone, catilage, blood vessel walls, soft tissues
AI for Vitamin K
120 micrograms/day (men)
90 micrograms/day (women)
sources of Vitamin K
synthesized by bacteria in the large intestine
green leafy vegetables, vegetable oils
vitamin K toxicity and deficiency
toxicity: none known
Deficiency: reduced blood clotting, excessive bleeding
causes of inadequate vitamin K consumption
fat malabsorption (celiac disease, Crohn's disease, and cystic fibrosis) long-term use of antibiotics can lead to deficiency
to prevent hemorrhagic newborn disease
injection of vitamin K at birth for newborns
