NTR 312 ch 11

how can aging pers minimize bone density with lifestyle

exercise max bone mass

food sources of vit D

fortified milk liver butter eggs fatty fish

illness assoc with vit D deficiency in chil and adults - what pop is vuln to deficiency

in children, rickets in adults - osteomalacia. - seen in obese people. prevents vit D from entering the body bc of fat tiss symptoms - weak muscles, susceptible to fracture

func of vit D

increase Ca absorption in SI works with PTH to retain Ca in kidney stimulates osteoCLASTS

Under what conditions are longer sun exposures needed for production of vitamin D?

pollution infants elderly dark skin areas with lil sun exposure

Describe the functions of calcium in the body?

provides strength for bones in the blood, its used for - muscle contraction - nerve transmission - blood clotting - cofactors - bone - BP - cell metabolism

In which life stages are calcium RDAs increased?

9-18 years, growth stage RDA for pregnant women is same as adulthood - The increase in hormones allows an increase in absorption. So no need for increase in intake

where is most of the calcium in the body found

99% of ca is found in bones and the rest is in the blood

pitfalls of ca supplemetation

supplements contain heavy metals - oyster shells - lead -arsenic - mercury exceed UL of vit D

bene of ca supplemtation

supplies Ca to lactose intol, vegans, those with milk allergies

risk fac of osteoporosis

aging inad intake of ca early menopause vit D deficiency genetics/race. morei n wom, more in white wom low body weight, <127 lb smoking/alcohol abuse lack of phys activity

why is ca in the blood strictly regulated within narrow limits

bc it has to do a lot of tings - muscular contrac - nerve transmission - bones - blood clott - maintain homeo

how should one supplement with ca to assure max absorp

1. Ca carbonate (TUMS) - 40% ca - req stomach acid 2. Ca citrate - 20% ca - no need for stomach acid - for elderly who dont have as much 3. ca glutamate - 9% ca supplement btwn meals bc of stomach acid low dose supplements

What percentage of dietary calcium is absorbed when active vitamin D is present in the intestines?

20-30%

Describe bone remodeling during growth, adulthood and old age.

Bone is constantly changing - Every 10 years, we have new bones During adolescence - We put on 50% of bone mass - Growth stage, very important Reach peak bone mass at 25 - Around mid-30s, aging occurs and we start to lose bone -Women lose more bone than men (menopause)

factors that increase calcium absorption

Increase in calcium absorption Vit D lactose growth/pregnancy hormones low calcium intake stomach acidity Decrease in absorption 1. Vit D deficiency 2. Phytates Phosphorus containing compounds in fibers Nuts, seeds, grains 3. Oxylate Spinach rhubarb, strawberries, carrots High fiber

how is vit D activated in the body

PTH secreted when Ca lev in blood drop trig osteoclasts, bones are broken down to release Ca also acts on kidneys to retain Ca stimulates activa of vit D

Explain how the body synthesizes vitamin D from sun exposure on the skin. Can you meet your needs for vitamin D through sun exposure only?

Sun exposure causes cholesterol => vit D3 in skin (inactive, can also get from food) =>vit D3 in liver (hydroxylates (OH), not really regulated) => vit D3 in kidneys (hydroxylates again, very tight regulation on how much vit D is going to be activated) -Calcitriol = active form Cannot meet needs for vit D through sun alone - Only makes ¼ of what YA needs

Describe how active vitamin D and parathyroid hormone work together to maintain blood calcium levels (raise blood calcium when it is low).

When calcium levels in the blood drop, parathyroid hormone (PTH) is produced & activates vit D - It acts like a hormone - It increases calcium absorption

describe the cause and symptoms of vit D toxicity

caused by taking too much supplementation 4000 IU symptoms - high blood ca - deposits in soft tiss - kidney stones

food sources of Ca

dairy tofu kale broccoli sardines (has bones) OJ grains

effec of menopause on bone loss in women

menopause is the loss of estrogen. estrogen inhibits osteoclast (loss of bone) so no estrogen means more bone loss

What are osteoblasts and osteoclasts?

osteoblasts make new bone osteoclasts remove bone

what effec does life long inad intake of ca have on the body does dietary ca influ blood ca

osteoporosis - bone loss - affects more than 25 mil ppl in US - loss of estrogen, inad intakes of ca, lack of exer - bones become porous which can lead to fractures -dowagers back blood ca is regulated by hormones not intake