nutrition and musculoskeletal growth and development

Question 1

Vitamin D function

Answer 1

primary function is to maintain calcium and phosphorus levels

Promotes absorption of calcium and phosphorous in the GIT to support neuromuscular function, support bone calcification

Inadequate vitamin D will lead to decreased calcium absorption, prevent osteoblast action, result in the failure of the bones to mineralize=rickets

Question 2

Vitamin D metabolism

Answer 2

Oral intake: absorption requires normal fat metabolism, including pancreatic secretion, bile acid, adequate small intestine length, and normal functioning lymphatic systme

Stored in the liver and activated in the kidney

Internal synthesis: can be made from UV light by converting cholesterol from pre vitamin D3

High Sun exposure does not guarantee adequate vitamin D

Question 3

Vitamin D deficiency concerns

Answer 3

inadequate intake: picky eaters, solely breastfed infants, inadequate formula intake, vegan diets

Malabsorption: vit D is a fat soluble vitamin so requires pancreatic enzymes for digestion and absorption, pancreatic insufficiency, CF, celiac IBD, surgery

Dark skin: high amounts of melanin protect against UV rays which prevents vit D activation

Inadequate sun exposure: common in infants and young children

Question 4

vitamin d sources and requirements

Answer 4

During pregnancy: 600IU (deficiency while pregnant can predispose child to deficiency state)

Infancy: 400 IU (concentration is very low in breast mil, amount necessary for rickets prevention)

Early childhood: 600 IU (adequeate intakes necessary for calcium utilization)

Most common diet sources are animal forms (fatty fish, dairy products

Sun exposure

Question 5

Calcium function and metabolism

Answer 5

Primary function is to maintain bone structure

Also aid sin coagulatin, endocrine and exocrine function, neuromuscular activity and elecetrophysiology of heart and smooth muscle

Calcium absorption is highly dependent on vitamin D

Question 6

Calcium Deficiency concerns

Answer 6

Risk for deficiency: pre term infants, majority of calcium is absorbed in 3rd trimester

Glucocorticoid therapy, impais bone mineralization, decreases absorption, increases renal secretion

inadequate intake

Malabsorption, fat malabsorption leads to calcium deficiency secondary to vitamin D deficiency, high fiber foods can bind calcium and prevent absorption

advanced age=less calcium absorbed

Caution: low albumin levels may cause serum calcium levels to appear low, albumin has lesser impact on ionized Ca

Corrected Calcium can be used to estimate actual serum ca: Corrected Ca=(.8 x (4 - pt albumin)) + serum Ca level