Vitamin D

New zealand 09 08 survey.

% of nzers with: severe deficiency 0.2% mild-mod deficiency 4.6% Below recomended 27.1% Equal/above reco 68.1% High level 1.7% nmol/L Severe deficiency less 12.5 mild-mod def: 12.5-24.9 Below recommended 25-49.9 Equal/above recommend 50.0+ high levels it D 125+

Objectives

-recognise the structure and dietary sources of vitamin D -List 2 health consequences of vitamin D deficiency -state 2 populations or communities who may be at risk of vitamin D deficiency -state what current guidelines suggest is adequate intake of vitamin D for NZ -Describe a strategy to improve vitamin D status if needed ( while acknowledge the limitations of that strategy) what, how much do we need, how do we definedeficiency, why important to health, what affects d status . who at risk, how we improve, recent research in nz

NZ survey 97 08 09

08 09 mainly determined by sun exposure.- d levels in nzers/ diet had little impact on d status estimates 2-3ug day in 90s

How do we improve vitamin D status (3)

1) Physical activity -Improves vitamin D status -especially outside 2) Supplementation -Supplementation can lead to toxicity symptoms include -dehydration -Vomit -Fatigue -muscle weak -Itritability - suppressed appetite -constiation Therefore supplementation only if symptoms and signs of deficiency not for general population At risk groups may be prescribed at 1.25 mg month, b3 3) Sunlight Must balance risk of skin damage against risk of d deficiency ADVICE: -SEPTEMBER to APRIL Sun protection ( clothing hat, screen sunglass) 10am-4pm -exercise out late afternoon/ early morn MAY- AUGUST -some sun exposure important -best around 12pm face hands, arms exposed -use sun protection at high altitudes or near snow/water if a history of skin cancer> use sun protect all year

How much vitamin do we need>

1ug cholecalciferol (D3) =0.2 ug 25 (OH)D (divided by 5) Also in international al units AI ( adequate intake) 5.0 ug : infants, children and adolescence ( 1-1) Adults (19-50) 10.0 ug: older men/ woman ( 51-70) 15 ug: middle/ old and v old men and woman ( 70+)

STDUY PRE

20 weeks intervention [rovide red meat or fortified milk 12-20 months age 225 toddlers saseline information- social, measurements weighed food records

RESULTS

Baseline mean all year round serum 25 (OH)D: 53 nmol mean Seasonal prevalence low 25 (OH)D: 27.5- 50 mol norma Low levels in winter less 27.5 Independent predictors of vitamin d STATUS: Gender ethnicity season exposure to breastmilk and smoking ( parent) parental education level Summer: no signify difference between 3 groups Winter: Not enough in meat group fortified/ placebo milk was better n winter Meat group: Lower vitamin D compared to milk

Who is at risk of low status vitamin D

Cultures with covered clothing -less UV radiation. Dark skin -need more UV exposure. elderly -often in doors more Babies - if low in mother low in baby. -Affects development and growth -need vitamin D exposure Patients who have skin cancer -avoid sunlight

Conversion D3 and D2 in the body GRAPH

Form made in our skin when exposed to sunlight lighter skin= more D3 needed: more UV needed to make vitamin D Animal sources make D3- come in via diet as D2. Go into liver then into kidney -Calcitriol increases intestinal absorption of calcium. =Calcitriol increases parathyroid hormone PTH release which- increases calcium moving out of bone -Calcitriol decrease calcium excretion in urine so you retain more

Calcium and it d

High vitamin D= ca absorption into intestine High Calcium ca into bone low calcium -VIt D active form and PTH mobilise -Calcium out of bone

How do we define vitamin D deficiency

No cut point cause not legit, some labs have said specific cut points very high. New zealand: different studies fluctuate what the believe i deficient, insufficient, optimal ad higher levels ideal 125 mols optimal over 50 mols.

Bone health - affected by low vitamin D -lots of vitamin D in blood means you deposit lost of calcium into bones

Role of it D - maintaining serum CALCIUM concern by ensuring intestinal absorption Ca from diet Blood supersaturated with calcium and calcium deposited IN bones. production of active from vitamin D 1,25 dihydroxyvitamin D regulated by: 1) PTH 2) plasma calcium 3) Plasms phosphorous WHEN Low calcium= lots of active form D and PTH: causes calcium moving out of bone

What affects Vitamin D status ( seasonal latitude)

Solar Zenith Angle season latitude lots of UV distort through atmosphere- longer path for nz in winter- further form sum vis versa in summer

Conclusions

Sunshine ( not diet) is the most important source of vitamin D in NZ. 2) Groups at particular risk of developing D deficiency are therefore those who have limited su exposure ( elderly, ocbvered cultures, babies) 3) Sun exposure to prevent deficiency must, however be blanked with high skin cancer risks in nz

Is vitamin D a problem for new zealand toddlers? STUDY

Toddlers: 1) to asses vitamin D status and identify the predictors of 25(OH)D in a sample nz todlers 2) Examine relationship between serum 25(OH)d AND PTH 3) To investigate the relationship of providing VIT D fortified milk on D status of young children

What os vitamin D

Vitamin D3 and D2 D3= cholecalciferol D2=Ergocalciferol -Precursor for many hormones. (pro hormone) with a secosteroid structure SUNLIGHT= humans can manufacture vitamin D3 diet can provide either D2 or 3. -Fish oil, eggs= D3 -table spread D2/3 -Mushrooms- small D2

Deficiency D disease 3 of them

deficiency lead to : Not enough calcium uno bones= not strong 1) Inadequate mineralization of bone (rickets- children) 2) Demineralisation of bone (adults) -osteomalacia ( soften bone younger) -increase bone turnover with reduced bone mineral density and deterioration of bone micro- architecture -osteoporosis (older) -elevated risk of fracture 3) other deficiency causes USA outcomes of: - not legit need 30-40 years study- these are just pos neg associations: cancer CHD hypertension diabetes and metabolic syndrome fails and physical performance autoimmune disorders immune functioning infections neuropsycological functioning

STUDY DESIGn

groups 1) Red meat 90 2) Fortified milk 45 3) Placebo- norm milk all year round No signify VIT D diff between milk groups average vitamin D intake 3.8 mcg/d (EAR 10 mcg/d)

CONTIN

more likely to be deficient in winter and early spring. Obses: lower Vit D Socioeconic living: low vit D Pacific people 2.3 times more likely to have low it D than non-pacific people Lowe in central and south NZ than northern top: 65.1 NMOL/L central 62.6 south: 60.5

Sunscreen High body fat

screen: -Block UV tradition. especially if broad spectrum High bf -Low vitamin D in blood -Fat soluble vitamin -adipose tissue can take vitamin D out of blood and therefore less in your blood