Sunshine and vitamin D

Dr.Manoj Prabhakar.M, Resident (Dept of Pediatrics)

What is Vitamin D?

• Fat soluble vitamin.• Essential nutrient needed for healthy

bones, and to control the amount of Calcium in our blood.

There is recent evidence that it may prevent many other diseases.

Natural source of Vitamin D?•Sunshine is the main source of Vitamin D. •Only a few natural foods such as oily fish

and eggs contain significant amounts of Vitamin D.

•There are two types of Vitamin D: Ergocalciferol (Vitamin D2) a plant product and Colecalciferol (Vitamin D3) which is a fish or mammal product.

Schematic representation of synthesis and metabolism andthe various factors that influence cutaneous synthesis of vitamin D

Vitamin D Deficiency in Childhood

•Vitamin D deficiency is considered to be the most common nutritional deficiency and also one of the most common undiagnosed medical conditions in the world.

•vitamin D deficiency is very common in all the age groups and both the sexes across the country and world

.

Etiology of Vitamin D Deficiency Decreased vitamin D synthesis Skin pigmentation, physical agents

blocking UVR exposure, clothing, latitude, season, air pollution, cloud cover, altitude

Decreased nutritional intake of vitamin  

Strict vegan diet

Age and physiology related Elderly, obese and institutionalisedDecreased maternal vitamin D stores Exclusive breast feedingMalabsorption 

Celiac disease, pancreatic insufficiency (cystic fibrosis), biliary obstruction (biliary atresia)

Decreased synthesis Chronic liver diseaseIncreased degradation of 25 (OH) D

Drugs such as rifampicin, isoniazid, anticonvulsants, glucocorticoids.

Definition of Vitamin D Status

•Vitamin D deficiency is defined as serum levels of 25(OH)D less than 20 ng/dL.

Vitamin D deficiency, why it happens?•The major source of vitamin D for

children and adults is exposure to natural sunlight. Thus, the major cause of VDD is inadequate exposure to sunlight.

•Obesity is associated with VDD.•Fat malabsorption syndromes and

bariatric patients

Vitamin D deficiency: Consequences•Results in abnormalities in calcium,

phosphorus, and bone metabolism.•Causes a decrease in the absorption of

dietary calcium and phosphorus, resulting in an increase in PTH levels.

•  Causes muscle weakness; affected children have difficulty in standing and walking

Groups at risk of vitamin-D inadequacy•Breastfed infants•Older adults•People with limited sun exposure•People with dark skin•People who are obese or who have

undergone gastric bypass surgery

Blood tests•25hydroxyVitaminD is the standard blood

test, and is an excellent marker of body stores.

• •Basic bone biochemistry (Calcium,

phosphate and alkaline phosphatase) is often normal despite significant Vitamin D deficiency.

•High alkaline phosphatase implies rickets.

Sources of vitamin D

•A major source of vitamin D for most humans is synthesized from the exposure of the skin to sunlight

•Vitamin D produced in the skin may last at least twice as long in the blood compared with ingested vitamin D.

Clinical benefits of vitamin D

•Cancer•Heart disease•Hypertension•Obesity•Type 2 diabetes•Depression•Cognitive impairment

Guidelines for Vitamin D Intake

•The recommended vitamin D intake is 400 IU/day in infants less than 1 year and 600 IU/day in children more than 1 year of age.

•Children at risk (on anticonvulsants, glucocorticoids, antifungals and medications for AIDS) need 2 to 3 times the requirement for their age.

Recommended dietary intakes of vitamin DLife Stage

Recommended Amount

Birth to 12 months 400 IU

Children 1–13 years 600 IU

Teens 14–18 years 600 IU

Adults 19–70 years 600 IU

Adults 71 years and older 800 IU

Pregnant and breastfeeding women 600 IU

Treatment of deficiency with symptoms

Category Vitamin D dose and frequency Duration

Up to 6 months 1,000 units - 3,000 units daily 4 – 8 weeks 6 months - 12 years 6,000 units daily 4 – 8 weeks

12 -18 years 10,000 units daily 4 – 8 weeks

CONCLUSION

•Vit D supplements may be effective in preveting rickets, in children who are at risk but still further investigations are required for specific recommendations.

•Excessive exposure to sunlight dose not lead to vitamin D toxicity.

•Supplementation and fortification need serious consideration in the Indian context.

•Children who are dark skinned, veiled, exposed to reduced sun light or who have underlying medical condition should receive 400 IU daily to prevent vitamin D deficiency.

THANKYOU