VITAMIN D USEFUL INFORMATION YOU SHOULD KNOW OBJECTIVES

VITAMIN D USEFUL INFORMATION YOU SHOULD KNOW

OBJECTIVES What is Vitamin D and how do we get it? How does Vit D help us? What are the normal, low, high levels of Vit D in blood? What are the common reasons for Vit D deficiency? Vit D deficiency in Indians Signs, symptoms and consequences of Vit D deficiency Doses of Vit D Adverse effects of excess Vit D References

WHAT IS VITAMIN D (VIT D) AND HOW DO WE GET IT? Vitamin D is a fat soluble vitamin, plays an important role in several body functions Naturally present in very few foods Produced in our body when Ultra-Violet rays (UV rays) from Sun hit our skin that triggers Vit D synthesis in skin Vit D obtained from food, supplements, Sun is biological inert or inactive It undergoes two chemical reactions (first in liver, second in kidney) after which is becomes active

SOURCES OF VITAMIN D Vit D occurs in two natural forms: Vit D 2 or ergocalciferol – through plant sources and in fortified food Vit D 3 or cholecalciferol – from animal sources and from Sunlight Fish: Rawas, Tuna, Oysters, Prawns Fish Liver oil (especially Cod liver oil) Milk, cheese egg yolk (in small amount) Wild Mushrooms is the only plant source of Vit D – produced when they are exposed to U-V rays Fortified foods: In developed countries, many foods are fortified with Vit D – such as milk, orange juice, yogurt, soy milk, cereals Endogenously produced by our skin when exposed to Sunlight

Vit D promotes absorption of calcium from our intestines (gut) FUNCTIONS OF VITAMIN D IN OUR BODY It helps maintain adequate and balanced concentration of calcium and phosphorus in our blood These are needed for our bone health – bone growth, remodelling and adequate mineralization required for strength Vit D also has a possible role to play in, • • • Regulating our immune function Improvement of muscle function Lowering BP and enhancing heart health Warding off depression Regulating blood sugar levels, increasing evidence that Vit D may help delaying type 2 diabetes • Preventing several types of cancers

VITAMIN D LEVELS IN OUR BLOOD MEASURED AS SERUM 25 -HYDROXYVITAMIN D (25 (OH)D) Nmol/L Ng/ml < 30 < 12 Associated with Vit D deficiency, leading to Rickets in infants and children and osteomalacia (weak bones) in adults 30 to < 50 12 to < 20 Generally considered inadequate for bone and overall health in healthy individuals >=50 >=20 > 125 Health Status Generally considered adequate for bone and overall health in healthy individuals Emerging evidence links potential adverse effects (harm) to such high levels, particularly over 150 Nmol/L or 60 ng/ml of Medicine, USA Values as recommended by committee of Institute > 50 • • Carefully review the unit of measurementioned in your report while drawing conclusions In India, < 20 ng/ml is considered as deficiency, 20 – 29 ng/ml as insufficiency (borderline) and > 30 ng/ml as adequate levels of Vit D in blood Serum levels do not reflect the Vit stored/trapped in body fat

COMMON REASONS FOR VITAMIN D DEFICIENCY Vulnerable Group Reason/s Breast fed infants Milk contains low Vit D, hence unless given supplement of Vit D, infants purely fed breast milk may develop deficiency Older people Skin becomes thinner with age, not able to efficiently produce Vit D, also less exposure to Sunlight, as mobility may decrease with age Obesity On one hand, increased requirement, on the other hand excess body fat traps Vit D, thus making less active Vit D available in blood for its activities Pregnancy Increased demand Darker skin Contains higher concentration of pigment melanin, which interferes with Vit D synthesis Gastric bypass surgery Interferes with the absorption of Vit D Serious liver or digestive disorders Interfere with absorption and converting Vit D to active vitamin in the body

VITAMIN D DEFICIENCY IN INDIANS Vit D deficiency is widespread in India (for e. g. , despite fish eating habits, many from Bengal still have it) For those, who are pure vegetarian, there is hardly any food source to get the vitamin. High phytate content in vegetarian diet also interferes with absorption of Vit D Overall poor nutritional status in large number of people in India Foods are not commonly fortified with Vit D in India (Amul is one brand that offers fortified milk) Shunning the Sun: tendency of people to avoid going out in Sun, changing lifestyle of “global” workers Dark skin tone: Skin pigment reduces the ability of skin to make Vit D. Dark skinned people may need 20 to 30 times more exposure to Sun to make adequate Vit D compared to light skinned Excess use of Sun screens: Sunscreen with SPF 15 can block 93% of U-V rays from Sun, thus blocking Vit D production High level of pollution in the air, high food contamination This Photo by Unknown Author is licensed under CC BY-SA

WHAT HAPPENS WHEN THERE IS VIT D DEFICIENCY Without Vit D, our bones become weak, thin, brittle and may misshapen. There is loss of bone In infants and children, Vit D deficiency may lead to rickets (pot belly and bow legs) In adults, it may cause osteomalacia – weak bones, leading to pain Osteoporosis leading to increased risk of fractures in older people Several other body functions may also get affected

HOW MUCH VITAMIN D WE NEED NORMALLY? Age/group Vit D needed/day 0 – 12 months 400 International Units (IU) 1 to 18 years 600 IU 19 to 70 years 600 IU > 70 years 800 IU Pregnancy, lactation 600 IU For preventing osteoporosis and fractures in older adults 400 to 1000 IU In case of Vit D deficiency, the doctor may prescribe higher doses to treat the deficiency Even in deficiency, the upper limit of Vit D to be prescribed is, • Adults – maximum 4000 IU/day or 28000 IU per week • Children – maximum 1000 – 3000 IU per day This Photo by Unknown Author is licensed under CC BY-ND

SIDE EFFECTS OF VITAMIN D Vit D is generally safe when taken within allowable limits (both by mouth and intramuscular injection) and most people do not experience any side effects It can, however, interact with several medications which can affect its actions: Steroids prescribed for many illnesses such as asthma, rheumatoid arthritis etc. Some anti-epilepsy medications such as phenobarbitone, phenytoin Laxatives (prescribed for constipation) Digoxin, prescribed for heart failure Some drugs that increase urine output, Statins prescribed for high cholesterol levels It is, therefore, important to share with your doctor if you are taking Vit D supplements

VITAMIN D OVERDOSE AND TOXICITY Vitamin D intake and levels in blood beyond defined limits do not offer any additional benefit and may cause harmful side effects Intake of > 4000 IU/day of Vit D over a long period, increases the risk of hypervitaminosis The signs and symptoms of Vit D toxicity include: Loss of appetite Nausea, vomiting Loss of weight Dry mouth, metallic taste in mouth Weakness, fatigue Headache, sleepiness Excess urination Irregular heart beats Excess Vit D intake over a long period can raise calcium levels in blood, which can cause damage to heart, blood vessels and kidneys, raise the risk of kidney stone Consult your doctor immediately if you develop any of the above

REFERENCES: National Institute of Health (NIH), USA Web MD and Medscape Drugs. com G Ritu, G Ajay. Vit D deficiency in India: Prevalence, causalities and interventions. Nutrients 2014; 6(2): 729 -75 On line picture library