The prevalence of Vitamin D deficiency in India is 50-90% in various studies. Factors such as low sunlight exposure, age-related decrease in cutaneous synthesis, and low dietary intake of Vitamin D contribute to the high prevalence of Vitamin D inadequacy which has emerged as a highly pervasive condition.
Bone diseases such as rickets in children, osteomalacia and osteoporosis in adults are related with Vitamin D insufficiency.
Literature evidences show that low Vitamin D levels are also related with increased risk of falls, fractures, muscle pain, muscle weakness, cardiovascular risk, diabetes mellitus, polycystic ovary syndrome (PCOS), infections, and autoimmune disorders also.
Adequate intake of Vitamin D is necessary for all individuals of any age group. Sunlight exposure, food fortification and routine supplementation can only fulfill the deficiency of Vitamin D.
What is Vitamin D?
Vitamin D is a fat-soluble Vitamin that is naturally present in very few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet rays from sunlight strike the skin and trigger Vitamin D synthesis.
Vitamin D obtained from sun exposure, food and supplements is biologically inert and must undergo two hydroxylation’s in the body for activation.
The first occurs in the liver and converts Vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol. The second occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D [1,25(OH)2D], also known as calcitriol.
Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal mineralization of bone and to prevent hypocalcemic tetany.
Daily requirement of Vitamin D
The amount of Vitamin D needed on daily basis depends on your age. Average daily recommended amounts from the Food and Nutrition Board (a national group of experts) for different ages are listed below in International Units (IU):
|Birth to life 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|
Who is at risk for Vitamin D deficiency?
Those at risk for deficiency include:
- Breastfed Infants, because human milk is a poor source of the nutrient.
- Older Adults, because their skin doesn’t make Vitamin D when exposed to sunlight as efficiently as when they were young, and their kidneys are less able to convert vitamin D to its active form.
- People with dark skin, because their skin has less ability to produce Vitamin D from the sun.
- People with disorders such as Crohn’s diseaseor celiac disease: Vitamin D is a fat soluble Vitamin, in patients where fat is not absorbed properly; they become deficient in such Vitamins.
- Obese people, because their body fat binds to some Vitamin D and prevents it from getting into the blood.
- People whose exposure to sunlight is very limited.
- People who have kidney or liver disease.
Diseases caused due to deficiency of Vitamin D
People can become deficient in Vitamin D because they don’t consume enough or absorb enough from food, their exposure to sunlight is limited, or their kidneys cannot convert Vitamin D to its active form in the body.
- In Children, Vitamin D deficiency causes Rickets, a condition in which the bones become soft and bend.
- In Adults, Vitamin D deficiency leads to Osteomalacia, causing bone pain and muscle weakness.
Low levels of Vitamin D may also play a role in the development of osteoporosis (thinning of the bones), which can lead to fractures.
How to fight deficiency
Vitamin D can be obtained from:
- SUN EXPOSURE
- FOODS THAT CONTAIN VITAMIN D
The body makes Vitamin D when skin is directly exposed to the sun, and most people meet at least some of their Vitamin D requirement this way.
NOTE: Despite the importance of the sun to Vitamin D synthesis, it is prudent to limit exposure of skin to sunlight in order to lower the risk for skin cancer.
Food Sources of Vitamin D are mentioned below-
People who avoid the sun or who cover their bodies with sunscreen or clothing should include good sources of Vitamin D in their diets or take a supplement.
- Cod liver oil (excellent source)
- Fish – Salmon, mackerel, sardine.
- Cheese and Egg yolks provide small amounts.
- FORTIFIED FOODS (Food fortificationor enrichment is the process of adding micronutrients (essential trace elements and vitamins) to food)
Vitamin D is added to many Breakfast cereals and to some brands of – orange juice, milk, yogurt, margarine, and soy beverages (Please check the labels of the product).
Toxic effects of excess Vitamin D
Vitamin D toxicity, also called Hypervitaminosis D is not a result of sun exposure but from chronic supplementation.
Excessive supplement use will elevate blood calcium levels and cause loss of appetite, nausea, vomiting, excessive thirst, excessive urination, itching, muscle weakness, joint pain and disorientation.
Calcification of soft tissues can also occur.
The content mentioned in the article is for general information purpose only and should not be construed as professional medical advice. Always consult your doctor before adopting any of the suggestions.
NATIONAL INSTITUTE OF HEALTH – Consumer – Office of Dietary Supplements: Vitamin D (Apr, 2016)
NATIONAL INSTITUTE OF HEALTH – Office of Dietary Supplements: Vitamin D (Nov, 2018)
JAPI: Treatment of Vitamin D deficiency and comorbidities, 2018
Vitamin D Council: How do I get the vitamin D my body needs.