Vitamin D Information

You should be know the facts about vitamin D including its safe levels, effects of overdoses, its deficiency symptoms and foods that are high in vitamin d.

Vitamin D is a fat-soluble micro-nutrient. It is produced by our skin when it is exposed to ultraviolet radiation from natural sunlight. Vitamin D refers to several different variations of this vitamin.

For humans, two forms of vitamin D are important: Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol).

While vitamin D2 is synthesized by plants, vitamin D3 is synthesized by humans in the skin when it is exposed to ultraviolet-B (UVB) rays from sunlight. Vitamin D3 is also found in animal products, especially fish liver and vitamin D2 in yeast.

Though it is called a vitamin, its function is actually a pro hormone. It helps absorb calcium and phosphorous from the food in the intestine. The function of vitamin D is to cause increased absorption, longer retention and better utilization of calcium and phosphorus in the body. This is needed to form and maintain strong bones.

Vitamin D influences key biological functions that are vital to our health.

1. It is needed in the development of strong and healthy bones.
2. Vitamin D reduces back pain and osteoporosis.
3. It keeps minds of older men sharp.
4. Vitamin D fights asthma.
5. It reduces the risk of cancer: Vitamin D is the most effective medicine against cancer, more than the benefits of any cancer drug known to modern science!
6. Vitamin D is used to treat Psoriasis.
7. It prevents depression, breast cancer, prostate cancer and the effects diabetes and obesity.

How much vitamin d should one take? The Adequate Intake (AI) levels of Vitamin D have been established by the U.S. Institute of Medicine of the National Academy of Sciences. The following are the current recommended adequate doses to meet physiological needs.

[Source: Institute of Medicine, Food and Nutrition Board - Dietary Reference Intakes. Washington, DC: National Academy Press, 1997]

Vitamin D For Adults

IU = International Units

Male, female, pregnant/lactating women

Under the age of 50 years: 5 micrograms (200 IU or )

From 50-70 years-old: 10 micrograms daily (400 IU)

Over 70 years-old: 15 micrograms daily (600 IU)

Children (under 18 years old)

From birth to 50 years old: 5 micrograms per day (200 IU).

Children younger than one year should not exceed 25 micrograms (1,000 IU) per day.

Some experts are of the view that the current recommended AI levels are insufficient to meet physiological needs, particularly for individuals who do not receive regular sun exposure.

In 2008, the American Academy of Pediatrics (AAP) recommended the following:

Pregnancy and Breastfeeding

The mother's milk is deficient in vitamin D, it contains only about 25 IU per liter. AAP recommends that the infants on breast feed should, therefore, receive each day vitamin D supplements of 400 IU shortly after birth and continue until they consume ≥1,000 mL/day of vitamin D-fortified formula or whole milk. Consult your Doctor.

All non-breasted infants taking <1,000 mL/day of vitamin D-fortified milk or formula milk should receive each day vitamin D supplements of 400 IU.

Older children who do not obtain 400 IU/day through vitamin D-fortified milk and foods should take a 400 IU vitamin D supplement daily.

Vitamin D Overdose Side Effects: Vitamin D Toxicity

The upper limit for vitamin D has been recommended as 50 micrograms (2,000 IU) per day for adults and 1,000 IU per day for infants, toxicities can occur with overdose, i.e. when taken in higher doses.

As vitamin D is stored in the body in fatty tissues and in the liver, an overdose (excessive intake) is harmful. The too much intake of vitamin d side effects may include nausea, vomiting, anorexia, thirst and drowsiness. Hypercalcaemia can occur due to the increased intestinal absorption and mobilization of calcium from bones. The cardiac and renal failure may occur.

One in seven U.S. teens, 70% whites and 97% of African Americans are deficient in vitamin D.

Low vitamin D levels or vitamin D deficiency in the blood can lead to many diseases such as hypertension, heart disease, stroke, osteoporosis, osteoarthritis, cancer, autoimmune diseases, diabetes, birth defects and many more.

What Causes Vitamin D Deficiency?

A vitamin D deficiency can occur due to the following reasons:

1. The intake of vitamin D is lower than recommended vitamin D levels over a long time. The low vitamin D intake may be due to Vitamin D deficient diets.
2. Exposure to sunlight is limited. 20-30 minutes exposure to sun rays can synthesize about 20,000 IU of vitamin D.
   People with dark skin have reduced skin's ability to produce vitamin D from exposure to sunlight.
3. Excessive use of sunscreens. Even weak sunscreens (SPF=8) block body's ability to generate vitamin D by 95%.
4. Adults aged 50 and older can develop vitamin D insufficiency, because as people age, skin cannot synthesize vitamin D efficiently and also the kidney is less able to convert vitamin D to its active form.
5. Some disease of liver and kidneys so the formation of vitamin D is less.
6. Absorption of vitamin D from the digestive tract is inadequate due to renal problems or intestinal problems such as Crohn's disease.
7. Genetic defect
8. Obesity: People who are obese with a body mass index BMI ≥30 may be deficient in vitamin D. Obese people need twice as much vitamin D, because obesity impairs vitamin D utilization in the body.

Vitamin D Deficiency Symptoms

The broad vitamin d deficiency symptoms or signs are listed below. Note that these symptoms may be due to other medical conditions.

1. Rickets in children and osteomalacia (soft bones) in adults
   The vitamin deficiency causes increased loss of calcium and phosphate in the stool, leading to bone deformity, muscular hypotonia, tetany and convulsions due to hypo calcemia. The bones become soft and can be easily bent in children of 6 to 18 months age. Their joints lose their shape and are not able to function properly. In young infants, the head may be flattened on one side due to softening of the bones of the skull. Premature infants and breast-fed babies are more prone to have rickets.
2. muscle pain
3. Alzheimer's
4. Allergies
5. Several types of cancers
6. Daytime sleepiness
7. Deficiency during pregnancy increases risk of childhood dental problems
8. Depression
9. Diabetes, Type 1 and 2
10. Fatigue
11. Heart disease, hypertension, stroke
12. Infertility
13. Misaligned teeth and cavities, periodontal disease
14. Multiple sclerosis
15. Muscle weakness
16. Parkinson's disease
17. Psoriasis
18. Schizophrenia
19. Sleep irregularities
20. Vision problems
21. Weaker bones, bone pain and frequent fractures
22. Weaker immune system becomes weak
23. If it hurts to press firmly on your sternum, chances are that you are suffering from chronic vitamin D deficiency. The sternum (breastbone) is a long flat bone shaped like T in the chest below the neck, located in the center of the chest.

How to Prevent Vitamin D Deficiency

1. Expose your face, arms, legs and back without sunscreen to sun in the early morning and late afternoon. The further you live from the equator, the longer exposure you need to the sun in order to generate vitamin D. People with dark skin may need 20 times as much exposure to sunlight as fair skinned people to generate the same amount of vitamin D.
2. Eat a diet rich in foods that contain vitamin D or take a vitamin D supplement.

What Foods Are High In Vitamin D

Vitamin D is available only in some foods, but the best way to obtain vitamin D is through the exposure to sunlight. A person would have to drink ten glasses of vitamin D fortified milk each day just to get minimum levels of vitamin D into their diet.

Fatty fish like mackerel, tuna and sardines and fish liver oils are among the best sources. Small amounts of vitamin D are found in egg yolks, fortified milk, fortified dairy products, fortified cereals are good natural sources of D. The milk is fortified with 100 IU/cup of vitamin D, which is 25% of the Daily Value.

If you look at the food labels, you will not find the Vitamin D content as the food labels are not required by law to list vitamin D content unless it has been fortified with vitamin D.

* IUs = International Units, ug = Microgram

Source: U.S. Department of Agriculture, Agricultural Research Service. USDA Nutrient Database for Standard Reference, Release 16. Nutrient Data Laboratory Home Page, 2003.