Vitamin D
Vitamin D
Vitamin D is a fat-soluble vitamin that is found naturally in a few different types of foods. Vitamin D plays an important role for our body by controlling calcium and phosphate levels in our blood. Because of this Vitamin D deficiency can cause several symptoms and health related problems.
Food Sources of Vitamin D
- Cheese
- Butter
- Fortified Milk
- Fish
- Oysters
- Fortified Cereals
- Margarine
- Eggs
- Mushrooms
Vitamin D is also synthesized when sunlight hits the skin.
People at Risk of Vitamin D deficiency
Vegetarians and Vegans tend to have difficulty getting enough Vitamin D because it is not found naturally in foods other than animal products.
During winter months there is a higher probability of Vitamin D deficiency because of the lack of sunlight. People with dark skin are also less likely to synthesize Vitamin D.
At Risk People:
- Live in climates with little exposure to sunlight
- Work indoors during daylight hours
- Children ages 6 to 24 months of age
- Vegans and Vegetarians
- Pregnant Mothers
- Have lactose intolerance
- Digestive tract problems (Chron’s Disease)
- Kidney related problems
- Older Adults
- People with dark skin
- Obese individuals
- Fat Malabsorption Syndromes (Cystic Fiborsis)
Diseases Related to Vitamin D Deficiency
- Rickets or Osteomalacia (Softening of the Bones)
- Osteoporosis
- Cardiovascular Disease
- Cancer (breast cancer, colon, ovarian, bladder)
- Cognitive Impairment
- Type 1 and Type 2 Diabetes
- Multiple Sclerosis
- Depression
- Muscle Weakness
Evidence for some of these diseases comes from in vitro, animal, and epidemiological studies, and not considered definitive.
Health Risks of Vitamin D Toxicity
- Anorexia and Weight Loss
- Polyuria (excessive urination)
- Heart Arrhythmias
- Vascular and Tissue Calcification
- Kidney Stones
Excessive sun exposure will not result in Vitamin D toxicity. Toxicity is most likely to occur with excessive supplement intake.
Daily Tolerable Upper Intake Limits (ULs) of Vitamin D
Limits are the same for both male and female including pregnant and lactating women for their age group.
- 0-6 months: 1,000 IU (25mcg)
- 7-12 months: 1,500 IU (38mcg)
- 1-3 years: 2,500 IU (63mcg)
- 4-8 years: 3,000 IU (75mcg)
- ≥ 9 Years: 4,000 IU (100mcg)
For the treatment of diseases 600,000 IU (15,000mcg) may be used. This will be determined by a doctor.
Recommended Dietary Allowances (RDAs) of Vitamin D
Recommendations are the same for both male and female including pregnant and lactating women for their age group.
- 0-12 months: 400 IU (10mcg)
- 1-13 years: 600 IU (15mcg)
- 14-18 years: 600 IU (15mcg)
- 19-50 years: 600 IU (15mcg)
- 51-70 years: 600 IU (15mcg)
- > 70 Years: 800 IU (20mcg)
Some authors suggest that Vitamin D requirements for pregnant women may be greater than the recommended daily amounts.
Vitamin D Supplementation
In supplements Vitamin D is available in two forms, D2 (ergocalciferol) and D3 (cholecalciferol) that differ chemically only in their side-chain structure.
Vitamin D2 is manufactured by the UV irradiation of ergosterol in yeast, and vitamin D3 is manufactured by the irradiation of 7-dehydrocholesterol from lanolin and the chemical conversion of cholesterol [6].
Both forms have traditionally been regarded as equivalent based on their ability to cure rickets and increase serum 25(OH)D levels. Studies have found that at high doses vitamin D2 is less potent than vitamin D3.
Medications That Interact With Vitamin D
Steroids such as corticosteroids can reduce calcium absorption and impair Vitamin D Metabolism.
Phenobarbital and Phenytoin known as Dilantin to help control seizures, metabolizes Vitamin D into inactive compounds and reduces the absorption of calcium.
Cholestyramine found in Questran, LoCholest, and Prevalite can reduce the absorption of fat-soluble vitamins including Vitamin D.
Importance of Vitamin D
Vitamin D is vital for the body to function and grow properly. Supplemental doses of Vitamin D have been found to help treat several diseases and are thought to help reduce the risk of several different types of cancer. Vitamin D is also used to treat Psoriasis and several other types of disease.
