Taking about 1,000 to 4,000 international units (IU) of vitamin D a day is generally enough for most people to reach optimal vitamin D blood levels. Some people may require a much higher dose, especially if their current levels are very low, or they have had little exposure to sunshine.
Although optimal vitamin D blood levels are up for debate, it is estimated to be between 20 and 50 ng/mL in most cases.
According to the Recommended Daily Allowance (RDA), the following are vitamin D requirements for different groups of people:
- Adults 19 to 70 years: 600 IU (15 mcg) daily
- Pregnant or lactating women: 600 IU (15 mcg) daily
- Vitamin D to prevent and treat osteoporosis in people older than 50 years: 800 to 1000 IU (20 to 25 mcg) orally one time daily with calcium supplements
- Vitamin D to prevent and treat hypoparathyroidism: 50,000 to 200,000 IU (0.625 to 5 mg) orally once daily with calcium supplements
- Vitamin D to prevent and treat vitamin D-resistant rickets: 12,000 to 500,000 IU (0.3 to 12.5 mg) orally once daily
- Vitamin D to prevent and treat familial hypophosphatemia: 10,000 to 60,000 IU (0.25 to 1.5 mg) orally once daily with phosphate supplements
Vitamin D is an important part of healthy aging, so dose recommendations increase with age.
What are different types of vitamin D?
Vitamin D is a family of fat-soluble vitamins. There are two main types of vitamin D:
- Vitamin D2 or ergocalciferol: Found in some species of mushrooms and yeast
- Vitamin D3 or cholecalciferol: Found in egg yolks and fatty fish and produced by the body when exposed to sunlight.
Though both types of vitamin D are beneficial, studies have reported that vitamin D3 may be better absorbed in the body.
Why is vitamin D so important?
Vitamin D promotes bone health, supports the immune system, boosts lung and cardiovascular health, and may even increase life expectancy.
- Prevent disease: Scientists recommend vitamin D as preventative therapy for a wide range of diseases, from the flu to colon cancer. In addition to protecting against chronic diseases, vitamin D can help the immune system fight common infections by boosting natural antibiotic-like compounds in the lungs.
- Boosts mental health: Lower vitamin D levels have been linked to symptoms of depression and disturbed sleep. Researchers continue to investigate the potential of using vitamin D as a supplemental antidepressant.
- Promotes bone health: Several studies have found a connection between vitamin D and bone health. Vitamin D helps prevent bone weakening and can help protect against osteoporosis, which causes bones to become brittle and weak. To maximize benefits, vitamin D should be taken with calcium.
- Protects oral health: Studies have shown that patients with optimal vitamin D levels had a reduced risk of developing oral diseases. This may be due to the link between vitamin D and calcium absorption.
- Good for the heart: According to a recent study, individuals with very low vitamin D levels had an 81% increased risk of dying from heart disease, 64% increased risk of heart attacks, and a 57% increased risk of dying prematurely.
- Pregnancy: Vitamin D insufficiency during pregnancy is linked to an increased risk of bacterial vaginosis and gestational diabetes. Pregnant women who do not have enough vitamin D are more likely to develop preeclampsia, which is a pregnancy complication characterized by high blood pressure and damage to other organs.
What is the best way to increase your vitamin D levels?
You can obtain vitamin D through foods such as:
- Fatty fish
- Egg yolks
- Fortified foods
Vitamin D can also be obtained by sunlight. Spending 10-20 minutes in the sun every day can help the body synthesize vitamin D.
You can also take vitamin D supplements if you cannot get enough vitamin D through diet or lifestyle.
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Balvers MG, Brouwer-Brolsma EM, Endenburg S, de Groot LC, Kok FJ, Gunnewiek JK. Recommended intakes of vitamin D to optimize health, associated circulating 25-hydroxyvitamin D concentrations, and dosing regimens to treat deficiency: workshop report and overview of current literature. J Nutr Sci. 2015;4:e23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463009/
WebMD. Vitamin D - Uses, Side Effects, and More. https://www.webmd.com/vitamins/ai/ingredientmono-929/vitamin-d
VitaminExpress. Vitamin D dosage - This much is really necessary. https://www.vitaminexpress.org/en/vitamin-d-dosage-information