Adults aged up to 70 years old should be getting at least 600 IU. Adults older than 70 should be getting at least 800 IU of vitamin D. However, some sources say you should consume up to 1000 IU of vitamin D past the age of 70.
In the winter, in addition to high vitamin D food, adults should take additional vitamin D from foods or supplements to get at least 600 IU per day of vitamin D.
In summary, long-term supplementation with vitamin D3 in doses ranging from 5000 to 50,000 IUs /day appears to be safe.
Advice for adults and children over 4 years old But since it’s difficult for people to get enough vitamin D from food alone, everyone (including pregnant and breastfeeding women) should consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter.
In the winter, people have a reduced ability to make vitamin D when they go outside, so amounts of at least 600 IU per day of vitamin D from food or supplements would help maintain vitamin D status at summer levels. But, just like many things, too much vitamin D can be harmful.
While the upper limit of this recommendation is 2,000 IU per day, research shows that high doses of vitamin D (10,000 to 50,000 IU daily) may be necessary for patients who have a history of malabsorption. While vitamin D toxicity (also called hypervitaminosis D) is rare, it can have serious side effects.
Vitamin D recommended intake is at 400–800 IU/day or 10–20 micrograms. However, some studies suggest that a higher daily intake of 1,000–4,000 IU (25–100 micrograms) is needed to maintain optimal blood levels.
Mayo Clinic recommends that adults get at least the RDA of 600 IU. However, 1,000 to 2,000 IU per day of vitamin D from a supplement is generally safe, should help people achieve an adequate blood level of vitamin D, and may have additional health benefits.
The Endocrine Society Practice Guidelines recommend that up to 10,000 IUs daily was safe for adults. This is in contrast to the recommended UL at 4,000 IU/d from the IOM.
Vitamin D2 and D3 50000 IU are available with a prescription. Vitamin D2 and D3 400 – 5000 IU are available over-the-counter (OTC).
Most people can make enough vitamin D from being out in the sun daily for short periods with their forearms, hands or lower legs uncovered and without sunscreen from late March or early April to the end of September, especially from 11am to 3pm.
The “Loading Dose” The calculation for the loading dose is based on the formula published by van Groningen et al (2010) as follows: Vitamin D Loading dose (IU) = 45 multiplied by the desired rise in vitamin D level (target vitamin D level – starting vitamin D level in ng/mL) multiplied by body weight in pounds.
Taking supplements Any one at risk of not getting enough vitamin D should take a vitamin D supplement – especially during the winter months but ideally all year round.
Adults aged up to 70 years old should be getting at least 600 IU. Adults older than 70 should be getting at least 800 IU of vitamin D.
Vitamin D Vitamin D is known as the “sunshine vitamin” because your body can make it by using cholesterol and absorbing natural sunshine. Your mood may improve with as little as 10 minutes of sun exposure. This is why light therapy is an important treatment for SAD.
Oral vitamin D3 can be taken once a day but also with longer intervals because of its long half life, being around 25 days. It is not known whether equivalent doses once a week or once a month are equally effective.