Editing How to Absorb Vitamin D (section)

== Recommended Daily Intake ==
The amount of vitamin D you need each day can depend on your age, life stage, and other factors. Various health organizations have set guidelines for daily vitamin D intake to ensure most people maintain healthy levels. Below are the '''recommended dietary allowances (RDA)''' or adequate intakes for vitamin D as established by the Institute of Medicine (now National Academy of Medicine) and used by many countries ( Vitamin D - Consumer ) ( Vitamin D - Consumer ):

* '''Infants (0–12 months):''' 10 micrograms per day (400 IU). Babies who are exclusively or mostly breastfed should receive a vitamin D supplement, because breast milk typically does not provide enough vitamin D ( Vitamin D - Consumer ). Standard pediatric recommendations are 400 IU vitamin D daily for infants, starting soon after birth for breastfed babies.
* '''Children and Teens (1–18 years):''' 15 micrograms per day (600 IU) ( Vitamin D - Consumer ). This level supports growing bones in children and adolescents. It assumes minimal sun exposure, so children who play outside a lot might be getting some vitamin D from sunshine, but 600 IU from diet/supplement is considered a healthy target.
* '''Adults (19–70 years):''' 15 micrograms per day (600 IU) ( Vitamin D - Consumer ). This includes women and men, and also covers pregnant and breastfeeding women up to age 70 (note: some organizations recommend slightly higher for pregnant women, but the general RDA is 600 IU). This amount, combined with typical sun exposure, is thought to maintain bone health and normal calcium metabolism for most adults.
* '''Older Adults (71 years and above):''' 20 micrograms per day (800 IU) ( Vitamin D - Consumer ). As people age, their skin makes less vitamin D and their risk of osteoporosis increases. Therefore, the recommendation rises to 800 IU daily for seniors. Many older adults do not get much sun exposure, so relying on diet and supplements is common. In fact, some experts suggest that even 800 IU may be on the low side for older adults at high risk of falls or fractures, and doses of 1000–2000 IU are often used in practice (always considering the 4,000 IU upper limit unless supervised by a physician).
* '''Pregnant and Breastfeeding Women:''' 15 micrograms per day (600 IU) ( Vitamin D - Consumer ). Surprisingly, the official requirement is not increased during pregnancy or lactation in many guidelines. However, maintaining adequate vitamin D is particularly important in these groups because it affects the mother’s health and the developing baby. Some prenatal vitamins contain 400 to 800 IU of vitamin D. In lactating women, since breast milk is a poor source of vitamin D, either the breastfeeding mother should ensure she’s replete or the infant should be supplemented (or both) ( Vitamin D - Consumer ). There is ongoing research into whether higher vitamin D intake in pregnancy leads to better outcomes (such as improved infant bone mass or immune function), but as of now 600 IU is the standard recommendation, with some healthcare providers advising 1,000–2,000 IU for pregnant women who are deficient or at risk.

It’s worth noting that these recommended intakes assume minimal or no vitamin D from sunlight (they are designed to cover needs via diet alone). If you do get regular sunlight exposure, your body might make enough that you don’t need the full RDA from diet. However, because sun exposure varies so much, these intake recommendations serve as a safe baseline. Also, some expert groups and researchers argue that a higher daily intake (such as 800–1000 IU for adults) would better cover population needs, given the high prevalence of vitamin D insufficiency.

In any case, '''4,000 IU (100 mcg) per day for adults''' is considered the ''upper limit'' (the highest long-term daily intake unlikely to cause harm for nearly all individuals) ( Vitamin D - Consumer ). Intakes above this should be done only under medical supervision. Short-term higher doses might be used to treat deficiencies, but for maintenance, sticking to the recommended levels (or slightly above if your doctor advises) is usually sufficient. Always consult with a healthcare provider before taking high-dose vitamin D, especially if you have health conditions or are on medications.