Do I need to supplement Vitamin D if I drink fortified milk?

It depends...

Our evidence-based analysis features 7 unique references to scientific papers.

Written by Michael Hull
Last Updated:


The Recommended Dietary Allowance (RDA) for Vitamin D is currently set at 600–800 IU/day (15–20 mcg) for adults. Fortified milk typically provides 100 IU per 8 oz serving (236 mL).[1] So while milk can provide a good amount of vitamin D it may not be sufficient to ensure adequate daily intakes.

In fact, adults who rely on food sources alone for vitamin D may only be getting half their daily vitamin D requirement on average.[2][3] Those who take a vitamin D supplement are much more likely to achieve the RDA.[2][3][4]

Doses higher than the RDA may be warranted in cases of deficiency, non-response at lower dosages, or in those with a BMI >30.[5][6][7] In these cases, a 1,000–2,000 IU/day (25–50 mcg) dose (or greater) of vitamin D may be necessary.[5][6][7]

So, unless you are drinking 6+ glasses of milk a day, consuming other vitamin D rich foods (fatty fish, egg yolks) or considering supplementation will be required.

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  1. ^ Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium, et al. Dietary Reference Intakes for Calcium and Vitamin D.
  2. ^ a b Fulgoni VL 3rd, et al. Foods, fortificants, and supplements: Where do Americans get their nutrients?. J Nutr. (2011)
  3. ^ a b Blumberg JB, et al. Contribution of Dietary Supplements to Nutritional Adequacy in Various Adult Age Groups. Nutrients. (2017)
  4. ^ Moore CE, Radcliffe JD, Liu Y. Vitamin D intakes of adults differ by income, gender and race/ethnicity in the U.S.A., 2007 to 2010. Public Health Nutr. (2014)
  5. ^ a b Zittermann A, et al. Vitamin D supplementation, body weight and human serum 25-hydroxyvitamin D response: a systematic review. Eur J Nutr. (2014)
  6. ^ a b Kennel KA, Drake MT, Hurley DL. Vitamin D deficiency in adults: when to test and how to treat. Mayo Clin Proc. (2010)
  7. ^ a b Bordelon P, Ghetu MV, Langan RC. Recognition and management of vitamin D deficiency. Am Fam Physician. (2009)