Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Cancer Health Center

Font Size

Vitamin D for Cancer Prevention?

Reviewers Recommend Vitamin D Dose That's Far Above Recommended Level
WebMD Health News
Reviewed by Louise Chang, MD

Sept. 5, 2007 -- Getting enough vitamin D might cut colon cancer and breast cancer in North America, according to a new research review.

The reviewers suggest that adults should daily take 2,000 international units (IU) of vitamin D -- in a form called vitamin D3 (cholecalciferol) -- to help prevent some cancers, including colon cancer and breast cancer.

But that's not a prescription or a guarantee. The review is based on observational studies, which didn't directly test vitamin D for cancer prevention.

The 2,000-IU daily dose of vitamin D suggested by the reviewers is currently considered the "tolerable upper limit" for vitamin D, according to the National Academy of Sciences' Institute of Medicine (IOM).

The IOM hasn't set a "recommended intake" for vitamin D. But it has previously determined that "adequate intake" of vitamin D is 200 IU per day for the first 50 years of life, 400 IU per day from 51-70, and 600 IU per day after age 71.

Vitamin D and Cancer Review

The new research review on vitamin D and cancer comes from scientists including Cedric Garland, DrPH, of the University of California at San Diego's family and preventive medicine department.

They cite 29 observational studies in their report, which appears in the journal Nutrition Reviews.

Garland and colleagues combined data from the observational studies. They conclude that in North America, "a projected 50% reduction in colon cancer incidence would require a universal intake of 2,000 IU per day of vitamin D3."

"A similar reduction in breast cancer incidence would require 3,500 IU per day," write the reviewers, cautioning that such a dose exceeds the Institute of Medicine's tolerable upper limit for vitamin D.

Vitamin D may help prevent cancer in several ways, including maintaining healthy cells with normal life spans, discouraging out-of-control cell reproduction, and hindering the formation of new blood vessels for tumors, according to the reviewers.

Vitamin D doesn't just come in supplements. It's also found in some foods -- including salmon, tuna, and some fortified dairy products and cereals.

The body also makes vitamin D when exposed to sunshine. Garland's team recommends getting three to 15 minutes of sun exposure on sunny days, with 40% of the skin exposed without sunscreen.

Today on WebMD

Colorectal cancer cells
New! I AM Not Cancer Facebook Group
Lung cancer xray
See it in pictures, plus read the facts.
sauteed cherry tomatoes
Fight cancer one plate at a time.
Ovarian cancer illustration
Real Cancer Perspectives
Jennifer Goodman Linn self-portrait
what is your cancer risk
colorectal cancer treatment advances
breast cancer overview slideshow
prostate cancer overview
lung cancer overview slideshow
ovarian cancer overview slideshow
Actor Michael Douglas