Vitamin D

CautionSuggested

3 studies · 2 recommendations

Last updated: February 25, 2026

Caution1 studies

Moderate vitamin D levels may be optimal; both low and high levels raise risk

A U-shaped relationship between plasma vitamin D and prostate cancer risk means both deficiency and excess are associated with increased risk. Men with adequate vitamin D levels should avoid unnecessary supplementation, as pushing levels too high may be harmful. The optimal range appears narrow.

Evidence

Plasma Vitamin D and Prostate Cancer Risk: Results from the Selenium and Vitamin E Cancer Prevention Trial

Authors: Goodman, G. E, Goodman, P. J, Klein, E. A, Kristal, A. R, Meyskens, F. L, Minasian, L. M, Neuhauser, M. L, Parnes, H. L, Schenk, J. M, Song, X., Tangen, C. M, Thompson, I. M, Till, C.

Published: April 14, 2014

In this nested case-cohort analysis within the SELECT trial (1,731 cases, 3,203 cohort members), plasma 25-hydroxyvitamin D showed a U-shaped association with total prostate cancer risk. Compared with the lowest quintile, the third quintile had the strongest protective association (HR 0.74, 95% CI 0.59-0.92, P = 0.008), while the highest quintile showed no benefit (HR 0.98, 95% CI 0.78-1.21, P = 0.823). For high-grade disease (Gleason 7-10), the second and third quintiles were protective (HR 0.63, 95% CI 0.45-0.90, P = 0.010; HR 0.66, 95% CI 0.47-0.92, P = 0.016), but the highest quintile was not (HR 0.88, 95% CI 0.63-1.22). The authors conclude supplementation of men with adequate levels may be harmful.

View Source →

Suggested2 studies

Vitamin D supports bone health and may help prevent prostate cancer progression

Two studies—a randomized controlled trial (n=96) and a systematic review—support Vitamin D supplementation for prostate cancer patients. In RTOG 0518, Vitamin D and calcium were administered as universal standard care to men with high-grade or locally advanced non-metastatic prostate cancer undergoing LHRH agonist therapy and radiotherapy. Over 35 months median follow-up, observation patients experienced moderate bone mineral density declines (−5% lumbar spine, −8% total hip and femoral neck) with only 1 fracture among ~48 patients, establishing Vitamin D as baseline bone health management during androgen deprivation therapy. A separate systematic review across multiple databases identified prostate cancer among tumor types where Vitamin D demonstrated antiproliferative, pro-differentiating, and chemopreventive effects, with experimental models confirming delayed tumor growth. The combined evidence positions Vitamin D as both a protective bone health measure during treatment and a potential chemopreventive agent for prostate cancer.

Evidence

Vitamin D in cancer chemoprevention

Authors: Aiello, S, Crescimanno, M, Di Majo, D, Flandina, C, Giammanco, M, La Guardia, M, Leto, G, Tumminello, FM

Published: April 9, 2015

A systematic review searching ISI Web of Science, Medline, PubMed, Scopus, and Google Scholar evaluated Vitamin D's role in cancer prevention. Experimental studies demonstrated Vitamin D's antiproliferative and pro-differentiating effects on tumor cells in vitro, with in vivo studies confirming delayed tumor growth. Clinical and experimental observations specifically identified prostate cancer among the tumor types where Vitamin D and its analogues showed effectiveness in preventing malignant transformation and disease progression. The combined evidence from multiple databases supported Vitamin D as a potential chemopreventive agent for prostate cancer.

View Source →

RTOG 0518: Randomized Phase III Trial to Evaluate Zoledronic Acid for Prevention of Osteoporosis and Associated Fractures in Prostate Cancer Patients

Authors: Gore, Elizabeth, Kachnic, Lisa A., Kim, Harold E., Lawton, Colleen AF, Martin, Andre-Guy, Nabid, Abdenour, Pugh, Stephanie L, Shah, Amit B., Smith, Matthew, Tai, Patricia

Published: July 7, 2014

In RTOG 0518, a randomized controlled trial of 96 eligible patients with high-grade or locally advanced non-metastatic prostate cancer receiving LHRH agonist and radiotherapy, Vitamin D supplementation was given to all patients as standard care. Over a median follow-up of 34.8–36.3 months, observation arm patients receiving Vitamin D and calcium without bisphosphonate experienced BMD changes of −5% at lumbar spine, −8% at total hip, and −8% at femoral neck. Only 1 fracture occurred among approximately 48 observation patients. While these supplements did not fully prevent bone density decline from LHRH agonist therapy, their inclusion as universal standard care in this cooperative group trial supports their role in baseline bone health management for prostate cancer patients.

View Source →