Professor Emeritus, Department of Family and Preventive Medicine
University of California, San Diego
Principal Investigator, Vitamin D*action Study
GrassrootsHealth Nutrient Research Institute
PubMed: https://pubmed.ncbi.nlm.nih.gov/?term=Cedric+F+Garland
University Profile: https://profiles.ucsd.edu/cedric.garland?
Read how Dr. Garland’s research supports colorectal cancer prevention
ABOUT DR. GARLAND
Dr. Cedric F. Garland is a renowned epidemiologist and Professor Emeritus at the University of California, San Diego (UCSD), known globally for his pioneering work linking vitamin D, sunlight exposure, and cancer prevention.
He earned his Doctor of Public Health (DrPH) degree from UC San Diego and is a Fellow of the American College of Epidemiology. Over his career, Dr. Garland has published more than 150 scientific articles and book chapters exploring the role of vitamin D in chronic disease prevention, including cancer, diabetes, and heart disease.
Together with his late brother, Dr. Frank C. Garland, and colleague Dr. Edward D. Gorham, he introduced the UVB–Vitamin D–Cancer Hypothesis, a paradigm-shifting theory proposing that adequate sunlight exposure and sufficient vitamin D levels can dramatically reduce the risk of several cancers.
Dr. Garland’s collaboration with GrassrootsHealth began in 2007, when he became the Principal Investigator of the Vitamin D*action Study, a long-term public health initiative enabling individuals to measure and improve their vitamin D status through home testing and education. His work continues to guide global understanding of vitamin D’s role in preventive medicine.
KEY CONTRIBUTIONS AND STUDIES
Vitamin D and Cancer Prevention
- In 1980, Dr. Garland and his brother published their groundbreaking paper, “Do Sunlight and Vitamin D Reduce the Likelihood of Colon Cancer?” in the International Journal of Epidemiology, which first proposed that insufficient sunlight (and low vitamin D) increases cancer risk.
- Their 2006 review in the American Journal of Public Health summarized 63 studies showing that higher vitamin D levels (40–60 ng/mL) are associated with reduced risks of breast, colon, and other cancers.
- A 2009 meta-analysis in Annals of Epidemiology projected that maintaining vitamin D levels of 40–60 ng/mL could prevent tens of thousands of cancer cases each year in North America.
- In 2018 (PLoS One), Garland and GrassrootsHealth researchers found women with vitamin D levels ≥60 ng/mL had substantially lower breast cancer risk than those below 20 ng/mL, results later supported by similar findings in 2023 (JAMA Open Network).
UVB–Vitamin D–Cancer Hypothesis
- The Garlands were the first to propose that ultraviolet B (UVB) exposure—which triggers vitamin D synthesis—plays a protective role against cancer.
- Using NASA satellite data, they demonstrated that regions with more sunlight exposure had lower rates of colon, breast, and ovarian cancers.
- Their work emphasized that moderate, non-burning sun exposure and supplementation can safely achieve optimal vitamin D levels for cancer prevention.
Other Health Outcomes
- Garland’s research has also linked vitamin D deficiency to type 1 and type 2 diabetes, and his team was among the first to show that secondhand smoke contributes to fatal heart disease, leading to California’s public smoking restrictions.
- He continues to advocate for maintaining serum 25(OH)D levels of 40–60 ng/mL, typically through moderate sun exposure and supplementation, as a key public health measure.
AWARDS & ACCOLADES
- Fellow, American College of Epidemiology
- Seelig Award for Research Excellence (2017) – American Nutrition Association
- NBJ Award for Excellence in Education (2018) – GrassrootsHealth
- Mercola Achievement Award (2018) – GrassrootsHealth
- Humanitarian Award (2016) – American College of Nutrition, for “Moving Research into Practice”
TOP PUBLICATIONS
Peer-Reviewed Original Manuscripts
Garland CF, Garland FC. Do sunlight and vitamin D reduce the likelihood of colon cancer? Int J Epidemiol. 1980;9(3):227–231.
https://doi.org/10.1093/ije/9.3.227
Garland CF, Gorham ED, Mohr SB, Garland FC. Vitamin D and prevention of breast cancer: Pooled analysis. Am J Public Health. 2006;96(2):252–261.
https://doi.org/10.2105/AJPH.2004.045260
Garland CF, Kim JJ, Mohr SB, Gorham ED, Grant WB, Giovannucci EL, et al. Meta-analysis of vitamin D and colorectal cancer risk. Ann Epidemiol. 2009;19(7):468–483.
https://doi.org/10.1016/j.annepidem.2008.10.009
McDonnell SL, Baggerly CA, French CB, Garland CF, Gorham ED, Holick MF, et al. Serum 25-hydroxyvitamin D concentrations ≥60 ng/mL are associated with a reduced risk of breast cancer. PLoS One. 2018;13(6):e0199265.
https://doi.org/10.1371/journal.pone.0199265
