Published on September 19, 2022
Depending on the type of cancer, vitamin D alone can potentially reduce the risk of cancer by about 25% to 80%… learn more about vitamin D’s known anticancer effects
September is Gynecologic Cancer Awareness Month, bringing awareness to all gynecologic cancers, including cervical, ovarian, uterine/endometrial, vaginal and vulvar cancer. There are many known links between cancer and diet, lifestyle, weight, and other factors, as well as the steps individuals can take on a daily basis to help reduce cancer risk.
Vitamin D has known anticancer effects, and much research has been published over the last several decades showing a link between vitamin D levels and cancer risk. How is it that vitamin D helps to fight and prevent cancer?
Summary of Overall Benefits of Vitamin D to Help Fight & Prevent Cancer
Anti-cancer functions of vitamin D include:
- Inhibits cancer cell growth and proliferation
- Reduces cancer metastasis
- Stimulates maturation of healthy cells (differentiation)
- Induces death of cancer cells (apoptosis or programmed cell death)
- Prevents blood vessel growth in tumors (angiogenesis)
- Prevents inflammation associated with cancer
- Reduces the risk of incidence and/or death due to cancer
Cancers associated with low vitamin D include:
- Colorectal cancer
- Breast cancer
- Prostate cancer
- Lung cancer
- Ovarian cancer
- Liver cancer
- Bladder cancer
Vitamin D is a Likely Causal Factor for Cancer Risk Reduction
The evidence associating vitamin D and cancer is so strong that vitamin D is now thought to be a causal factor in the risk-reduction of most types of cancer. Causation can be determined using Hill’s criteria for causality, a scientific set of guidelines for looking at data based on the strength of association, consistency between studies, temporality, biological gradient, plausibility, coherence with known scientific facts, experiment, and analogy. Two separate publications (WB Grant and Mohr et al.) have confirmed vitamin D as a causal risk-modifying factor for most cancers using Hill’s criteria.
How Vitamin D Fights Cancer
The active form of vitamin D, calcitriol, controls multiple pathways associated with the life cycle of the cell including those involved with reproduction, maturation and programmed death. Calcitriol regulates the production of a number of signals and growth factors at the genetic level. As detailed in the table below, some of the signals turned on by vitamin D stimulate growth, development, maturation and programmed cell death while other signals inhibit inflammation, prevent blood vessels from being made that can feed cancer cells, and stop the spread of the cancer to other parts of the body.
Specifically, calcitriol stops the uncontrolled reproduction of cancer cells by decreasing production of growth factors and increasing “stop” signals. In addition, calcitriol pushes the cell towards maturation and away from reproduction, and can also activate an internal process that starts programmed cell death in the cancerous cell. Part of the process for cancer growth and metastasis involves creating an inflammation response, building new blood vessels within the tumor, and breaking up surrounding tissue to allow the cancer to spread to other parts of the body. Calcitriol prevents inflammation, new blood vessel growth (called angiogenesis) and spread through inhibiting the signals needed.
Interestingly, some cancer cells find ways to stop vitamin D metabolism by the cell (by preventing the vitamin D receptor from being expressed, increasing the breakdown of calcitriol, or decreasing the production of calcitriol), which may help the cancer evade detection and continue to grow.
GrassrootsHealth Analysis Shows 71% Lower Cancer Risk
In April 2016, GrassrootsHealth partnered with leading vitamin D and cancer researchers Drs. Garland, Gorham, Heaney, and Lappe to publish Serum 25-Hydroxyvitamin D Concentrations ≥40 ng/ml Are Associated with >65% Lower Cancer Risk: Pooled Analysis of Randomized Trial and Prospective Cohort Study, a paper focused on achieved vitamin D serum levels and cancer incidence. Data was combined for women 55 and older from our GrassrootsHealth cohort (N = 1,135, median serum level = 48 ng/ml or 120 nmol/L) and the cohort of a previously published randomized controlled trial (RCT) of vitamin D and calcium supplementation with respect to cancer (Lappe RCT paper; N= 1,169, median serum level = 30 ng/ml or 75 nmol/L). The pooled cohort was analyzed to investigate cancer incidence over time (median = 3.9 years) for all invasive cancers combined, excluding skin cancer. Pooling the data allowed for a broader range of serum levels, more data, and thus improved statistical power.
In the analysis, without adjusting for other risk factors, we found that women with a mean vitamin D serum level greater than or equal to 40 ng/ml (100 nmol/L) had a 71% lower risk of cancer than women with serum levels <20 ng/ml (<50 nmol/L; P-value = .02). The greatest decrease in risk occurred between about 10 – 40 ng/ml (25 – 100 nmol/L).
The graph below shows the plot of cancer incidence versus vitamin D level. The blue dotted lines are called the ‘confidence interval’, the closer they are to the actual plotted line (green line) the surer we are of the data, meaning the more data points we had in this region to ensure accuracy. Because we used D*action data with the Lappe data, we had a lot of people in the 40-60 ng/ml range (our recommended range) and can say clearly that cancer incidence is much lower when vitamin D levels are within this range.
This second look at the combined data uses a Kaplan Meier curve to clearly illustrate the difference between the proportions of cancer-free participants at the end of the 4 year observation period.
The lines in the chart above represent the percent of participants without cancer for each vitamin D level group. Lines that are closer to the bottom of the chart represent higher cancer incidence and lines that are closer to the top of the chart represent lower cancer incidence.
Other Important Cancer Fighting Co-Nutrients
Don’t forget that vitamin D works along with other essential nutrients for our health. For anti-cancer effects, these include:
- Omega-3s for breast cancer and non-melanoma skin cancers
- Magnesium for breast cancer and cancer in general
- Vitamin C
Are you getting enough vitamin D and other nutrients to help prevent or reduce cancer?
With almost 90% of the general population having vitamin D levels below the recommended 40-60 ng/ml (100-150 nmol/L), it is obvious that most people need more vitamin D. While most of us cannot achieve a vitamin D level of 40-60 ng/ml from sun alone, either due to our lifestyle, where we live, or other circumstances, we can certainly reach those levels with the right amount of supplementation.
By joining the GrassrootsHealth projects, you are not only contributing valuable information to our study, but you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it. Do you know what your status of vitamin D, omega-3s, and other essential nutrients is? Could your levels be improved? Test now to find out!
How Can You Use this Information for YOUR Health?
Having and maintaining healthy vitamin D and other nutrient levels can help improve your health now and for your future. Measuring is the only way to make sure you are getting enough!
STEP 1 Order your at-home blood spot test kit to measure vitamin D and other nutrients of concern to you, such as omega-3s, magnesium, essential and toxic elements (zinc, copper, selenium, lead, cadmium, mercury); include hsCRP as a marker of inflammation or HbA1c for blood sugar health
STEP 2 Answer the online questionnaire as part of the GrassrootsHealth study
STEP 3 Using our educational materials and tools (such as our dose calculators), assess your results to determine if you are in your desired target range or if actions should be taken to get there
STEP 4 After 3-6 months of implementing your changes, re-test to see if you have achieved your target level(s)