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NMU 303 – Vitamin D Supplementation Reduces Cancer Relapse and Death in High-Risk Intestinal Tract Cancer Survivors (Colo-Rectal, Stomach, Esophageal, Small Bowel Cancer Survivors)

Nutrition/Natural Medicine Update No 303 (September 12, 2023)

with Dr. James Meschino

Topic: Vitamin D Supplementation Reduces Cancer Relapse and Death in High-Risk Intestinal Tract Cancer Survivors (Colo-Rectal, Stomach, Esophageal, Small Bowel Cancer Survivors)

Source: Journal of the American Medical Association (JAMA) August 22, 2023


In previous Lifestyle Medicine Updates, I have cited the emerging research showing how vitamin D may help to reduce risk of certain cancers. The research paper published in JAMA in August 2023 provides further evidence of vitamin D’s protective effects in this regard. So, I wanted to share it with you. The study showed that providing patients who underwent surgery for their digestive tract cancer (colo-rectal cancer, stomach cancer, esophageal cancer or small intestine cancer) with 2,000 IU of vitamin D daily following the surgery, resulted in reduced risk of cancer relapse or death by 73% compared with patients taking the placebo. But these positive results were limited to patients showing positivity for what is called p53 immunoreactivity. This means that in many cases of cancer the p53 tumour suppressor gene is mutated or dysfunctional. In these cases, the immune system produces antibodies against the abnormal protein produced by the faulty p53 gene. These p53 gene defects and serum antibodies against p53 proteins can be detected with our modern-day technologies.  As a rule, cancers showing a high degree of p53 immunoreactivity tend to be more advanced and more life-threatening.

The good news from this study is that providing patients with 2,000 IU of vitamin D, who had p53 positive immunoreactivity (very high-risk patients) significantly reduced their risk of cancer relapse or death, once their digestive tract cancer was dealt with via surgical resection. Regarding Vitamin D’s overall effects on cancer and immunity the researchers stated, “Vitamin D was previously demonstrated to upregulate innate and adaptive immunity. A meta-analysis of randomized clinical trials (RCTs) showed that vitamin D supplementation reduced the incidence of acute respiratory tract infection compared with placebo.  In addition, vitamin D supplementation reduced the risk of relapse in the subgroup of patients who had sufficient infiltration of immune cells into the tumour microenvironment in our previous research. They also noted that in Vitamin D and Omega-3 Trial (VITAL) study, 2000 IU of vitamin D3 administered daily reduced all cancer mortality by 25% when the first 2 years of observation were excluded. As well, a 2023 meta-analysis of randomized clinical trials (RCTs) found that daily vitamin D3 supplementation was associated with reduced cancer mortality in the general population and improved survival in patients with cancer, although the results are still controversial, and they stated that the beneficial effects of vitamin D have been reported for cancers at various sites in the human studies.

The present study included 392 patients with a history surgically treated colo-rectal cancer (47%), gastric or stomach cancer (43%), esophageal cancer (9%) and small bowel cancer (05%). The post hoc analysis found that, among the p53- positive immunoreactive group of 80 patients, relapse or death occurred in only nine of the 54 patients (relapse or death in only 17%) in the vitamin D supplemented group and 14 of 26 patients (54% had relapse or death) in the placebo group. The 5-year relapse free survival (RFS) was significantly higher in the vitamin D group than the placebo group (81% vs 31%). As such, in the p53-immunoreactive subgroup, daily vitamin D supplementation (2,000 IU per day after surgery) reduced the risk of relapse or death by 73%. That is a remarkable reduction. As one of the researchers stated, “The main findings of this study were that daily supplementation of 2000 IU of vitamin D reduced the risk of relapse or death compared with placebo in the p53-immunoreactive subgroup, and “suggest the importance of developing cancer immunotherapy targeting mutated p53 proteins.”

I think the take-away message is once again to ensure that your vitamin D blood level is in the ideal range, which is between 75-150 umol/L (30-60 ng/ml).

This level of vitamin D is most strongly associated with a reduced risk of severe infection and certain types of cancer. It also helps to reduce risk of osteoporosis. Most people can achieve this level by simply supplementing with 2,000 IU of vitamin D per day. I have included the JAMA research reference in the text below.


Kanno K et al. Effect of vitamin D supplements on relapse or death in a p53-immunoreactive subgroup with digestive tract cancer. Post Hoc Analysis of the AMATERASU Randomized Clinical Trial. JAMA. August 22, 2023.

“Game Changer: Data for Vitamin D in Digestive Tract Cancers. Medscape. September 11, 2023. Megan Brooks (August 25, 2023):


Eat Smart, Live Well, Look Great,
Dr. Meschino

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