Gastric cancerPatient friendly summary

  • Sunlight has a direct effect on reducing stomach cancer risk.
  • Vitamin D has been shown to block cancer growth and spread.
  • Vitamin D levels greater than 40 ng/mL (100 nmol/L) may reduce the risk of stomach cancer.

Stomach (gastric) cancer is a moderately important cause of disease and death. In the United States each year, it affects about 21 thousand people and kills approximately 11 thousand.

Risk factors

Of the many risk factors associated with gastric cancer, the most important include:

  • Helicobacter pylori bacteria infection is the leading cause of stomach cancer. It can be eliminated with antibiotics.
  • Smoking: Smoking is associated with risk of stomach cancer.
  • Salt and salted food intake is associated with stomach cancer.
  • Exercise is protective against stomach cancer.
  • Obesity: Obesity is a weak risk for stomach cancer.
  • Dried fish, meat, and simple carbohydrates such as sugar are associated with increased risk of stomach cancer.
  • Diet-eating fruits and vegetables and high fiber grain products reduces the risk of stomach cancer.

Sunlight exposure and stomach cancer risk

Sunlight has a direct effect on reducing risk of many types of cancer.

The shortwave ultraviolet portion of sunlight, ultraviolet-B (UVB), stimulates the body to produce vitamin D, which protects against cancer.

Many ecological studies (comparison of disease rates where people live to disease risk factor values) have found lower rates of stomach cancer with respect to higher amounts of ultraviolet-B (UVB) from sunlight. Such studies were conducted in China, Japan, and the United States.

Vitamin D and stomach cancer

Vitamin D levels

No study has reported reduced risk of stomach cancer with higher vitamin D blood levels. In fact, observational studies in China found an increased risk of stomach cancer associated with higher vitamin D blood levels. This finding may be explained by some risk factors not included in the study.

The rates of breast, colon, and rectal cancer decrease rapidly as vitamin D levels increase from very low levels [less than 10 ng/ml (25 nmol/] out to 20-30 ng/ml, then decreases at a slower rate until levels reach about 50 ng/ml (150 nmol/l). No comparable findings have been reported for other types of cancer. However, it is assumed that they behave in a similar manner.

How vitamin D works

Vitamin D has been shown to block the growth of cancer tumors. Calcitriol, an active form of vitamin D, is produced by the body from vitamin D processed by the liver. Calcitriol provides numerous benefits against cancer. This form of vitamin D encourages cells to either adapt to their organ or commit apoptosis (cell suicide). Calcitriol also limits blood supply to the tumor and reduces the spread of cancer. 


High levels of vitamin D are associated with a lower risk of many types of cancer and reduced tumor growth.

Based on studies of breast, colon, and rectal cancer, vitamin D levels of 40–60 ng/mL (100–150 nmol/L) may reduce the risk of cancer. Taking 1000–4000 international units (IU) (25–100 mcg)/day raises vitamin D levels to those amounts for most people.

Vitamin D and calcium

There is evidence that calcium is also associated with reduced risk of stomach cancer.


People with higher vitamin D levels at time of cancer diagnosis often have a higher survival rate. This has been verified for people with breast, colorectal, lung, and prostate cancer; non-Hodgkin’s lymphoma; and melanoma. These studies suggest that increasing vitamin D levels after cancer diagnosis may improve chances of survival.

Some cancer treatment centers are now giving at least 5000 IU (125 mcg)/day vitamin D3 (calcitriol) to patients with cancer. Outcome results have yet to be published.

Find out more...

Do you want to find out more and see the research upon which this summary is based?  Read our detailed evidence summary on gastric cancer.

Page last edited: 16 January 2012