Higher vitamin C intake lowers your risk of stomach cancer

Stomach cancer is rather common and is a disease with a poor prognosis. There are many things that cause the condition. However, vitamin C is known to reduce the risk, according to a large analysis published in Gastric Cancer. The study also shows that we need a lot more vitamin C than the official recommendations in order to obtain optimal protection against stomach cancer.

Stomach cancer is caused by cellular changes in the gastric mucosa. The disease is the fifth-most common cancer form globally and the fourth-most frequent cause of cancer-related deaths. In 2020, there were more than one million new cases and 777,000 deaths. More and more people get stomach cancer. Although it primarily affects older people, this cancer form is gaining foothold among people younger than 55 years of age. The prognosis is poor, as only around half the patients survive more than one year, while 25 percent are alive still after five years.
Earlier studies show that alcohol abuse and a high salt intake, infection with the Helicobacter pylori bacterium, and enlarged waist circumference can increase the risk, whereas an increased intake of fruit and vegetables does the opposite and lowers the risk. This is ascribed to the fact that this type of food contains different antioxidants that counteract oxidative stress and cell damage caused by free radicals. There has been a lot of focus on vitamin C, which is primarily found in citrus fruits, red bell pepper, and certain other vegetables. Vitamin C is a very powerful antioxidant and supports a host of different metabolic processes.

Much higher vitamin C intake protects against stomach cancer

The new study is a so-called pooled analysis that gathers data from several epidemiological studies. The researchers collected data from 14 studies, including 5,262 patients with stomach cancer and 11,497 healthy controls. Using food frequency questionnaires (FFQ), they compared the participants’ dietary vitamin C intake with the rate of stomach cancer. The participants were divided into four quartiles, depending on their vitamin C intake. Vitamin C supplementation was excluded from the analysis, as there is limited information about this. The scientists also adjusted for confounding factors such as gender, age, BMI, smoking habits, and alcohol intake.
The study showed that the quartile with the highest dietary vitamin C intake had the lowest risk of stomach cancer compared with the quartile with the lowest vitamin C intake. This was the case for different types of stomach cancer. According to the analysis, daily intake of vitamin C in the range of 150-200 mg lowers the risk of stomach cancer. The best effect is seen with an intake of around one gram of vitamin C. For the record, this is way above the official recommendation for vitamin C intake, which is 80 mg for adults.

Vitamin C’s functions and its ability to protect against stomach cancer

Vitamin C is an essential, water-soluble vitamin that functions as a unique antioxidant and even serves as a pro-oxidant (in much smaller concentrations). Vitamin C is important for cell protection and a host of different metabolic processes such as collagen and carnitine synthesis, intestinal iron uptake, production of neurotransmitters in the nervous system, the metabolism of the amino acid tyrosine, and for demethylation of protein.
In the stomach, vitamin C may offer a protective effect by reducing oxidative stress and DNA damage. Vitamin C is also able to prevent the formation of different carcinogens such as nitrosamines (NOCs) from nitrite that is a food additive used to preserve meat and cold cuts. Vitamin C is also important for the immune system and helps it to fight harmful microorganisms and toxins from food and beverages, thereby preventing them from causing harm to the gastrointestinal tract. Vitamin C also appears to protect against infection with the Helicobacter pylori bacterium that is considered one of the major causes of stomach cancer.

Reference:

Michele Sassano et al. Dietary intake of vitamin C and gastric cancer: a pooled analysis within the Stomach cancer Pooling (StoP) Protect. Gastric Cancer. 2024