Antioxidant-rich food lowers risk of gastric cancer

Eating foods that are rich in antioxidants appears to reduce the risk of gastric cancer (GC), suggests a recent study.

“Increased consumption of vitamin C- and selenium-rich foods may represent effective dietary strategies for GC prevention, particularly in high-risk populations and regions with high GC incidence,” the investigators said.

A total of 336 newly diagnosed GC patients were recruited from a hospital in Southeast China for this case–control study conducted from July 2023 to November 2024. Participants were sex-matched to 336 healthy controls selected from local communities. 

The investigators obtained dietary data from a validated food frequency questionnaire. These data were then used to calculate composite dietary antioxidant index (CDAI) scores.

Of the participants, 56.5 percent were male. The mean CDAI value was 0.47 in GC patients and –0.04 in controls (p=0.134). However, the CDAI quartile distribution significantly differed between groups (p=0.009). [Nutrients 2025;17:3473]

Multivariable analysis of CDAI components revealed a significant inverse relationship between vitamin C intake and GC risk, with the strongest protective effect seen in the highest quartile (odds ratio [OR], 0.48, 95 percent confidence interval [CI], 0.30–0.77; p=0.002).

Selenium intake also had significant protective benefits, particularly in the second (OR, 0.52, 95 percent CI, 0.32–0.83; p=0.006) and third quartiles (OR, 0.50, 95 percent CI, 0.30–0.82; p=0.006).

Compared with the lowest CDAI quartile, the second (adjusted OR, 0.56, 95 percent CI, 0.36–0.87), third (adjusted OR, 0.59, 95 percent CI, 0.38–0.90), and fourth (adjusted OR, 0.60, 95 percent CI, 0.39–0.92) quartiles correlated with greater reductions in GC risk.

The protective effect of antioxidants against GC risk appeared to be more pronounced in participants aged >55 years, those who were unmarried, and nonsmokers. Furthermore, a significant nonlinear dose–response relationship was observed in restricted cubic spline analysis.

“In summary, this case–control study demonstrated that higher CDAI scores, indicative of antioxidant-rich diets, were significantly associated with lower GC risk,” the investigators said. 

“These findings provide scientific evidence for dietary prevention and intervention strategies targeting oxidative stress in GC,” they added.

Mechanisms

Vitamin C, a water-soluble antioxidant, “scavenges” reactive oxygen species and lessens oxidative DNA damage in the gastric mucosa. It also prevents the reaction between nitrite and amines in the stomach, which inhibits the endogenous formation of carcinogenic N-nitroso compounds. [Int J Biochem Cell Biol 2007;39:44-84; Int J Mol Sci 2020;21:6451]

On the other hand, the anticancer effects of selenium are facilitated through its role as an “essential component of selenoproteins.” These antioxidant enzymes, such as glutathione peroxidases and thioredoxin reductases, protect the gastric mucosal DMA from oxidative damage and modulate tumour-related signalling pathways. [Lancet 2012;379:1256-1268; Physiol Rev 2014;94:739-777]

“Public health initiatives should integrate antioxidant-rich dietary guidance into chronic disease prevention frameworks, especially in GC-endemic regions,” the investigators said. 

“Community-level interventions, including systematic nutritional assessments, personalized dietary recommendations, and early nutritional risk screening, may enhance public awareness of the link between dietary antioxidants and cancer risk,” they added.