# Effects of Nutritional Supplementation on Tumor Growth: A Systematic Review and Meta-Analysis of Studies Using Animal Models of Mammary Cancer

## TL;DR

This study finds that dietary supplements like fish oil and shark liver oil can significantly reduce tumor growth in animal models of breast cancer.

## Contribution

The study provides a meta-analysis showing that specific nutritional supplements significantly inhibit tumor growth in the Walker-256 mammary cancer model.

## Key findings

- Nutritional supplements significantly reduced tumor growth in Walker-256 models.
- Fish oil and shark liver oil had the strongest inhibitory effects on tumor growth.
- Amino acids and linoleic acid-rich supplements also showed promising anti-tumor effects.

## Abstract

Breast cancer is the most common type of cancer affecting women worldwide. To develop new treatments, researchers often use experimental tumor models before clinical studies. The Walker-256 tumor model is commonly used because it shares similarities with human carcinoma and grows quickly, allowing efficient testing. In this systematic review and meta-analysis, we examined 21 studies and performed a detailed analysis of 12 of them to investigate whether dietary supplements could reduce tumor growth. We found that many supplements, particularly fish oil and shark liver oil, significantly reduced tumor growth. Other supplements, including amino acids and those rich in linoleic acid, also showed promising effects. We conclude that nutritional supplementation has the potential to reduce tumor growth in Walker-256 models.

Breast cancer remains the most prevalent malignancy among women worldwide, and experimental tumor models are essential for evaluating new therapeutic approaches before clinical application. The Walker-256 carcinoma model exhibits biological behavior comparable to human carcinoma and allows short-term assessment of tumor progression. This study aimed to conduct a systematic review and meta-analysis of the effects of dietary supplementation on Walker-256 tumor growth. We followed the PRISMA guidelines and searched the PubMed, Embase, and Cochrane databases without time restrictions. The meta-analysis included clustering based on the type of supplementation received, comparing treatment groups with control groups. Twenty-one studies were included, analyzing 18 different supplements, and 12 studies were considered for quantitative synthesis. The overall effect indicated a significant reduction in tumor growth with supplementation (SMD = 2.83, 95% CI = 1.99–3.66, p < 0.001), despite high heterogeneity (I2 = 93.3%). Oils had the greatest impact, particularly fish oil (SMD = 6.99, 95% CI = 3.15–10.83, p < 0.001) and shark liver oil (SMD = 4.43, 95% CI = 2.19–6.67, p < 0.01).