New research published in the scientific journal Clinical & Experimental Metastasis states that a diet rich in marine omega-3 fatty acids helps in slowing the growth and spread of breast cancer cells in female mice. Diets enriched with omega-3 also improved the survival of mice in cases of breast cancer. Reportedly, the fatty acids were said to have delayed tumours from forming and further blocked cancerous cells from spreading to other organs in mice.
Research, in the past, has hailed the numerous benefits of a diet rich in omega-3 fatty acids. Such fatty acids are generally found in fish, seafood, nuts and seeds, as well as in fish oil, plant oils and some fortified foods. Researchers have explored the link between omega-3 and cancer; their observational studies have linked diets rich in marine omega-3 fatty acids with a lower risk of breast cancer. Recent studies have also suggested that omega-3 fatty acids may stop cancer by activating the body’s natural pain-killers. “Our study emphasizes the potential therapeutic role of dietary long-chain omega-3 fatty acids in the control of tumor growth and metastasis,” explained lead author Saraswoti Khadge, of the University of Nebraska Medical Centre (USA). By conducting experiments in mice, this new study has added to the mounting evidence that dietary omega-3 may have cancer-fighting properties.
The research team fed two groups of adult female rodents nearly identical liquid diets for which the calorie count and percentage of fat contained were same. However, the main difference was that one group ate a diet contained plant oils rich in omega-6 polyunsaturated fats while the other diet contained fish oil rich in omega-3 fatty acids. The researchers then injected the mice with 4T1 breast cancer cells which spread quickly to form aggressive tumours in the breast glands. These cells are known to spread spontaneously to other parts of the body, such as bones, the lungs and liver, but less frequently to the heart, kidneys and ovaries. After a period of 35 days, the researchers autopsied the mice to uncover the effects of the two diets.
The research team found that, in the group of mice that were fed omega-3 rich diet, breast cancer cells were significantly less likely to have spread to the breast glands. In these mice, the tumours that did develop in the breast glands also grew a lot more slowly which affected their size. Specifically, the tumours in the omega-3 group were 50% smaller than those in the omega-6 group. The likelihood of the cancerous cells growing and spreading to other organs in the omega-3 group was also lower and these mice also had better survival rates.
Furthermore, relatively more T-cells were found in the tissue of the mice in the omega-3 group than in the tissue of omega-6 group; this correlates to dying tumour cells. T-cells are anti-inflammatory white-blood cells that play a crucial role in keeping the immune system strong and healthy. Interestingly, the mice fed an omega-3 diet also had less inflammation. Hence, Ms Khadge has hypothesised that a diet rich in fish oil may help in suppressing the type of inflammation that can trigger the rapid development and spread of tumours as well as promote T-cell responses to tumours. However, she cautions that this does not necessarily mean that the diet would also prevent breast cancer from forming in the first place.
This study was based entirely on dietary consumption during adult life. Its findings, however, are in line with previous studies that showed that eating fish oil-based diets during pregnancy, and as a child, markedly suppress the development and spread of breast cancer.