Can Eating Certain Fish Reduce Risk?

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Omega-3 fatty acids, also called n-3 polyunsaturated fatty acids (n-3 PUFA), are important nutrients involved in many body functions, especially immune system responses. Your body doesn’t produce n-3 PUFA and must get them from the food you eat.

The highest concentrations of n-3 PUFA are in cold water fish such as sardines, salmon, herring, and mackerel. These fatty acids are also found in lower concentrations in plant foods such as flaxseed, walnuts, kidney beans, and navy beans.

A study suggests that eating one to two portions a week of cold water fish that are rich in n-3 PFA is linked to a 14% reduction in breast cancer risk later in life. n-3 PUFA from plants didn’t seem to affect risk.

The study was published online on June 27, 2013 by BMJ. Read the abstract of “Intake of fish and marine n-3 polyunsaturated fatty acids and risk of breast cancer: meta-analysis of data from 21 independent prospective cohort studies.”

This study was a meta-analysis – a study that combines and analyzes the results of many earlier studies. In this case, results from 21 studies involving nearly 900,000 people were analyzed.

While the results are encouraging, other researchers have some questions about the study:

  • The 21 studies that were analyzed used very different methods to estimate how much n-3 PUFA the people in the studies were eating. So the actual amount of n-3 PUFA in each person’s diet could be dramatically different.
  • The studies lasted for different times, so there was no average follow-up time for the meta-analysis. So we don’t know if the link between risk reduction and eating n-3 PUFA in fish lasted for decades, years, or months.
  • Many of the studies didn’t adjust for other factors that can affect breast cancer risk, such as body mass index, drinking alcohol, and family history. So it’s not clear if eating n-3 PUFA from fish was the only thing affecting risk in the studies.

This study doesn’t prove that eating fish rich in n-3 PUFA will lower the risk of breast cancer. It could be that women who ate fish also took other steps that kept their risk of breast cancer as low as it could be, such as not smoking or drinking, maintaining a healthy weight, and exercising regularly. More research is needed so doctors can understand the association between n-3 PUFA and lower risk.

To keep your risk of breast cancer as low as it can be, it makes sense to make healthy diet and lifestyle choices, including:

  • eating a diet low in added sugar and processed foods
  • eating a diet rich in unprocessed, nutrient-dense foods
  • exercising regularly at the highest intensity level you’re comfortable with
  • avoiding alcohol
  • not smoking

For more information on other risk-lowering steps you can take, visit the Breastcancer.org Lower Your Risk pages.

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