Omega-3 in Fish May Lower Risk of Breast Cancer

Salmon on cutting board with sea salt and onions
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“Fish in the hands of a skilled cook can become an inexhaustible source of gustatory pleasures.” -- Jean-Antheleme Brillat-Savarin, The Physiology of Taste

What is Omega-3 Fatty Acid?

Fish is a good source of protein and unlike meats, it's not high in saturated fats and extra calories. It also contains omega-3 fatty acids, which have numerous health benefits, including possibly reducing a person's risk of developing certain cancers and protecting a person's heart.

 

The two types of omega-3 fatty acids are:

  • eicosapentaenoic acid, or EPA
  • docosahexaenoic, or DHA 

How Did a Potential Link Between Omega-3 and Breast Cancer Come About?

Curiosity over the health benefits of omega-3 fatty acids began when scientists saw that higher rates of breast cancer occurred in western societies, as opposed to low rates in Japan, Alaska, and Greenland, where people consume diets high in marine omega-3 fatty acids.

In addition, studies have found an increase in the presence of breast cancer in people who moved from countries where there were low rates of breast cancer to western countries and/or if they adopted a western diet.

Does a Diet High in Fatty Fish Prevent Breast Cancer? 

The answer is still somewhat unclear, but very promising. According to a 2013 meta-analysis in BMJ, which analyzed 16 other studies, people who consumed high intakes of omega-3, as compared to people who consumed low omega-3, had a decrease in their breast cancer risk.

 

The "why" behind this is still unclear, but it's likely that a diet rich in omega-3 fatty acids causes a reduction in inflammation and inhibits certain factors that promote cancer growth. 

It's interesting to note that more research is being done on the role omega-3 fatty acids plays once a woman is diagnosed with breast cancer — like whether supplementation can improve chemotherapy-induced loss of muscle or nerve pain.

For instance, one 2014 small study in Nutrition and Cancer found that a high intake of omega-3 fatty acid — 3 grams per day — reduced bone loss in women taking aromatase inhibitors. Aromatase inhibitors are a common hormone therapy given to postmenopausal women with estrogen receptor-positive breast cancer to prevent breast cancer recurrence.

What Other Health Benefits Does Omega-3 Have?

Scientific data also supports the role of omega-3 in reducing blood pressure, triglycerides levels, fatty deposits buildup in a person's arteries, and irregular heart beats. It may also improve brain function and help reduce joint symptoms in inflammatory arthritis, like rheumatoid arthritis

Is There Good Fish and Bad Fish?

Yes. Not all fish are equally good for your diet. The healthiest fish, with the most omega-3 fatty acids live in cold water such as cool streams or oceans. These are not the largest fish, but they are readily available fresh, frozen and canned, and have the least amounts of mercury. Examples include:

  • salmon, wild or canned
  • shrimp
  •  tuna
  • pollock
  • catfish
  • sardines
  • mackerel
  • herring
  • seabass

According to the American Heart Association, larger, warm water fish, like king mackerel, shark, tilefish, and swordfish, tend to have higher levels of mercury, polychlorinated biphenyls (PCBs), dioxins, and other environmental pollutants. Steer clear of the big fish, or have small servings of these only on special occasions.

What Should I Do?

Talk with your doctor about whether increasing fish in your diet would be helpful. Remember do not take any supplements without consulting your personal physician first.

“Last year I went fishing with Salvador Dali. He was using a dotted line. He caught every other fish.” -- Steven Wright, comedian

Sources:

American Heart Association. (2015). Fish and Omega-3 Fatty Acids. Retrieved October 15th 2014.
The Importance of the Omega-6/Omega-3 Fatty Acid Ratio in Cardiovascular Disease and Other Chronic Diseases. Artemis P. Simopoulos. Experimental Biology and Medicine 233:674-688 (2008).

Fabian CJ, Kimler BF, & Hursting SD. Omega-3 fatty acids for breast cancer prevention and survivorship. Breast Cancer Res. 2015 May 4;17:62.

Hutchins-Wiese HL et al. High-dose eicosapentaenoic acid and docosahexaenoic acid supplementation reduces bone resoprtion in postmenopausal breast cancer survivors on aromatase inhibitors: a pilot study. Nutr Cancer. 2014;66(1):68-76.

Yates CM, Calder PC, & Ed RG. Pharmacology and therapeutics of omega-3 polyunsaturated fatty acids in chronic inflammatory disease. Pharmacol Ther. 2014 Mar;141(3):272-82.

Zheng JS, Hu XJ, Zhao YM, Yang J, & Li D. Intake of fish and marine n-3polyunsaturated fatty acids and risk of breast cancer: meta-analysis of data from 21 independent prospective cohort studies. BMJ. 2013 Jun 27;346:f3706.

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