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A 10-Year Evaluation of Oily Fish, Fish Oil, and Health

By Gretchen Vannice, MS, RDN

Around the globe……one in 20 persons under the age of 50 have it; one in 7 between age 50-70 have it, and one in 5 adults over 70 years of age have it. It does not discriminate by gender; it equally effects men and women.  It is likely you know someone who has it.

I am referring to type 2 diabetes.  Type 1 and type 2 diabetes are different conditions. About 95% of people who have diabetes have type 2.  Diabetes can be managed, but that starts with knowledge of the condition. In the USA, about one-third of people who have the condition or the precursor to it don’t know it.  What if we could reduce risk for it?  Well, in fact, we can.

It is true; if people ate ‘as-if’ they had diabetes, we would have less of it. The diet is basic: a variety of real food, balanced/not excessive intake, on a regular schedule. Like sleep and physical activity, routine is important for healthy hormone and blood sugar balance. Unmanaged type 2 diabetes is costly, both financially – doubling the cost of medical care – and in quality of life, as it can lead to early blindness and amputation. What’s more, people with type 2 diabetes are 2-3 times more likely to have depression and more than half also have heart disease.

There is good news!

While we can’t control our age or genetic history, we do control our nutrition, physical activity, daily habits and these together make a real difference.

Here, let’s focus on one group of nutrients: omega-3s from fish and fish oil. 

Research into the relationship between type 2 diabetes and omega-3 from fish oil has waxed and waned over the years. I recall an intriguing study published 18 years ago: in more than 5,000 women who had healthy hearts and type 2 diabetes, those who regularly consumed more oily fish maintained much better heart health 15 years later.

To be sure, the strong evidence that EPA and DHA omega-3 reduce symptoms of depression and significantly improve heart health are some big reasons for everyone to include oily fish and fish oil – excellent sources of EPA and DHA omega-3 – in our diets.

It was an exciting day recently when a study on oily fish, fish oil, and incidence of type 2 diabetes was published!  Let’s dive in.

Nearly 400,000 generally healthy, ethnically diverse men and women between age 37-73 years were followed for 10 years (let’s pause to note that this large number of human volunteers allows researchers to do extensive investigation). Dietary and supplement intake was measured and correlated with risk of diagnosed type 2 diabetes. In the 10 years, five formal assessments of diet and supplements were completed, enabling the researchers to get accurate, real-time assessments, and look at the impact of diet and supplement habits over time.

Here is what they discovered:

  • People who took fish oil supplements:
    • At one time point over the 10 years, had a 9% lower risk for type 2 diabetes
    • At the beginning and one other time point over the 10 years, had a 15% lower risk
    • At the beginning and two other time points over the 10 years, had a 22% lower risk
    • At the beginning and three or more other times, had a 23% lower risk
  • When it came to including fish in the diet:
    • People who consumed oily fish two or more times per week had a 22% lower risk for type 2 diabetes, compared to those who never ate oily fish
    • Indeed, each additional weekly serving of oily fish lowered risk by an average of 8%
    • There was no association between risk and eating nonoily fish

Anyone questioning the evidence on the relationship between diet and fish oil supplement use on incidence and risk for major, costly, and life-altering events need not look any further.

Gretchen Vannice is the Director of Nutrition Education and Research for Wiley Companies.  She is a globally recognized expert, author, and speaker in omega-3 research and education.

Disclaimer: This information is offered for educational purposes only. It is the opinion and scientific interpretation of the author. It is not intended as medical advice of any kind. The educational information provided is not intended to diagnose, treat, mitigate, or cure any disease nor has this been reviewed or approved by the FDA.

Scientific References are available upon request.