Omega 3 fats obesity cure?

FishMarketAre omega-3 fats the solution to obesity?

That’s the gist of an editorial published in a recent edition of Open Heart/British Medical Journal.  The authors, Artemis Simopoulos MD and James DiNicolantonio, PharmD argue that processed food and industrial agriculture have changed the fatty acid balance in our diets, drastically increasing consumption of omega-6 fatty acids from vegetable oils, while decreasing omega-3 intake.

Omega-3 fatty acids are concentrated in a few foods like fatty fish, flax seed and walnuts.  Long ago, animal-sourced foods, from meat to eggs to dairy foods, would also have contained some omega-3 fats if the animals grazed on plants that had those.  Processed foods didn’t exist.  High omega-6 vegetable and seed oils were not in wide use.  According to the authors, the omega-6-to-omega-3 ratio in our diets has gone from roughly 1:1 to 16:1 as a direct result of increased consumption of omega-6-rich vegetable oils by humans, and use of omega-6-rich grains, like corn and soy, to feed livestock.

So why is high omega-6 intake a bad thing?  The editorial includes a table that compares the different metabolic effects of omega-6 vs. omega-3 fatty acids.  For all of the 20 systems listed, these two fatty acid types have opposing effects.  For example:

Omega-3: decreases fat cells, inflammation, triglycerides and insulin resistance

Omega-6: increases all of the above.

The authors argue that omega-6 fatty acids fundamentally change human metabolism, increasing inflammation, insulin resistance, fat storage and triglycerides.  They point to studies linking higher blood levels of omega-6 fatty acids with weight gain.  Worse, some people are genetically predisposed to be especially sensitive to a high omega-6 intake, exacerbating the adverse effects.

The argument about omega-6 vs omega-3 fats sounds pretty simple and compelling.  But keep in mind, many other things have changed about our diets and lifestyle.  According to another chart included with the article, we’re eating more total fat and saturated fat.  Plus we’re eating more salt and refined sugar, and we’re much more sedentary.  And we’re just now starting to appreciate the effects of the gut microbiome on health and metabolism.  Eating a more processed and refined diet, with less fiber and fewer whole foods has certainly impacted the balance of gut microbes.

It’s not about pills

This editorial doesn’t suggest that adding a few fish oil pills to your daily diet is going to make a difference.  Changing the ratio of omega-6-to-omega-3 fats is about changing your whole diet to reduce your intake of omega-6 fats from vegetable oils and meats.  Omega-6 fats predominate because our entire food supply has changed drastically over the past 100-odd years, from one based mostly on simple whole foods to one based on processed foods.  Particularly foods made with or cooked in vegetable oils: chips, fries, doughnuts, cookies, cakes, pastries, pies, crackers, snack foods, margarine, shortening, breaded foods, fried foods, snack/granola bars, sauces and gravies, mayonnaise, and … whew!   This list could go on and on.

So how does this translate into actual food choices?  If you can’t eat all that stuff, what’s left?  It’s probably not practical to attempt to eat a diet with a 1:1 O6:O3 fatty acid ratio.  Even in Japan — where high omega-3 fish are a dietary mainstay — the ratio is around 4:1.  Here are some steps you can take to reduce your consumption of omega-6 fats.

  • Use canola oil instead of corn, soy or other vegetable oils.  It’s higher in the alpha linolenic acid, an omega-3 fat.
  • Use primarily mono-unsaturated olive oil for salad dressings or cooking.
  • Avoid commercially fried foods like french fries, breaded fish, chicken and the like.
  • Avoid fatty snack foods like chips.
  • Limit use of mayonnaise and salad dressings made with vegetable oils.
  • Avoid/limit commercial bakery products, especially higher fat items like cakes, cookies, pastries, crackers and pies made with vegetable shortening.
  • Limit use of margarine and other vegetable shortenings
  • At restaurants, avoid foods cooked on a griddle using vegetable oils/shortening, such as pancakes, hash browns, eggs, sautéed meats or vegetables.
  • Look for alternative products made with canola or olive oil.

You can also make an effort to increase omega-3 intake by eating more fatty fish like salmon or sardines or adding walnuts or flax to your diet.  You can look for speciality eggs or meats from animals fed omega-3 fats.  There are claims that grass-fed beef is higher in omega-3 fats, but there is no standard for this claim, so don’t rely on unsubstantiated claims. Another solution: omega-3 supplements.  This is a choice plenty of people are making, but capsules will not fix a high omega-6 diet.  You’d still need to make an effort to reduce consumption of all those omega-6 sources.

If you make many of these changes, will you lose weight?  You might, but it won’t be drastic or fast.  Weight loss is still a complex problem, depending on calories, exercise, dietary composition, genetics and possibly gut microbes.  Lowering your omega-6-to-omega-3 ratio might help, but it isn’t the sole solution.

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