Diabetes Self-Management Blog

Last week (in "Essential Fatty Acids: What You Need to Know [Part 1]"), we looked at the difference between omega-3 and omega-6 fatty acids — the "backbones" of fats, so to speak. This week, we’ll take a closer look at the omega-6 fatty acids.

Sources of Omega-6 Fatty Acids
As I mentioned last week, the typical American diet is proportionally too high in omega-6 fatty acids compared with omega-3’s. While the ideal ratio would be 1:1, even something closer to a 4:1 ratio would be much better for us than what we’re consuming now.

Where do we get all these omega-6 fatty acids, anyway? Most of our intake of these essential fatty acids (or EFA’s) comes from vegetable oils: soybean, safflower, sesame, and corn oil, as well as from nuts, seeds, and some vegetables. The main omega-6 fatty acid in these foods is linoleic acid (LA). The body converts linoleic acid to gamma-linolenic acid (GLA), which then can be broken down into arachidonic acid (AA) and other substances.

GLA: The Good Guy
Even though we get too many omega-6’s in our diets, GLA is considered the “good guy,” in a sense, because it helps to reduce inflammation in the body. (Remember that inflammation can lead to a whole host of problems, such as heart disease, Type 2 diabetes, asthma, and arthritis.). GLA is used by the body to make eicosanoids, substances (such as prostaglandins) that are highly anti-inflammatory and that can reduce blood clots. It’s thought that Americans don’t get enough of this particular EFA.

GLA is found in evening primrose oil, black currant oil, and borage oil, as well as in spirulina, or blue-green algae. These oils are available in capsule form and are taken as dietary supplements. Let’s look at the more popular supplements: evening primrose oil, borage oil, and black currant oil.

Evening Primrose Oil (EPO)
EPO, which contains between 8% and 10% GLA, has been used for many years as a treatment for eczema, and is actually an approved treatment for many skin disorders in other countries. More recently, EPO has been used to help treat other conditions, such as rheumatoid arthritis, cancer, breast pain, PMS, and diabetic neuropathy. Unfortunately, there’s no good evidence supporting the use of this EFA for these conditions. Fortunately, EPO is considered to be quite safe, with the main side effects being gastrointestinal upset and headache. However, anyone with a seizure disorder should not take EPO, as this EFA may increase the risk for seizures. And pregnant women should avoid taking EPO as well.

Borage Oil
Borage oil (also known as borage seed oil or starflower oil), another source of GLA, comes from the borage plant, a large plant with blue flowers found throughout North American and Europe. Borage oil is the richest source of GLA, containing between 20% and 26% of this EFA. Like EPO, borage oil has been used to treat various skin disorders, and has been used with success in infants with dermatitis. And borage oil may be helpful for some people with rheumatoid arthritis. Side effects include nausea, indigestion, and headache. Long-term use may lead to liver damage. As with EPO, pregnant women and anyone with a seizure disorder should avoid taking borage oil.

Black Currant Oil
Black currant oil is derived from the seeds of the black currant. This oil contains about 15% to 20% GLA, and, as with its other cousins, is used to treat rheumatoid arthritis. It’s also used to help treat skin disorders, PMS, and menopausal symptoms. Black currant oil may possibly help lower blood pressure, although you shouldn’t take this without first checking with your physician. Black currant oil is relatively safe, but again, pregnant women and people with a history of seizures should not take it.

In addition, people taking cyclosporine, certain antibiotics, chemotherapy for cancer, medication for schizophrenia, and nonsteroidal anti-inflammatory medications (such as ibuprofen) should probably not take any of these EFA supplements due to possible serious drug interactions.

More on EFAs next week!


Essential Fatty Acids: What You Need to Know (Part 1)
Essential Fatty Acids: What You Need to Know (Part 2)
Essential Fatty Acids: What You Need to Know (Part 3)
Essential Fatty Acids: What You Need to Know (Part 4)

  1. Dear Amy.

    Is the great excess in our omega 6 consumption if we eat a lot of veggy oils like canola a serious problem ?

    Some people on a good diabetic blog site even suggest going back to lard or coconut oil. Which have very little polyunsaturated fats. Some blame our present consumption of omega 6 causing inflammation of the arteries and our present increase in cardio vascular events.

    This goes against the grain of what I have been told and seen over the years. My father who had severe artherosclerosis in the 1960’s was put on a heavy diet of corn oil by the Cardiac institute of Montreal a Research and treatment group. The only other veggy oil available at that time was olive. He got much better and lived into his late 70’s. Now I think corn oil is frowned upon because of way too much omega 6.

    I like canola because of the low saturated fat and lower ratio of omega 6 / omega 3. It is relatively cheap and of neutral taste for most applications. My wife makes a canola butter mix that is even acceptable to his furriness a very fussy gourmet. Are we making a big mistake?

    Posted by CalgaryDiabetic |
  2. Hi,

    I just read this information about omega-6 fatty acids that you might find of interest:
    The American Heart Association is saying that omega-6 fats aren’t as harmful as some might make them out to be. Omega-6 fatty acids can be both anti and pro-inflammatory, if that makes sense. Studies have shown that people who eat diets high in omega-6 fatty acids have less heart disease. But part of the issue is that we tend to not eat enough omega-3 fatty acids. So, I don’t think using canola oil is a problem. But you should make sure you get sources of omega-3s in your diet, too.

    Posted by acampbell |
  3. Dear Amy.

    Thanks a lot for this reference I will pass it on. The article does seem to put the worry to rest.

    Posted by CalgaryDiabetic |

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