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Food for Thought: Are Polyunsaturated Oils Healthy?

Fat Full Fall

Anyone want to disagree with me? Question my research? Please, do. Really. This may sound confrontational at first, but I truly appreciate and welcome those wiser than me helping me understand the science of nutrition and sharing other sources that I may not have discovered on my own. I’m not a researcher. I love reading books, but that and an elementary teaching degree are about the only qualifications I bring to the table as far as science goes.

If you read my posts when they first come out or via email only, you may have missed some fascinating discussion on grassfed beef and dairy, saturated fats (and fats in general), and oxidized cholesterol and homogenized milk. I’m counting on some of those commenters to help me fill in the gaps that I’m sure are evident in my research today. I’m tackling a big subject, and one rich with controversy. (Catch up on the Fat Full Fall series starting here.)

What Kind of Fats?

Let’s start with basic, elementary science (here’s where I excel!):

There are four major classifications of fat, determined by how their molecules are arranged:

  1. saturated fats
  2. polyunsaturated fats (both omega-3s and omega 6s)
  3. monounsaturated fats
  4. trans fats

The label readers among you probably already knew that from your time scanning the Nutrition Facts on various food packages. To learn more about monounsaturated fats, which I tackled first because EVERYONE agrees that they are good for you, click here. For the scoop on trans fats, including how to find them on super sneaky food packaging labels, read this. Everyone (mostly) agrees that trans fats are terrible for you. Nobody can agree about butter, so for some controversy and to learn more about saturated fats, read this.


Important note: All foods with fats have some of each of the natural fats (saturated, polyunsaturated, and monounsaturated). They’re usually classified by that which they have the most of, like avocados in the mono category and butter in the saturated fats. In reality, butter also has mono- and poly-unsaturated fats (in an ideal ratio of omega-6s to omega 3s).

Check out The Slow Cook for a very cool explanation of fats for kids (but easy to read for adults, too).

Polyunsaturated Fats: Good Fat, Bad Fat?

Today we’re moving on to the second group of unsaturated fats, the polyunsaturated ones. I’ve saved them for last because they’re more complicated and (of course) under discussion for the “good fat, bad fat?” award.

I say polyunsaturates are more complicated because we know them under so many titles. While I feel confident in saying, “Eat more monounsaturated fats,” I can’t make a blanket statement about the polyunsaturated fats because the category includes both omega-3 and omega-6 fatty acids. One is in, one is on the outs.

Americans Need More Omega-3s

We expect to find our omega-3s in fish because of the recent fish oil supplement push, but omega-3s are found in plants (leaves, to be precise) at their origin. (Fish get them from algae.)  Unfortunately, scientists and farmers have been selecting for plants with less omega-3 for the past few decades because omega-3s spoil more quickly. (Enter processed foods.)

The net result of the fear of fats in our country and the increased demand for foods that will last a long time sitting on a shelf is that Americans are quite deficient in their omega-3 fats, called essential because our bodies absolutely cannot manufacture them; they must be consumed from other sources. You can read more about the health benefits of omega-3s, particularly salmon and flax, and get some ideas for increasing omega-3s in your diet as a result of KS’s Super Foods series.

Finding the Balance

Want to get more omega-3s in your diet? Eat less omega-6. It turns out that the function of the omegas in our bodies is totally dependent upon the ratio of the two. Kind of like Kitchen Stewardship®it’s all about the balance.

Both are essential fats:  we need ‘em, and we can’t make ‘em. They have kind of opposing roles in the body. Check out this comparison of the functions of the omegas and you’ll start to see why you don’t want too much of one or not enough of the other:



Brain development and processingFat storage
Clear vision 
Thins blood (prevent stroke, heart attack)Clotting (helps heal from skin injuries)
Permeability (porous-ness, spongy, in-and-out-ability) of cell membranesRigidity of cell walls
Metabolism of glucose 
Calms inflammationInitiates inflammation (as an appropriate response to attack)
Promotes ovulationSuppresses ovulation
Prevents premature birthPrompts labor to begin

There are various numbers given for the proper ratio of 6s to 3s:

  • Smart Balance claims it has “the ideal blend of 4 to 1 omega 6 to omega 3”
  • Nina Planck in Real Food says it should be 1:1
  • Pollan’s numbers are 3 to 1 (more omega 6s than 3s)
  • Nourishing Traditions, p. 10:  “The best evidence indicates that our intake of polyunsaturates should not be much greater than 4% of the caloric total, in approximate proportions of 1 1/2 % omega-3 … and 2 1/2 % omega-6. (See the context at the WAPF website.)

Regardless, you should consume more omega-6s than 3s, but they should be fairly close in amount and kept in balance.

As Michael Pollan says in In Defense of Food, “Too much omega-6 may be just as much a problem as too little omega-3.”  He calls the 3s “fleet and flexible” and the 6s “sturdy and slow.”  Some of the health risks of too much “sturdy and slow” and not enough “fleet and flexible” include “blood clots, inflammation, high blood pressure, irritation of the digestive tract, depressed immune function, sterility, cancer and weight gain (NT p. 11)” and “obesity, insulin resistance, premature labor, depression [and increased risk of heart disease] (Real Food p. 205, 267).”

We Need FEWER Omega-6s

As omega-3s are found in plant leaves, the omega-6 fatty acids are from the seeds of the plant. As we have industrialized our food supply, we’ve eaten far fewer leaves (and leaf products) and a great deal more seeds. Nourishing Traditions says that Americans often get 30% of their total calories from polyunsaturated fats; Pollan quotes our American ratio of omega 6:3 as 10:1; Planck says we eat 20 times more omega-6s than 3s. All are a far cry from any of the possible recommended ratios listed above.

You think you don’t eat very many seeds? If you’ve paid attention to the places you find “soybean oil” or “corn (vegetable) oil” as I challenged you to do last week, then you know that corn and soy (both seeds!) are prolific in anything boxed, bottled or sold with a label.


Corn and soybeans are both inexpensive, U.S.-grown sources of oils, liquid at room temperature (convenient) and with a decent shelf life once in a processed food. However, Dr. Weston A. Price, a dentist who studied the diets of isolated traditional peoples around the world, found zero cultures who consumed polyunsaturated fat in the form of oils. This is an invention of the last century. That always makes me nervous! Strike two? Corn oil has an omega-6:3 ratio of 60:1. Yowza – that’s going to throw off your ratio no matter whose numbers you use if you eat a lot of corn oil!

By the way, guess who’s eating a lot of corn these days? Cows. Chickens. Pigs. Fish. (Conventionally farmed, that is.)  Ahem. If you eat any of these delectable items at dinner, you’re consuming more omega-6s and fewer omega-3s than your grandparents did when they ate the exact same meal.

The Real Dangers of Omega-6 Oils

As convenient as the liquid oils are, the method of extraction to get that soybean or corn oil from the seed into your bottle of Italian dressing is troublesome and a downright health hazard. The food processing industry uses high heat, intense pressure (more heat), and doesn’t protect the oils from light and oxygen. The resulting oils are:

  1. full of free radicals (damaged molecules that attack the body, causing skin wrinkles, sets the stage for tumors, and causes plaque buildup. The majority of fat in artery clogs is polyunsaturated. Free radicals have also been linked to autoimmune diseases, Parkinson’s, Lou Gehrig’s, and Alzheimer’s. NT, p. 10-11)
  2. oxidized (any time damaged cells come in contact with air, they become oxidized. The recent buzz about anti-oxidants is how we can combat this problem. Another lovely word for this would be rancid oil. Sound appetizing?)
  3. lacking in natural antioxidants (many fats come with their own antioxidants, fat-soluble Vitamin E for example. Many of these are heat-sensitive, and thus are lost in the processed oils.)

If you need a liquid oil, you’ll want to look for terms like “expeller-expressed” and “unrefined” on the bottle. Extra Virgin Olive Oil is always processed under low heat and pressure, so you’re safe there, too. (Read: Good olive oil choices and safe handling.)

There’s a bit of a myth out there that heating liquid oils too high can form trans fats. Not true, says Mary Enig. Heating liquid oils, especially polyunsaturated oils, is damaging to the oil and damaging to your body, but it’s because of the free radicals caused by oxidation, NOT trans fats.

The Other Balance: Sources on Both Sides

As always, I’m going to tell you that I don’t know much. What I do know is that I can find sources to contradict what I’ve just told you, and I’m a big believer in balance – I’ll let you pray on it and sort it out for yourself.

  • For example, The American Heart Association and Cooking Light both point to polyunsaturates as heart healthy choices, but neither discusses omega-6s in particular.
  • The Help Guide is a rather balanced source. The chart showing the percentages of types of fat in butter, safflower oil, margarine and olive oil is fascinating (about 4 pages down).
  • is another source that is influenced by the mainstream but acknowledges that there are some health risks to the polyunsaturated fats.

Final Word on Omega-6 Oils

  • Omega-6s include all the “yellow oils”:  corn, soybean, sunflower, safflower
  • They often go rancid and/or are oxidized in processing
  • They are modern oils
  • They’re never to be used for cooking
  • Best practice would be to cut them out entirely
  • Would you still get enough omega-6 if you had no “yellow oils”? Yes – from olive oil, nuts and whole seeds, plus that from the other fats you eat – your beef, butter, eggs, etc.
  • Balance omega-6s with omega-3s:  eat your fish, walnuts (use the code STEWARDSHIP for 10% off at that site!), pastured eggs (yolks too!), flax
  • You don’t need a lot of polyunsaturated fat – about 4% of your total calories will do you just fine.

A Quick Note on GMOs


GMO means Genetically Modified Organism. Scientists are quickly changing our food supply by creating tomatoes that look redder, soybeans that are resistant to certain pests and corn that won’t fall over when it’s crowded into close-knit rows. These are genetically-modified plants. It’s hard to talk about corn and soy without touching on this subject, because it’s hard (impossible?) to find corn or soy that isn’t GMO in a store unless you see a USDA Organic label on the package (the organic label prohibits GM crops).

I don’t know much about GMOs other than that plenty of people are saying they’re bad. (No source! Just me!)  I don’t avoid them entirely – yet? – baby steps happening here! But at first glance, without doing my research, I have an uncomfortable distrust of GMOs, first because they’re relatively new and unproven, and second because it seems a bit like playing God, and I’m always wary about humanity’s pride in that sense.

For a practical step you can take to deal with this onslaught of possibly new information, move on to the Monday Mission for the week.

Practical Steps to Create Balance

Omega 6s and 3s need a proper ratio. Once you understand the delicate dance omega-3s and omega-6s perform in your body and the need to balance them, you quickly understand that a deficit of omega-3s has the same net result as a surfeit of omega-6s. If you live in America (or probably another industrialized nation) and you consume things with more than one ingredient that you purchased in a store, chances are your diet has an excess of omega-6 fatty acids. Here are various practical steps you can take to cut down (choose one – baby steps, remember!):

  1. Make your own salad dressings. Salad dressing have a ton of soybean oil in them – you can cut down omega-6s and increase your monounsaturated fat intake by using extra virgin olive oil. Here are my recipes for Italian, Balsamic Vinaigrette, and Caesar Dressings. My latest is Asian Toasted Sesame Dressing, and I’ve been liking Kelly’s ranch (I use at least half EVOO where she uses sesame oil in the mayo and did refined coconut oil (use the code STEWARDSHIP to get 10% off) once, but it’s really firm that way).
  2. sourdough crackersMake your own crackers. Hopefully there will be a few recipes to choose from in this week’s “Un-Processed Foods” carnival. King Arthur’s faux Wheat Thins are fabulous, and if you have a sourdough starter, Sarah has a great sourdough cracker recipe (no longer available).
  3. Get rid of your vegetable/corn oil. When you need a liquid fat for baking, use melted butter. Try sauteeing at low heats with EVOO and higher heats with coconut oil. (Why not canola?)
  4. Read labels closely. If you can find an alternative with a safer fat (or no fat if it comes to that), choose it. Some salad dressings are made with olive oil (or at least partly EVOO – it’s better than 100% soybean!), refried beans don’t always have industrial oils added, better spaghetti sauces have better oils, etc.
  5. Avoid packaged breakfast cereals. You might choose to make your own granola, try this amazing soaked baked oatmeal or just have oatmeal, try your hand at making homemade yogurt (or a plain tub of full-fat yogurt will suffice, of course), or have easy scrambled eggs. [UPDATE:  I actually took the time to check some cereal boxes, rather than just assuming they used soybean and vegetable oils. Lazy me. Most don’t use fats, just lots of sugars! This is probably not a place to avoid the oils, but if you’re nervous about consuming too much CORN, period, breakfast is a great place to cut down.]
  6. Make from scratch. Really, corn and soybean oils are so pervasive in processed foods, if you’re going to avoid them, you’re going to have to make your own of some things. I’m pleased to invite bloggers and others to share their “Un-Processed Foods” recipes this Thursday at KS. Hopefully you’ll find some great ideas there. Until then, here are some of mine:

Read about the incredible health benefits of omega-3 fats here, but remember this:  our brains and hearts NEED omega-3s, and most American’s aren’t getting enough. This is a big deal worth a little of your time, especially moms of young children.

  1. Eat more fish, especially salmon (once a week is great!) – How to Buy Salmon Safely
  2. Add flax to your diet (oil or seeds) – try this Banana Flax Muffins Recipe
  3. Eat more walnuts
  4. Ask your doctor about fish oil supplements (see below)

Remember, good Kitchen Stewards…just choose one baby step at a time. When you have accomplished that one, come on back for a second. No need to overwhelm yourself or your menu plan with too much all at once!

My “Eat More Fish” Tip

The only tip I have that isn’t included in the above posts is one way I try to eat more fish: since I never prepared it at home before my husband gave the okay this winter (he hates fish but will eat this spicy fish recipe!), I try to almost always order it when given the opportunity at a restaurant. You may not want to do this with salmon, unfortunately, unless you have the nerve to ask your server every time: “Where is this fish caught?”

RELATED: How to Find Sustainable Seafood.

Until then, you can always consider making an “eat every week” list in your meal plan that includes fish, broth, beans, a meatless meal, and other items of importance for your family (beef, chicken, pasta, salad, eggs, etc.).

An Important Note About Supplements:

If you’re thinking that maybe the easiest and most low-cal way to get omega-3s is with fish oil capsules, not so fast. Many nutritionists say it’s a bad idea.


“There is something about whole food that when it goes into the body it’s more than 90% absorbed, while [with] a supplement you absorb only about 50%,” says Sandon.

Moreover, says Sandon, because the components of different foods work together, they may offer a more complete and balanced source of nutrients.

“It could be something more than just the omega-3s in fish that make it so healthy,” says Sandon. “It could be the amino acids that provide benefits we are not going to see in fish-oil supplements alone.”

And if you’re thinking fish-oil capsules will help you avoid the contamination risks of fresh fish, think again. Because supplements are not regulated in the U.S., Sandon says, some may contain concentrated amounts of the same toxins found in fresh fish. And because the oil is so concentrated, the supplements can also produce an unpleasant body odor.

More important, experts say, there is a danger of overdosing on fish-oil supplements, particularly if you take more than the recommended amount. Doing so can increase your risk of bleeding or bruising. This isn’t likely to happen when you get your intake from foods.

The one-time fish oil supplements can really help is if you need to reduce your levels of triglycerides, a dangerous blood fat linked to heart disease. The American Heart Association recommends that people with extremely high triglycerides get 2 to 4 daily grams of omega-3s (containing EPA and DHA) in capsules — but only in consultation with their doctors.

“The key here is to never take these supplements without your doctor’s consent,” says Magee. “This is not something you want to fool with on your own.”

From Web MD

What baby step will you take this week to balance out the Omega 6 and Omega 3 fats in your diet?

Images used with permission from

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22 thoughts on “Food for Thought: Are Polyunsaturated Oils Healthy?”

  1. Thanks so much, Katie! I’m enjoying looking at your Kids Cook Real Food curriculum and came upon this page. I have a bit of a background in biochemistry and I have professional exposure to the health field (though not a doctor or a nutritionist). I try to feed my family healthy food, but we also keep the motto, “everything in moderation” to keep a balance life, where food is not an idol or religion. I appreciate your giving two views! Thanks for that information and modesty. 🙂 I do want to address GMOs. Although there is so much “scare” about it today, I think it’s good to realize that in a sin cursed world, we’re fighting disease, pestilence and thorns. GMOs have provided for decreased costs of food and even providing food to areas that are constantly fighting starvation. They are not all bad. I totally relate to the comment about science playing God (rather, men who call themselves scientists playing God), but there are also the aspects of discovery that God awarded us even in the Garden when he gave mankind the gift of the Garden, animals and plants alike. I believe research done rightly, should give God glory for the wonders of His creation and the way He has given us the ability to explore it! Beautiful roses are genetically modified. Food for starving people is genetically modified. I just wouldn’t cut it out whole-sale without a more nuanced look at the positive sides of exploring the world. Prov 25:2
    It is God’s privilege to conceal things and the king’s privilege to discover them.

    1. I do not see the proof that gmo’s are helping starving countries. Ask the advocates in India like Dr. Vandana Shiva where big corporations are making poor farmers come back to them for seed because the corporations want the farmers to rely on them, not God. You used to be able to save your seeds from your own harvest to plant the next year (like God’s design, always giving!), but not gmo’s. They do not leave seeds that you can plant and grow another crop. Scripture says not to mix seeds. Genesis tells us that like kind produce like kind. It tells us that plants, animals and man has a seed. Do you not know that they mix human and animal seeds to the plant seed to make genetically modified organisms? Stop believing what they want you to believe.

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  3. Yesterday I made my own mayo with macadamia nut oil! It turned out AMAZING- too much so- I have eaten about 5 ham and cheese sandwiches since just because it is so good with the mayo 🙂

    On the GMO subject- we avoid it like the plague. Not only is that stuff bad for you- it is horrific for the environment and devastating small farmers. Please watch “The world according to Monsanto”- it’s even available on Youtube

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  6. Amy via Facebook

    Also…just read about the mono-saturated fats, and was excited to see your thoughts on the natural pb being a super food…I ate it a lot as an added fat/protein with my carbs during my pregnancy, only gained about 12 or 13 lbs (I am overweight though, so this number is good…I actually think pregnancy made my metabolism higher!!), and my midwife kept giving me such a hard time about pb! If the Lord allows me to conceive again, I am printing this for her benefit!

  7. Amy via Facebook

    Thanks for sharing! I keep getting into argumen…I mean discussions with people over this, especially when they find our I use real butter and coconut oil. GASP!! LOL.

  8. Hi Katie! Here’s a little more info on GMOs: they’re dangerous for many reasons but mainly because they are manipulated (usually by injecting foreign viruses) to withstand pesticides used on the crops. Another note – even products labeled as organic *can* contain GMO soy/corn. The rule is that a product can be labeled as organic as long as a certain percentage of the ingredients are organic (I think it’s 97 or 98%). Some products do use organic soy/corn, but not all. Either way it’s a small percentage. Just a few tidbits! Love your posts, keep up the great work!! 🙂

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  11. Ah. So if the Omega-3’s are in the leaves and the Omega-6’s are in the seeds, that explains why grassfeed beef has more 3’s and less 6’s than conventionally-raised beef.
    .-= Rachel R.´s last blog ..Quotable – housework =-.

  12. Please, stop already! Just kidding. Really, this information is wonderful. You have such a great way of laying it all out. Thanks!
    .-= Greta´s last blog ..Menu Plan Monday =-.

  13. Lenetta @ Nettacow

    I’m still trying to wrap my mind around the GMO info I sent you on Friday (cleverly disguised as a reply to the comment e-mail on my book giveaway post). I really think there’s a ton of truth on both sides and the honest to goodness truth is somewhere in the middle, but where???
    .-= Lenetta @ Nettacow´s last blog ..Link Roundup, Anniversary Edition =-.

    1. I know…my mind hasn’t had a chance to get wrapped up in your info, but I did read it! Put it right on my “post ideas” list, too. Hmph. That’s the last time I leave a cute little note on YOUR blog! 😉 j/j

      I don’t know much about GMOs, and I’m sure you’re right about the middle. Hopefully we can find a workable solution together! Hope you’re having a great week!
      Blessings, Katie

  14. Katie,

    Have you read “Eat Fat, Lose Fat” by Mary Enig and Sally Fallon? I am in the middle of it, and while I’m a little freaked out by ALL the coconut, a lot of what I’ve learned is what you laid out here. I was just curious if you had any thoughts on the book.

    Also? Not only did I eat a bunch of butter tonight, but I made it myself in my Kitchenaid stand mixer! SO fun!
    .-= April´s last blog ..A giveaway, and some bloggy love =-.

    1. April,
      Way to go on the butter! 🙂

      I haven’t read that particular book, but it’s on my to-read list. Enig and Fallon tend to have the same themes, so any source from them will have the basics about fats (I think!). And what are your thoughts?
      Thanks for sharing!

  15. Musings of a Housewife

    Katie, this is a wealth of information. You did a great job summarizing. I’m definitely linking over!
    .-= Musings of a Housewife´s last blog ..What I Learned This Week IS ON! =-.

  16. I am so glad you linked to the comments on your other posts! I like to get as much information as possible and then pray, try to decide for myself, and trust God (very similar to your methods).

    Great posts! Thanks for all of the links and for keeping discussion going in the comments!
    .-= Andrea´s last blog ..Menu Plan Monday – October 19 =-.

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