Frankly, it rankles me when people use the term “healthy fats.”  We don’t make a distinction like that when we’re talking about carbohydrates, although there are certainly carbs that are nutritious and carbs that are not.   

Consider the Atkins diet.  I like to believe that Dr. Atkins was on the right track, but that he had some of the details wrong.  Clearly, he realized that there was something about carbohydrate in the American diet that was causing a problem.  But he did not understand that there is a big difference between muffins and mangoes, white flour and lentils, table sugar and peaches.  So people who tried the Atkins diet lost lots of weight when they removed virtually ALL the carb from their diets, even green beans, and then regained it when they got tired of the restriction and began to eat breakfast cereal again.  Along with doughnuts, pasta, bread, cookies, cake, and potato chips.  

Dr Atkins also did not understand that there is a big difference between a slice of salmon and a scoop of Crisco.  To him, all fats were the same and they all were good.  We know now that that is not true.

We are still sorting out the differences among the three main families of fats: saturated, monounsaturated, and polyunsaturated.  We know for sure that omega-3 polyunsaturated fatty acids are very good for us, and that the standard American diet is extremely deficient in them.  We know that we can increase our consumption of omega-3s by eating more fish, walnuts, flax seed, and green, leafy vegetables.  

We have seen the benefits of the Mediterranean diet, in which olive oil (a monounsaturated fat) is the main fat used for cooking, and from this we understand that olive oil, too, is good for us.  Conversely, we know that trans fats (partially hydrogenated polyunsaturated fats) damage blood vessels, causing heart attacks and strokes.  We know they also increase the risk of diabetes, high blood pressure, and high cholesterol.  So trans fats are definitely NOT good.

But there is still a great deal to figure out.  We know, for example, that cocoa butter is one of the most highly saturated fats on the planet.  But….isn’t dark chocolate supposed to be good?  And aren’t saturated fats supposed to be bad?  So what does this tell me?  That we still have a lot to learn.  

Want another curious example?  Most animal fats are actually a mixture of a variety of monounsaturated, polyunsaturated and saturated fats.  Which animal fat contains the most monounsaturated fat, similar to olive oil?  Lard.  Yes, believe it or not, that is true.  So what is most clear to me at this point is that we still, indeed, have a lot to learn.

At the same time, there are some things that I do understand.  The fact is that there are good examples of nutritious foods from each of the three main nutrient groups (fats, carbohydrates, and protein).  If I’m going to make a recommendation that you try one, or if I use one in a recipe or an explanation, I don’t think I need to qualify it with the word “healthy.”   Fat IS healthy.  Protein IS healthy.  Carbohydrates are healthy, too, as long as you get most of them the way our ancestors did, from the garden, with the fiber still intact.  Think fruits, vegetables, legumes, whole grains.  These are carbohydrates, through and through.  When I include one in a recipe, I don’t need to say “healthy” apples.  You can assume that I am referring to apples without worms or pesticides. 

When I talk about fats and oils, you can assume the same.

This week I’ve been doing some reading about omega-3‘s, and I thought I’d pass along some of the things I’ve learned.

Omega-3 fatty acids have lots of double bonds, which act as pivot joints.  That’s why they are so important for movement and flexibility.  They are also essential in photosynthesis, wherein green leaves convert sunlight to food.  So you find lots of omega-3s in greens, especially leafy ones.  Omega-3s owe their flexibility to all those double bonds, the last of which is located just 3 carbons from the tail (omega) end of the molecule.  That’s why it’s called an omega-3 fatty acid.  “Omega” means end.

Omega-3 fatty acids are found in all green plants, so eat your vegetables!  Interestingly, the largest mass of greens on Earth is phytoplankton, tiny sea plants that are eaten by little fish, which are then eaten by bigger fish, and so on.  Sea creatures eat tons of phytoplankton; in order to survive in their cold water environments, fish need at least 1% of their calories to come from omega-3s.  Warm-blooded animals need only half that.  This is why fish, fish oil, and algae are such good sources of omega-3s. 

Two important omega-3 fatty acids are DHA and EPA.  EPA is a blood thinner and has anti-inflammatory properties.  DHA is a component of cell membranes, keeping them flexible and functional.  With hundreds of possible configurations, DHA is like a “quick change artist.”  According to Susan Allport (author of The Queen of Fats: Why Omega-3s were Removed from the Western Diet and What We Can Do to Replace Them), “DHA creates membranes with…behavior that is almost liquid-like.”  Cell membranes aren’t inert, like dry wall.  They live and breathe, and they work hard to keep the internal environment of a cell completely separate from the outside environment. 

DHA makes up 25% of brain tissue.  It prevents abnormal heart rhythms, or “arrhythmias.”  It helps the eye to see better by increasing the amount of rhodopsin, a light-responsive protein found in rod cells in the retina.  DHA also appears to improve insulin sensitivity, which would mean that it lowers the risk of developing obesity and diabetes.  

 

Omega-3s have one important limitation:  Double bonds react easily with oxygen, which makes them unstable, chemically speaking.  In fact, fat oxidation is the major cause of food rancidity.  This reactivity makes omega-3s an unreliable way to store fat in nature.  That’s where omega-6s come into play.

Omega-6s, less reactive because they have fewer double bonds, are a much better choice for a different job: storage.  That’s why omega-6s are the main fat in grains and seeds, where long-term storage is all-important.  The stability of omega-6s makes them the preferred form of stored fat in plants.  Plants can convert omega-6s into omega-3s whenever they need some.  They store fat as omega-6s until seeds germinate and initiate photosynthesis.  Then they release an enzyme that converts omega-6s to omega-3s.  

Animals and humans do not have this enzyme, so once an omega-6, always an omega-6.  All the omega-6s we eat end up in our cell membranes as stiff as always.  

The stable chemical configuration of omega-6s increases shelf life considerably, which is why they’re the leading polyunsaturated fat of choice for processed food products, including vegetable oils.  It’s also why it’s not a coincidence that the ratio of omega-6s to omega-3s in our diet has climbed from about 1:1 throughout history to upwards of 75:1 today. 

Omega-6 fatty acids in plants serve as a stable, reliable system for storing fat until the plant needs omega-3s.  Omega-3s are flexible, and omega-6s are stiff.  Omega-3s are reactive, whereas omega-6s are stable.  Omega-6s, with fewer double bonds, are more stable and, therefore, less prone to oxidation and breakdown.  That is why omega-6s are found in highest concentration in grains and seeds.  Dry beans can remain viable for centuries under certain circumstances.  That’s clearly not true of lettuce, under any circumstances.  

 

Stiff membranes are good for seeds and grains, but not for green leaves or for  human brains, blood vessels, eyes, or joints.  High blood pressure, inflammation, insulin resistance, and platelet aggregation are predictable consequences of stiff cell membranes and suboptimal function.