WHAT WE WISH WE REMEMBERED FROM SCIENCE CLASS (OR, WHAT WAS NEVER TAUGHT)
Note: The goal of this article is to remain brief and informative using layman's terms. Much of what is said here is fuzzy (as is everything in science if you look at the details) but it is the only way we can build any structure of this in our brain to remain in memory.
FAT is a bad word. Literally. We should rename it TRIG or something along those lines. Why? Because it is misused and misunderstood and you'll soon see why. The spare tire around our waist is also called FAT, but is referring to cells specialized in storing TRIGs as energy (a.k.a. Adipose Tissue). Because they all seem to blend - and due to much misinformation - there is a major confusion with PHOSPHOLIPIDs (Lecithin), FAT, and OIL.
You need to know that MONO-, DI-, and TRI- GLYCERIDES are a common structure of molecules that have a GLYCEROL backbone attached with the specified number of FATTY ACID arms. Our flesh is composed of these molecules and needs these to survive!
[Heck, instead of using the term "GLYCEROL" or "GLYCERIDE", lets use a name that we are more used to: GLYCERINE (It is an edible colorless, odorless, thick liquid that is sweet-tasting and non-toxic)].
"MOG" - SINGLE (MONO) GLYCERINE - has one FATTY ACID leg. Used as a food additive, but also occurs in nature. I suppose you can bind something to the other two legs...
"DIG" - DOUBLE (DI) GLYCERINE - a.k.a. Glycerophospholipids (Phosphatides) have two legs of FATTY ACIDS and one leg Phosphorous-connected to another molecule such as Choline, (see "Lecithin" below). A dietary supplement.
"TRIG" - TRIPLE (TRI) GLYCERINE - have three FATTY ACID legs.
Image source: http://www.aquaculture.ugent.be/Education/coursematerial/online%20courses/ATA/analysis/lip_glyc.htm
FATTY ACIDs are labeled as Saturated or Unsaturated(mono- & poly-) depending on how bound it is, or how 'thick' it is. All the FATTY ACID ingredients have an effect. GLYCERIDES, as explained above, can be composed of variations of these. And don't forget, foods also have FREE FATTY ACIDS in them.
In general, AT ROOM TEMPERATURE:
SAT (Saturated) = solid
UNSAT (Unsaturated) = liquid
Therefore, it makes sense that fats have a predominance of saturated fatty acids (solids), and oils are composed largely of unsaturated acids (liquids)!
Remember: All the FATTY ACIDS aren't included in the nutrition label on foods - only TRIGS are! ON A NUTRITION FACTS LABEL, "Fat" is defined as total lipid fatty acids expressed as triglycerides.
Now, back to our main focus:
There are three major cell membrane lipid families. They are cell membrane building blocks and are DIGs.
a.) Our most popular is PHOSPHOLIPIDs.
- There is GLYCOPHOSPHOLIPIDS with a GLYCERINE backbone as mentioned above.
- The SPHINGOPHOSPHOLIPID shares the characteristic of having a PHOSPHATE third leg but has a SPHINGOSINE backbone. Ceramide or Sphingomyelin, anyone?
The other two we don't hear much about are:
b.) GLYCOLIPIDS (with GLYCERINE [technically another DIG] or SPHINGOSINE backbone and third leg having a sugar). The sugar can be a monosaccharide, oligosaccharide, or polysaccharide (this is another story).
c.) STEROLS (with very different structure). Cholesterol, steroid hormones, or bile salts, anyone?
Image source: http://essays.biochemistry.org/content/59/43
FAT is energy molecules and areTRIGs.
And OIL? Well, it is a mixture of these and other molecules, as shown below. Oils are mostly composed of TRIGs and LECITHIN of which the FATTY ACIDS are mostly liquid UNSAT - although coconut & palm have lots of SAT.
Generally, GOOD = POLY-UNSATURATED FATTY ACID. Think of it as being very liquid so it can be broken down by our body using less energy. This may be important so use the mnemonic "Good Polly Stood ('Un-sat') on her cracker and demanded gluten-free!"
[Note: companies like to 'hydrogenate' TRIGs to modify properties such as thickness (ie. convert it from unsaturated to saturated), which ends up with by-products of quite un-natural (thus quite unhealthy) TRANS-fats.]
EXAMPLE: LECITHIN WHICH WE TAKE AS an ULTIMATE ANTIAGING SUPPLEMENT
"LECITHIN" (PHOSPHOLIPIDS) as a dietary supplement or food additive IS REMOVED FROM THE OIL (or other source such as egg-yolk).
Image from mdpi.com: "Vegetable Oils as Alternative Solvents for Green Oleo-Extraction, Purification and Formulation of Food and Natural Products"
Lecithin is defined as a mixture of PHOSPHATIDES (DIGS) only. To be precise, we should use the term GLYCOPHOSPHOLIPIDS. In practice, it is commonly composed of some TRIGs and lots of DIGs.
A Comparison of a specific brand of lecithin glycophospholipid content. Image source: https://www.novastell.com/Lecithins.html
Think of liquid Lecithin as solid lecithin with small amounts of liquid FATTY ACIDS remaining (and possibly more liquid TRIG that doesn't belong).
...and remember that some "lecithins" such as sunflower can be mixed in water! [Oils can't - however, if you ever have to swallow a nasty oil for health benefit, you could add the oil to the lecithin/water and mix to break the oil up so its easier to drink!]
Wishing all a healthy fatty diet,
Mark Kuoppala, BEng.
Please contact us if you have anything to add.
Did you know? Sterols in our body (such as steroid hormones) are derived from Cholesterol!