What are Fatty Acids?
People keep telling you that life forms consist of carbon, hydrogen and oxygen. But how can everything be made up of just a few atoms? Human beings consist of hardly anything else and yet we’re all different — complex systems of biological and chemical processes — that make us unique. In nutrition, carbon ( C ), hydrogen ( H ) and oxygen ( O ) play a fundamental role as well, since eating is nothing but breaking those atoms out of complex food to build and maintain our system.
This also applies to fat — more precisely fatty acids. Why you need fatty acids for survival, and how the right choice of fatty acids can affect your health, you can discover here
The entire world is made out of carbon, hydrogen and oxygen.
Fatty acids at prom
Think of it as a dance. At first, all the atoms lost in a big hall, awkward silence, until carbon ( C ) makes the first move. The C-atoms line up in their intended position and then reach out their hands. Each one grabs the hand of their neighbor. Oxygen ( O ) is also caught up in the dance fever, forms the end of the chain. Finally, the slightly shy hydrogens ( H ) join the ball. Carbon has a total of four arms and can, depending on its position, ask two to three hydrogens to dance. Quite efficient!
This is how a fatty acid is formed. All fatty acids have this basic structure and only differ in lenght. It’s called a hydrocarbon chain (poor oxygen being ignored).
Fatty acids can’t keep dancing all night, especially the shy hydrogens (H) are not well-trained dancers and must rest from time to time. Usually, hydrogen atoms show the female characteristic to always walk in pairs, so after they’ve left, two carbons (C) remain on the dance floor alone, with one useless arm each. In order not to look silly, they grab each other in place of the hydrogens and form a double bond.
The process of splitting off hydrogen atoms is called dehydrogenation. This creates a double bond between the carbon atoms. What you see now is an unsaturated fatty acid.
Why Unsaturated Fatty Acids are better friends
Depending on the amount of double bonds you call them mono- (MUFAmono unsaturated fatty acid (einfach ungesaettigte Fettsaeure) haben nur eine Doppelbindung in ihrer Kohlenwasserstoffkette, aus der die Fettsaeure besteht.) or polyunsaturated fatty acids (PUFApoly unsaturated fatty acid (mehrfach ungesaettigte Fettsaeure) haben mehrere Doppelbindungen in ihrer Kohlenwasserstoffkette, aus der die Fettsaeure besteht.). Going back to the prom metaphor, saturated fatty acids are the ones with their hands full — they won’t hold your hair or walk you home. But the unsaturated ones do. They can be your best friends.
It’s widely accepted that MUFAs and PUFAs are beneficial to health — particularly by reducing LDL and increasing HDL — so overall they reduce cholesterol levels. Therefore, they can reduce the risk of fatal heart attack, ischemic stroke, and lipid metabolism disorders.
This mechanism is currently a matter of debate, as some studies have emerged that don’t confirm — but also cannot refute — this thesis. For example, a recent review (February 2020) showed, that there’s “only a slightly reduced risk of coronary death and coronary events”. Also, this study suggests that the positive effects of PUFAs don’t apply for all of them — the single substitution with linoleic acid (omega-6) didn’t have the same positive influence as substituting a mixture of omega-6:omega-3 did.
PUFAs aren’t a miracle cure and need more scientific investigation — especially to evaluate the optimal ratio between omega-6:omega-3— but still, they’re essential
What's so special about omega-3 and omega-6?
Omega fatty acids are a special breed. They take care of several key tasks in your body — making sure that the inflammatory reactions work when you’re sick, promoting communication between cells, and influencing the activity of DNA. Without them, you could never be.
They get their name from their structure. Opposite the oxygen end is the omega end (the one without oxygen). And do you remember when you were a kid counting to make sure everybody was present? That’s how the carbons do it. Starting at the omega end, the carbon atoms start counting until they reach a double bond. And if it’s in the third position, they scream “3! I’m an omega-3!”. If the first double bond they reach is in the sixth position, it’s an omega-6 fatty acid.
Furthermore, the two fatty acids that are essential for you are also omega fatty acids. Essential means that your body can’t synthesize them (because you lack a certain enzyme), but in fact, you need them to stay alive — you have to take them in with food or it looks grim. These two fatty acids are the alpha-linolenic acid (an omega-3 fatty acid) and the linoleic acid (an omega-6 fatty acid).
Where to find Fatty Acids
Deficiency doesn’t happen overnight, an unbalanced diet doesn’t kill you immediately. A chronic deficiency, however, will take its revenge sooner or later. It can take months or even years before you show symptoms of a deficiency of omega-3 or omega-6 fatty acids.
According to current knowledge, 250 mg of long-chain omega-3 fatty acids (especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)*) are sufficient to prevent death from coronary heart disease. You can find these in fish — but not all fish are the same. Cod, saithe, hake, place, or redfish are low-fat fish and therefore contain less omega fatty acids, whereas salmon, mackerel, and herring are very high in fat. So: fish once or twice a week and you are good to go! If you want to top this off, make sure that the fish you buy is from sustainable sources. Of course, there’re also other sources for unsaturated fatty acids — especially vegetable oils. But make sure that you’re not heating them too strong and don’t use them for frying, since they’re quite unstable due to their structure.
To summarize, fat should be consumed in moderation, because they have a high caloric density (9 kcal/g). Unsaturated fats are preferable to saturated ones, because of their benefits regarding cardiovascular diseases and omega-3 and omega-6 fatty acids, which are essential to your body. They can be found abundant in fish and vegetable oils.
References
- Evidence-Based Guideline of the German Nutrition Society: Fat Intake and Prevention of Selected Nutrition-Related Diseases | Wolfram et al. (2015) (PDF)
- Fat intake and prevention of selected nutrition-related diseases | Dinter et al. (2015) (PDF)
- Fish intake and prevention of selected nutrition-related diseases | Dinter et al. (2016) (PDF)