Molecules in focus: Fat as the link between my work- and free-time

What is fat, actually? 
From a chemical point of view fats are certain types of lipids. Lipids represent one of the three macronutrients – the main molecular sources of energy we get from the food we consume. (Proteins and sacharides are the other two types.) Even though chemically there is a difference between a lipid and a fat (as was just said, lipids are superior to fats), both terms are often mutually interchanged outside of chemistry world. (And so happens in this post :) A chemist could describe lipids as mixtures of carbon (C), hydrogen (H), and oxygen (O) atoms. (Even though some lipids contain other elements, too.) There are different classes of lipids. The classification is based on how these atoms are assembled into the lipid molecules.

 
Fatty acids - the central lipid group 
Fatty acids (FA) contain a chain of carbon atoms. In the chain two carbon atoms are connected through a chemical bond. The bond is either "simple" or the carbon atoms are tighten stronger together through a "double bond".

Fatty acids themselves are classified based on two criteria: the length of that carbon chain, i.e. the number of containing carbon atoms, and the number of the double bonds. If the chain contains no double bonds whatsoever, the FA is called saturated. If there is but one, the FA belongs to a monounsaturated class. More than one double bond means the fatty acid is polyunsaturated. Both types of classification are usually combined to describe a particular fatty acid. For example "FA 20:4" stands for a fatty acid with 20 carbons and 4 double bonds.

Why we need lipids/fat? 
FA are parts of more complex lipids such as triglycerides (these are technically the real chemical FATS), phospholipids, sphingolipids, glycolipids, and others. These have different functions in our bodies: Triglycerides are primarily storage of energy. Phospholipids are part of the membranes that surround all cells in the body and the smaller structures inside the cells. Sphingolipids and glycolipids are found mainly in brain and nerve cells. Various lipids also act as "molecular messengers" in our body system. In a way the mediate the communication between the cells.

Fate of fat in our bodies 
We take on lipids in the food we consume. Some foods are in particular rich in fat whereas some others, such as most of the fruit and veggies, lack the fatty content. When we intake fat, the body starts a digestion process. This basically causes the more complex lipids to be degraded into the basic components – the fatty acids. The fatty acids are further oxidized (= degraded) which releases energy for our body to use. FA can also be used for synthesis of compounds that the body needs. If there is too much lipids intaken, the excess of FA is built into triglycerides and these are stored as fat cushions.

Kinda different accumulation of fat... 
However, in some people the degradation mechanism of the lipids is impaired. Either not enough enzyme that controls the degradation is produced or it is missing completely. People with such metabolic disorders accumulate harmful amounts of lipids in various cells and tissues in the body. Over time, this excessive storage of fats can cause permanent cellular and tissue damage, particularly in the brain, peripheral nervous system, liver, spleen, and bone marrow. The thing is not that these patients get fat... the accumulated lipids in different organs cause for example various motoric disorders, decreased development and malformations of the organs.

Among the lipid storage disorders, as these malfunctions are called, belong for instance: Gaucher’s disease, Farber’s disease, Niemann-Pick disease, or Fabry disease. Different classes of lipids accumulate in patients with the particular disorder. The accumulation of fatty acids with a very long chain (i.e. with high amount of carbon atoms) is specific for Zellweger syndrome, and x-dependant adrenoleukodystrophy. All of the diseases have two major features in common: there is no cure for them & the patients typically don’t survive more than a few years. Intensive research is conducted to understand the mechanism of the diseases so that possible treatment could be assessed.

I am currently working on a big collaborative project that is investigating the molecular base of one of the lipids storage disorders. What I especially like about the project is the co-ordination of people with different expertise in a hunt to solve a sciencie question. Science has become so complex, that some questions cannot be answered by a single person but a joint effort of teams is required.

Good and bad fat  
These are examples of diseases that the patients cannot influence as they are caused by a mistake in their genes. Different lipid types will be accumulated independent of fat consumption. Our overall health, however, can be influenced by the type of the fat that we intake. The trick is to consume a little bit of (almost) everything. The health benefits of different fats are yet again based on the type of fatty acids they contain – on their number of double bonds and the length of the carbon chain.

Mono- and especially polyunsaturated FA are attributed a galore of health benefits. Monounsaturated FA are found mostly in veggie oils. The most often mentioned polyunsaturated FA are the famous omega-3 and omega-6, also called as anti- and pro-inflammatory fatty acids. (The numbers 6 and 3 stands for the position of the last double bond within the carbon chain.) After these types of FA are released from the particular fat types, they are used for synthesis of compounds that either fight against or support inflammation in our bodies. Now, inflammation is important for us as it is a defending mechanism. However, too much of inflammation is not good, hence increased intake of pro-inflammatory FA is not beneficial either. Since the western diet is rich on the pro-inflammatory FA, we should make sure we consume enough of their counterbalance mates – the omega-3 FA. The latter are found in cold water fish and in some seeds such as flax seeds.

Saturated FA (without any double bonds) were in the past linked with high cholesterol levels were linked with heart disease. Current research, however, cannot find the direct connections and saturated FA containing foods (such as butter) are being reprieved.

Coconut oil is a health hit at the moment. With the highest content of saturated fatty acids! It contains FA that have a relatively short carbon chain. In general, the shorter the carbon chain the easier are the fatty acids utilized. That has both, dietetic and medical advantages. So called medium chain triglycerides (MCT) present in coconut oil contain FA with a relatively short carbon chain.

On the other pole are the most harmful fats: the trans fatty acids. They are mostly created during a bad handling of good fats, particularly those containing the double bond(s). By the bad handling is usually meant heating them and moulding them into margarines.

Fat for athletes 
Now as athletes concentrating on the best body performance, me and my friends wanna make sure our bodies get the right fuel. That explains the hassle around the fat consumption that I mentioned at the very beginning of this post. It is simple: we are not afraid of fat… we just consume the good fat. So avocado smoothie with coconut oil? Yes! Please! French fries and a bread roll with margarine? No. Way.

 
 
Saturated – butter, coconut oil (MCT!); 
Monounsaturated – veggie oil, e.g. olive oil; 
Polyunsaturated – omega-3: flax seed oil, cold water fish;  
Polyunsaturated – omega-6: soybean, sesame & sunflower oil; 
Trans – processed food