Re: An introduction to ApoE4, biochemistry, and possible prevention strategies
Posted: Sat Jun 20, 2015 5:11 pm
THIRD IMPORTANT KIND OF LIPID: TRIGLYCERIDES
It is best to use the word fat to denote fatty acids and triglycerides and to use the word lipids to denote all the different kinds of lipids including cholesterol, phospholipids, fatty acids, triglycerides etc. However we colloquially say fat when we mean all lipids.
We now understand what the building blocks called fatty acids look like, BUT they don't occur like this in food. They are found joined to a glycerol molecule.
The glycerol looks like this. Please note it has three little sticky out thingies that are available to hold hands with something
It loves to hold hands with three fatty acid chains. Thus we get the word triglyceride. Tri meaning three.
Now the word acid comes into play. Acid means the fatty acid molecule can give up a hydrogen atom, thus freeing a hand. It can then use this hand to hold onto one of the hands on the glycerol molecule.
Here is a picture of a triglyceride, you should be able to recognise the three fatty acids in this triglyceride. The carbons are not denoted by C's because it there can only be a C at each link in the chain. It is not necessary to write the C each time like in the ring. But it is important to denote if there is a single bond or a double bond at each place.
The red one is polyunsaturated. It has three double bonds. They are each denoted by a double line between the carbons.
Can you work out what the blue and green ones are?
(Answer is here: viewtopic.php?f=6&t=1305&start=10 )
So what is the deal with triglycerides?
We eat triglycerides in our food. The triglycerides are made up of glycerol and three fatty acids each. We eat the triglycerides and they are chopped into the fatty acids and glycerol in our intestines so they can be absorbed. They are then reformed back into triglycerides in our blood. I will be calling triglycerides TG's from now on. The TG's are packaged together with cholesterol into particles by the liver, and the particles go through stages to eventually form LDL particles. They then go to the cells of the body for various purposes.
If there are more than we need, they are stored as fat. They are mainly stored inside the abdomen (Women store fat also under their skin and on their hips - less detrimental). This is belly fat. It is unfortunately not good for many reasons. It promotes IR, but it also secretes various hormones which cause inflammation in the body and make us hungry. Excess glucose is also converted to TGs for storage. So high TGs in the blood are a direct marker of IR. They are the excess glucose you can't burn being shuttled to your fat cells.
This is why we should not have an excess of calories. Excess TG's are stored as fat. Excess glucose is converted to TG's stored as fat. Excess protein is converted to glucose and then converted to TG's and stored as fat.
So let us assume that we are eating just enough fat for our needs. We then use it for various structural components - the skin of each cell, called the cell membrane, is made up of fats. Fats form the basis of many hormones. There are many other complex functions, but we can also use fats as fuel. This is called β-oxidation. It is pronounced "beta-oxidation". The β is the Greek symbol for the equivalent of "b" in our alphabet. This has implications for what I mentioned earlier - our mitochondria.
I will first briefly mention the last group of lipids and then get back to our mitochondria.
Glossary for Primer
It is best to use the word fat to denote fatty acids and triglycerides and to use the word lipids to denote all the different kinds of lipids including cholesterol, phospholipids, fatty acids, triglycerides etc. However we colloquially say fat when we mean all lipids.
We now understand what the building blocks called fatty acids look like, BUT they don't occur like this in food. They are found joined to a glycerol molecule.
The glycerol looks like this. Please note it has three little sticky out thingies that are available to hold hands with something
It loves to hold hands with three fatty acid chains. Thus we get the word triglyceride. Tri meaning three.
Now the word acid comes into play. Acid means the fatty acid molecule can give up a hydrogen atom, thus freeing a hand. It can then use this hand to hold onto one of the hands on the glycerol molecule.
Here is a picture of a triglyceride, you should be able to recognise the three fatty acids in this triglyceride. The carbons are not denoted by C's because it there can only be a C at each link in the chain. It is not necessary to write the C each time like in the ring. But it is important to denote if there is a single bond or a double bond at each place.
The red one is polyunsaturated. It has three double bonds. They are each denoted by a double line between the carbons.
Can you work out what the blue and green ones are?
(Answer is here: viewtopic.php?f=6&t=1305&start=10 )
So what is the deal with triglycerides?
We eat triglycerides in our food. The triglycerides are made up of glycerol and three fatty acids each. We eat the triglycerides and they are chopped into the fatty acids and glycerol in our intestines so they can be absorbed. They are then reformed back into triglycerides in our blood. I will be calling triglycerides TG's from now on. The TG's are packaged together with cholesterol into particles by the liver, and the particles go through stages to eventually form LDL particles. They then go to the cells of the body for various purposes.
If there are more than we need, they are stored as fat. They are mainly stored inside the abdomen (Women store fat also under their skin and on their hips - less detrimental). This is belly fat. It is unfortunately not good for many reasons. It promotes IR, but it also secretes various hormones which cause inflammation in the body and make us hungry. Excess glucose is also converted to TGs for storage. So high TGs in the blood are a direct marker of IR. They are the excess glucose you can't burn being shuttled to your fat cells.
This is why we should not have an excess of calories. Excess TG's are stored as fat. Excess glucose is converted to TG's stored as fat. Excess protein is converted to glucose and then converted to TG's and stored as fat.
So let us assume that we are eating just enough fat for our needs. We then use it for various structural components - the skin of each cell, called the cell membrane, is made up of fats. Fats form the basis of many hormones. There are many other complex functions, but we can also use fats as fuel. This is called β-oxidation. It is pronounced "beta-oxidation". The β is the Greek symbol for the equivalent of "b" in our alphabet. This has implications for what I mentioned earlier - our mitochondria.
I will first briefly mention the last group of lipids and then get back to our mitochondria.
Glossary for Primer