Nutrition series: How is sugar metabolised ? - DAY 2 ( 30 days writing challenge)
This is my second post in the nutrition series that I will be covering for the next 30 days. If you want to know more about why I'm doing this series you should check out this post here.
Before I jump head first in the sticky business of how sugar works in our bodies I want to make a short recap of some very important distinctions in terminology. Sugar, or to be more precise, table sugar is also called sucrose. Unfortunately people use the term "sugar" to describe everything from carbohydrates to blood sugar. I'm going to avoid jumbling your neurons and only use table sugar and sucrose to describe that sweet powdery stuff.
Like I said last time table sugar is composed of glucose and fructose and once ingested it is broken down into these two parts in the small intestines. This is where the interesting stuff begins because fructose and glucose have different effects on the metabolism.
Glucose is funny in a way because it's the body main source of energy but it can't enter most cells except in the presence of insulin, a hormone that is secreted by the pancreas. You can think of insulin like a gentleman, opening the door for the "posh" glucose who can't be bothered to do it herself.
There are exception to this rule: the brain, red blood cells and muscle cells during exercise kind of ignore the fact that glucose wants to be treated like a high society member and basically tells her that she can let herself in because they're not going to deal with that sort of shenanigans.
The rest of the cells do need insulin and that's why glucose determines an increase in insulin levels, it's like glucose is calling for it's personal butler to open the right dors.
Going back to when glucose was absorbed into the bloodstream; from there about 1/3 goes to the muscles and fat tissue, 1/3 to the liver and 1/3 to the brain and red blood cells.
As you can see the liver doesn't process but of fraction of the glucose ingested, that will be important when we look at fructose.
The thing is, because table sugar contains such simple molecules and does not come with any fiber (when we get it from processed food), it will rapidly increase glucose levels in the blood which in turn will cause a big secretion of insulin from the pancreas.
One of main effects of this big and abrupt rise in insulin levels is that it decreases glucose levels very rapidly to a level that is usually below what we started with and gives the sensation that we are hungry and tired - the sugar low. This will make us eat more even if we don't really need it.
The other big side effect is that insulin will promote the conversion of all that excess glucose into fat.
So too much glucose too quickly is bad. And what about fructose, it is contained in fruit so it can be that bad, right? WRONG.
Fruits don't contain a lot of fructose even if they contain a lot of simple sugars like glucose. In addition to that, fruits come with fiber and polyphenols that regulate the absorption of glucose and indirectly fructose because glucose stimulates the absorption of fructose.
So, why is fructose bad? Because it's not an essential substance for our survival and it's metabolised in our liver where it is converted mostly into triglycerides ( a form of fat). This can lead to fatty liver over time and other metabolic problems. Fructose has even more bad attributes but I will cover them in the next post.
The main thing you should remember so far is that table sugar is bad; but fruits, mainly because of their fiber content, are good despite the fact that they contain glucose and fructose just like sugar.
See you tomorrow when we will discuss in depth how sugar negatively impacts our health. Stay tuned !
Previous post in the series:
What is sugar?
My name is Adrian a.k.a "The nearsighted traveler". I'm a running enthusiast who loves to spend time enjoying nature. I write mostly about running, the places I explore and the interesting stuff I learn here on steemit.
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5 Easy Rules for Navigating The Steem Ecosystem
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