Food to Fuel
Before I start talking about what the liver does, let’s start by breaking down the chemical composition of our food. Four macromolecules make up all the food you eat: proteins, carbohydrates, lipids, and nucleic acids. Vitamins and minerals make up only a small percentage of food. Imagine eating an orange slice, the majority of what you are chewing and swallowing is water, sugar, and fiber. Digestive enzymes breakdown these macromolecules into their respective building blocks.
- Monomers of proteins are amino acids
- Monomers of carbohydrates are monosaccharides (or simple sugars)
- Monomers of lipids are fatty acids
- Monomers of nucleic acids are nucleotides
The small intestine absorbs the monomers and dumps them into your bloodstream. They travel to the liver via a big vein called the hepatic portal vein. Think of this giant organ as customs in an airport: everything that wants to enter the general circulation must first pass through inspection. Extra sugar is stored here as glycogen (debunking the glycemic index myth). The kidneys breakdown and excrete extra amino acids. Most importantly, non-food molecules are processed and detoxified. One example is your liver processing lactic acid produced by your muscles from anaerobic respiration. Another example is that of a common toxin we ingest for entertainment purposes: ethanol. Your liver produces an enzyme (alcohol dehydrogenase) that converts ethanol into acetaldehyde. Another liver enzyme, acetaldehyde dehydrogenase, then converts acetaldehyde to acetic acid.
Livers Detoxify Stuff!
There’s a reason why detox diets and glycemic index diets still exist in a world of growing obesity. These diets sound good, but try to poke around their logic with a bit of basic biology and you’ll quickly see all the holes in them. So remember:
- Food does not and cannot detoxify your body, your liver does.
- “Clean” diets aren’t any cleaner or better than simply cutting back on high-calorie, processed foods.
- Eating foods high in carbohydrates don’t cause sugar spikes because your liver and pancreas (and the insulin produced by the pancreas) regulates blood sugar levels.
- The glycemic index measures glucose in the blood; however, insulin regulates blood glucose levels. Therefore, this index isn’t a direct measure of glucose absorption from the small intestine.
We live in a world where capitalism is king. That means, making a profit is what drives businesses. Companies distort the fact, manipulate the studies, and market the results to sound titillating and magical. Through it all, the liver will still process and detoxify everything in your bloodstream. The day your liver stops working is the day you stop working, and no amount of detoxing or cleansing can bring you back from that.