Commusings: It’s Hard to Be a Cell

Dear Commune Community,

It's not a Sunday, but we come to you with a bonus musings on the surprisingly complex journey of nutrients from outside to inside you. This piece is inspired by our partners at LivOn Labs, who are offering free samples (a $30+ value) of their high-absorption, liposome-encapsulated supplements with any purchase.

As you will hear from a tiny yet impassioned narrator, it’s one thing to consume a supplement, but quite another for those nutrients to reach your cells.

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It’s Hard to Be a Cell

I am Mildred C. Myocyte, a muscle cell in the left ventricle of Jeff’s heart, and although he seems to exercise a lot lately, I’m currently 53 years old and still going strong.

Fun fact about my family: While cells in the intestinal wall turn over every few days, during Jeff’s life, less than half of us cardiomyocytes will renew.¹ Now that’s commitment!

Let me tell you, though, it’s not easy being a cell.

Back in the old days – and by that, I mean 1.7 billion years ago – my unicellular eukaryotic ancestors simply ingested their nutrients directly from the primordial soup.

But, you know, solo life is a drag in a microbe-eat-microbe world, so a few of us got together, and one evolutionary thing led to another, until these days I live in this cozy apartment in Jeff’s thoracic cavity.

It’s a sweet neighborhood, but giving up my independence as part of a multicellular organism means that everything I need to function has to go through … Jeff!

More specifically, since I can’t sip straight from the primordial soup, I have to belly up to the sushi bar conveyor belt known as the bloodstream. And just like your 20-year-old nephew, I am hungry for a lot of sushi!

I help the heart beat about 100,000 times a day, and that requires not only ample fatty acids and carbohydrates for my mitochondria to convert into energy, but also an array of micronutrients such as CoQ10, L-carnitine, taurine, and other amino acids that serve as cofactors for energy production and transfer. Not to mention I need to build and deploy a wide variety of proteins and lipids to stay in working order.

So how do all those things get into the bloodstream? Mostly, Jeff has to eat them, and it’s not as simple as “once it’s inside Jeff’s mouth, it’s inside of him.”

Humans are doughnuts — the tube of your intestines is still “outside” you from the body’s perspective. Nutrients that survive the acid bath of the stomach still have to cross into the cells of the small intestine and then make their way into the bloodstream and to me.

Cell walls are mostly made of phospholipids (i.e. they are fat-based) and yet the blood is water-based. So everything I need has to move across lipid-based, water-repelling barriers and yet also be carried through the river of the blood. No simple feat.

For instance, Vitamin C is absorbed by intestinal cells through sodium-dependent Vitamin C transporters, while some B vitamins like Vitamin B12 require a special protein called intrinsic factor. You don’t need to remember the details, just that this process of facilitated diffusion can be inefficient — with the body only absorbing 50% or so of Vitamin C at higher doses, for example.² And while water-soluble vitamins circulate well through the blood, any excess isn’t easily stored and you pee it out.

Fat-soluble vitamins (A, D, E, K) also have a complex journey. They require bile salts for emulsification, which allows them to form micelles—small particles that can pass through the intestinal cell membrane. Once inside the cell, they are often repackaged into chylomicrons — tiny lipoprotein capsules that transport nutrients into the lymphatic system before entering the bloodstream. It’s not easy to deliver a fat on a watery river!

And finally, let’s say you want to supplement my poor, aching back (metaphorically speaking) with something like glutathione. This “master antioxidant” is great for mopping up the oxidative mess my mitochondria generate as they make energy so Jeff’s heart can keep beating. Glutathione is a peptide composed of three amino acids – glycine, glutamate, and cystine – and when that goes into the stomach, the same enzymes that would chew up your steak will chew up that peptide into amino acids for absorption. The body can make glutathione out of those amino acids, but, again, it’s not that efficient. The best way is to take it in a form that protects the peptide as it goes through the digestive system — such as in a phospholipid sphere known as a liposome.

I could go on, but I barely scraped through Organic Chemistry like most of my fellow multicellular pre-meds, so suffice it to say: The next time you take a bite of food, take a moment to wish it well on its long, convoluted journey into your hungry cells. It’s a miraculously complex process to move nutrients across your intestinal wall, into your bloodstream, and finally into a cell like me.

And, if you are going to treat your cells to a little something extra nice like glutathione, some B-vitamins, or maybe a smidge of magnesium, make sure you are thinking about how those nutrients will be getting through the digestive system to where they are useful.

On behalf of all your cells, I thank you from the bottom of Jeff’s heart. 

Footnotes
1. Cardiomyocyte Renewal
2. Vitamin C Fact Sheet for Health Professionals