As an Integrative & Functional Nutritionist I’m always looking for new ways to help people get well, heal, feel and look better in ways that the usual dietitian mantra of ‘eat a balanced diet‘ just won’t deliver.
When it comes to anti-aging nutrition, protein has gotten a lot of press.
This is because eating more of it, along with some resistance exercise (a.k.a weight training/lifting), helps to delay age-related muscle loss (sarcopenia) – that’s a good thing.
With the exception of leucine, other individual amino acids (that proteins are made up of) have been left out of the discussion
Enter glycine
What is glycine?
Glycine is 1 of 20 amino acids that make up the human body. Under normal healthy conditions, the body can make about 12 of the 20 amino acids on its own either from scratch or by recycling old amino acids as part of the normal turnover of the body [a.k.a. they’re considered ‘non-essential‘]. Cells and tissues are constantly being broken down and rebuilt.
The other 8 amino acids are called ‘essential‘ and therefore must be obtained from the diet.
Glycine has long been assumed to be a conditionally essential amino acid; that we need more of it only during times of illness and stress where supply cannot meet demand but new research suggests otherwise.
It’s estimated that the majority of glycine, 85% of it, comes from the conversion of another amino acid called serine; this provides the body with about 3 g per day with diet providing about another 1.5 to 3 g.
Taking this all together, the body has about 4.5 to 6 g of glycine that’s available for metabolic demands, not the least of which is collagen production, but here’s the rub – a 70 kg, or 153 pound, person needs about 15 g of glycine daily, leaving a deficit of about 8.5 to 10 g/day, give or take. A person weighing less will have less of a deficit but a deficit and still ‘be in the red’
It’s all about collagen
Collagen is the protein that is unique to the animal kingdom, and that includes us humans.
It is the most abundant protein in the body, accounting for over 25% of the total. It is a unique 3 strand protein molecule that provides ‘multi-cellular flexibility’, without it we couldn’t make the flexible tissues that allows us to move in these wonderful, mutli-jointed bodies.
Collagen is the primary structural protein that gives us form. Collagen is found in the skin, tendons, ligaments, cartilage, bones, teeth, corneas, blood vessels, and intervertebral discs; the tough spongy material that allows our spines to bend. Try doing yoga without that ability – it ain’t happening.
Thing is, in order for healthy and optimal collagen turnover, the body needs a steady supply of glycine everyday to meet its needs. For the longest time however, renewal of collagen (and all the tissues it’s found in) was not seen as a cause for concern for two reasons:
- collagen turnover/renewal was assumed to happen at a VERY slow rate
- glycine was always seen as a non-essential amino acid with the assumption that the body could make all that it needs
With better clinical research over the past 20 years it’s now understood that the body cannot make all of the glycine it needs from serine and that in a perfect world, dietary sources would make up the slack.
So what happens if we don’t get enough glycine?
If the body doesn’t get enough glycine from the diet and/or if the diet is low in total protein, it compensates by slowing down the rate of collagen turnover.
This is a problem because collagen, and the tissues rich in collage, get damaged to some degree (oxidation, advanced glycation end products) over time.
If the collagen isn’t getting repaired/rebuilt, the damaged proteins build up in the tissues such as skin, bone, ligaments, blood vessels etc. In turn, these tissues which can lead to many of the signs and symptoms of aging; to stay youthful, these tissues need new collagen to be made daily.
As I said, it’s now recognized that collagen turnover represents a significant proportion of the total amount of protein that the body turns over. You’ll see below that the body ‘wants’ to make a lot of new collagen every day – check out the net daily collagen synthesis of the different organs.
The other way the body compensates if it doesn’t get enough glycine it needs for neurotransmitter, bile acid, creatine and glutathione production, is to steal it from collagen from other tissues.
How is glycine anti-aging?
When we talk about anti-aging, we’re not talking about ‘not aging’ like a vampire but rather we strive for ways to greatly slow down and minimize the negative affects on the body that living long and living well does.
By supplying our bodies with ample glycine, we’re poised to make optimal amounts of collagen thereby providing the various tissues with what they need.
Gycine benefits possibly include more youthful attributes: stronger bones [since bones are essentially mineral scaffolding with collagen layered upon it], more flexible blood vessels, healthier corneas, better skin, and better quality ligaments, tendons and cartilage.
I want more glycine!
Historically the human diet was rich in glycine because humans left nothing to waste, they ate ‘from tail to snout’. By boiling the bones of animals with the ligaments, tendons and cartilage intact, bone broths, soups and stews were a rich source of glycine.
Since skin has a lot of collagen, and by extension glycine, fish, chicken and pork skin were also very rich sources of glycine but animal skin was erroneously thought to be bad since it’s high in fat and for decades fat was vilified when it comes to heart health.
check out these recipes at the Food Network, Great Lakes Gelatin and Paleo Parents. Including some of these strategies are but one option.
Because vegetarian diets are low in animal products, it’s not surprising that vegans and vegetarians show signs of more severe glycine deficiency. Another possible option is using a glycine supplement. Wondering how much glycine to take? Well, 1 tsp supplies 5 g of glycine, 50% of the conservative estimated deficit that most of us face.
The powder dissolves completely in water and has a nice sweet taste to boot making it an easy supplement to add to protein shakes, smoothies, juice, or even plain water. I love being my own Guinea pig so I’ve started to take a glycine supplement. I wonder as I provide more glycine if I’ll see a difference in the quality of my skin.
Doug Cook RDN is a Toronto dietitian and functional nutritionist with a focus on digestive, gut, mental health. Follow me on Facebook, Instagram and Twitter.