As an Integrative and 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 eating a balanced diet just doesn’t deliver.
When it comes to anti-aging nutrition, protein is recommended because eating more of it, along with some resistance exercise (weight training/lifting), helps to delay age-related muscle loss (sarcopenia). However, the 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. They’re considered ‘non-essential‘; where the cells and tissues are constantly being broken down and rebuilt. The other 8 amino acids are essential and must be obtained from the diet. Glycine is 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. However, new research states otherwise.
It’s estimated that the majority of glycine, about 85% of it, comes from the conversion of another amino acid called serine. This provides the body with about 3g per day, while the diet provides another 1.5 to 3g. Taking all this together, the body has about 4.5 to 6g 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 a 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.
It’s All About Collagen
Collagen is the protein that is unique to the animal kingdom including 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’. Collagen is the primary structural protein that gives us form. It is found in the skin, tendons, ligaments, cartilage, bones, teeth, corneas, blood vessels, and inter-vertebral discs; the tough spongy material that allows our spines to bend. Try doing yoga without that ability, you’ll see how hard it is!
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.
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 collagen 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. The buildup in these tissues 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.
How is Glycine Anti-aging?
When we talk about anti-aging, we’re talking about striving for ways to greatly slow down and minimize the negative effects on the body that aging causes. 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. Higher glycine intakes may result in a body with 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. Skin has a lot of collagen and by extension glycine, due to which we may turn to chicken, fish and pork skin as rich sources of glycine. However, 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.
Another option for getting glycine into the diet is through supplementation with a high quality gelatin. Gelatin is essentially the hydrolyzed collagen from animals and thus has many of the same beneficial nutrients and implications of bone broth. It is convenient and easy to incorporate into your diet. Add an extra scoop into your stocks, soups or sauces as a thickener or toss some into your daily smoothie.
Because vegetarian diets are low in animal products, it’s not surprising that vegans and vegetarians show signs of a more severe glycine deficiency. Another possible option is using a glycine supplement; 1 tsp supplies 5 g of glycine, 50% of the estimated deficit that most of us face. The powder dissolves completely in water and has a nice sweet taste, making it an easy supplement to add to protein shakes, smoothies, juice or even plain water.