Glycine, Obesity and Heart Disease: What the Evidence Actually Shows
Dr. Joel Brind argues that obesity and cardiovascular disease are essentially glycine deficiency diseases. Nick, a molecular medicine researcher, pulls up the cited studies and finds the associations are real but far narrower than the claim. Glycine looks genuinely useful, just not the single missing key.
Overview
This episode of The Centrifuge examines glycine claims made by Dr. Joel Brind on the Rethink Health podcast with Dr. Autumn Smith. Brind first criticises modern research for starting from large untargeted datasets rather than from a hypothesis, which the host partly disputes: omics technology compresses years of single-molecule work into days. The centrepiece is the EPIC study, where vegans showed higher blood glycine (452) than meat eaters (390) despite meat eaters consuming far more of every amino acid, a pattern Brind attributes to methionine consuming glycine.
The host confirms the numbers but notes glycine was only one of many amino acids that differed, and the study was never designed to explain disease rates. Brind then cites Mayo Clinic work on childhood obesity, where lower blood glycine tracked with insulin resistance markers before any disease appeared, and argues obesity itself suppresses glycine synthesis. The host again finds the study and again finds the association uncontrolled for other contributors.
He also surfaces an uncomfortable counter-signal: at least one study links higher glycine intake to greater stroke-related mortality. His conclusion is measured rather than dismissive, since randomised trials do point toward real glycine benefits, including on sleep. The takeaway is that glycine deserves attention, but confidence in it as the sole explanation outruns the data.
Key quotes
5In the old days, they used to call that a fishing expedition.
The meat eaters had the least amount of glycine in their blood.
You learn more and more about less and less until you know everything about nothing.
Obesity shuts down glycine synthesis.
It is unlikely that it is the only factor.
Key ideas
9Hypothesis-driven versus data-driven science
Brind contrasts classic science, where an observation leads to a hypothesis and an experiment, with today's omics-first approach. He sees the newer style as searching without knowing what you are looking for.
Why untargeted screening earned its place
The host defends omics as a practical accelerator: thousands of molecules can be compared between healthy and sick groups in days rather than years. The most divergent molecules then become targets for proper testing.
The EPIC amino acid comparison
European researchers tracked intake and blood levels of amino acids across vegans, lacto-vegetarians, fish eaters and meat eaters. Every amino acid behaved predictably except one.
The glycine paradox
Meat eaters ate the most glycine yet carried roughly twenty percent less of it in their blood than vegans, at 390 versus 452. The gap was statistically confirmed.
Methionine as a glycine consumer
Brind's explanation is that methionine, abundant in muscle meat, uses up glycine. Animal work going back decades showed methionine loading stripping glycine from the liver.
The nose-to-tail argument
Bones, cartilage and connective tissue carry the glycine that muscle meat lacks. Brind suggests eating the whole animal closes the gap that shows up when only muscle is eaten.
One amino acid cannot carry the whole story
The host points out that glycine was far from the only difference between the groups. Fat composition, iron and many other compounds also separate plant-based from animal-based eating patterns.
Glycine markers in children
Mayo Clinic cardiologists looked for adult cardiovascular signatures in obese children before disease appeared. Lower blood glycine tracked with higher insulin resistance scores.
The counter-signal nobody quotes
At least one study associates higher glycine intake with increased stroke-related mortality. The host raises it not to alarm but to show the picture is unfinished.
Practical takeaways
6- 1
Intake and blood levels are different questions 6:20
Eating more of a nutrient does not guarantee more of it circulating. Glycine is the clearest example of that gap in this discussion.
- 2
Balance matters more than a single amino acid 9:50
Methionine and glycine interact, so the ratio in a meal pattern is more informative than either number alone.
- 3
Traditional whole-animal eating had a logic 11:30
Broths, cartilage and connective tissue were part of classic cuisines and carry glycine that muscle-only eating leaves out.
- 4
Read the study, not the headline 13:00
Both of the studies cited here support a narrower claim than the podcast statement built on them, which is only visible if you open them.
- 5
Early markers appear long before symptoms 15:20
The children's data show metabolic patterns shifting years before any diagnosis, which is why tracking markers over time is more useful than a single snapshot.
- 6
Interest without certainty is the honest position 19:20
Randomised trials do point to real glycine benefits, including on sleep, while the disease-cause claim stays unproven. Both can be true at once.
Topics & chapters
15The Centrifuge format and today's guest
Nick introduces the show and Dr. Joel Brind, a biomedical sciences researcher who focuses on glycine. Three claims are set up for review.
What counts as science
Brind describes the classic observation-hypothesis-experiment loop. He argues that what is now called data-based science skips the question entirely.
Omics and the fishing expedition
Measuring hundreds of metabolites at once and letting the computer find differences strikes Brind as backwards. He compares it to fishing without a target.
The host's counterpoint
Nick argues untargeted screening compresses years of sequential testing into days. The divergent molecules it surfaces still get tested properly afterwards.
Setting up the EPIC comparison
A European consortium compared amino acid intake and blood levels across four dietary groups of a hundred people each. Diets were tracked closely.
The one amino acid that broke the pattern
More lysine eaten meant more lysine in blood, and the same held throughout, except for glycine. Meat eaters ended up lowest.
Checking the numbers
Nick opens the study and confirms 452 for vegans against 390 for meat eaters, statistically significant. He also flags the many other amino acids that differed.
The methionine mechanism
Decades-old animal work shows methionine loading depleting liver glycine. This underpins Brind's argument about muscle-meat-heavy eating patterns.
Eating nose to tail
Bone, cartilage and collagenous tissue are offered as the fix for the shortfall. Nick agrees it could help while resisting the idea that glycine is the missing key.
Specialisation and the joke about knowing nothing
Brind blames narrow expertise for leaving findings unconnected for decades. He praises nutrition for thinking about the whole person.
The Mayo Clinic childhood obesity work
Cardiologists searched obese children's blood for adult cardiovascular patterns before disease onset. Glycine was what they found.
A self-reinforcing loop
Brind argues that obesity itself suppresses glycine synthesis, deepening an existing shortfall. Nick locates the study and finds the association tied to insulin resistance.
The stroke signal
Nick raises research linking greater glycine consumption to higher stroke-related mortality. It sits awkwardly against the protective narrative.
Where the evidence lands
Three conclusions close the review: plant-based eaters do carry more blood glycine, glycine is unlikely to be the only factor, and supplementation still looks broadly favourable.
Closing notes
Nick points to trial evidence on sleep and previews a follow-up episode on the same podcast.