It has been known for some time that excess methionine, an amino acid, accelerates aging, is carcinogenic, and has other pathological effects.
in modern society excess methionine results from a diet that we did not evolve with and are not engineered for. specifically, we evolved eating much more of the animals we hunted, not just their muscle, including bones and cartilage as well. while muscle is high and methionine, bone and cartilage are high in glycine. Methionine is used in many different reactions. One of them which essentially eliminates it from the body occurs in conjunction with glycine. both glycine and methionine are eliminated together.
So we eat much more methionine than glycine, leaving the unmatched methionine to accrue and wreak havoc.
A new study provided below published in June reveals an underlying mechanism common to many known causes of aging and leading to significant longevity. It is the increased down regulation of folate metabolism with age The rather complex biochemical mechanism through which reduced folate extends life is reduction of methionine and modulation of the methionine cycle intermediates.
And so we see in this incredibly rigorous and detailed paper that there is the simplest of levers, a single amino acid, common to many of the known processes that drive aging. It’s impact is hard to believe. According the authors, “Methionine restriction has a profound effect on physiology and regulates longevity through multiple mechanisms. First described to prolong life span in rodents, it shows overlapping but also distinct features from other longevity models. Notably, MR reduces adiposity, IGF-1, insulin, thyroid hormone levels, increases stress resistance, energy expenditure, insulin sensitivity as well as adiponectin and FGF21 levels. In concert with these changes, MR reportedly alters mitochondrial function, increasing aerobic capacity, and fatty acid oxidation utilization, as well as affecting redox state, reducing mitochondrial ROS production and altering glutathione and peroxidase levels48. Further, it can prolong life span in progeria models, and delay age-related decline in immune and cardiovascular function, as well as reduce cellular senescence in the kidney45. More recent work has suggested possible benefits of MR on human health including obesity, cancer, and various serum biomarkers.”
The only thing that makes it a challenge to reduce dietary methionine is that there is so much of it in so many foods. High-glycine foods are not as appetizing. We also synthesize in the body from other sources. It turns out that one of the ways the drug Metformin works is by reducing methionine synthesis.
So if you’re over 50 stop taking folate supplements and start eating metformin like peanuts.
Summary: https://www.mpg.de/1...eing-discovered
Full paper: https://www.nature.c...467-021-23856-9
