Limit Your Methionine and Live LongerOctober 24, 2022
Limit Your Methionine and Live Longer
When your body codes for a new protein, it has a "start button" that signals "begin protein synthesis". After that start button, the protein construction begins by interpreting different codons of three DNA base pairs to add a new amino acid to the lengthening chain. That very first start codon is the same for methionine. Methionine, one of 8 essential amino acids we don't make on our own, is one of only two that have sulfur in it. Sulfur is a very active ion that plays a huge role in sucking up extra electrons, leading to glutathione (made from methionine) being so important as your natural, internal antioxidant. And sulfur ends up making your urine acidic. Bottom line: All protein synthesis starts with methionine. You can't make any new proteins without methionine. That's a given.
Curiously, we are now finding that methionine restriction plays a role in turning on your longevity genes, much like calorie restriction. The beneficial effects of calorie restriction that can be demonstrated in all mammals kick in strongly at the 40% calorie reduction mark. The problem with methionine restriction is that you likely have to get to some 80% restriction to get the same threshold of effect. That's harder to do. But methionine restriction likely explains why we should eat more plants and fewer animals. Plant-based proteins, just like animal proteins, all start with methionine but have a lot less of it. So plant-based diets are usually alkaline whereas animal-based diets result in a net acid milieu. Now, frozen peas only have 0.47%methionine whereas roast beef has 2.68% and eggs have 2.90% methionine. Likewise dairy and fish all have 2.5-3.0% methionine and similar effect on acidification.. Then there are Brazil nuts at 6%. The more vegan you eat, the less methionine you get (except for the Brazil nuts).
Is that a problem? Paul Saladino (author of the Carnivore Code) claims that it is not. He argues that methionine toxicity is overcome by having sufficient glycine (the simplest amino acid that is present at about 8% in meat and tendons). In other words, the whole animal, not just the meat. If you eat a pure cut of meat, he argues you better get some bone broth or eat some collagen to make of for the "gristle" you didn't eat. Then, the glycine repairs any "toxicity" of methionine and explains why you need to eat the whole animal, tendons and bones included.
The real key of methionine restriction may also come from understanding its roles in multiple downstream effects. For starters, methionine restriction appears to increase autophagy (eating old, garbage cells) due to the suppression of mechanistic target of rapamycin (mTOR). Secondly, it also decreases reactive oxygen species production in mitochondria. It plays a big role in methyl group donation and in that context, that opens up the whole field of our epigenome management and homocysteine balancing. Finally, it increases the production of hydrogen sulfide a molecule that has its own biology of lifespan extension.
But the final key may be the increase in glutathione production. Glutathione, the natural line of defense against free radicals, might be the most important chemical in your body. You make it from methionine but reducing methionine intake results in more available glutathione. Sounds paradoxical, but there it is. You want higher levels of glutathione to live longer and have less cognitive decline.
www.What will Work for me. I'm a bottom-line kind of guy. I'm finding more and more folks who have high levels of environmental toxins in them, which basically indicates inadequate glutathione production. We can now measure glutathione levels and I'm adding that to my testing of folks who are intent on keeping their brains safe. The low methionine idea is not practical. We can't eat an 80% reduced methionine diet, which is what it takes to induce measurable enhancement of longevity in animal models. We have enough challenges in calorie restriction. No one can do 40% calorie restriction, and maintain normal function. And, methionine "toxicity" is reversed by sufficient glycine. I'm back to chewing on the tendons and connective tissue in my steak. But we can choose to tilt the slope to more vegetables. Ok, that I can do. And now I have a good, concrete reason why that is helpful. Less methionine, more glutathione. More vegetables. Or more tendons. I have a hunch the more glycine hypothesis explains a lot.
References: Biomedicines, Fight Aging, Josh Mitteldor, Innovation in Aging, Saladino: Carnivore Code, Aging Cell,
1. What role does methionine play in protein synthesis? Answer: It is the first amino acid in all proteins and is the starting point. And it acidifies urine.
2. Methionine starts many cellular pathways. Can you name one? Answer: It is the compound that balances homocysteine and regenerates it. It plays a role in stimulating autophagy, the natural process of taking out the garbage of old cells. It helps build glutathione and make H2S which is a longevity inducer.
3. What foods have the lowest methionine content? Answer: Vegetables
4. Is there a nut that has very high levels of methionine? Answer: Brazil Nuts at 6%
5. Is methionine reduction really necessary? Answer: if you listen to Paul Saladino, he argues cogently that no, you simply need to add glycine which is the most abundant amino acid in beef at 8%, and even higher in bones and cartilage.