Methionine

Methionine is a sulfur-containing amino acid that plays a crucial role in energy metabolism and cellular function. Methionine is probably the main activator of mTOR complex 1 1, a key regulator of cell growth and metabolism. The activation of mTOR by methionine is a normal process, but chronic elevation of mTOR can lead to increased cell growth and inflammation, contributing to aging and disease 5.

In contrast to its role in activating mTOR, methionine has also been shown to have protective effects against oxidative damage and inflammation. For example, a study found that a 40% restriction in methionine intake decreased mitochondrial oxygen radical production and leak at complex I, lowering oxidative damage to proteins and mitochondrial DNA in rat kidney and brain mitochondria 2.

Methionine's role in cellular function is closely tied to its ability to donate methyl groups, which are essential for various cellular processes, including the methylation of histones and DNA. With aging, DNA methylation is increased, and methylation is thought to stabilize and protect cells when growth and regeneration are not possible 3.

In certain contexts, such as cancer, methionine may have a more complex role. Georgi Dinkov has suggested that depletion of methionine may be therapeutic for brain cancer (glioblastoma) 4, although the mechanisms underlying this effect are not fully understood.

In terms of dietary intake, Ray Peat has emphasized the importance of balancing methionine intake with other nutrients. He has noted that a diet rich in polyunsaturated fats (PUFAs) can activate mTOR and contribute to cancer risk, and that excess iron can also be carcinogenic 6. In contrast, a diet rich in monounsaturated fats, such as olive oil, may be less problematic 6.