Tryptophan

Tryptophan is an essential amino acid for life, and its metabolites, including serotonin, are crucial for various bodily functions. Every kind of organism is built with proteins containing tryptophan, which gives them the electronic property that allows them to sense and move 1. This property is at the heart of sensation, movement, secretion, and consciousness, and disturbances in tryptophan or its metabolites can have profound effects on life.

Tryptophan is also involved in the regulation of the immune system, with research showing that administration of serotonin or its precursor, S-hydroxy-L-tryptophan, can lead to a marked depression of the immune response in mice 2. Furthermore, the thymus weight is reduced, suggesting that the effects may be due to thymus involution.

The amount of tryptophan required decreases with time as the rate of growth slows, and in some animals, such as rats, growth stops just a short time before they die 3. This suggests that tryptophan may play a role in the aging process. Additionally, nutritional recovery does not reverse the activation of brain serotonin synthesis in the ontogenetically malnourished rat, indicating that tryptophan metabolism may be affected by early life experiences 6.

Ray Peat has also suggested that deranged autonomic control in hypothyroidism may be caused by changes in central serotonergic activity, and that prenatal administration of L-tryptophan can increase brain serotonin synthesis and Na+,K+-ATPase activity in infant rats 5. However, he also notes that nutritional recovery does not reverse the activation of brain serotonin synthesis in the ontogenetically malnourished rat, suggesting that tryptophan metabolism may be affected by early life experiences 6.

In terms of dietary recommendations, Ray Peat advises against taking L-tryptophan supplements, as they can lead to negative effects such as inflammation and diabetes 8. Instead, he recommends a diet that includes unsaturated fats, which are known to contribute to diabetes and inflammation, and avoiding sugar, which has been used as a cure for diabetes.