@karim22 Dairy isn’t lower in tryptophan,but I found these quotes from Ray Peat&Danny Roddy that migth explain it.
“Peat explained that the ratio of calcium to phosphate is a major contributor in whether or not tryptophan is converted into excess serotonin or into the preferable b-vitamin, niacin.
“The ratio of calcium to phosphorous should be very high. If you’re under stress, the phosphate becomes more a problem and adds to the stress. Meat and whole grains are major sources of phosphate. You have to be more concerned with your calcium intake if you have a meat or grained based diet.”
“Regarding milk and it’s tryptophan content, The calcium helps to keep the metabolic rate high, and the other nutrients help to steer tryptophan away from the serotonin path.”