Milk & Tryptophan

[QUOTE=ChangeOfStyle;1592667481][url]https://www.dairynutrition.ca/facts-fallacies/health-concerns/sleep-and-tryptophan[/url]

[url]https://www.ncbi.nlm.nih.gov/pubmed/26027501[/url]


Like I said mate, I might also be wrong but it says that there is Tryptophan in the milk but only low traces of it.

Tryptophan being the amino acid chemically involved in producing Serotonin and Melatonin

[url]https://www.healthline.com/nutrition/tryptophan#section1[/url][/QUOTE]

Read the snopes article I posted. I'm not saying milk doesn't have tryptophan - it does. But, any protein source contains tryptophan. But you have to take it in isolation away from other protein sources in order for it to make you sleepy.

In particular, tryptophan can be converted into a molecule called 5-HTP (5-hydroxytryptophan), which is used to make serotonin and melatonin (2Trusted Source, 3Trusted Source).

Let's take a look at the 2 sources they cite for tryptophan converting to melatonin.

2: Role of Melatonin in Traumatic Brain Injury and Spinal Cord Injury https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4283270/

I don't feel like digging up the whole study, but I would say this is not particularly relevant.

3: Conversion L-tryptophan to melatonin in the gastrointestinal tract: the new high performance liquid chromatography method enabling simultaneous determination of six metabolites of L-tryptophan by native fluorescence and UV-VIS detection.
https://www.ncbi.nlm.nih.gov/pubmed/23388477

In this study, the conversion of L-tryptophan to melatonin was determined in the serum collected from rats administered intragastrically with this amino acid acting as melatonin precursor.

[...]

We conclude that 1) L-tryptophan is converted to melatonin in the GI-tract *** during the day when the pineal gland synthesis is inhibited ***, and 2) the reverse phase high performance liquid chromatography (RP-HPLC) is a new sensitive and reliable method that could be successfully applied to the study of kinetics and metabolism of L-tryptophan in GI-tract.

So again, not very relevant to what we're talking about.

I'll just say this: in my YEARS of studying tryptophan and melatonin, I've never heard of tryptophan converting to melatonin. But, even if it does, milk would not be the ideal way of taking this. You would need to take tryptophan on any empty stomach as a supplement, or 5 hydroxy tryptophan. One other thing to consider is that serotonin and serotonin receptors are found all over the body, it converts in the blood stream, in the stomach and elsewhere. That's why 5HTP doesn't work well as an anti-depressant and SSRIs are used instead. It's just not a reliable method of increasing brain levels of serotonin.

Anyway, your point being, drink a glass of milk before bed to help you sleep. Hey, if that helps, go for it. But it's probably not the tryptophan in the milk that's helping you sleep.  ;)

*** Sleep and Tryptophan
Does drinking milk make you sleepy? Yes and no. Protein foods such as milk and milk products contain the sleep-inducing amino acid tryptophan. Having warm milk at bedtime is a good way to work towards reaching the recommended number of servings of Milk and Alternatives each day, and can be a comforting way to unwind.
*** Yet, consuming milk as such is unlikely to induce sleep, as the amount of tryptophan present in milk is too small.

Tryptophan is an amino acid that promotes sleep and is found in small amounts in all protein foods. It is a precursor to the sleep-inducing compounds serotonin (a neurotransmitter), and melatonin [hey, okay, maybe -- pogue](a hormone which also acts as a neurotransmitter). Thus, for tryptophan to have a sedative effect, it needs to enter the brain by crossing the blood-brain barrier. Additionally, since tryptophan uses the same transport system as other amino acids, it has to compete against them to enter the brain.1
Source: https://www.dairynutrition.ca/facts-fallacies/keyword/tryptophan

There's a lot more at that source, but that's kind of the main point.

Amount of tryptophan in milk:

Milk, whole, 3.25% milkfat
Tryptophan: 75mg
Milk, nonfat, fluid, protein fortified, with added vitamin A (fat free and skim)
Tryptophan: 56mg
Milk, reduced fat, fluid, 2% milkfat, protein fortified, with added vitamin A
Tryptophan: 56mg
Milk, lowfat, fluid, 1% milkfat, protein fortified, with added vitamin A
Tryptophan: 55mg
Source: https://nutritiondata.self.com/foods-001079000000000000000-3w.html

The typical dose of tryptophan used in supplements to induce sleep is around 500mg. 5-HTP is around 50-200mg.