Tryptophan in food: The best sources

*Note: The header image is AI-generated

Tryptophan keeps popping up in your social media feed right now, sometimes as an insider tip for poor sleep, sometimes as the explanation for feeling tired after Christmas dinner. But what actually is tryptophan? Tryptophan is an essential amino acid, meaning a protein building block from your food that your body can't make itself. Among other things, it is turned into serotonin, a messenger substance in the nervous system, and later into melatonin, which signals evening to your body. In this blog post, we show you which foods give you a tryptophan-rich diet and how to make sure some of it actually reaches your brain.

The best tryptophan foods: Ranking with mg values per 100 g

Ranking of tryptophan sources:

Even within a group, it pays to take a second look. Cod and trout are at around 240 mg, herring at about 130 mg. Sunflower seeds reach around 310 to 350 mg, pork liver and tuna about 300 to 310 mg, chicken breast around 280 to 290 mg. Sausage doesn't do so well: salami has around 180 mg, frankfurters only about 110 mg. Lentils provide around 250 mg, rolled oats around 190 mg.

And the banana? It has a reputation as a tryptophan supplier, but only manages around 18 mg. Spinach comes to about 40 mg, kale to just over 60 mg, tomatoes and cucumbers to a single-digit number. Vegetables and fruit are valuable, but for tryptophan they're just supporting actors. Even milk, at around 80 mg, is far behind cheese.

Good to know: The same soybean is listed at 415 mg in one table and at almost 600 mg in the next. That depends on the variety, on the database (German tables or the US database USDA) and on whether the food was measured raw, dried or processed. For your shopping list, the order of magnitude is completely sufficient.

Plant-based tryptophan sources: How to cover your needs on a vegan diet

On a plant-based diet you're well set up: soy, seeds, nuts, legumes and whole grains play in the same league as meat and fish. Exactly how much they contain depends heavily on the database and the product. That's why looking at the groups helps here.

These plant-based ingredients are rich in protein and accordingly bring tryptophan with them:

If, as a vegan, you secretly worry that you're missing something without noticing: totally understandable, but with tryptophan there's no reason for it. If you regularly eat legumes, nuts, seeds and whole grains, you can realistically cover your needs with a balanced combination. Variety helps as well, because the protein building blocks of different plants complement each other.

Daily requirement: How much tryptophan does your body really need?

Adults need around 4 mg per kilogram of body weight per day, according to the reference value from the WHO, FAO and UNU (1). At 60 kg that's about 240 mg, at 70 kg around 280 mg, at 85 kg about 340 mg. There is no separate German value. The German Nutrition Society (DGE) follows this international reference.

Sounds like a lot of math, but you don't need to count in everyday life.

For a sense of scale: 150 g of chicken breast alone provides over 400 mg. All in all, a balanced diet usually covers the daily requirement without any additional measures.

What tryptophan does in the body: From protein building block to serotonin and melatonin

Tryptophan is an essential amino acid (meaning: your body can't make it itself, it has to come from food). Most of it goes into building protein, another part is converted into niacin (vitamin B3). Only a small share takes the route that people like to talk about so much.

This route has three stations: First, an enzyme converts tryptophan into 5-HTP (5-hydroxytryptophan). In the second step, this becomes serotonin, a messenger substance in the nervous system. Vitamin B6 is involved in this step and contributes to normal psychological function. In the third step, the pineal gland in the brain makes melatonin from serotonin in the dark, the hormone that signals evening to your body.

One detail is important for later: serotonin itself does not get from the blood into the brain. The brain makes it on site, and for that, tryptophan first has to get there.

Does food really make you tired? The turkey myth and what studies say about sleep

The tiredness after a turkey roast has little to do with its tryptophan. Experts consider this explanation to be disproven. Turkey doesn't contain more tryptophan than chicken, beef or cheese. In the ranking above, Parmesan and Edam come well ahead of any poultry. The heaviness after a festive meal is more likely attributed to the sheer amount on the plate.

The look at warm milk is similarly sobering. A 200 ml glass brings around 160 mg of tryptophan, along with plenty of other protein that competes for the same route into the brain. If the glass does you good in the evening, there's nothing against it. But it's hardly likely to be down to the tryptophan.

And the research? The most solid analysis is a meta-analysis by Sutanto et al. (2022) in the journal Nutrition Reviews, which summarizes 18 studies (2). Participants who received 1 g of tryptophan or more as a supplement spent less time awake after falling asleep than the group with less than 1 g. The authors themselves stress that further clinical studies are needed to clarify who benefits and at what amount.

For your plate, this means: the studies use isolated tryptophan in gram amounts, roughly three to four times the typical daily requirement of an adult. So for supplements there are first indications. Whether tryptophan-rich foods measurably change your sleep is still unclear.

If you want to know more about sleep and melatonin, this article might interest you: restful sleep in summer.

Meal ideas and combinations: How tryptophan reaches the brain

Tryptophan reaches your brain best when there's a portion of carbohydrates on the plate too. The reason lies at the blood-brain barrier, the filter between the blood and the brain. There, tryptophan competes with other large amino acids for the same transporters.

Carbohydrates make insulin levels rise. Insulin sends some of the competition into the muscles, and tryptophan then has a clearer path. A pure mountain of protein, on the other hand, brings lots of competitors along. A small irony, then: for this purpose, a steak night is less clever than a lentil curry with rice.

Here's what that looks like in everyday life:

By the way, the evening snack can be exactly that: a snack, not a sin. The seeds are rich in protein, the chocolate brings cocoa and a little sweetness. Works.

When food isn't enough: Supplements, interactions and when to see a doctor

For healthy adults with a balanced diet, a supplement with L-tryptophan or 5-HTP is usually not necessary. If you've been sleeping badly for weeks or feel persistently low, it's best to have the cause checked by a doctor before a dietary supplement comes into play.

If you take medication, this step is a must. Tryptophan and 5-HTP increase the production of serotonin. Certain medicines and plant substances enhance the effect of serotonin in a different way. In combination, serotonin syndrome can occur, an overreaction of the nervous system that requires medical treatment (3). These groups are affected:

For triptans, the German Migraine and Headache Society (DMKG) now considers the risk in combination with SSRIs or SNRIs to be very low (3). If tryptophan or 5-HTP is added on top, the decision still belongs in the doctor's office. Totally understandable if you're now wondering whether you're allowed to supplement anything at all. That's exactly the question your doctor will discuss with you. Your ongoing treatment remains unaffected.

If a supplement is an option for you, the following criteria help with the choice:

In studies, amounts from about 1 g of tryptophan were used. The recommended intake of the respective product is the limit you stick to. If you want to know more about 5-HTP, this article might interest you: what's behind 5-HTP.

Advertisement: CLAV 5-HTP 100mg + Vitamin B6 contains 100 mg of 5-HTP from the seeds of the African black bean (Griffonia simplicifolia) contributes to the regulation of hormonal activity. If you take medication, check with a doctor first. View the product

The shopping list as a first, realistic lever

What supports your tryptophan balance is the combination over the day: rolled oats in the morning, legumes, cheese or fish at lunch, a handful of seeds in the evening. Your next step is correspondingly small. Put last week's meal plan next to the ranking and see on which days none of the top sources was included.

If something is missing there, one more ingredient per meal is usually enough. And if sleep or mood don't play along for a longer time despite eating well, getting checked by a doctor is the right way to go.

Sources

1. (1) WHO/FAO/UNU (2007): Protein and amino acid requirements in human nutrition. WHO Technical Report Series 935.
2. (2) Sutanto et al. (2022): The impact of tryptophan supplementation on sleep quality: a systematic review, meta-analysis, and meta-regression. Nutrition Reviews 80 (2), 306 ff. PMID: [CHECK SOURCE]
3. (3) Pharmazeutische Zeitung, issue 35/2012: Lebensbedrohlicher Überschuss.

FAQ: Common questions about tryptophan in foods

What is the difference between tryptophan and 5-HTP?

5-HTP is the intermediate step between tryptophan and serotonin. Tryptophan is found in protein-rich foods and is first converted into 5-HTP in the body; 5-HTP itself hardly occurs in foods and is obtained from Griffonia seeds for supplements. The same interactions with serotonergic medications apply to both.

Can you get too much tryptophan from food?

No, practically not. The tolerable upper limit is considered to be 4.5 g per day; to reach it, you'd have to eat around a kilo of Parmesan. This limit only becomes relevant with supplements, which is why the manufacturer's recommended intake is what counts there.

What role do vitamin B6, magnesium and iron play in tryptophan utilization?

Iron and vitamin B6 are directly involved; for magnesium, the role is less clearly described. Iron is needed by the enzyme that converts tryptophan into 5-HTP, vitamin B6 for the step to serotonin. Whole grains and legumes supply both at once, and the banana at least plenty of B6.