One of the Most Overlooked Nutrients for Better Sleep

 Unlocking Better Sleep: The Tryptophan Amino Acid Connection

Tryptophan, an essential amino acid, is necessary in the synthesis of serotonin and melatonin, key regulators of sleep and circadian rhythms. A recent study published in Nutrients looked at the impact of dietary tryptophan intake on sleep quality among over 11,000 university students, a group notorious for erratic sleep patterns.

The study revealed that students consuming the highest amounts of tryptophan (over 800 mgs/day) experienced longer sleep and higher-quality sleep. Interestingly, even students who met the recommended daily intake of tryptophan (4-5 mg per kilogram of body weight) but were in the lowest quartile for intake, reported poorer sleep outcomes compared to their peers with higher intake levels.

Findings:

• tryptophan amino acid intake: Students in the highest quartile (over 804 mg/day) reported the best sleep outcomes.
• tryptophan as a sleep aid: Higher tryptophan intake was associated with reduced sleep onset latency and improved overall sleep quality, particularly in females.
• Dietary considerations: incorporating more tryptophan-rich foods may be a simple, yet effective strategy to enhance sleep quality.

This connection between tryptophan and sleep is not new but often overlooked. While many seek out flashier sleep aids, adjusting your diet to include more tryptophan might be a natural and effective solution. For those looking to improve their sleep, its important to remember diet is a key factor in sleep theory—what you eat can significantly impact how well you rest.

https://www.mdpi.com/2072-6643/16/14/2376 

Transcript

Speaker 0: 0:00

Hello everyone, I'm William Wallace and welcome back to Daily Value. Today, we're going to explore the connection between diet and sleep, specifically focusing on the essential amino acid, tryptophan, and how, even when meeting the recommended daily intake of dietary tryptophan, we may still not be getting enough to support sleep as best we can. This topic was raised by interesting research highlighting how tryptophan intake might influence sleep quality among university students, the population notorious for erratic and sufficient sleep schedules. This episode will dive into the details of how tryptophan could be a key player in improving sleep patterns and, again, how it's possible that, even when meeting national guidelines for dietary tryptophan intake, we may still not be getting enough. As always, a quick reminder this podcast is for educational purposes only. The information presented here should not replace professional medical advice, diagnosis or treatment, so please consult with a healthcare provider before making any significant changes to your diet or supplement regimen.

Speaker 0: 1:03

Sleep, as we all know, is a biological necessity. It's one of the pillars of physical, mental and social health. Short sleep durations have been tied to obesity, hypertension and the development of chronic conditions. Now, according to the Journal of Clinical Sleep Medicine, chronic insomnia affects 30% of the US population. According to a national health interview survey conducted in 2020, 15% of the US population. According to a National Health Interview survey conducted in 2020, 15% of adults have trouble falling asleep most days or every day, and 18% of adults have trouble staying asleep. Sleep troubles reach numbers as high as 75% in university and college students. There are several models built and proposed to understand sleep problems, most of which are based on something called the 3P model of predisposing, precipitating and perpetuating factors. Among these factors are medical, psychiatric, environmental, behavioral conditions, and diet and nutrition would also be included as one of those factors.

Speaker 0: 2:00

One of the primary propositions for how diet affects sleep is its influence on melatonin and its synthesis in the brain from the amino acid tryptophan, which is a precursor to the neurotransmitter serotonin, which can then be further converted into melatonin. Tryptophan, as most of us know, is an essential amino acid, meaning that our bodies cannot make it and we need to get it in adequate amounts through food. Tryptophan is necessary for several key processes in the body, including appetite regulation, sleep-wake rhythm and pain perception. It's tryptophan's conversion to serotonin that is thought to be necessary to fulfill most of these functions. Actually, research in rodents has showed that a single and ongoing oral doses of tryptophan can improve glucose metabolism and blood pressure, with those benefits being mediated by the actions of serotonin in the body. In fact, vasodilation and a reduction in core body temperature are two mechanisms that through which tryptophan and its conversion to melatonin has been proposed to improve sleep onset times. Interestingly enough, the enzyme that synthesizes serotonin operates at 50% saturation with its substrate under normal conditions, and what this means is that any change in tryptophan availability in the brain can significantly impact serotonin synthesis and by proxy melatonin.

Speaker 0: 3:21

As such, how much tryptophan we are taking in matters significantly, but not only that. The ratio of tryptophan we are taking in matters significantly, but not only that. The ratio of tryptophan to other large neutral amino acids, tyrosine being an example, is critical because it determines how much tryptophan will be able to compete for transport across the blood brain barrier. This is why taking large supplemental doses of specific amino acids in favor of others, done consistently, is thought to be detrimental in some cases. A good example would be high, consistent intakes of an amino acid like tyrosine, which is very common in energy drinks and pre-workout supplements. Taking in high doses could potentially be out-competing other amino acids like tryptophan that we aren't taking in at such high concentrations, and it could be out-competing amino acids like tryptophan for transport into the brain, thereby potentially limiting the brain's substrate to make other adequate amounts of serotonin. Of course that's theoretically, but mechanistically plausible. Any time one amino acid is supplied in abundance, it can compete with others for absorption, transport, synthesis and metabolism. Now think about how that might affect bodily function when stretched over time.

Speaker 0: 4:33

Now the study that we're focused on was published in the journal Nutrients in July of this year, and it involved 11,000 university students, more than 50 of which reported short sleep duration and 55% of people reported inadequate sleep efficiency. The study found a significant association between tryptophan intake and sleep quality among university students, and although studies are usually population dependent, it's not so much the student aspect that I want to focus on, albeit a very notable characteristic of the findings. Now, the results showed that students who consumed higher amounts of tryptophan-rich foods were more likely to experience longer sleep durations and better sleep quality. The study divided students into quartiles based on their daily tryptophan intake, with the medium tryptophan intake being around 700 milligrams per day. For reference, beef contains about 374 milligrams of tryptophan per 100 grams, meaning that a standard four ounce serving of beef would yield close to 115 milligrams of tryptophan.

Speaker 0: 5:38

Now, participants in the lowest quartile of intake, that was, under 525 milligrams of tryptophan a day, had a higher risk of experiencing short sleep duration and insomnia. Interestingly, female students were particularly affected, with those consuming the least tryptophan reporting the worst sleep outcomes. Consuming the least tryptophan reporting the worst sleep outcomes. Those in the highest quartile of tryptophan consumption, that was, over 804 milligrams per day, had the best reported sleep, with the fewest reports of short sleep durations or trouble falling asleep.

Speaker 0: 6:11

One of the most interesting things about this study was that people in the lowest quartile for tryptophan intake were taking in the daily recommended amount of dietary tryptophan, that being between four and five milligrams per kilogram of body weight. So these people were still taking in recommended amounts of tryptophan, but their sleep suffered compared to their counterparts with higher levels of intake. Now I'm roughly 180 pounds, so according to national recommendations, I should be getting in at least 369 milligrams of tryptophan per day, which would put me below the average of the lowest quartile in this case. Now, it's worth noting that, due to the design of this study, the results might indicate that diet as a whole in this population was of lower quality, but given that dietary tryptophan requirements were covered at a minimum. That would suggest that the diet would not be the only reason for poor sleep in this population, which is unsurprising.

Speaker 0: 7:08

We all know that there are plenty of other factors that contribute to poor sleep in college students. However, this connection between tryptophan and sleep is one that is well supported by previous research in animals and humans. Several large population studies conducted in different areas and geographical regions have all demonstrated that tryptophan influences sleep through increasing levels of hypnotic neurotransmitters, serotonin and melatonin Notably. A meta-analysis published in 2022 found that doses of at least one gram of supplemental tryptophan can shorten sleep onset latency, meaning the time it takes somebody to fall asleep after getting into bed, and it can also improve someone's subjective sleep quality somebody specifically with insomnia.

Speaker 0: 7:54

Incorporating tryptophan-rich foods into daily meals is another very straightforward and practical way to improve sleep quality. Potentially, some of the best sources of tryptophan include turkey, beef, pork, chicken, cheese, yogurt, eggs, tofu, and then there, of course, there are some seeds and nuts. In conclusion, the link between tryptophan intake and sleep quality is not a new one, but it may be an often overlooked one, one that we may take for granted and don't pay much attention to while we search for flashier sleep aids by making simple dietary adjustments, it may be possible to achieve better sleep, which, in turn, can lead to improved daily performance and overall well-being. Thank you for tuning in to Daily Value. If you found this episode helpful, please subscribe and share it with others who might benefit from this information. If you haven't yet, please give the YouTube page a follow so that I can continue to build this show out. Until next time, sleep well and stay healthy.