A person may start to experience more health issues such as gaining extra weight along with sleep problems when he or she gets older. While you may say that that is a normal part of aging, there may be some common causes other than aging, such as a diet missing some important nutritional factors that may play a role.

 

    To get a good night of sleep, a person needs to feel relaxed where serotonin production is important. Serotonin in your brain regulates your mood. It’s often called your body’s natural “feel good” chemical. When serotonin is at normal levels, you feel more focused, emotionally stable, happier, and calmer. Low levels of serotonin are associated with depression. Serotonin, together with another neurotransmitter dopamine, plays a role in the quality of your sleep (how well and how long you sleep). Your brain also needs serotonin to make melatonin, a hormone that regulates your sleep-wake cycle.

 

    Serotonin is made from the essential amino acid tryptophan in the human body. An essential amino acid means it can’t be made by your body. It has to be obtained from the foods you eat. During the synthesis of serotonin from the essential amino acid tryptophan, many cofactors or coenzymes are needed for the production to occur. Serotonin synthesis requires many cofactors or coenzymes which include pyridoxal-5-phosphate (an active form of vitamin B-6), niacin (vitamin B3), methyl B-12 (vitamin B12), folic acid (vitamin B9), and magnesium.

 

    Without an adequate amount of these nutritional factors, serotonin production may be reduced, and you may not feel relaxed or fall asleep easily. Among these important nutritional factors, one is vitamin B6, also known as pyridoxine. Vitamin B6, or pyridoxine, is a water-soluble vitamin found naturally in many foods. Pyridoxal 5' phosphate (PLP) is the active coenzyme form and most common measure of B6 blood levels in the body.

 

    One study investigated dietary contributors to relationships between sleep and all-cause mortality among elderly men and women in Taiwan. This study examined the relationships between diet quality to sleep and mortality, and whether gender and diet-associated sleep patterns predict survival during a 10-year follow-up of an elderly Taiwanese population (1).

 

    The data used for the analysis were from one thousand eight hundred sixty-five individuals aged ≥ 65 years (942 men and 923 women) subjects from Nutrition and Health Survey in Taiwan (NAHSIT) for elders during 1999-2000. Dietary diversity scores (DDS) were from 24-hour dietary recalls. Participants were examined and fasting blood was taken. Sleep quality was assessed by questionnaire and classified as poor, fair, or good. Death registry linkage was made until December 31, 2008 (1).

 

    For the vitamin B biomarkers examined (vitamins B-1, B-2, and B-6 and folate), only plasma pyridoxal phosphate (PLP, biomarker for vitamin B6) had a significant joint effect with sleep on mortality (interaction for men: p < 0.01, for women: p = 0.03). For women, poor sleepers had significantly lower vegetable and vitamin B-6 intakes compared to good sleepers (p < 0.05). For men, good and fair sleepers had a lower risk of death compared to poor sleepers after adjustment with hazard ratios (HRs) and 95% confidence intervals (CIs) of 0.60 (0.42-0.87) and 0.55 (0.36-0.86). The joint HRs for "DDS > 4 and good sleep" were 0.38 (0.22-0.66) for men and 0.52 (0.30-0.88) for women compared to "DDS ≤4 and poor sleep." The joint hazards ratios for "plasma pyridoxal phosphate (PLP, vitamin B6) adequate and fair sleep" were 0.27 (0.11-0.65) and 0.49 (0.23-1.07), meaning reduced risks 73% and 51%, respectively, compared to "insufficient and poor sleep" for men and women (1).

 

    The results from this study suggested that sleep quality played an important role in mortality. Sufficient dietary diversity in men could offset the adverse effect of mortality from poor sleep. In women, PLP (vitamin B6 status) predicted mortality more than sleep did (1).

 

    The relevance of vitamin B-6 to sleep was substantiated by the observation that there was a joint effect of insufficient PLP (biomarker for B-6) and poor sleep on mortality. As we know that the primary role of vitamin B-6 is to act as a coenzyme. It has a role in neurotransmitter synthesis, including that of serotonin. Serotonin helps regulate sleep and appetite. A deficiency of vitamin B-6 may cause sleep disorders due to serotonin insufficiency. Sleep problems and a diet low in nutritional factors can both contribute to mortality risk.

 

    The National Health and Nutrition Examination Survey (NHANES) is a program of the National Center for Health Statistics to assess the health and nutritional status of the population in the United States. A study examined the associations between serum PLP concentration and sleep-related problems (sleep quality and sleep duration) in adults, using the data of the NHANES 2005-2010. High-performance liquid chromatography (HPLC) was used to test PLP in blood samples. Sleep quality and sleep duration were based on self-reported data, with sleep quality categorized as a sleep disorder, trouble falling asleep, waking up during the night, and daytime sleepiness. Data from 9710 adult people were included to study sleep quality and 15,206 were included to study sleep duration (2).

 

    Compared with the first quartile (Q1), the odds ratios (ORs) and 95% confidence intervals (CIs) of daytime sleepiness for the Q2 and Q3 of serum PLP concentrations were 0.76 (0.59-0.99) and 0.78 (0.62-0.98), respectively. This means that a person with a higher vitamin B 6 level is less likely to feel daytime sleepiness (2).

 

    Compared with the normal sleep duration (7-<9 hours) group, serum PLP concentrations were negatively associated with the risks of very short (<5 hours), short (5-<7 hours), and long sleep duration (≥9 hours), with relative risk ratios of 0.58 (0.43-0.81) (Q4), 0.71 (0.61-0.83) (Q4) and 0.62 (0.34-0.94) (Q3), respectively. This means that a person with a higher vitamin B 6 level is more likely to have normal sleep duration and less likely to have either too short or too long of sleep duration (2).

 

    The relationships between vitamin B6 status and sleep quality found in the general adult population were as follows: people with normal sleep duration had the highest average serum PLP concentrations; serum PLP concentrations were negatively associated with daytime sleepiness; and serum PLP level was also inversely related to abnormal sleep duration (very short, short, long) compared to normal sleep duration (2).

 

    One Japanese study investigated whether a combination of tryptophan and vitamin B6-rich breakfast and light with the low color temperature at night could enhance melatonin secretion and encourage earlier sleep times. The rationales for the study were that earlier epidemiological studies in Japan had documented an association between morning type and a tryptophan-rich breakfast followed by exposure to sunlight in children. The association may be mediated by enhanced melatonin synthesis, which facilitates sleep at night. However, melatonin is inhibited by artificial light levels with high color-temperature common in Japanese homes at night. Therefore the authors proposed to study a few key components of a good night's sleep which included 1) having breakfast with protein- and vitamin B6 - rich foods and 2) exposure to sunlight after breakfast plus 3) exposure to incandescent light (low-temperature light) at night (3).

 

    The participants were 94 members of a university soccer club, who were divided into 3 groups for the intervention (G1: no intervention; G2: asked to have protein-rich foods such as fermented soybeans and vitamin B6-rich foods such as bananas at breakfast and sunlight exposure after breakfast; G3: the same contents as G2 and incandescent light exposure at night). Salivary melatonin was measured around 11:00 p.m. on the day before the beginning, a mid-point, and on the day before the last day a mid-point and on the last day of the 1-month intervention (3).

 

    In G3, there was a significantly positive correlation between the total hours the participants spent under incandescent light at night and the frequency of feeling sleepy during the last week (p = 0.034). The salivary melatonin concentration of G3 was significantly higher than that of G1 and G2 in combined salivary samplings at the mid-point and on the day before the last day of the 1-month intervention (p = 0.018), whereas no such significant differences were shown on the day just before the start of the intervention (p = 0.63) (3).

 

    The combined intervention of breakfast, morning sunlight, and evening lighting seemed to be effective for students including athletes to keep higher melatonin secretion at night which seems to induce the easy onset of night sleep and higher quality of sleep (3).

 

    This intervention also showed a positive impact on the students’ mental health. The participants in G3 after the intervention showed a lower anger/irritation index than before the intervention (p = 0.002). Two components of the anger/irritation index, the frequency to be irritated and the frequency to become angry due to small triggers, were also reduced after the intervention in comparison with before the intervention in G3. A lack of serotonin can cause depression, panic disorder, obsessive-compulsive disorder, sleep disorders, and eating disorders and induces aggression, anxiety/aggression-driven depression, impulsive behavior, and suicidal attempts. Serotonin thus has a strong relationship with mental health (3).

 

    The reason why vitamin B6 may benefit sleep is related to serotonin production. Stress and anxiety are inevitable for people who live busy lives. Without a healthy and nutritionally adequate diet, your body may not be able to synthesize the “feeling good” neurotransmitters for you to relax and fall asleep at night. That’s why the more worries you have, the less likely you would eat healthy meals, which would make it even less likely for you to have a good night's sleep.

 

    As you may have noticed that there are various cofactors needed for serotonin production, and other cofactors are needed for melatonin production from serotonin, a good night of sleep can only be possible if you have a well and balanced healthy diet with all these nutritional factors sufficiently present. Deficiencies in many of these cofactors are widespread due to how poorly most Americans eat, thus a healthy and well-balanced diet would be very likely the solution for the sleep issues you may experience, which may not be “corrected” by supplementation of a single factor. A previous blog talked about magnesium and sleep, for example, talking about other than vitamin B6 mentioned here, magnesium may also play a role in sleep.

 

    What are some of the vitamin B6-rich foods? Here are some numbers from Wikipedia for your reference:

Food Source, Amount (mg of vitamin B6 per 100 grams of food)

Whey protein concentrate, 1.2

Beef liver, pan-fried, 1.0

Tuna, cooked, 1.0

Beef steak, grilled, 0.9

Salmon, cooked, 0.9

Chicken breast, grilled, 0.7

Pork chop, cooked, 0.6

Turkey, ground, cooked, 0.6

Banana, 0.4

 

    Meat is a good source of vitamin B6 as well as tryptophan. Having some high-protein foods for breakfast can be a good strategy to boost intake for both. For commonly consumed fruits, bananas stand out as good sources of vitamin B6, which contain 0.4 mg/100 g vitamin B6. Even a small banana is typically over 100 g in weight.

 

    The recommended dietary allowance (RDA) for vitamin B6 in the United States is: for males, the RDA is 1.3 mg daily for those 19-50 years old, and 1.7 mg daily for those over 50 years; for females, the RDA is 1.3 mg daily for those 19-50 years old, and 1.5 mg daily for those over 50 years.

 

    We have learned from the study of older adults in Taiwan that people with poor sleep quality consumed less vitamin B6 than those with good sleep quality (1). We also learned from the analysis of data from the United States adult population that people with normal sleep duration had the highest plasma vitamin B6 levels, and people with higher vitamin B6 levels were less likely to experience sleep problems (2).

 

   From the college study (3), we have learned a demonstrated effective way of improving your sleep by eating more vitamin B6 and tryptophan-rich foods (meats are good sources of both vitamin B6 and tryptophan, and bananas for vitamin B6) at breakfast, then going outdoors to have some morning sunshine which can enhance serotonin production, and importantly to use “low-temperature light” emitted from incandescent bulbs at night to allow serotonin to be processed to melatonin. This method worked in young college students, and you probably can benefit from that and start to enjoy a good night's sleep as well.

 

References:

 

1. Huang, Y.-C., Wahlqvist, M. L., & Lee, M.-S. (2013). Sleep Quality in the Survival of Elderly Taiwanese: Roles for Dietary Diversity and Pyridoxine in Men and Women. Journal of the American College of Nutrition, 32(6), 417–427. doi:10.1080/07315724.2013.848158.

2. Ge L, Luo J, Zhang L, Kang X, Zhang D. Association of Pyridoxal 5'-Phosphate with Sleep-Related Problems in a General Population. Nutrients. 2022 Aug 26;14(17):3516. doi: 10.3390/nu14173516. PMID: 36079774; PMCID: PMC9460331.

3. Wada K, Yata S, Akimitsu O, Krejci M, Noji T, Nakade M, Takeuchi H, Harada T. A tryptophan-rich breakfast and exposure to light with low color temperature at night improve sleep and salivary melatonin level in Japanese students. J Circadian Rhythms. 2013 May 25;11:4. doi: 10.1186/1740-3391-11-4. PMID: 23705838; PMCID: PMC3691879.