Getting a good night’s sleep is not always as simple as it sounds. While the Centers for Disease Control and Prevention (CDC) recommends that adults ages 18 to 60 get at least 7 hours of sleep per night, around 30% of adults get less than the recommended amount of sleep.
A number of things can affect sleep patterns, including sleep hygiene and mental health issues. Researchers from Finland’s University of Helsinki, National Institute for Health and Welfare, and Turku University of Applied Sciences recently examined how total sleep duration might influence dietary choices.
Their study, which appears in Frontiers in Nutrition, found that people who eat around 460 grams of fruits and vegetables per day were more likely to get an ideal amount of rest than those who ate fewer of these foods.
The researchers observed that lower consumption of these foods was associated with sleeping for inadequate or excessive amounts of time, both of which have negative implications.
Analyzing self-questionnaires and sleep chronotypes
When people sleep, their bodies undergo cell repair, hormone regulation, and store new memories. Not getting enough sleep can disrupt these natural processes.
As the National Institutes of Health explains: “During sleep, your body is working to support healthy brain function and maintain your physical health.”
While some people have no problem sleeping, others experience trouble with sleep due to poor sleep hygiene, sleep apnea, and insomnia. Also, some people sleep excessively – more than 9 hours per night, and according to the Sleep Foundation, this can contribute to mental health and heart issues.
The current study examined the sleep and nutrition habits of 5,043 adults in Finland. During various questionnaires, the participants provided information about their sleep duration and food intake.
The participants also provided information about their socioeconomic status, body mass index, physical activity, and health problems.
Since the World Health Organization (WHO) recommends eating 5 servings of fruits and vegetables per day, or 400 grams, the researchers wanted to see which people were coming close to that recommendation.
The researchers also analyzed the participants’ chronotypes, as a prior study found no influence of chronotypes (sleep timing) on fruit and vegetable intake the following day. According to the scientists, chronotype “reflects an individual’s preference for timing of activities during the day (morning or evening preference).”
Fruit and vegetable intake matter
After analyzing the self-questionnaires, the researchers divided people into groups based on how long they reported sleeping each night:
Short sleepers (21% of participants) slept an average of 6 hours per night.
Normal sleepers (76.1% of participants) slept an average of 7.7 hours per night.
Long sleepers (2.9% of participants) slept an average of 10.1 hours per night.
The researchers found that “normal sleepers” who slept 7 to 9 hours per night had a higher fruit and vegetable intake than the other groups.
“Normal sleepers” consumed an average of 463.1 grams of fruits and vegetables per day, which was higher than both the short and long sleeper groups.
Short sleepers consumed an average of 37 fewer grams per day than normal sleepers. Both short and normal sleepers fell within the WHO’s recommended daily intake but consumed less than the Nordic Council of Ministers’ recommendation of 500 to 800 grams daily.
Long sleepers consumed an average of 73.4 fewer grams compared to normal sleepers.
Upon further analysis, the researchers noted some differences in the consumption of specific types of foods.
When dividing vegetables into subgroups, they noticed “significant differences” in the amount of green leafy vegetables, root vegetables, and fruit vegetables (such as tomatoes and cucumbers) in short sleepers compared to the normal sleepers. Long sleepers also consumed fewer green leafy vegetables and fruit vegetables than normal sleepers.
In fruit subgroups, researchers also observed significant differences in berries as well as other fresh and canned fruit varieties in short sleepers compared to normal sleepers. Apples were the only fruit subgroup that appeared to differ significantly between long and normal sleepers.
The researchers also examined whether the subjects’ self-reported chronotypes factored into their sleep duration. They sorted people into the following categories based on whether the participants considered themselves most productive in the morning, evening, or somewhere in between.
morning type
intermediate type
evening type
This analysis suggests there is little influence of chronotype on the link between sleep patterns and dietary choices.
“Its impact on the specific relationship between sleep duration and [fruit and vegetable] consumption is minimal,” write the authors.
Overall, the study findings emphasize the need to focus on nutrition to improve sleep. For those looking to improve their diet quality, it may be helpful to keep a food diary to assess fruit and vegetable intake and adjust accordingly.
While the researchers acknowledge that relying on self-reported data is a limitation of the study, they encourage longitudinal studies “to better understand these associations and their public health implications.”
The study raises more questions
Sudha Tallavajhula, MD, a neurological sleep disorders physician at UTHealth Houston, spoke with Medical News Today about the study.
“The conclusions from this study should be interpreted in the context of associations and not necessarily causation,” Tallavajhula commented.
“Poor sleep behavior is associated with poor food choices,” Tallavajhula explained. “Poor sleep usually translates into less daytime energy levels; this may lead patients to pick ‘easy’ foods like canned and processed items rather than fresh ingredients that may need more work.”
Tallavajhula also commented on what this study means from a public health perspective.
“The main implication for public health is that when introducing interventions to improve dietary lifestyle, we cannot ignore the importance of sleep and other lifestyle parameters.”— Sudha Tallavajhula, MD
Devika Bhushan, MD, a pediatrician, public health leader, and chief medical officer of Daybreak Health based in San Francisco, also spoke with MNT.
“The association here with atypical sleep patterns – both less than and more than what’s normative or healthy – and lower fruit and vegetable consumption makes a lot of sense,” Bhushan noted.
“But for me, it raises the question of which came first – the sleep atypicality or the lower fruit and vegetable intake – and whether both are in fact referable to underlying stress biology,” Bhushan continued.
Bhushan explained how stress-related conditions can impact sleep and contribute to people’s food choices.
“Many stress-related health conditions ranging from depression to chronic pain to heart and lung disease can disturb healthy sleep habits and lead to atypical sleep duration,” noted Bhushan. “And stress pathway activation can also promote cravings for higher-calorie, higher-fat, and carbohydrate-rich foods, often decreasing overall fruit and vegetable intake.”
“So while these findings make intuitive sense, it is hard to draw causal inferences and infer the direction of the associations from these findings alone,” said Bhushan.