Feb. 25, 2013 at 9:59 AM ET
If you're trying to maintain a healthy diet while managing the circus that is your life, then it's typical for those three squares a day to get pretty repetitive: Oatmeal for breakfast, a sandwich for lunch, a stir-fry for dinner...wake up, and repeat. But even if your daily intake seems nutritious, those monotonous meals might have a surprising downside--messing with your sleep.
In a fascinating new study from the Perelman School of Medicine at the University of Pennsylvania, researchers set out to investigate whether nutrient variety might be linked to sleep length. To do it, they examined data on several thousand Americans, culled from the Centers for Disease Control and Prevention. By comparing each individual's daily dietary intake with his or her sleep patterns, researchers were able to parse out a specific relationship between food variety and quality of rest.
"We didn't know much going into this study," says lead study author Michael Grandner, PhD, a member of the Center for Sleep and Circadian Neurobiology at UPenn. "People have talked about the relationship between diet and sleep for ages, but there's very little data on these connections."
Grandner and his colleagues determined that individuals who ate the widest array of nutrients also had the healthiest sleep patterns, logging between seven and eight hours of rest each night. Individuals who slept the least tended to be short on protein and carbohydrates, along with nutrients like iron, zinc, and selenium, they found. And in a conclusion that reinforces previous studies, the team noted that short sleepers also tended to consume the most calories (experts suspect that sleep-deprived people suffer from hormonal imbalances that augment hunger and food cravings).
"Sleep and diet are more similar than you'd think," Grandner explains. "They both touch every system in the body, and the body depends on both of them to keep working. That they interact isn't surprising--but how they interact might be."
Despite the study's intriguing findings, the interplay between sleep and diet remains somewhat mysterious--good sleep habits might prime us to consume more nutritious foods, or some nutrients in a balanced diet might be crucial for helping us fall (and stay) asleep. Earlier research, after all, has suggested that a lack of iron, calcium, and magnesium, among other nutrients, can impair sleep quality.
Given what experts currently know, Grandner says, your best bet for solid sleep is to keep your diet relatively clean and varied to a reasonable extent (maybe swap out that pb&j a few days a week, for instance). "One thing we can pretty reliably say is that you don't have to do anything drastic," he notes. "It's simple: A healthy diet helps your body work better, and as a result, sleep better too."