Over the past year I’ve been experimenting with chocolate cake recipes. Not any chocolate cake. It’s always “The Best Chocolate Cake EVER!!” How can there be more than one Best Chocolate Cake recipe? In fact, I think you could publish an entire book of Best Chocolate Cake recipes, there are so many. Anyway, the one I prefer tastes good and bakes up consistently, so I made it a few days ago for a birthday party. Put a seriously chocolatey frosting on it (which is in my humble opinion, the only chocolate frosting recipe you’ll ever need, hands down).
There were leftovers; they were calling my name. When I woke up at 2:30 a.m., I thought about all that chocolate. Not good for sleep.
We’re sleeping badly these days
The past 18 months of pandemic lock downs played havoc with sleep. In a survey late last year, more than half the respondents did not have “refreshing sleep.” Sleep disruption was common, along with difficulty falling asleep and nightmares. A review of sleep studies from around the world found that over 40% of people reported problems with sleep.
It’s been a rough 18 months. Anxiety and stress are bad for sleep. Excess screen time is also probably bad. All of which is now common. But food choices and eating habits can also play havoc with sleep.
Food and Sleep
There are plenty of beliefs about foods that impact sleep:
- Caffeine (coffee, tea, chocolate, green tea) keeps you awake. NOTE: when I say chocolate, I’m not just talking about chocolate bars. Anything made with significant amounts of chocolate or cocoa, such as my Best Chocolate Cake and Best Chocolate Frosting can also cause problems.
- Thanksgiving dinner makes you sleepy (supposedly it’s the turkey)
- A glass of milk at bedtime helps with sleep
If you have trouble falling asleep or staying asleep, eating Thanksgiving dinner every night isn’t a practical solution. A variety of studies have investigated sleep-food effects. Data from these studies isn’t very reliable due to small number of subjects (some studies only had 6 people, many had around 12) or short duration (many studies were only for one day!).
A meaningful study needs to collect data on the phases of sleep:
- Rapid Eye Movement (REM — associated with dreams)
- Slow Wave Sleep (SWS — a deep restorative sleep)
- Sleep-Onset Latency (SOL — how long it takes to fall asleep)
- wake after sleep-onset (WASO — insomnia)
- sleep efficiency (SE – quality of the sleep experience)
- and possibly other metabolic variables.
That’s a lot of variables to keep track of. Not to mention, subjects are hooked up to all kinds of measuring equipment while sleeping in a lab. Who is going to volunteer for that? Most people are too busy to go to a lab somewhere and spend the night hooked up to monitors. No wonder many of the studies are done with “healthy young adults” (i.e. college students who need the cash).
CONCLUSION: Sleep is complicated, so measuring it accurately is also going to be complicated, and study results may not be very helpful.
What Do We Know?
Melatonin is a hormone made by humans and animals. It regulates the sleep-wake cycle and other metabolic systems. Plants don’t sleep, but some plants produce melatonin, which may have a protective role as an anti-oxidant. Two foods stand out because of their unusually high melatonin content:
- Tart Cherries
While kiwis are a popular and widely available fresh fruit, tart cherries are another matter. These are pie cherries, not the cherries you eat fresh. They have a mouth-puckering tang, which makes them good for pie as long as you use enough sugar. Who decided to investigate them for sleep enhancement? Surprise! A lot of the research on tart cherries is funded by cherry producer organizations.
Adults with insomnia experienced improved sleep when drinking two 8-oz glasses of tart cherry juice/day. Studies using kiwi found that eating 2 kiwi fruits an hour before bedtime reduced sleep disorders. For the person with insomnia, this might sound like a natural solution using healthful foods. The problem is you have to eat/drink those foods every day. It’s not a quick fix cure. Kiwis are juicy, high fiber, have significant vitamin C and are modest calorie (about 40-45 each, or not quite 100 for two). Not a bad choice.
Tart cherry juice is, well,… tart. It’s not super-acidic like lemon juice, but it’s not sugary sweet. It has a rich, deep fruity flavor. Two glasses a day might get to be a bit much. Also it will set you back $2-$3 per day, along with about 300 calories. If you’re watching calories, you’d have to shave 300 calories off your diet somewhere else. And be sure to buy pure tart cherry juice, not some sugar-sweetened cherry drink.
Other foods with above average melatonin content include bananas, plums, grapes, wine, pineapple and olive oil. A sleep-enhancing dinner might include a salad with olive oil dressing, a glass of red wine or tart cherry juice, and a fruit salad with banana, pineapple and kiwi.
What about melatonin supplements?
Melatonin supplements are popular as a sleep aid. Since melatonin is not a nutrient, I can’t advise on use of those products. Some people find them helpful; others do not. Follow package directions for use. And keep in mind, these are over-the-counter products and are not tested for efficacy the way prescription drugs are tested.
We’ve all heard the advice to drink a glass of milk — or better yet warm milk — before bedtime, because milk is supposed to enhance sleep. True? In fact, milk doesn’t have a consistent impact on sleep quality, but there’s a slight wrinkle to this. So-called “nighttime milk” may have some beneficial impact on sleep quality.
Cows make melatonin too. When cows are milked in the evening, the milk is higher in melatonin than morning milk. Research suggests the concentration of melatonin needs to be about 10 times higher than daytime milk to have a sleep-promoting effect.
How do you tell if the milk you buy is high melatonin? You don’t. There is no labeling requirement or official measurement standards for melatonin in any foods, nor are there approved label claims for melatonin content. There’s no labeling for “nighttime milk”. You might have to buy your own cow and milk it at night.
It’s not just individual foods that impact sleep. Your total diet is important. High carb, low carb, high fat, high protein, low glycemic index and ketogenic diets have all been studied. There are a few general conclusions.
- High carb, particularly simple carbs and sugar, tend to increase REM sleep and reduce the restorative slow wave sleep.
- High fat is associated with poor sleep efficiency and less REM.
- A Mediterranean style diet was linked to better sleep efficiency.
There are plenty of possible reasons for these findings, such as the effects of higher insulin and energy availability from a high intake of simple carbs. And of course, not everyone will react the same to the same types of diets or meals.
At the moment there is no evidence that any one nutrient will fix sleep problems. People with diets high in certain nutrients — magnesium, B vitamins, omega-3 fats — may report better sleep, but is it those nutrients or the type of diet? My money is on the total diet: less processed, with plenty of vegetables, fruits and grains, and low in simple sugars.
Avoid sleep disrupting effects of caffeine by avoiding caffeinated foods, especially late in the day:
- Black Tea
- Green Tea
- Chocolate and Cocoa (Cake. Cookies. Ice creams, especially with chocolate bits)
- “Energy” bars and supplements that contain caffeine
- Soft drinks with caffeine
Big meal (high fat/high sugar) close to bedtime
While a big heavy meal may make you feel sluggish and sleepy (think Thanksgiving dinner), it may end up keeping you awake in the middle of the night, or disrupting sleep quality.
Wine, beer and cocktails might make you feel relaxed, but the effect doesn’t translate to good sleep. Don’t rely on a nightcap for better sleep.
Sleep apnea is more common with obesity, and sleep apnea is a major disruptor of sleep.
Do any foods and nutrients improve sleep? Perhaps. More research is needed. Sleep is impacted by plenty of other factors, from stress and anxiety to breathing problems, medical problems, prescription drugs, alcohol use, caffeine intake, hydration and allergies. If you want to take the Whole Diet approach, the Mediterranean-style (or “sometimes vegetarian”) diet was linked to better sleep efficiency. It’s also linked to better weight control. If you want to boost melatonin intake, the high melatonin foods are healthy for other reasons, so adding them to your diet could be a win-win strategy.