What To Eat and Drink For a Good Night’s Sleep
Getting enough high quality sleep each night is emerging as a key factor in reducing Alzheimer’s risk. If you don’t always sleep well, or struggle to get enough sleep, it’s worth taking a look at not just what you eat and drink, but when.
The link between poor sleep and Alzheimer’s disease
How we sleep is key to keeping our brains healthy. If you ever suffer from insomnia, you know your brain doesn’t work as well the next day, or even the day after that. Lack of sleep is one of the most common causes of impaired short-term memory. Now researchers are untangling the complicated relationship between sleep and Alzheimer’s disease.
More than 60% of Alzheimer’s patients have a sleep disorder. But which came first, the sleep problem or the Alzheimer’s? Studies in mice show that sleep deprivation leads to a buildup of amyloid protein in the brain, the same protein implicated in Alzheimer’s pathology. Recent studies have determined that amyloid protein gets cleared from the brain during non-rapid eye movement (REM) sleep cycles by the brain’s newly discovered glymphatic system. Like a dishwasher that starts rinsing when we fall off to sleep, the glymphatic system washes out toxins from the brain through a pressure gradient of cerebral spinal fluid.
Chronic poor sleep is now considered an important risk factor for Alzheimer’s and dementia. Luckily, this is one factor we have the power to change.
Check out these 6 science-based tips to make the way you eat and drink less sleep-disrupting and more sleep-promoting.
1. Set a caffeine curfew
We are all genetically predisposed to metabolizing caffeine at different rates. Some of us have livers that crank out tons of the enzyme cytochrome P450 1A2 that inactivates caffeine, and some of us just don’t. If you enjoy a caffeinated beverage or two, keep in mind that it can take up to 12 hours for your body to rid the brain-stimulating effects from your bloodstream.
Let’s not forget other sources of caffeine that we consume. There are significant amounts of caffeine in certain teas, soft drinks, energy drinks, snack foods, chocolate and ice cream. If you enjoy caffeinated beverages or foods, choose a caffeine curfew based on your experience. Most of us would be wise to stop consuming caffeine at midday.
2. No wine after 9
Drinking alcohol before going to sleep is like taking a strong sedative that lasts for 3 to 4 hours. It effectively blunts the senses and plunges us into a deep “sleep-like” state. But the brain on alcohol is not really going through the healthy stages of non-REM and REM sleep known to be essential for good quality rest. Alcohol is a potent suppressor of REM sleep, especially in the key early morning hours when the alcohol wears off and the brain goes through withdrawal.
In the words of Matthew Walker, sleep scientist and author of Why We Sleep: “Alcohol fragments sleep, littering the night with brief awakenings. Alcohol-infused sleep is therefore not continuous and, as a result, not restorative.”
Women who are in the perimenopausal years (between 40 and 55) are especially vulnerable to the havoc alcohol brings to their sleep cycles. The combination of hormonal fluctuations and alcohol-induced REM suppression means frequent bouts of waking up in the night. (Hello, hot flashes.)
Stop drinking alcoholic beverages at least 3 hours before going to bed. Or, take a break from drinking alcohol for several consecutive weeks. You might realize that even occasional drinking has a negative impact on your sleep quality.
3. Magnesium helps you fall asleep
Magnesium helps with sleep by activating the parasympathetic nervous system (which calms your nerves) and relaxing skeletal muscles. It relaxes smooth muscles, too, such as those that line the gastrointestinal tract. A common side effect is an increase in bowel motility; too much and you’ll have diarrhea. (You may recall that magnesium is the active ingredient in a common laxative — Milk of Magnesia.)
Does boosting your diet with magnesium rich foods help you sleep better? Yes, if your magnesium levels are depleted. Serious magnesium deficiency is rare but can be seen in those with specific medical conditions: type 2 diabetics, chronic alcoholics, elders with low calorie diets, and people with gastrointestinal disorders that impede absorption.
Mild magnesium deficiency, however, is thought to be quite common — an estimated 50% of Americans have depleted magnesium stores. Certain diets, such as an elimination diet that avoids entire food groups, could set you up for a magnesium deficiency. Also, some blame magnesium deficiency on the lack of minerals in our soil. So although we may be trying to eat a well-balanced diet, our food supply contains produce that’s magnesium-poor.
For most of us, it’s easy to avoid magnesium depletion by eating high quality whole foods and less processed junk foods. And, it’s preferable to get magnesium through food than supplements. The fiber in whole foods allows the magnesium to get absorbed more slowly, leading to more stable blood levels without side effects.
Good news: Some of our favorite brain healthy foods are also rich in magnesium. Eat plenty of magnesium-rich foods as part of your brain healthy diet: almonds, black beans, avocados, whole grains, shellfish, bananas, kiwi, pumpkin seeds, Swiss chard and kale. And, my favorite: dark chocolate (just not before bed,!)
4. Hydrate, but not too much
Hydration is key for a healthy brain, good memory and heightened cognitive function. In fact, drinking 8 to 10 cups of water per day has been proven to boost the brain’s performance by 30%. Not getting enough water is also associated with dementia. One brain scan study shows accelerated brain shrinkage in aging brains that are chronically dehydrated.
You definitely want to stay hydrated throughout the day. But drinking too much water, especially close to bedtime, will lead to bathroom visits that interrupt precious sleep cycles. And, those with fragile sleep already know how hard it can be to get back to sleep after getting up.
Avoiding foods with a diuretic effect (watermelon, celery) too close to bedtime will also help.
Be strategic about staying hydrated. Drink plenty of water during the day; drink less in the evening as bedtime approaches. Less trips to the bathroom mean higher quality sleep.
5. Carbs, protein, fat, and sleep
Does the composition of your diet affect sleep quality? There’s not a lot of data to guide us, but one study showed that consuming a diet low in fiber and high in sugar (and simple carbohydrates) led to decreased non-REM sleep cycles and more awakenings at night. Another study showed that eating a high carb, low fat diet suppressed REM sleep more than a low carb, high fat one. Other studies suggest that going to bed too full or too hungry could have a negative impact on sleep.
If you are cutting back on calories to lose weight, one study showed that sleep improved significantly after two years. Cut back too much though, such as under 800 kcal/d, and sleep is impaired. For those who are overweight, losing weight improves sleep by reducing obstructive sleep apnea, a disorder that blocks the airway at night leading to snoring, lower oxygen levels and less REM sleep.
Bottom line: Solid scientific data is lacking regarding which dietary pattern is best for sleep. In general, the science supports not going to bed hungry or with a full stomach. Lose weight if overweight. Avoid fatty, spicy and high protein foods right before bed. And avoid a diet that’s high in sugar and low in fiber.
6. Melatonin and tryptophan-rich foods
There is a long list of foods that claim to help us sleep better. Tart cherry juice, which is rich in melatonin, is one of the few that has been actually studied. In one small study, participants who drank two 8-ounce cups of tart cherry juice per day (one in the morning and one at night) had improved sleep after 2 weeks. We should note that this study was industry sponsored (CherryPharm, Inc.) and that participants who used evidence-based behavioral techniques slept better than those who drank juice. Also, just one of those cups of cherry juice contains 140 calories and 25 grams of sugar!
Kiwifruit has also gone through some scientific evaluation. Known to be high in antioxidants and serotonin, one small study showed it can really help with sleep. How much kiwifruit? Participants ate 2 kiwi an hour before bedtime for one month. Researchers at Taiwan Medical University measured definite improvement in many sleep parameters — falling asleep faster, higher sleep efficiency and greater total sleep time. If you love kiwi, go for it!
There’s not a lot of good science behind most foods marketed as “sleep-promoting.” But it does make sense that eating foods rich in tryptophan, an important amino acid precursor to the neurotransmitter serotonin, may help with sleep. And many tryptophan-rich foods are important for overall brain health. Fill your diet with foods rich in tryptophan — sesame seeds, pumpkin seeds, raw cacao, chia seeds, whole yogurt, and whole grain bread.
The link between diet and sleep may have more to do with knowing which foods and beverages to avoid than boosting the diet with “sleep-promoting” foods.
Here’s wishing you a good night’s sleep!
PS: Have you read Why We Sleep, Unlocking the Power of Sleep and Dreams by Matthew Walker, PhD? It’s our Brain Health Kitchen Book Club selection this month.
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