do onions affect sleep

How Onions Affect Sleep: Our Quick Guide on Eating Onions before Bed

Do onions affect sleep? Onions make about everything taste better. So it commonly happens that you eat them with dinner, along with a nice grilled steak or in a delicious & fresh salad. But does eating onions have any impact on your sleep? Should you eat them or not?

In this article, we’re going to find out whether onions are your friend or enemy before bedtime and even more!

Question: Do onions affect sleep?

Answer: Yes, onions do affect your sleep negatively. Onions can cause acid reflux and bloating, both of which disturb your sleep quality. If you want to eat onions, eat them at least 2 hours before bed. This makes sure that the onions are digested (and can’t harm you) before you sleep.

Onions have a tremendous impact on your sleep. Let’s find out how they affect your sleep in a little bit more detail, so you know whether you can handle onions before going to bed or not.

As usual, everything that I say here depends entirely on your body. Some people might handle onions before sleep better than others. After reading this, you know whether you can eat onions before sleep or not.

Let’s start.

Onions can cause Reflux

First off, the Oklahoma Foundation for Digestive Research found that onions cause reflux. Here’s how they found out:

One day, the researchers gave plain hamburgers to study participants. The other day, they gave them hamburgers with sliced onions. As a result, on the second day, an increased amount of participants suffered from acid reflux.


The acid reflux did not affect healthy participants, just participants with heartburn.

They concluded:

“Onions can be a potent and long-lasting reflexogenic agent in heartburn patients.”

With this information, we can say that if you have heartburn, never eat any onions before sleep. You are more likely to get acid reflux, which is a total sleep disruptor.
Especially, because acid reflux is generally more likely to happen when you lie down. The combination of lying down and having eaten onions is definitely worth avoiding.

If you are a healthy person, you don’t need to worry about acid reflux caused by onions.

In case you feat acid reflux at night, give yourself at least 2 hours of digestion time, so the food gets processed and can’t come up your throat again.

Other food that induces acid reflux

According to Korean researchers, there are several other foods that induce acid reflux. Avoid eating them before going to bed. Here’s a short table summarizing the results of the study.

FoodPercentage of People with Acid Reflux
Ramen noodles84.2%
Fried food75.0%

If you don’t want to throw up throat-etching acid at night that prevents your sleep and makes you wake up with a throat-ache, avoid all of these foods 2 hours before bed.

Onions produce gases

Onions do not only cause acid reflux but they also produce gases. After eating onions, you usually feel bloated. Your comfortable pajama pants tighten because your belly keeps growing.

To get comfortable again, you just have to burp or break winds. Sadly, this does not also interrupt your sleep, but also your partner’s.

But does bloating affect your sleep? Luckily, a friendly-looking, retired man called Stephen Norman Sullivan from the University of Victoria decided to spend his life researching the human stomach. And even more luckily: In one of his studies, he investigated the psychological factors of bloating. I mean: Who on earth does that? Anyways, that’s just what we need and we should be thankful.

He says:

Bloating correlates with sleep difficulties.

During my hours-long sleep-inducing lectures at university, I picked up that correlation does not mean causality. We don’t know whether bloating causes sleep difficulties, or whether sleep difficulties cause bloating. We don’t know the direction. But we do know that it seems like people with bloating are also the ones with sleep difficulties.

Even though we are not sure how you should avoid food that causes bloating before going to bed. And onions are definitely among them.

Other food that causes gas and bloating

In one of his studies, Dr. Hasler from the University of Michigan concluded a short list of all the foods that cause a significant increase in gas production.

  • all dairy products
  • onions
  • beans
  • celery
  • carrots
  • raisins
  • bananas
  • apricots
  • pretzels
  • bagels

Please don’t eat before bed: bagel with fried onions and beans along with a glass of milk

How bloating blocks your sleep

I believe that bloating is a sign of digestive activity. Your stomach is working. Something is going on. This, in turn, means that your body can not properly prepare for falling asleep because it focuses attention on your tummy.

When you lie down in bed and can’t fall asleep after eating onions, it could be because your body is still active. As long as digestion is not finished, it is hard for you to relax and unwind.

And, obviously, if you burp or pass gas, you can’t fall asleep properly because you wake up every time you do.

onions cause bloating which makes it difficult to sleep

Do Onions contain Sleep-Inducing Substances?

Yes, onions contain tryptophan. That’s an amino acid that supports your melatonin production. Most natural sleep herbs are sleep-inducing just because they are rich in tryptophan.

The tryptophan level of onions is, however, only very small. They only contain about 5-10mg per 100g. This level is not very significant, compared to other foods. 100g of nuts, for example, contains over 570 mg of tryptophan. That’s up to one hundred times more!

Onions are very high in vitamin C and dietary fiber. Vitamin C can lower stress levels. But there’s not much evidence about direct sleep effects yet. Dietary fiber slows your digestive system down and can generally help you sleep.

Sadly, acid reflux and bloating cover the positive effects of tryptophan, vitamin C and fiber.

You just can’t effectively use onions to sleep better when there’s a lack of sleep-inducing substances.

Onions do affect your sleep. But it appears that it has only negative effects.

Tips for eating Onions before Sleep

If you decide to eat onions tonight, pay attention to the following tips:

  • Eat onions 2 or more hours before bed: Onions cause acid reflux. This makes them especially dangerous for anyone with heartburn. But onions could cause acid reflux for healthy people as well. To reduce the risk of acid reflux at night, eat onions 2 or more hours before you go to bed. This makes sure that the onions are digested when you lie down.
  • Never eat raw onions at night: Raw onions are much more biting and spicy than cooked or fried onions. If you have a meal with cooked onions at night, that’s fine. But please avoid eating salads, hamburgers, fish, etc. that you serve with raw onion slices.
  • Don’t eat more than one onion: Even when you cook them, onions retain their ability to produce gases. Therefore, please don’t eat more than one cooked or fried onion before going to bed. Any more will cause you serious trouble when you try to fall asleep.
  • Brush your teeth thoroughly afterward: After you ate onions, brush your teeth thoroughly (50% longer than normally) and try to brush off 100% of the onion residues. Also, brush your tongue! A thorough mouth-cleaning affects your sleep positively. The onion residues would otherwise start fermenting inside your mouth, leaving you with bad breath that will make you very unattractive to your partner.
    Additionally, bad breath could cause a decrease in sleep quality. Remember how you hate the taste in your mouth every morning? Onions will amplify it.
    Note: Wait at least 30 minutes before brushing your teeth, otherwise you can damage your enamel. The reason is that onions are acidic and can weaken your enamel, so when you brush your teeth, it is prone to damage.
  • Make sure your partner is OK: Eat the onions together with your partner. Otherwise, he/she will hate you at night and maybe even wake you up. Eating onions before sleep even though you sleep in a bed with someone else is ruthless.
brush your teeth thoroughly before sleep to reduce the effects of onion

Do Onions Affect Your Sleep? – Conclusion

Yes, onions have an impact on your sleep. Sadly, not a positive one. If you have heartburn, acid reflux will hunt you. And even if you are a healthy person, the bloating disrupts your sleep quality.

If you absolutely want to eat onions before bed, please make sure that you eat them 2 hours before you sleep. Otherwise, the negative side effects will affect your sleep.

Still, you seem to want to know which foods you can safely eat at night that will also boost your sleep quality and make you fall asleep faster. Therefore, I have made a huge list of natural sleep remedies – foods that have sleep-inducing properties.

Click me: 

47 Natural Sleep Remedies (With Helpful Explanations & Pictures)

For a lot of them, I noted how much you need to eat or drink before you go to bed. Also, at the bottom of the post, there’s a small shopping list for you: The (in my opinion) 3 best natural sleep remedies.