How Does Caffeine Affect the Body? - Ask a Nutritionist

April 6, 2023

Did you know that caffeine is considered a drug? 85% of the US population consumes at least one caffeinated beverage a day. Just like any drug there are good and bad side effects. Listen in to this week's episode of Ask a Nutritionist with Britni as she goes through everything you need to know about caffeine and how it affects our bodies.

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Welcome to the “Ask a Nutritionist” podcast, brought to you by Nutritional Weight and Wellness. We are thrilled to have you join us today as we discuss the connection between what you eat and how you feel and share practical real life solutions for healthier living through balanced nutrition. Now, let's get started.

BRITNI: Good morning and welcome to Dishing Up Nutrition's new midweek segment called “Ask a Nutritionist”. My name is Britni Vincent, a Registered and Licensed Dietitian. And on today's show, brought to you by Nutritional Weight and Wellness, we'll be answering a question we've received from our Dishing Up Nutrition listeners.

And today the question is “How does caffeine affect the body?” I think this will be a popular one because 85% of the U.S. population consumes at least one caffeinated beverage a day, according to a 2014 review from Food and Chemical Toxicology. And there's a lot of different aspects to consider when we're thinking about drinking caffeine, but I'm just going to focus on a handful that I think our listeners will resonate with.

Caffeine can be addicting

So let's start with the negative impacts of caffeine. You know, caffeine can be addicting. As a society, we don't necessarily always think of it as a drug, but caffeine is a drug. So like any other drug, it can become addicting for some individuals. And you know, and for some people they get that caffeine crash maybe a few hours after drinking something and then they gravitate towards more caffeine. So it can be addicting in that way as well.

Caffeine is not recommended if you have adrenal fatigue

Another negative is if you have adrenal fatigue, also known as HPA axis dysfunction, caffeine is not a good idea. And if you're not familiar with those terms, basically it means that you've been under chronic stress for a long period of time and caffeine is just going to act as another stressor on your body. And caffeine actually increases our cortisol. And cortisol is our stress hormone. So again, if you're under a lot of stress, then increasing your cortisol even more is not going to help your body. And in fact, it's just going to create a lot of extra stress.

And when caffeine increases your cortisol, that's going to increase your glucose, which will then tell your pancreas to output insulin. So it can contribute to glucose dysregulation as well. And the cortisol response that you get from caffeine does vary from person to person, and for some individuals it's not a huge concern if they're not under that chronic stress.

You know, another piece to think about in the, the individuals that are chronically stressed, really fatigued, a lot of people gravitate towards caffeine to get that boost when really they should probably be resting. And we're going to talk about the sleep component in a little bit as well, but that can be a vicious cycle. You're grabbing caffeine for that boost, but then that could be negatively impacting your sleep as well.

You know, I recently had a client and she has diabetes and she wears a continuous glucose monitor. And what she was seeing on her continuous glucose monitor is when she would have her cup of coffee in the morning, her glucose would increase by about 20 points, which is pretty significant. And at that time, she wasn't eating food while she was drinking her cup of coffee. But what she did do is she added some fat specifically in the form of MCT oil, and that dramatically improved the glucose response that that she got. And not everybody is going to get that dramatic of a blood sugar increase from drinking a cup of coffee. But you know, some individuals might just like my client did.

Caffeine can be a sleep disruptor

So something else to consider: I mentioned the, the sleep disruption aspect a little bit. Caffeine blocks adenosine receptors in the body, and adenosine is a neurotransmitter that is a sleep promoting chemical. So adenosine builds up throughout the day helping to make us drowsy when nighttime comes along. The half-life of coffee, which means the amount of time that it takes for half of the caffeine to be metabolized in our body is roughly five hours. But for some people it could be as much as nine hours. So what that means is it can take 10 hours or more for caffeine to be completely eliminated from the body. And we also know that caffeine too close to bed prevents restorative deep sleep as well.

Another thing to consider when consuming caffeine is about 50% of the population has a variant in the gene that leads to slow caffeine processing. And so we all metabolize caffeine differently, but about 50% of the population metabolizes it very slowly. And if that's you, then caffeine's going to be lingering in your bloodstream for long periods of the day. And that can have many negative effects, including the sleep that we did just talk about.

Caffeine is dehydrating & can leach minerals from the bones

You know, this is is not a new one. Caffeine is dehydrating. It increases blood flow and filtration in the kidneys, but and that increases urine output. So a lot of people are not drinking enough water to begin with, but drinking enough water to replenish what's being lost from the caffeine that they're drinking. Caffeine can also leach minerals out of our bones. So if you have osteopenia, osteoporosis, or at high risk of developing osteopenia or osteoporosis, that is a huge thing to consider.

Caffeine can negatively affect gut health

There's also can be gut impact when consuming caffeine, especially coffee has a negative impact on the gut. Coffee is naturally acidic and induces a stomach acid response by regulating our hormone, gastrin, and it will also relax the lower esophageal sphincter, which prevents stomach acid from coming back up through our esophagus. So this increase in acid can exacerbate stomach inflammation and reflux. What I have found too in in these cases is if you do have reflux and you determine what the primary cause of that reflux is, sometimes that caffeine doesn't have as much of a negative impact.

What else is in your caffeinated beverage?

And then some people are sensitive to seeds and coffee specifically is a seed. Now, one last thing to consider in regard to the negative impacts of caffeine is what else is in your caffeinated beverage? You know, pop energy drinks either have a lot of sugar or artificial sweeteners. If you are drinking coffee to get your caffeine in, what else are you putting in your coffee? Are you putting sugar in there? Are you going to a coffee shop and getting a flavored latte? Again, a lot of sugar can sneak into there.

Caffeine indirectly stimulates release of feel-good neurotransmitters

So now I want to switch gears and talk about some of the benefits of caffeine. You know, indirectly caffeine stimulates a release of some neurotransmitters, specifically GABA, dopamine and serotonin. These are feel good brain chemicals and can also help attention and focus.

Low doses of caffeine can improve memory and cognitive performance

Low doses of caffeine has been shown to improve memory and cognitive performance. You know, according to a 2021 review in the journal, Nutrients, researchers suspect this may be true because it helps promote dilation of blood vessels for more blood flow to the brain and provide some neuroprotective benefits as well.

Caffeine has some antioxidant properties

And caffeine does have some antioxidant properties because caffeine is a plant nutrient. So this helps to protect against free radical damage. And the antioxidant effect may also provide some brain benefits by mitigating neural pathways and protecting neurons in our brain.

Research shows some association between coffee consumption & reduced risk of some disease states

There has been a lot of research done on caffeine and sometimes we hear blurbs of it in the media. And so I'm sure some of you have heard blurs in regards to this that some research has shown in association between coffee consumption specifically and a reduced risk of total mortality. And there's also some research that has been shown that coffee can reduce the risk of developing cardiovascular disease, certain cancers and Parkinson's.

Ritual of have coffee or tea can provide happiness

And then the other benefit that is not necessarily scientific, but it is just the ritual of having your cup of tea or having your cup of coffee in the morning. You know, for a lot of people that routine and maybe that quiet time to sit and enjoy provides a lot of happiness. So I think there is a benefit in that as well.

Sources of caffeine & various amounts

I do want to share, I think this is interesting, the sources of caffeine and, and how much, how much caffeine is in each of them. So a cup of coffee on average is about 96 milligrams. An ounce of espresso is about 64 milligrams. A cup of black tea is about 47 milligrams. A cup of green tea is about 23, and an ounce of dark chocolate is about 23 milligrams. So that is something to think about if you like to have dark chocolate before bed as something a little sweet after dinner, that could possibly be negatively impacting your sleep.

Is it okay to drink caffeine or not?

So I'm sure a lot of you are wondering, well what do I do with all this information? You provided some negatives and some positives. So I, so do I drink caffeine or not? You know, I think it really depends on the individual. If you're somebody that is highly stressed, you have insomnia, a lot of gastrointestinal symptoms or osteoporosis or osteopenia, you might want to consider just eliminating caffeine to allow your body to heal more.

Also, if you're pregnant, you'd want to consider eliminating caffeine or at least limiting it to eight to 12 ounces. If you want to eliminate caffeine and you're worried about the withdrawal symptoms, drink lots of filtered water during the process of, of elimination. You know, starting your day instead of that caffeinated beverage with a cup of warm water with lemon provides a little natural detoxification.

You could drink a little bit of green tea for the first few days of eliminating the caffeine. Yes, that green tea does have a little bit of caffeine, but the antioxidants may help with some of those withdrawal symptoms. And generally those withdrawal symptoms pass within, you know, two or three days.

Or maybe you're just curious, how do you feel without caffeine? You know, I've had a lot of clients eliminate it and they say that they feel better. So it might be something to consider: eliminate it for a month. And you might be surprised. Those of you that do want to continue drinking your coffee or your tea, I would just, again, think about what you're putting in those caffeinated beverages and then limit it to one to two cups and I would try to keep it to before noon so it doesn't have that negative impact on, on your sleep at all.

Potential alternatives to caffeinated beverages

You know, a side note too, if you decide to switch to just decaf coffee, I would look for first and organic coffee because coffee is one of the, the most heavily sprayed crops with pesticides and herbicides. And that would be true for caffeinated and decaf. But then secondly, for a decaffeinated coffee, look for one that's been water processed. And a lot of times it'll say it right on the the label there, or you might be able to find it on the the company's website, and you want to look for that specifically because many decaf coffees are processed using a chemical process. So then you're going to get some of those chemicals in the coffee itself. So that would be a way to avoid that. Or chicory or dandelion root coffee. And it's not truly coffee. It's kind of more like an herbal drink, but they offer a similar taste to coffee when they're roasted. So that could be something else to look at.

Lots to consider when talking about caffeine. Thank you so much for listening to Dishing Up Nutrition’s “Ask a Nutritionist”. If you have a nutrition question you would like us to answer, we invite you to join our Dishing Up Nutrition Facebook community by searching Dishing Up Nutrition on Facebook. The private group is moderated by Nutritional Weight and Wellness nutritionists and nutrition educators, and provides our Dishing Up Nutrition listeners with a safe, supportive community to ask questions, share ideas, and just get inspired. So once you're a member of our community, we invite you to join the conversation and share your questions with us. So don't be shy. If you have a question, please let us know. We look forward to hearing from you.

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