Effects of Coffee on an Empty Stomach - Caffeine in Coffee and Blood Sugar Levels

Is it okay to drink coffee on an empty stomach?

The short answer is, I wouldn’t.

But my body is different from yours.

There’s a lot of hype from fitness influencers on this subject, and I’m here to provide the research and give you a holistic practitioner’s point of view, so you can make an educated decision based on your own body’s symptoms and history.

Hi friends. I’m Hilary Beckwith, ex-dieter and holistic nutrition expert. Clients come to see me with signs of adrenal stress and inflammatory conditions, and my job is to find the root causes so we can address their symptoms more effectively, and fill in the gaps between what their doctor is saying, and what their body is saying.

Because the clients I see are navigating symptoms of adrenal insufficiency and issues with blood sugar levels, to those individuals, I typically recommend not drinking coffee on an empty stomach.

In this article, you’ll learn:

• benefits of drinking coffee

• risks of drinking coffee (or caffeine)

• who should not be drinking coffee on an empty stomach

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Looking for information more focused on how caffeine affects the body? CLICK HERE.

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benefits of drinking coffee

Not everyone will agree, but the first benefit I think of is taste. I love the dark, rich, nutty taste of a good cup of coffee.

Opinions aside, below are some benefits of coffee found in research. In some cases, the benefits are specific to coffee or caffeine in coffee, and sometimes both. I’ve been careful to note the differences in this list.

EVIDENCE-BASED BENEFITS OF DRINKING COFFEE:

• the caffeine in coffee is an antioxidant, but only in very high doses (1)

• coffee (even decaf) reduces risk of gallstones (2)

• coffee increases salivary amylase secretion - Amylase is an enzyme responsible for breaking down sugars and carbohydrates, and when coffee is ingested, the polysaccharides contained in the coffee tell your brain to secrete amylase.

• coffee (even decaf) increases hydrochloric acid (HCl, known as stomach acid) temporarily, although caffeinated coffee much more so - this can aid in digestion, but can also be a risk

• coffee (even decaf) increases bile flow - aids in the digestion of fats and elimination of toxins

• coffee (even decaf) increases pancreatic juices - these are enzymes that aid in the digestion of food

• coffee can support microbiome in the gut - this can be a benefit to some, but not to others. Coffee consists of polysaccharides, undigestible fibers that, when fermented in the large intestine, support the growth of “good” bacteria, and thus produce short-chain fatty acids that support the mucosal barrier of the large intestine. Polysaccharides may present more of a risk if fermented in the small intestine, or when there is a higher “bad” bacteria to “good” bacteria ratio.

risks of drinking coffee

EVIDENCE-BASED RISKS OF DRINKING COFFEE:

• coffee (even decaf) increases hydrochloric acid (HCl, known as stomach acid) for 30-60 minutes after ingesting (2). The increase in HCl can aggravate ulcers, but does not cause them (5). This aggravation can lead to discomfort, pain, increased inflammation due to the irritation of the stomach tissue, and worsening of the ulcer(s).

• coffee alters microbiome in the gut - As I mentioned earlier, the polysaccharides in coffee, which are a type of fiber, can help support good bacteria in the gut. This can be good for some, but harmful to others.

  • Gut bacteria, specifically bacteroidetes, firmicutes, and prevotella, are supposed to live in the large intestine. Ther they ferment the undigestible polysaccharides, and produce short-chain fatty acids that help protect the lining of the digestive tract, acting as part of your immune system. For someone with bacterial imbalances, or bacteria populating in the small intestine (upper digestive), this could be a problem. In some cases, coffee was shown to enhance the growth of a certain clostridia species, which can be very harmful to health.

• caffeine increases cortisol levels (3) - Cortisol is a hormone produced by the adrenal glands, known as a glucocorticoid, meaning, it stimulates the pulling of stored glucose from tissues and metabolizing them into cellular energy known as ATP, or Adenosine Triphosphate.

  • Why is this a risk? This process is part of your body’s stress response, and activates the Sympathetic Nervous System (fight or flight), while also utilizing the HPA axis (Hypothalamus Pituitary Adrenal). If you are someone who drinks coffee often, or throughout the day, this will negatively impact your adrenal health, blood sugar levels, and sleep. CLICK HERE TO LEARN MORE ABOUT ADRENAL HEALTH AND CORTISOL

• coffee damage to gastric mucosa (4) - This is interesting because research shows no association between coffee or caffeine in coffee, with the development of ulcers (5). However, there is evidence that coffee causes damage to tissue lining the stomach, as well as increases intestinal permeability (you may have heard this called leaky gut), both of which would seem to contribute to ulcers.

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who should not be drinking coffee on an empty stomach?

A few things to consider when reading this section:

• This article is meant to provide education and resources to help you make more educated decisions about your own health. It is meant to be used for information purposes only, and not to be construed as health advice, medical advice, treatment, or prescription.

• Every body is different, having unique biochemical makeup and experiences that influence all aspects of health. Nutritional and lifestyle changes should never be considered without an individualized assessment by a qualified practitioner.

• The focus here is to help you determine whether or not it is okay to drink coffee on an empty stomach. We’ve seen already how the caffeine in coffee has an impact on blood sugar levels - let’s find out how that might affect you if consuming coffee without any food in your stomach.

WHO SHOULD NOT BE DRINKING COFFEE ON AN EMPTY STOMACH

• BLOOD SUGAR SYMPTOMS - If you have symptoms of poor blood sugar levels, such as feeling jittery after coffee, getting “hangry” between meals (shaky, loss of focus, headache, irritable), craving sugar, carbs, or salt, or feeling better after you eat. These are symptoms, that, on their own may indicate adrenal insufficiency, and drinking coffee on an empty stomach may worsen the problem.

  • caffeine in coffee (and other sources) stimulates cortisol release, and in essence, a stress response from your body, activating your Sympathetic Nervous System and HPA axis, as we discussed earlier. CLICK HERE TO LEARN MORE ABOUT ADRENAL HEALTH AND MANAGING BLOOD SUGAR LEVELS.

• DIGESTIVE SYMPTOMS - If you have symptoms of poor digestion, such as bloat after meals, excess fullness, chronic constipation or diarrhea (or alternating), heartburn, or cramping in lower abdomen.

  • These are all common symptoms of poor digestion, typically leading to (or may be a result of) a bacterial imbalance or other pathogenic infection. The research we looked at earlier in this article suggests that since caffeine in coffee irritates the mucosal lining in your colon, stimulates stomach acid production, and increases motility in the colon (makes you run to the bathroom), drinking coffee on an empty stomach may worsen these symptoms.

• ANXIETY OR OTHER MOOD VARIANCES - Anxiety can be caused by a number of things, including lack of protein/amino acids, chemical imbalance, chronic stress, and trauma. One thing we do know is that caffeine in coffee stimulates the fight or flight response. We also know that pairing caffeine with foods focused on quality protein, fats, and fiber, can help slow this process. Drinking coffee on an empty stomach may have the opposite effect, and may exacerbate anxiety symptoms.

• SLEEP ISSUES - You might argue that people with sleep issues may want to cut out caffeine in coffee altogether. Some have a genetic factor that changes the way they process caffeine, no matter what time of day they consume it, or whether or not they pair it with food. However…

  • Sleep issues can often be indicative of blood sugar issues as we discussed earlier. Fun Fact: Waking up around 2:00 am to pee is usually due to a drop in blood sugar levels (and a spike in cortisol), NOT because your bladder is full. READ MORE ABOUT IT HERE.

  • If you are someone who has trouble with sleep, consider how the caffeine in coffee may be impacting your adrenal health and blood sugar levels.

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what can you do instead?

• PAIR YOUR COFFEE WITH QUALITY, WHOLE FOODS - Wait to consume your coffee until you have a good solid meal balanced with quality proteins, fats, and fibers.

• TRY OTHER STIMULATING ACTIVITIES, FIRST - Instead of dragging yourself sleepily to the coffee pot each morning to “get going”, drag yourself sleepily out for a brisk walk first thing, getting sunlight on your face to let your adrenal glands know it’s time to wake up. Or drag yourself sleepily to a yoga class your Pelaton, or other activity that boosts cortisol levels first thing in the morning.

• SWITCH TO DECAF - I know, I know. I hear myself, too. As a coffee lover, myself, this feels like a big ask, but it may be just the right thing for your body that enables you to still enjoy coffee without the impact of caffeine in coffee.

• GET FOUNDATIONAL SUPPORT - If you are someone who deals with the digestive symptoms mentioned above, trouble managing blood sugar levels, trouble with sleep or anxiety, I have developed a number of resources that will help:

  • Reclaim Your Health program - A 3-month private coaching program to help pinpoint the root causes of your symptoms, and work to make foundational changes to repair and heal the underlying issues.

  • REBALANCE - a 4-week online course that specifically targets adrenal health, sleep, blood sugar, and hormone balance.

  • GET TESTED - Are cortisol levels an issue for you? There is a simple saliva test that will help you know how your cortisol levels look throughout the day, so you can understand the potential causes of blood sugar, sleep, and anxiety symptoms. Includes a free follow-up call with Hilary to review the results. CLICK HERE TO PURCHASE.

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ADDITIONAL RESOURCES

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BLOG REFERENCES

1. Iriondo-DeHond, A., Uranga, J. A., Del Castillo, M. D., & Abalo, R. (2020). Effects of Coffee and Its Components on the Gastrointestinal Tract and the Brain-Gut Axis. Nutrients, 13(1), 88. https://doi.org/10.3390/nu13010088

2. Nehlig, A. (2022, January 17). Effects of coffee on the gastro-intestinal tract: A narrative review and literature update. MDPI. https://www.mdpi.com/2072-6643/14/2/399

3. Lovallo, W. R., Farag, N. H., Vincent, A. S., Thomas, T. L., & Wilson, M. F. (2006, May 2). Cortisol responses to mental stress, exercise, and meals following caffeine intake in men and women. Pharmacology Biochemistry and Behavior. https://www.sciencedirect.com/science/article/abs/pii/S0091305706000645

4. Iriondo-DeHond, A., Uranga, J. A., Del Castillo, M. D., & Abalo, R. (2020). Effects of Coffee and Its Components on the Gastrointestinal Tract and the Brain-Gut Axis. Nutrients, 13(1), 88. https://doi.org/10.3390/nu13010088

5. Shimamoto, T., Yamamichi, N., Kodashima, S., Takahashi, Y., Fujishiro, M., Oka, M., Mitsushima, T., & Koike, K. (2013). No association of coffee consumption with gastric ulcer, duodenal ulcer, reflux esophagitis, and non-erosive reflux disease: a cross-sectional study of 8,013 healthy subjects in Japan. PloS one, 8(6), e65996. https://doi.org/10.1371/journal.pone.0065996