Coffee's got me feeling nauseous — What gives?

Dear Alice,

Recently, I have noticed that drinking coffee makes me somewhat nauseous. I have never had problems with caffeine before and still don't with caffeinated soft drinks. The only thing I can think of is that my diet at school tends to consist almost entirely of pizza and Chinese food. Could it be due to a dietary deficiency? What's up?

— B-real

Dear B-real, 

Ah, coffee — the drink so many turn to in the morning, noon, and sometimes even night for a dose of caffeine to create an energy boost. Unfortunately, the caffeine in that coffee may sometimes cause discomfort or exacerbate other issues in the body, such as nausea. Alternatively, it may be that your nausea is caused by other components of your diet instead of your coffee consumption. You may need to do a little investigative work on your own or with a health care provider to determine the culprit. 

When thinking about your discomfort, it may be helpful to reflect on a few questions to start. Do you notice your nausea after eating specific types of food? Does it show up even when you don’t drink coffee? Do you experience other symptoms as well in addition to nausea? If you’re experiencing heartburn and acid reflux in addition to your nausea, you may be experiencing gastroesophageal reflux disease (GERD). There’s limited evidence to the link between coffee and GERD, but it may be a possibility due to coffee’s stimulation of gastric acid secretion in the body, which can be problematic for people with GERD. Other exacerbating factors of GERD can include trigger foods such as alcohol, tomatoes, greasy or spicy foods, and chocolate. You may want to test cutting out certain food (maybe start with pizza or Chinese food) and monitoring your nausea to determine what’s a trigger for you. Approaches differ in the management GERD, but seeking out medical guidance can help with determining what’s best for you. 

Another way that coffee may result in nausea is the impact it can have on the absorption of nutrients in the body. Studies have shown that caffeine is most likely to reduce the levels of B vitamins, iron, calcium, and magnesium in the body. This can be further exacerbated if nutrient levels are already low due to a diet lacking in these nutrients. Some populations, such as pregnant people, children, and elderly people, are more sensitive to the effects of caffeine and may experience these negative effects at low levels of caffeine consumption. Although the link between nausea and the potential nutrient deficiency caused by caffeine isn’t well understood, it’s worth considering. If you suspect your nutrient levels are low, whether from caffeine or due to diet, supplements may provide some relief.  

While avoiding what makes you feel queasy is certainly a good way to go, you may not have to give up on coffee completely. The type of roast you choose or what time you drink it may make a difference. Some studies have examined the effect of different types of coffee (dark versus medium roast) on gastric acid secretion. Although additional research is needed to provide more conclusive evidence, these early studies suggest that it may be other ingredients in the coffee (besides caffeine) that make a difference. In addition to caffeine, βN-alkanoyl-5-hydroxytryptamides (C5HTs) and chlorogenic acids (CGAs) are compounds found in coffee that may irritate the stomach lining. Because dark roast has lower amounts of C5HTs and CGAs, it may help to switch to a darker roast. The effect of these other ingredients may also help explain why you react to coffee specifically and not to other caffeinated beverages. However, coffee has higher caffeine content than soda, so caffeine may still be impacting your body. Even more so, the body’s cortisol levels vary throughout the day, causing coffee to be less effective during certain times of the day. Coffee is most effective when cortisol levels are low. Varying the timing of your caffeine fix could be a way to see if this resolves your nausea. 

The research on coffee causing nausea isn’t definitive, but if you feel that it or other parts of your diet are the reason, then it may be helpful to avoid them to see if it makes a difference in how you feel. If you’d like more guidance on symptom management or the incorporation of supplements and healthy food options into your diet, a health care provider or registered dietitian could be a great resource for more guidance. 

Here's hoping your mug is now full with piping hot knowledge to inform next steps.

Last updated Apr 09, 2021
Originally published Jan 31, 1994

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