The short answer is:
According to the 2022 National Coffee Data Trends report, 66% of Americans now drink coffee every day. Coffee consumption increased 14% since January 2021 and is at a two-decade all-time high. Americans now drink more coffee than tap water (1)!!
The media and health experts often liken coffee to a superfood, as studies—not always conclusive—have suggested that coffee consumption may reduce the risk of Parkinson’s Disease and Alzheimer’s; may protect the liver; may contain anti-cancer properties; may lower risk of stroke; and can potentially boost fat-burning and metabolism.
BUT…whether YOU experience these purported health benefits will depend on various factors, including:
–What is your current health status?
–Are you prone to anxiety and irritability?
–Are you chronically stressed…as in overworked, overscheduled (personally and professionally) and regularly sleep-deprived?
–Do you have digestive health issues, like acid reflux, IBS (Irritable Bowel Syndrome), ulcerative colitis, Crohn’s Disease or stomach ulcers?
–Do you have high blood pressure or are you taking medication for high blood pressure?
–Are you diabetic or struggling with blood sugar issues?
–Do you struggle with insomnia or have other sleep issues?
–Do you rely on coffee to “give” you energy in the morning—or throughout the day?
–Are you experiencing adrenal issues that leave you feeling wired but tired?
–Have you been diagnosed with thyroid disease?
–Are you a woman in mid-life, experiencing hot flashes or other uncomfortable perimenopausal / menopausal symptoms?
–Do you have an underlying heart condition or heart problems?
–Are you a fast metabolizer or slow metabolizer of caffeine?
Full disclosure: I LOVE coffee (I only drink espresso, not brewed coffee), and I absolutely understand why that first morning cup of coffee is a treasured ritual for many people. I once even flirted with the idea of opening my own coffee bar…that’s how much I love coffee.
That said…my relationship to coffee has changed over the years, from regular, daily consumption to an occasional “treat”.
There are plenty of studies and “experts” touting the health benefits of coffee.
However, whether you experience the purported benefits of coffee will depend on your age, your stress resilience, your hormonal status, your lifestyle, and your body’s ability to tolerate and metabolize caffeine.
No two people will experience coffee in the exact same way. So, it is important to listen to your body—not the “experts”!
Coffee: The Good
It is high in antioxidants!
Coffee is a rich source—and for some people, the only source!—of antioxidants, protective molecules that can prevent or slow cell damage.
As “good guys”, antioxidants inactivate free radicals (unstable atoms that can damage our cells, causing aging and illness), preventing cellular damage. Natural antioxidants are found in fruits, berries, vegetables, honey, cocoa, tea, wine and in other foods and beverages (2). The most common dietary antioxidants are vitamins A, C, E, beta carotene and lycopene (3).
The antioxidants in coffee, to which the health benefits of coffee are typically attributed, are chlorogenic acid (CGA) and caffeic acid, as well as ferulic acid and p-coumaric acid. (4, 5)
It can support cognitive function.
Coffee is a psychostimulant that, ironically, restricts cerebral blood flow (6).
However, despite less blood flow to the brain, the caffeine in coffee actually stimulates certain regions in the brain more; this uneven distribution of stimulation effect (certain parts of the brain are stimulated; others are not) increases resting brain entropy (BEN), the number of neural states the brain can access. (7, 8, 9). In other words, increased brain entropy is a good thing! Researchers found that caffeine in coffee increased resting brain entropy in the cerebral cortex and, especially, in the lateral prefrontal cortex, the DMN (default mode network), visual cortex and motor network, regions of the brain where caffeine positively affected focus and attention, vigilance and action/motion functionality. (10)
It may lower risk of Alzheimer’s and Parkinson’s Disease.
Caffeine, one of the main ingredients in coffee, is thought to help maintain cognitive function in the elderly (11).
When mice with Alzheimer’s Disease (AD) were given caffeine in their drinking water from young adulthood to older age, these mice experienced protection from memory impairment and they had lower levels of amyloid-beta, the abnormal protein that is a key biomarker of Alzheimer’s Disease (12).
However, results from human studies have been mixed. Researchers found that, among 676 men born between 1900 and 1920 from Finland, Italy and the Netherlands, who participated in a 10-year study regarding their coffee consumption, those who drank 3 cups of coffee daily—not more, not less—experienced the least cognitive decline (13). On the other hand, other studies have found that while coffee consumption is associated with having a protective effect against dementia in the short-term, this protective effective does not seem to last long-term (14, 15).
Coffee has also been associated with lowered risk of Parkinson’s Disease (PD)—particularly in men. The association between caffeine consumption and lower risk of Parkinson’s Disease is weaker for women, especially for post-menopausal women on hormone replacement therapy. The lowest risk of PD has been associated with drinking 1-3 cups of coffee daily (16).
One study found found that coffee drinkers tended to develop Parkinson’s 8 years later (age 72) compared to non-coffee drinkers (age 64) (17). In a 22-year-long Finnish study of 6,710 men and women, ages 50-79—none of whom had Parkinson’s Disease at the outset—researchers found that the highest consumption of coffee was associated with the lowest risk of PD; it was 74% lower for high-consuming coffee drinkers than for non-coffee drinkers (18, 19). Moderate coffee consumption, about 300 mg daily (that’s apx. 2-3 cups of coffee, depending on how it is brewed), lowers risk of PD by 24% (20).
It can boost mood.
Coffee can confer a “pick-me-up” quality that helps boost mood.
Drinking coffee increases dopamine levels in the brain, which enhances mood and a sense of well-being. Dopamine is a neurotransmitter made in the brain. It acts as a chemical messenger that communicates messages between nerve cells in your brain to other parts of the brain and body.
Dopamine is also a “feel good” hormone associated with pleasure, motivation and reward. Certain foods, like dark chocolate and dairy products, as well as activities, like exercising, shopping as “therapy” and having sex, can increase dopamine levels. Caffeine also has this effect. Studies have shown that approximately 200 to 250 mg of caffeine can boost mood for up to 3 hours (21). In a study published in Translational Psychiatry, researchers found that caffeine blocks adenosine receptors, which leads to an increase in dopamine signaling and, consequently, the release of dopamine, which can enhance mood (22).
Keep in mind, however, that higher doses of caffeine, or drinking more coffee than your body can tolerate, can increase feelings or anxiety, irritability and tension (23).
It may lower diabetes, stroke and cancer risk.
Again, this will depend on the “big picture” of your overall health status.
Coffee is not a magic bullet or a quick fix for better health if you regularly consume foods that are ultra-processed, high in sugar, refined carbs and/or are cooked/processed in toxic fats, including industrial seed oils, such as soybean, corn, safflower and canola oils.
Diabetes. A meta-analysis of over 1.1 million study participants (men and women) suggests that participants who drank 6 cups of coffee/day vs. non- coffee drinkers had a 33% lower risk of diabetes (24). Moderate coffee consumption may be beneficial as well: the results of the Nurse’s Health Study II, indicated that women between the ages of 26 and 46—without a history of diabetes—and who consumed a moderate amount of coffee—2-3 cups daily—had a lower incidence of diabetes (25). Another large-scale review of 18 studies suggests that each cup of coffee consumed per day is linked to a 7% lower risk of developing Type 2 diabetes (26).
What’s the magic compound in coffee that can potentially help lower diabetes risk? Chlorogenic acid (CGA), a main polyphenol in coffee, has been shown to reduce blood sugar in animals. In studies, where rats, including obese rats, were administered CGA intravenously or orally, their insulin sensitivity improved, and they had lower post-meal blood sugar levels. (27, 28, 29)
Stroke. Moderation is a recurrent theme! A meta-analysis of 11 studies involving almost 480,000 participants and 10,000 stroke cases showed that, moderate coffee consumption (about 3-4 cups) may be associated with reduced risk of stroke (versus not drinking coffee at all). Drinking more than 6 cups of coffee, on the other hand, was associated with increased risk of stroke (30).
Cancer. Although studies link high coffee consumption (vs. low coffee consumption) with a lower risk of cancers, like prostate, endometrial melanoma, skin and liver cancers, this is dose-dependent, meaning beneficial outcomes were associated with drinking 1-3 cups of coffee (31, 32, 33). Lung cancer is one exception. Several studies indicate that lung cancer risk is apx. 47% higher among those who drink the highest amount of coffee versus those consume the least amount (34).
Coffee: The Bad
For many people, the caffeine in that beloved morning cup of coffee is addictive. Coffee is one of the most socially acceptable stimulants we consume, but most people do not realize that it is a drug. And its drug-like effects can impact mood, metabolism, blood sugar, energy levels and digestive health. A few things about coffee to consider that can negatively affect your health…
It contains caffeine.
Caffeine can overstimulate and overtax our bodies, adversely affecting our stress response, which creates HPA axis dysfunction.
HPA dysfunction involves your 1) Hypothalamus (H), the part of your forebrain that acts as a master hormone regulator; 2) Pituitary (P), a pea-sized gland under the hypothalamus that sits at the base of your brain; and, 3) Adrenal glands (A), located atop each kidney; they produce stress hormones involved in the fight-or-flight response.
That caffeine in your java travels to your hypothalamus, where it messages your pituitary gland to tell the adrenal glands to release more cortisol, a stress hormone. At the same time, caffeine also interferes with adenosine, a molecule that signals drowsiness between brain cells and the body, thereby preventing a state of sleepiness that would otherwise naturally occur.
“Adrenal fatigue” was a term coined in 1998 by Dr. James Wilson, author of Adrenal Fatigue: The 21st Century Syndrome. “Adrenal fatigue” has been used to refer to below-optimal adrenal function resulting from stress and the overproduction or underproduction of the stress hormone cortisol. Because “HPA dysregulation” or “HPA dysfunction” is technically more accurate in describing the complex feedback loop that results in either a positive or a negative stress response, I will be using these terms instead of “adrenal fatigue”.
Those who are sensitive to caffeine, or who are genetically slow metabolizers of caffeine will likely experience its negative side effects more acutely, including anxiety, insomnia, high blood pressure, irritability, rapid heart rate, fatigue, blood sugar imbalances and frequent urination.
It contributes to sleep issues and insomnia.
On average, caffeine has a half-life of apx. 5 to 5.7 hours (35, 36). However, the half-life of caffeine can range as high as 10 hours (37). This means that although you may feel the effects of caffeine immediately, it will take about 5 to 6 hours for the caffeine in your system to be reduced by half. Let’s say: you drink 2 cups of black drip coffee between 9 AM and 10 AM. Each cup of coffee contains 100 mg of caffeine, which means that you have consumed 200 mg of caffeine total. At 4 PM, 6 hours later, you will still have 100 mg of caffeine left in your system. This is its “half-life”. The caffeine from your last cup of coffee at 10 AM may not completely exit your system until 10 PM.
Even if you think you have a high tolerance for caffeine or are immune to the effects of caffeine…large sample and population-based studies show that regular, daily intake of caffeine is associated with disrupted sleep and daytime sleepiness (38).
Caffeine decreases 6-SMT, the main metabolite in melatonin, the hormone that promotes sleep; this translates into getting less sleep overall and experiencing less quality (deeper, restorative) sleep (39).
It can contribute to weight gain.
Yes, unfortunately. Drinking coffee when you are tired and/or when you need an energy boost disrupts your circadian rhythm. Also known as our internal master clock, circadian rhythms influence various natural processes that respond to cycles of light and dark; this includes the release of hormones; eating and digestion; and body temperature (40).
The caffeine in coffee disrupts the architecture of your sleep: you sleep less hours and/or you experience poor quality sleep. Coffee raises the stress hormone cortisol. Chronically high levels of cortisol promotes fat storage, especially around your mid-section and contributes to unwanted weight gain.
It can spike blood sugar levels.
Like sugar, caffeine can increase blood sugar levels (41), resulting in cortisol spikes that tax your adrenal glands. Those suffering from HPA dysfunction, Hashimoto’s/hypothyroidism or Graves’ thyroid disease are more likely to experience the negative effects of caffeine consumption. This is also bad news for hypoglycemics who are prone to low blood sugar—and feel shaky, irritable, dizzy, weak, moody and/or quick-to-anger when hungry.
Studies have shown that caffeine consumption can reduce insulin sensitivity in healthy people (42). This is not what you want on a regular basis!
Having low insulin sensitivity, a.k.a. insulin resistance, is associated with Type 2 diabetes. Ideally, you want to have a good sensitivity to insulin. In other words, you want to be “insulin-sensitive”.
It can trigger cravings for sugar and carbs.
Blood sugar that goes up must come down. When caffeine spikes blood sugar, it will crash. Your body then signals—through cravings for sugar and carbs—that it needs a “quick fix” to bring your blood sugar back up. When you drink coffee on an empty stomach, or have your coffee with cereal, toast, pastries, a bagel, or other processed / refined carbohydrates, you will have started a blood sugar rollercoaster—and likely find yourself craving sugar and/or carbs later in the morning or mid-afternoon.
It raises blood pressure.
Yes, it does. Researchers, who reviewed controlled clinical and epidemiological studies on caffeine, coffee and hypertension (high blood pressure) over a 30-year period, concluded that regular coffee consumption may be harmful for those who have hypertension (43). Coffee/caffeine has also been touted to improve athletic performance. However, overall health must be taken into consideration as consuming caffeine affects heart rate and blood pressure. In a study of healthy young males (average age 24), those who ingested 300 mg of caffeine (equal to apx. 3 cups of coffee) before engaging in moderate exercise experienced a delay in recovery of parasympathetic heart rate control (this refers to having a relaxed, slower heartbeat post-exercise) and an increase in blood pressure (both systolic and diastolic) that took longer to return to normal than those who had not ingested caffeine (44).
It can worsen digestive health problems.
Because coffee is acidic and contains caffeine, a stimulant, it can trigger or worsen digestive health problems like acid reflux, also known as GERD (gastroesophageal reflux disease) or IBS, a.k.a. Irritable Bowel Syndrome (45, 46).
Many people appreciate how their morning cup(s) of coffee promotes a bowel movement via peristalsis, an involuntary movement in your digestive tract that helps food and fluids exit the body as poop. However, the combination of acidity and caffeine in coffee can irritate the lining of your small intestine, triggering abdominal spasms, cramps and diarrhea alternating with constipation. Remember: caffeine speeds things up in your system, which can trigger diarrhea; it is also a diuretic that can leave you dehydrated—and constipated. You may want to rethink your relationship with coffee if you have digestive issues such as IBS, IBD, ulcers, Crohn’s or gastritis, where the intestinal lining is already inflamed.
It can worsen perimenopausal and menopausal symptoms.
At midlife, many women, juggling family, work and care-taking of aging parents—while going through peri-menopause or menopause—cannot fathom their life without coffee!
Unfortunately, coffee is a culprit in estrogen dominance, a condition where the level of estrogen is high, relative to the level of progesterone in the body (47). During perimenopause, estrogen levels can fluctuate wildly, sometimes spiking high, as the level of progesterone falls steadily (or, sometimes, significantly). At menopause, a woman’s level estrogen may now be low but still “high” relative to her level of progesterone, which may be close to zero.
The caffeine in coffee consumption has been linked with increased levels of estrogen, specifically estradiol (48).
At mid-life, drinking coffee can feel necessary in order to power through the day, yet it may be major contributor to estrogen dominance—and it’s likely fueling hot flashes and night sweats. Other symptoms of estrogen dominance include mood swings, irritability, anxiety, bloating, weight gain, bad PMS, anxiety, fatigue, sleep problems, heavy and/or painful periods and irregular periods.
If you’re a woman who would like to feel “saner” during this milestone hormonal transition, you may want to reconsider your relationship with coffee.
It can negatively affect the heart.
Over the years, studies on caffeinated coffee and risk of cardiovascular disease have been mixed and are skewed towards the benefits of drinking coffee. Some studies found no risk associated with coffee consumption and heart disease; other studies indicate that moderate coffee consumption may be associated with lower risk of heart disease due to the antioxidants in coffee (49).
However, research published in Epidemiology suggested that coffee can trigger myocardial infarction (heart attack) within an hour in some people. Researchers found the risk for heart attack to be highest among coffee drinkers who: 1) were “light” or “occasional” coffee drinkers (up to 1 cup of coffee per day); 2) had a sedentary lifestyle; and, 3) had 3 or more risk factors for heart disease (50).
In another study that assessed the relationship between coffee consumption and risk of having a first, non-fatal myocardial infarction (heart attack) in men under the age of 55, the results suggest that caffeinated coffee does increase the risk of heart attack and that men who drink at least 5 cups of coffee may increase their heart attack risk by twofold—or more (51).
In 2021, Dr. Gregory Marcus, a cardiologist who specializes in heart arrhythmias, conducted a randomized trial called CRAVE, a.k.a., the Coffee and Real-Time Atrial and Ventricular Ectopy trial to determine the effects of coffee on heart arrhythmias, physical activity, sleep and blood sugar (52). The 100 adult volunteers (median age was 38) were randomly chosen to drink coffee or to avoid drinking coffee over a two-week period. Each participant was fitted with a continuously recording electrocardiograph device, continuous blood glucose monitor, a Fitbit and genotyped as a fast or slow caffeine metabolizer (53).
The results of the CRAVE trial? Drinking coffee resulted in having more premature ventricular contractions (PVCs), extra, abnormal heartbeats that disrupt your regular heart rhythm.
Experiencing occasional PVCs is not necessarily concerning. However, if you have frequent PVCs or an underlying heart condition, PVCs can lead to a more serious heart condition. In addition to caffeine, other potential causes of PVC include heart disease or scarring, certain medications, alcohol, stress, exercise or low blood oxygen from COPD (54).
In the CRAVE trial, coffee drinkers increased their physical activity (by 1,056 more steps); however, they got less sleep (apx. 36 mins. less). There was no increase in atrial arrhythmia; atrial arrhythmia begins in the upper chambers of the heart and includes atrial fibrillation and atrial flutter (55).
Personally, if I was experiencing heart palpitations, a fluttering heart, or any kind of chest pain, I would avoid eating or drinking anything that could potentially trigger or accelerate an irregular heartbeat—no matter how “healthy” the purported food or drink.
The Bottom Line…
Drinking coffee in and of itself will not “give” you better health!
Have You Checked Out Café Gene?
Your genetics play an important role in your body’s ability to metabolize (break down) caffeine.Your genotype will greatly affect whether you experience positive health outcomes from coffee consumption—or not.
The gene, CYP1A2, contains instructions for an enzyme that breaks down 95% of the caffeine you consume (56). The rate at which your body metabolizes (breaks down) caffeine indicates whether you are a “fast metabolizer” or “slow metabolizer” of caffeine. Those who have a “homozygous genotype” have inherited an identical DNA sequence for a specific gene from both the mother and father. When it comes to caffeine, those who have a homozygous AA genotype can rapidly metabolize caffeine. Those with a mutation, like an AC genotype, are slow metabolizers of caffeine (57).
Your genotype is associated with health risks and benefits. For example, in a study published in Genes and Nutrition, researchers assessed whether a CYP1A2 genotype (fast vs. slow caffeine metabolizers) had any effect on coffee consumption and risk of heart attack in subjects under age 50. What they found: those who were genotyped as “fast” caffeine metabolizers benefitted from coffee consumption, even those who drank 4+ cups of coffee / day. On the other hand, coffee consumption was associated with higher risk of heart attack—drinking 4 or more cups of coffee daily—only among those who were genotyped as “slow” caffeine metabolizers (58).
Even if you are a fast metabolizer of caffeine, other things to consider are:
The Coffee Itself
–The quality of the coffee you are drinking (organic vs. non-organic)
–How the coffee is prepared (filtered vs. unfiltered)
–How you drink your coffee: black coffee vs. with coffee loaded with sugar, milk/cream and/or other add-on ingredients, where “coffee” morphs into “dessert”
–When and how much coffee you drink overall
–Are you overweight or obese?
–Do you have hypertension (high blood pressure) or not?
–Are you physically active or largely sedentary?
–Are you a smoker—or not?
–Are you chronically stressed?
–Are you always exhausted?
The best way to maintain a healthy relationship with coffee / caffeine is to take an occasional break from it.
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