Health and wellness influencers give a lot of advice. Sometimes, their advice may come from a place of good intentions, but it is not uncommon for wellness influencers to give advice that is not backed up by science. So, one of my favorite things to do is fact-check claims made by health influencers. And today we are going to be talking about caffeine. Is caffeine safe? Is caffeine healthy? How much caffeine can you consume? This is what we will discuss today!
*Disclaimer: As always, this is general information intended for healthy adults. Your needs may vary based on medical status, lifestyle, or life-stage. Please never replace generalized health information you’ve read online with individualized clinical care.
First of all, what is caffeine? What foods and beverages contain caffeine?

Caffeine is a bitter substance that occurs naturally in more than 60 substances including coffee beans, tea leaves, cocoa pods (made into coffee), and kola nuts (used to flavor soda).
Caffeine may also be added to various beverages, food products, and supplements, including ‘pre-workout.’ It is also found in some over the counter pain relievers.
Coffee is the primary source of caffeine in the American diet. Soft drinks, energy drinks, teas, supplements, and caffeinated food products are other sources.
A home brewed cup (8 ounces) of coffee contains about 40 mg caffeine. A cup of green tea has about 35 mg. A grande (16 ounce) cup of blonde roast coffee from Starbucks has 360mg. A grande (16 ounce) Nitro Brew from Starbucks has about 280mg caffeine.
Of note, ‘decaffeinated’ beverages are not always void of caffeine. Decaf coffees and teas do have less caffeine than their caffeinated counterparts, however, they may still contain low levels of caffeine. For example, a decaf coffee may have 2-15 mg of caffeine in an 8-ounce cup compared to a usual 40 mg, but it’s not caffeine-free.
What does caffeine do to the human body?
Caffeine has many effects on the human body. Of note, caffeine is considered a mild stimulant, as it stimulates the central nervous system. This can make you feel more awake, mentally alert, help you focus, and/or give you a boost of energy.
Caffeine is also a natural mild diuretic, meaning it helps the body remove extra salt, leading to increased urination.
How long do caffeine’s effects last?
It takes most people 3-6 hours to metabolize half of what has been consumed. Caffeine levels tend to peak 30-120 minutes post-consumption.
How much caffeine is safe?
Generally speaking, for most healthy people, consuming up to 400mg of caffeine per day is considered safe. Caffeine tolerance varies from person to person. Some people may be much tolerant of smaller amounts of caffeine than others.
The FDA and Health Canada have released guidelines that state healthy non-pregnant people can safely consume up to 400mg of caffeine (about 4-5 cups of home brewed coffees; one venti Pike’s Place roast at starbucks has 410mg, while a blonde roast has 475mg) with no adverse health consequences.
According to the American College of Obstetricians & Gynecologist, the FDA, and the European Food Safety Authority, pregnant women can safely consume up to 200 mg of caffeine per day.
Breastfeeding individuals may pass some caffeine to their babies via breast milk, although the amount is usually not enough to impact the infant. The American Academy of Pediatrics advises limiting caffeine during breastfeeding, but states that breastfeeding individuals don’t need to avoid it altogether.
Some people with certain medical conditions or those taking certain medications may need to limit caffeine intake. Check with your health care provider if you have questions or concerns about your unique case.
Is caffeine consumption dangerous?
In moderate amounts, caffeine is considered safe. Despite what some health influencers may tell you, caffeine is not linked to higher risk of cancer (in fact, some studies suggest it may be mildly protective), fibrocystic breast disease (although high amounts are linked to increased symptoms), cardiovascular disease, ulcers, infertility, osteoporosis, birth defects, ADHD, nor elevated blood cholesterol (although unfiltered coffee, like that made in a French press or percolator, has been linked to elevated LDL ‘bad’ cholesterol, likely due to the unfiltered oils that naturally occur in coffee).
Caffeine may temporarily raise blood pressure for a few hours, but it does not cause significant increases in long-term blood pressure nor is it to blame for chronic hypertension. That said, it’s recommended that you avoid caffeine shortly before having your blood pressure taken.
Does caffeine cause dehydration?

No. While it is true that caffeine is a mild diuretic, it will not cause dehydration. In fact, you can count caffeinated beverages towards your daily fluid intake.
Does caffeine cause adrenal fatigue?
No. Adrenal fatigue is not a real disease nor diagnosis. There are many adrenal disorders that require medical attention; however, adrenal fatigue is not one of them, and caffeine does not cause it. If you think you have an adrenal condition, it may be worth chatting to your doctor and/or seeing an endocrinologist.
What are potential side effects of too much caffeine?

As I always say, the dose makes the poison. There is a thing as too much caffeine.
Large amounts of caffeine may inhibit the proper absorption of essential vitamins and minerals, including vitamin B6, calcium, magnesium and iron.
However, for those who drink a moderate amount of coffee and consume a robust, diverse diet, this should not cause significant problems. And if you are concerned, you can space your coffee consumption between meals to ensure optimal absorption.
Toxicology data suggests that rapid consumption of 1,200 mg of caffeine may lead to toxic effects including seizures. That’s about 4 venti cold brews from Starbucks.
Depending on individual tolerance levels, some individuals may experience symptoms like jitters, anxiety, and insomnia after varied levels of caffeine intake. If you are sensitive to caffeine, you may want to limit consumption to lower levels compared to others to avoid adverse symptoms, and refrain from consuming 6-8 hours before bed time for optimal sleep.
Potential Health benefits of Caffeine:

Modest caffeine intake is associated with lower risks for certain chronic illnesses, including cardiovascular disease and type 2 diabetes. There is also weak evidence to suggest coffee (not caffeine) may prevent cognitive decline associated with aging.
It’s worth noting that most of the research done on caffeine has used coffee as the caffeine source. Thus, it remains unclear as to whether the long-term benefits were due solely to caffeine consumption, or if they were at least partially a result of other health-promoting substances found in coffee, including antioxidants such as flavonoids.
More research is needed to be able to parse apart these findings. When it comes to consuming coffee or caffeine for health, the US Dietary Guidelines for Americans advise that, based on existing evidence, that if you do not already consume caffeine, starting consumption in homes of improved health is not encouraged.
What are some symptoms of caffeine withdrawal?
If someone is used to drinking a certain amount of caffeinated foods and/or beverages and abruptly stops, they may experience withdrawal symptoms including headaches, nervousness, and anxiety. Caffeine withdrawal is not considered to be dangerous, but it can be unpleasant, so if you’re planning to go cold turkey, be prepared for potential side effects.
Take home: caffeine

Caffeine is a wildly popular, naturally occurring mild stimulant, found in many foods and beverages including coffee, tea, cocoa pods, and other food and supplement products. Modest consumption of caffeine is considered safe for most healthy people.
Consuming caffeine via filtered coffee or green tea is likely more beneficial overall compared to products like energy drinks, which may have lots of added sugars. Caffeine does not cause dehydration nor adrenal fatigue. Certain populations and people at various life stages (such as people with certain health conditions, and those who are pregnant or breastfeeding) may need to limit their consumption.
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That’s all for now! I hope you found this post somewhat useful. As always, feel free to drop me comments ore requests down below, and/or say hello on Instagram, Twitter, or YouTube!
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