I’m often asked by my clients if they have to give up their beloved coffee to be healthy. And my answer is: it depends! As with almost everything in functional nutrition, there is no “one size fits all” approach. We have to investigate how your unique body (DNA, microbiome, liver, hormones, etc.) handles caffeine before deciding whether coffee is a friend or foe.

First, we have to look at your symptoms following caffeine consumption. When you drink coffee, do you get jittery, wired, anxious, clammy and feel like your heart is going to beat out of your chest? Or do you feel focused, mentally clear, alert and ready to crush your to-do list or a gym workout? The way your body breaks down and responds to caffeine is actually influenced by your genes! We’re about to get a little science-y so hang on for the ride…

Caffeine consumption and metabolism are influenced by genetic markers near the CYP1A2 and AHR genes. CYP1A2 is a gene which contains instructions for an enzyme that breaks down 95% of the caffeine you consume. AHR is a gene that contains instructions for a protein that ramps up production of the CYP1A2 enzyme, which is involved in breaking down caffeine.

Variants in these genes may affect how quickly the body breaks down and clears away caffeine from your system. One variant of this gene causes the liver to break down caffeine really quickly so, if you’re blessed with two of the fast caffeine genes, you probably have no issues chugging coffee all day long and may even be able to have an after-dinner coffee and sleep like a baby. These fast metabolizers break down caffeine up to 4x faster than those people who have either one or two of the slow-variant version of CYP1A2.


Slow Caffeine Metabolizers

With one or two slow caffeine genes, it’s likely that you will experience more negative effects from caffeine, like feeling jittery and anxious, as well as interrupted sleep, digestive issues and cortisol spikes. There are other pretty significant issues associated with being a slow metabolizer and drinking too much caffeine, such as increased risk of hypertension and heart attack.


Fast Caffeine Metabolizers

Life isn’t fair. And one example that confirms this is the fact that fast metabolizers not only don’t have to worry about any of the increased health risks above, but they actually experience a plethora of benefits from consuming caffeine! These blessed ones drink coffee and experience a speedier metabolism, enhanced exercise performance, better mental clarity, improved mood and increased longevity.


How do you find out about your own caffeine genes?

Well, you can do genetic tests like 23andMe which can tell you if you possess a gene variant that codes for the enzyme CYP1A2.

If you don’t want to get the fancy testing, you can probably use your intuition to decide whether caffeine is right for you or not. If you know (or infer based on your symptoms) that you are a slow metabolizer, that doesn’t mean you can’t have any caffeine at all; just limit your amount and perhaps opt for tea instead of coffee. If drinking any caffeine makes you jittery, just cut back on quantity or drink decaf.

In my case, I know I am a slow caffeine metabolizer. If I drink coffee, I get all those uncomfortable side effects (jittery, anxious, frantic, sweaty, etc.), however I’m cool as a cucumber drinking green tea. This is likely for two reasons. One is the fact that green tea contains roughly half the amount of caffeine as coffee–in 8 ounces, there is roughly 50 mg in green tea versus 100 mg in coffee, depending on how it is prepared. The second reason is that green tea contains L-theanine which is an amino acid that ramps up the activity of our calming neurotransmitter, GABA, which helps to decrease anxiety.



So Let’s Talk About Coffee Versus Green Tea

Green tea is an antioxidant powerhouse. It contains high amounts of EGCG which is a catechin that slows down aging, decreases cancer growth, reduces heart disease risk, decreases inflammation and boosts metabolism.

There are several varieties of green tea, such as the uber-popular matchasenchagyokuro and bancha. All are good and each has a slightly different taste, price tag, amount of caffeine and concentration of EGCG.

In green tea, the caffeine and L-theanine work together to produce sustained energy and improved brain function. Many people love the fact that green tea gives them enough caffeine for a mental and physical boost without the crash a couple hours later.

Coffee, too, is a great source of inflammation-taming antioxidants. There is data to show that drinking coffee can help boost exercise performance, burn fat, increase insulin sensitivity, decrease risk of neurodegeneration and increase longevity.

Caffeine levels vary between different types of coffee based on the beans used, how much used, length of brew cycle and how much the end product was diluted with water or cream. As a general rule, cold brew tends to have slightly less caffeine than drip coffee. Blonde roasts tend to be higher in caffeine than dark roasts.

Conventionally grown coffee is heavily sprayed with pesticides, chemicals and combined with solvents. Since coffee is one of the most contaminated crops worldwide, if you’re an avid coffee drinker, I highly recommend buying and drinking organic coffee whenever possible. If you choose to drink decaf coffee, select water-processed decaf, such as Swiss Water, which doesn’t use toxic chemicals to remove the caffeine.

Now that you’ve got the low-down, back to our original question: which should you drink: green tea or coffee? Either, both or neither! Figure out what’s right for you.

As a nutritionist, I see some people who tolerate coffee and some who don’t. I also see some who thrive on matcha, and others who feel it’s too stimulating. Both green tea and coffee contain health-promoting antioxidants, amino acids and minerals so one isn’t “better” than the other. It comes down to personal preference, as well as experimenting with how you personally respond to each. If you feel great drinking a coffee or green tea each day, go for it! If you can tell caffeine isn’t serving you, how about opting for one of the many delicious herbal teas out there? Here is a guide to medicinal teas to help get you started on your caffeine-free tea journey!