Everything you need to know about caffeine intake

From selecting the right barista and dedicating every morning to them, to investing in a Moccamaster, for many of us the coffee is the highlight of our morning—or the necessary evil to get us out of bed. But it’s the caffeine in our coffee that really keeps us coming back; the energy and focus it offers us can be akin to a little euphoric high. And it’s often noticeable when we lessen our caffeine intake, to the point where you might feel dependent on that morning latte.

But is too much caffeine bad for you? How do you know what the limit is? And, which coffee is healthiest? We investigated.

How much caffeine can I have daily?

There is actually quite a bit of research around caffeine intake, and you might be surprised by how much is recommended as the maximum level for an adult over 18. According to Food Standards Australia & New Zealand (FSANZ), the Australian Government Health statutory authority, it’s recommended that an adult over 18 have a maximum of 400mg of caffeine per day. That, according to nutritionist Kristen Beck, is the equivalent of around four cups of coffee or two energy drinks.

However, that’s the maximum recommended amount—if your concern is increased anxiety, for example, analysis by FSANZ determined that beyond 240mg per day (around three cups of instant coffee), anxiety levels in adults spiked.

How much caffeine is too much?

There are two parts to this question—how much caffeine is too much in an individual beverage or intake (say, a caffeine pill), and how much across a day is too much. 

Let’s talk about stress and anxiety, because for many of us, the concern is less about caffeine overdose, and more about tipping over from increased focus to feeling jittery. “Caffeine is a stimulant which increases the activity of your brain and nervous system,” explains Beck. “The main way caffeine works is by stimulating your adrenal glands (the small glands that sit just above your kidneys) to release stress hormones adrenaline and cortisol.”

That adrenaline and cortisol is what gives you that slightly euphoric, awake feeling after drinking a piccolo. But as Beck notes, these hormones can also make you feel worse. “In the short term, consuming too much caffeine is likely to lead to dizziness, irritability, anxiety, sleep disturbances, dehydration, restlessness and an even bigger slump of energy when the caffeine wears off,” she explains, adding that long-term, you’re looking at confusion, lethargy and even increased weight gain around your stomach, paired with increased cravings for sugars and processed carbs.

The problem is, the level of caffeine that is too much for you may be different for someone else. While it’s advised that no one consumes more than 400mg of caffeine a day, you might be one of the people who finds their anxiety spikes after 240mg—or even less. So the best way to determine if you’re consuming too much caffeine is to look for the symptoms Beck lists above.

When it comes to caffeine in an individual serving—say, how many shots in one cup of coffee, or how much caffeine in an energy drink or pill form, the maximum recommended dose is 200mg per serving. Beverages with added caffeine are regulated in Australia and New Zealand, with no more than 145 mg/kg allowed. Also, Pure and highly concentrated caffeine powders are banned from retail sale in Australia as of 2019, as they can contain the same amount of caffeine as 25 to 50 cups of coffee in a single teaspoon—a terrifying thought. However, there are supplements you can buy that contain caffeine, so check the label to ensure the dose per tablet or teaspoon is under 200mg. 

Which coffee is healthiest?

If you can’t face another Instagram post claiming your oat latte is calorific—new research suggests there are plenty of benefits to milk lattes. Take that black americano drinkers.

A new study by the University of Copenhagen has discovered that a cup of coffee with milk may have an anti-inflammatory effect. Inflammation occurs when we are exposed to bacteria, viruses and other foreign substances—or experience an injury—and is all part of the body’s defence and healing process. To protect us, our immune systems react by deploying white blood cells.

Coffee, known for reducing our risk of high blood pressure and improving gut health, is rich in antioxidants—also called polyphenols. These plant chemicals (polyphenols) ease inflammation by “helping reduce oxidative stress in the body that gives rise to inflammation.” But largely under-researched, there’s little known about polyphenols (also found in fruits, vegetables, red wine etc.)—particularly its reaction with other molecules.

Researchers, therefore, investigated what happens when polyphenols are combined with amino acids, the building blocks of proteins. By applying artificial inflammation to immune cells, they found that immune cells treated with the combination of polyphenols and amino acids were twice as effective at fighting inflammation as the cells to which only polyphenols were added.

“In the study, we show that as a polyphenol reacts with an amino acid, its inhibitory effect on inflammation in immune cells is enhanced,” says professor Marianne Nissen Lund from the department of food science, who spearheaded the study. “Our result demonstrates that the reaction between polyphenols and proteins also happens in some of the coffee drinks with milk that we studied. In fact, the reaction happens so quickly that it has been difficult to avoid in any of the foods that we’ve studied so far.”

In a nutshell (or an oat latte), it’s probable that milky coffee has a higher anti-inflammatory effect than a standard black coffee. And if you’re not a huge coffee drinker—have no fear as the effects aren’t limited to caffeine intake. Anti-inflammatory benefits are likely to occur from your brekky banana smoothie or nourishing granola bowl too.

“I can imagine that something similar happens in, for example, a meat dish with vegetables or a smoothie, if you make sure to add some protein like milk or yogurt,” says Marianne Nissen Lund.

But me personally, I’m going to relish my nearly three coffee cups a day…to keep the doctor away.

What does caffeine overdose look like?

According to the Alcohol and Drug Foundation, you should call an ambulance (000) immediately if you experience: tremors, nausea and vomiting, abdominal pain, diarrhoea, rapid breathing, nervousness/anxiety, irritability/agitation, a very fast or irregular heartbeat, confusion, panic attack or seizures.

While the ADF says it’s “unlikely” that you can consume a toxic amount of caffeine from caffeinated beverages alone, “there have been deaths from people consuming caffeine in tablet or powder form.” Supplements that include caffeine in their ingredients list won’t necessarily be for energy or focus, so it’s crucial you check any supplements you take, to ensure you don’t go over the recommended maximum dose of 400mg.

Related: How to get into yoga if you’re a beginner, according to Steph Claire Smith

How can I reduce my caffeine intake?

If you want the energy and focus caffeine gives you, but feel you need to reduce your intake, Beck has some suggestions—especially for that 3pm slump. That slump is actually our body’s way of encouraging us to take a little nap, but since that’s not always possible, there are ways to reboot your system a little.

“Eating a small snack will keep your blood sugar better-balanced and will also keep your body temperature slightly warmer,” explains Beck. She also suggests a short walk or stretch to increase blood supply to your brain. Finally, Beck says putting on that hype-up playlist isn’t a placebo. “Music can increase your feel good neurotransmitters and give you a moment to reset and re-energise,” she explains.

Story written by Melissa Mason and Hayley Peppin.

This piece originally appeared in Harper's Bazaar Australia.