When Caffeine Kills
A dietitian speaks out and presents some caffeine facts
The stimulation, the sharp alertness, that get-up-and-go; caffeine. The rich smell, the bittersweet flavour, that morning joy; coffee, or tea — each to their own.
Tea and coffee, consumed through the ages, have become synonymous with caffeine. Nowadays, caffeine is in many products, and the substance has become so common it’s easy to consume without even knowing it.
So, let’s see where caffeine resides, and while we’re at it, discover seven dietitian-informed caffeine facts.
Fact #1 — Drinks with Caffeine
The world’s most popular psychoactive substance, caffeine, has been a stimulating favourite for centuries. Today, we still drink the traditional beverages, along with some “energising” additions. Below describes how they differ by caffeine content, according to the Food & Drug Administration (FDA):
- Tea = 30 to 50 mg caffeine per 8 ounces (oz) / 227 millilitres (mills)
- Cola drinks = 30 to 40 mg caffeine per 12 oz / 340 mills
- Coffee = 80 to 100 mg caffeine per 8 oz / 227 mills
- Energy Drinks = 40 to 250 mg caffeine per 8 oz / 227 mills
Bonus fact: You may know that cola drinks use the ‘kola nut’ for flavouring. Interestingly, this nut of evergreen trees, contains similar caffeine amounts to those found in coffee beans.
Fact #2 — Caffeine Discovery and Synthesis
The habit of coffee and tea drinking began in Southern Arabia and Asia, but Fredlieb Runge, in 1819, was the first person to discover, or chemically ‘isolate’ caffeine.
In 1895, caffeine was first synthesised by Hermann Emil Fisher using the N-mythylation technique on uric acid, and his efforts won him the Nobel Prize for Chemistry in 1902.
Interestingly, scientists in more recent years have genetically modified tea and coffee to produce the enzyme N-methyltransferase. Essentially, this enzyme biosynthesises caffeine while tea and coffee grows. So come maturity, they have internally metabolised the caffeine and become decaffeinated varieties. This genetic modification removes the need for the chemical decaffeination process that takes place after a tea or coffee harvest.
Bonus fact: Caffeine is a purine-like alkaloid, and its biochemical name is ‘1,3,7-trimethylxanthine’
Fact #3 — The Plants Containing Caffeine
It’s believed that over 60 plant species host the stimulant. One of which is the guarana plant, and most of us have probably consumed this without knowing. The last time you took a painkiller you probably had guarana, as it’s used as flavouring to coat the otherwise unpleasant taste of medications.
Bonus fact: Guarana, from Brazil, rich in antioxidants and originally used as an aphrodisiac, contains up to four times the amount of caffeine found in coffee beans. Scientists have also discovered the plant has added stimulating effects compared to caffeine alone. With this in mind, guarana has become particularly popular for creating “energy” drinks.
Fact #4 — How Nature Uses Caffeine
Scientists call caffeine a “co-evolutionary protecting agent” because it is a natural pesticide. Numerous insects and animals, especially herbivores, can be extremely sensitive to caffeine. Indeed, it can kill slugs and snails and help control these agriculture pests.
Bonus fact: Compared to other neurotoxic pesticides, caffeine is naturally occurring and potentially “an environmentally acceptable alternative” for protecting crops from unwanted guests.
Fact #5— When Caffeine Kills
A scientific case study describes extreme toxicity in a woman who ingested 50 grams of caffeine — that’s equivalent to about 500 eight oz coffee cups! On hospital admission, she suffered seizures, hypothermia — and after numerous lung problems, cardiac arrest, and five days of intensive care — she lived to tell the tale. While recovering, she was referred to a psychiatrist, because, as you might have guessed, this level of caffeine consumption was a suicide attempt.
Even more sadly, others have died, after taking ‘pure and highly concentrated caffeine’ (caffeine powder). According to the FDA, just one teaspoon is equivalent to the caffeine found in 28 cups of coffee.
Fact #6 — Caffeine Toxicity
Consuming 1.2 grams “rapidly” can trigger a toxic reaction such as seizures. To put that figure into context:
- 1.2 grams of caffeine = 12 to 15 cups of coffee or six energy drinks.
As long as caffeine is consumed as a beverage, and not in its powder form, toxicity and seizures are easily avoidable in adults. The balancing act is avoiding the caffeine amounts that can cause unpleasant feelings and potential health consequences.
About 5–7 cups of coffee can trigger problems, according to researchers:
“A dose of 500mg was shown to increase tension, nervousness, anxiety, excitement, irritability, nausea, paresthesia, tremor, perspiration, palpitations, restlessness and possibly dizziness.”
Fortunately, these symptoms usually resolve within 1–4 hours, depending on a person’s sensitivity to caffeine. Studies have shown that these sudden or ‘acute’ symptoms are unlikely to cause lasting health problems.
Three health agencies; The FDA, Health Canada, and the European Food Safety Authority, agree that 400 mg of caffeine a day (about 4 cups of coffee) is unlikely to cause harm to the general population.
Fact #7 — Safe Consumption Levels
Caffeine intakes up to 250 mg in adults can heighten concentration and overall wellbeing with feelings of “elation, peacefulness and pleasantness.”
“Single doses of caffeine up to 200 mg (about 3 mg/kg of body weight for a 70‐kg adult) do not give rise to safety concerns.”
Notice the caveat in brackets above — the advice is dependant on body weight. So, caffeine sensitivity is especially relevant to children.
A young boy age 7–10 may weigh about 28 kilograms (62 lbs), so caffeine tolerance would be:
- 28 x 3 = 84 grams of caffeine (about one eight-ounce cup of coffee)
Health Canada goes a step further and recommends caffeine intake in one day should be no more than 2.5mg per kg of body weight.
- 28 x 2.5 = 70 grams of caffeine (less than one eight-ounce cup of coffee)
The difference makes you think that coffee for kids is probably not a good idea.
Bonus fact: For pregnant women, up to 3 cups of coffee are said to be safe, but experts air on the side of caution and suggest no more than 2 cups (200 mg caffeine) to be “prudent.”
The Facts: A Dietitian Speaks Out
Some of the points above are interesting anecdotes to share with friends — a bit of fun. The pertinent caffeine facts are those associated with our health and, as a dietitian, people often ask me about safe caffeine intake.
Certainly, we should completely avoid pure and highly concentrated caffeine as the likelihood of toxicity is very high. Considering caffeine evolved in plants to kill pests, it’s not surprising it can kill people too.
Caffeine toxicity and deaths are the extreme. But I’ve had clients, desperate to lose weight, tell me about their use of stimulants to help them control their hunger in attempts to ‘shred’ body fat. So, it is possible to lose our way and take unhelpful actions when we’re feeling insecure.
Energy drinks are the most concentrated beverage source of caffeine, so having them rarely or avoiding them would be wise. There is a risk of adverse effects in young children who drink energy drinks that contain caffeine over 80 mg per serving (there are many available that exceed this). It is understandable then that businesses have enforced rules to help keep these beverages away from kids.
Tea and coffee contain polyphenols that are associated with many health benefits, and they don’t have the high levels of sugar often found in energy drinks.
So, if you’re a tea and coffee fan — and you tend to have your cups early in the day — it makes sense to keep enriching your life with that morning joy before you get-up-and-go.
Certainly, we should completely avoid pure and highly concentrated caffeine as the likelihood of toxicity is very high. Considering caffeine evolved in plants to kill pests, it’s not surprising it can kill people too.
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