Tag Archives: caffeine

Why can’t dogs eat chocolate?

The Conversation

File 20171220 4995 ii78km.jpg?ixlib=rb 1.1
As little as three squares of chocolate can make dogs sick. Duffy Brook

Susan Hazel, University of Adelaide

Most pet owners know chocolate and dogs don’t mix. Despite this, chocolate poisoning in dogs remains a problem, particularly at Christmas, as a new study in the journal Vet Record shows.

Chocolate and cocoa are products of cacao beans (Theobroma cacao) after they are fermented, roasted, shelled and ground. Chocolate contains two ingredients potentially lethal to dogs – theobromine and caffeine.

There is 1-9 milligrams of theobromine per gram of chocolate, with higher levels in darker chocolate. White chocolate has zero risk of toxicity.

How much chocolate makes dogs sick?

Toxicity to chocolate starts at around 20mg of theobromine per kilogram of body weight. In a small dog weighing 5kg, this means 100mg of theobromine (around 70g of milk chocolate or 20g of dark chocolate) will cause problems. There’s about 25g per square of a chocolate block, so that’s around three squares of milk chocolate.

Cocoa powder contains higher levels – only 4g of cocoa powder contains 100mg of theobromine.


Further reading: Should you ever get a puppy at Christmas? Here’s all you need to know


A few years ago, my best friend’s dog, a dachshund, ate cake decorating chocolate stored in her spare room. How she managed to jump up onto the bed to get it remains a mystery. Dogs will find chocolate even if you think they can’t.

Luckily in this case, her dog vomited a large part of the chocolate before it could cause problems (although not so lucky for the cream carpet) and she was OK.

What are the signs your dog has eaten chocolate?

One of the first signs to look for if you suspect your dog has eaten chocolate is restlessness and hyperactivity. Caffeine is absorbed ten times faster than theobromine, which takes up to ten hours to peak. Signs are usually seen two to four hours after eating the chocolate and can last up to 72 hours.

It’s hard to say no to dogs, but when it comes to chocolate, we have to. Jay Wennington

Both caffeine and theobromine cause elevated heart rate and blood pressure, and abnormal heart rhythms.

Vomiting, diarrhoea, muscle tremors/shaking and hyperthermia (high body temperature) can occur at toxic levels. Your dog might seek out cooler places, although will be unlikely to settle anywhere. The hyperthermia causes panting, the main way dogs lose body heat.

In more serious toxicity, it may cause muscle rigidity (stiffness), ataxia (uncoordinated movement), seizures and coma. Death results from problems with heart rhythm or failure of the respiratory system.

Theobromine causes increased levels of cyclic adenosine monophosphate (cAMP), an important chemical messenger in the cell. Theobromine and caffeine also increase the release of adrenalin, and affect the calcium flow in and out of the cell. This increases muscle contractions.

When combined, all of these biochemical changes stimulate the central nervous system and the heart muscle. Other types of muscles in the rest of the body called smooth muscles relax, which can cause respiratory problems and increased urination.

Why do so many dogs manage to eat chocolate?

The first reason is dogs like sweet things, unlike cats who lack the taste receptor for sweet.

The second is we underestimate the motivation and sense of smell of dogs. They can smell chocolate a mile away.


Read more – Canine and able: how dogs made us human


Once we had a family Christmas in a local park, and while I was unwrapping a present my Labrador swept past and grabbed the parcel. I didn’t know there was chocolate in it but she did! Twenty of us ran after her screaming “Don’t eat it!” but by the time I caught her all I got was the paper. Luckily there wasn’t enough chocolate to hurt her.

Dogs have an amazing sense of smell and love sweet things. Erik Cid

Remember, chocolate is potentially lethal to our best friend, so put it somewhere impossible to reach. A closed cupboard will be safer than somewhere a motivated dog can jump.

The problem at Christmas time is that everything is so hectic we forget or don’t notice. If you have a dog, educate everybody you know on the risks of chocolate and keeping it out of their reach. If you have young children, you will need to keep a close eye on them as they won’t understand and love to feed dogs – children and dogs should always be closely supervised anyway.

In the case of an accident or if you suspect your dog has eaten some chocolate, contact your veterinarian. There will be time to give it something to induce vomiting if they have only just eaten the chocolate.

Humans and dogs are on the same wavelength in so many ways, but while some of us run on chocolate and caffeine, dogs just can’t. Remember that and have a happy Christmas with all your four legged family members.


The ConversationFurther reading – Curious Kids: How can you tell if your cat is happy and likes you?


Susan Hazel, Senior Lecturer, School of Animal and Veterinary Science, University of Adelaide

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

Leave a comment

Filed under Reblogs

Health Check: does caffeine cause dehydration?

The Conversation

Image 20170405 11395 tcgcmy
Studies have found caffeinated drinks retain about as much fluid as water or sports drinks. Kyle Meck/Unsplash

Ben Desbrow, Griffith University

For a long time people have been told that caffeine is a diuretic. For some, this translates into advice to avoid or remove caffeinated beverages from the diet of people at risk of dehydration, or during periods of extreme summer heat. The Conversation

While possibly well meaning, this advice is wrong.

By definition, a diuretic is a product that increases the body’s production of urine. Hence water, or any drink consumed in large volumes, is a diuretic. Importantly, urinating more does not inevitably lead to dehydration (excessive loss of body water).

Drinking simultaneously provides the body with fluid for absorption (avoiding dehydration) and initiates urine production. Depending on the urine losses that occur following drinking, a beverage might be more accurately described as a “poor _re_hydrator” if large fluid losses result.

Caffeine is a weak diuretic, and tolerance to this effect is acquired rapidly (in four to five days) with regular caffeine intake. What’s somewhat concerning is that this has been known for almost 100 years!

In 1928, a study involving three people showed that when participants consumed no caffeine for more than two months, a dose as little as half a milligram per kilogram of body mass (roughly the amount in half a cup of coffee) caused a “noticeable” increase in urine loss.

But regular caffeine intake (for four to five days) created a tolerance to the diuretic effect, so that over a milligram per kilogram of body mass (one cup of coffee) was needed before an effect was detected. This suggested that regularly consuming caffeinated drinks wouldn’t lead to chronic dehydration.

While the study had obvious sample size limitations, an investigation employing contemporary research methods and analysis confirmed these findings more than a decade ago.

This study involved 59 healthy individuals being monitored for 11 days. The investigation was designed to determine if drinking caffeine resulted in fluid loss or dehydration.

Initially, each participant’s caffeine intake was stabilised for six days at 3mg per kilogram of body mass (approximately two to three cups of coffee per day). Following this period, caffeine intake was manipulated for five days at a dose of either zero, low (one cup) or moderate (two cups) levels.

Caffeine was found to have no effect on almost every measure of hydration. Dai KE/Unsplash

The researchers monitored myriad hydration measures such as urine production and colour. Almost every hydration measure we currently use for monitoring fluid balance was not influenced by regular caffeine intake.

In hydration science, the effect of any beverage on fluid in the body is judged by the balance between how much the body retains of any volume consumed. Recently, the creation of the “beverage hydration index” has been established to describe the fluid retention capacity of different beverages by standardising values compared to still water.

Again, the beverage hydration index shows commonly consumed caffeinated beverages such as coffee, tea and cola have similar fluid retention capacity to water or commercial sports drinks.

One strength of the beverage hydration index is that it recognises all beverages make a contribution to total fluid intake (ranking some as more effective than others). By advising people not to consume drinks they enjoy (just because they contain caffeine), individuals may not automatically replace drinks, leading to a reduction in total fluid intake.

The evidence linking poor hydration status to poor health (particularly in vulnerable groups) is well established. Dehydration can produce disruptions in mood, brain and heart function and has also been found to be an indicator for worse prognoses in older patients admitted to hospital.

So while some caffeinated beverages such as cola and energy drinks have their own health implications such as high levels of sugar, in terms of optimising fluid balance, there’s no need to worry about caffeine.


Update: gram was corrected to milligram in the paragraphs outlining the 1928 dehydration study.

Ben Desbrow, Associate Professor, Griffith University

This article was originally published on The Conversation. (Reblogged by permission). Read the original article.

Leave a comment

Filed under Reblogs