There’s little doubt that non-alcoholic beer is better for you than its full-strength equivalent, especially if you have an active lifestyle.
One reason for this is it’s supposed to be isotonic – a description commonly associated with sports drinks.
But what does this actually mean? And can we use non-alcoholic beer in place of sports drinks?
In this article, we’ll look at what makes a drink isotonic and whether or not non-alcoholic beer is actually isotonic.
We’ll also highlight the advantages of consuming isotonic drinks and see how non-alcoholic beer compares to a sports drink.
A fluid is isotonic when it has the same concentration of dissolved particles – such as salt, sugar and minerals – as a comparable fluid. (“Iso” means “equal” or “the same”.)
In the case of a drink, the comparable fluid is body fluid, specifically blood serum – a yellowish liquid that separates from the rest of the blood when it clots.
Measuring dissolved particles
The concentration of dissolved particles is known as osmotic concentration or tonicity, which we can measure by its osmolarity (dissolved particles per litre) or osmolality (dissolved particles per kg).
Blood serum has an osmotic concentration of 280–295 mOsm (milliosmole) per kg.
But the accepted definition of an isotonic drink is usually in the range of 270–330 mOsm per kg.
Hypotonic and hypertonic
A drink that isn’t isotonic is either hypotonic or hypertonic.
A hypotonic drink has a lower osmotic concentration than blood serum (fewer dissolved particles), while a hypertonic drink has with a higher osmotic concentration (more dissolved particles).
Advantages of isotonic drinks
So what’s the benefit of isotonic drinks and are they better for us than hypotonic or hypertonic drinks?
It’s to do with how the water in a fluid moves across the types of barriers (membranes) that separate our body cells through a natural process called osmosis:
- If a fluid has the same osmotic concentration as the other fluid (isotonic), water will naturally move both ways
- If a fluid has a lower osmotic concentration than the other fluid (hypotonic), water will naturally move into the fluid with the higher osmotic concentration
- If a fluid has a higher osmotic concentration than the other fluid (hypertonic), water will naturally move from the fluid with the the lower osmotic concentration
This means it takes us longer to absorb a hypertonic drink, because our bodies have to move water into it to lower its osmotic concentration before it’s absorbed.
In contrast, isotonic and hypotonic drinks enter our bodies more easily, because we can start absorbing them quickly.
This is why sports drinks, which are designed to provide the water, energy and salts our bodies lose when we exercise, are usually hypotonic or isotonic.
Osmotic concentration of common drinks
This study measured the osmotic concentration of common soft drinks. It found:
- water has an osmotic concentration of 13–119 mOsm per kg (hypotonic)
- juice, energy drinks and soda drinks have an osmotic concentration of 492–784 mOsm per kg (hypertonic)
Osmotic concentration of non-alcoholic beer
So, what about non-alcoholic beer? Does it have an osmotic concentration in the range of 270–330 mOsm per kg, making it isotonic?
It depends on the beer – and how much fizz it has.
Researchers at the University of Applied Sciences in Austria measured the osmotic concentration of popular alcoholic and non-alcoholic beers in their 2016 study, Suitability of Beer as an Alternative to Classical Fitness Drinks.
The alcoholic beers they measured (including popular brands like Heineken and Budweiser) had an osmotic concentration of 928–1027 mOsm per kg, making them hypertonic.
Remove the alcohol however, and the osmotic concentration falls significantly.
Out of the six non-alcoholic beers they measured, the osmotic concentration of three of them was within the isotonic range of 270–330 mOsm per kg. Another two fell just outside this range.
The non-alcoholic beers they measured were:
- Beck’s Blue – 307 mOsm per kg – isotonic
- Weihenstephaner – 324 mOsm per kg – isotonic
- Paulaner – 329 mOsm per kg – isotonic
- Clausthaler Classic – 340 mOsm per kg – near-isotonic
- Erdinger – 340 mOsm per kg – near-isotonic
- Schneider Weisse – 444 mOsm per kg – hypertonic
Therefore, there’s a good chance the non-alcoholic beer you’re drinking is isotonic – or only slightly hypertonic.
However, the researchers also concluded the carbon dioxide that gives your beer its fizz contributed significantly to non-alcoholic beer’s osmotic concentration.
And as our bodies effectively “de-gas” liquids when they enter our digestive systems, it’s likely that many non-alcoholic beers are actually hypotonic by the time our bodies absorb them into our bloodstream.
Non-alcoholic beer as a sports drink
If non-alcoholic beer is isotonic or hypotonic, does this mean you can use it as a sports drink if need to top up your carb and sodium levels when you exercise?
Although many experts agree that sports drinks should contain carbohydrates and sodium, in most regions there’s no legal definition of what constitutes a sports drink.
The researchers at the University of Applied Sciences used the following definition in their study. They say a sports drink needs to be isotonic and have:
- 500–1200mg (milligrams) of sodium per litre
- 20–80g of carbohydrates per litre
They found that the isotonic and near-isotonic beers they analysed all had the required amount of carbohydrates.
But the amount of sodium they contained ranged from only 1mg (0.001g) in Clausthaler Classic to 20mg (0.02g) in Beck’s Blue.
However, this doesn’t mean non-alcoholic beer isn’t useful for exercise and sports, especially when we consider most of us will only need the additional sodium provided by sports drinks when we’ve been doing high-intensity exercise that last an hour or more.
We’ve already highlighted how our bodies can absorb the water and carbohydrates in non-alcoholic beer more easily because it has a lower osmotic concentration than drinks like cola and fruit juice.
It also has many other health benefits.
This makes it a great post-exercise beverage, especially if you fancy something more interesting than plain water.
The carbs and lack of alcohol also means it’s a handy hydrating and energy-providing alternative to water before exercise.
Over to you
Do you drink non-alcoholic beer before or after exercise?