Short answer: Your gut absorbs sodium and glucose together, through a transporter called SGLT1, and water follows them in. That's why the oral rehydration solution (ORS) used worldwide to treat dehydration contains both salt and sugar. But the amount matters. The World Health Organization's ORS uses a small amount of glucose, about 13.5g per litre. Sports drinks often carry 60-80g per litre and soft drinks around 100g, and too much sugar can slow fluid absorption. Zero sugar misses the effect altogether. For an everyday drink, the sweet spot is a little, not none and not a lot. That's why Zuum Energy Powder is intentionally low in sugar, with no added sugar: from 0.3g of natural sugars per sachet, depending on the flavour.
"Zero sugar" sounds like the healthiest option for a hydration drink, and for many drinks it is. But when it comes to getting electrolytes and water into your body, a small amount of sugar does a real job. Here's the science.
How your gut absorbs sodium and water
Water doesn't get pumped into your body directly. It follows dissolved particles, mainly sodium, across the wall of your small intestine.
One of the main ways sodium gets across is a transporter called SGLT1 (sodium-glucose linked transporter 1). As described in a review of human sodium glucose transporters, SGLT1 moves sodium and glucose into the cells lining your gut together, at a ratio of 2 sodium to 1 glucose. Without glucose, that particular route is switched off.
In simple terms:
- Glucose and sodium arrive together in your small intestine.
- SGLT1 carries both across into the gut lining.
- Water follows the sodium and glucose into your body.
The medical breakthrough behind it
This isn't sports marketing. It's one of the most important discoveries in modern medicine.
In the 1960s and 70s, researchers showed that a simple drink of water, salt and glucose could rehydrate people with severe diarrhoea, including cholera, without a drip. In 1978 The Lancet called it potentially the most important medical advance of the century. Oral rehydration solution has since saved millions of lives.
Why "more sugar" isn't better
If some glucose helps, you might think more would help more. It doesn't.
When a drink contains a lot of sugar, it becomes very concentrated (high osmolality). A very concentrated drink can actually draw water into your gut rather than out of it, slowing absorption and upsetting your stomach.
The ORS story shows this clearly. The WHO's original ORS was later replaced by a "reduced osmolarity" version with less glucose and less sodium. A Cochrane review found the lower-concentration formula led to fewer unscheduled IV drips, less vomiting and lower stool output in children with diarrhoea.
| Drink | Approx. sugar per litre | Sodium |
|---|---|---|
| WHO reduced-osmolarity ORS | About 13.5g glucose | About 1,700mg |
| Typical sports drink | 60-80g | Usually 300-700mg |
| Soft drink | About 100g | Very little |
| Zero-sugar electrolyte drink | 0g | Varies |
So the WHO's formula uses far less sugar than most sports drinks and far more than zero.
But it's worth being clear about what ORS is built for. Its sugar content is set for maximum absorption in someone who is seriously dehydrated, usually from illness. It isn't designed for everyday performance, and it doesn't weigh up the cost of drinking that much sugar day after day: extra sugar and kilojoules you don't need, and more sugar on your teeth. For a drink you have at your desk, in the gym or on game day, the trade-off is different.
What this means for hydration drinks
Research on hydration supports the same balance:
- Sodium matters most for holding on to the fluid you drink. A review of post-exercise rehydration found that adding sodium helps your body keep fluid rather than passing it straight out, and that adding carbohydrate can also help by influencing how water is absorbed and distributed.
- ORS beat water for fluid retention. In a study comparing 13 common drinks, an oral rehydration solution was one of only three drinks (alongside full-fat and skim milk) that left people better hydrated than still water 2 hours later.
- Different sugars use different routes. A study of intestinal absorption found drinks with more than one type of carbohydrate (like glucose plus fructose) produced more water absorption at the same concentration than drinks with only one.
When does this matter?
For a short gym session or a normal day at the desk, water and a balanced diet usually cover you. The glucose-sodium effect matters more when:
- You're sweating a lot, in long sessions, in the heat or on game day.
- You need to rehydrate quickly, between sessions or after a hard effort.
- You're unwell with vomiting or diarrhoea. In that case use a pharmacy ORS and follow medical advice. A sports or energy drink isn't a substitute.
Food also counts. A meal with some salt and carbohydrate after training does the same job, which is why the ACSM and sports dietitians often suggest eating as well as drinking to rehydrate. See our hydration and electrolytes guide.
Why Zuum sits in the sweet spot
Zuum Energy Powder is intentionally low in sugar, with no added sugar. Coconut water powder adds from 0.3g of natural sugars per sachet, depending on the flavour, so a little glucose is there alongside the sodium without turning your bottle into a sugary drink.
| Per serve | Sugar | Added sugar |
|---|---|---|
| Zuum Energy Powder (1 sachet) | From 0.3g | None |
| WHO ORS (500ml) | About 6.75g glucose | Yes |
| Typical sports drink (500ml) | 30-40g | Yes |
| Soft drink (375ml can) | About 40g | Yes |
| Zero-sugar electrolyte drink | 0g | None |
Zero-sugar drinks leave glucose out entirely. ORS-style formulas push glucose up to maximise absorption, sports drinks go further still, and you pay for it with anywhere from 7g to 40g of sugar per bottle. We think an everyday drink belongs in between: a little natural sugar working alongside a properly dosed electrolyte blend, without the downsides of a sugary drink.
And the electrolytes are where we went big:
| Per sachet | Everyday Energy Powder | Performance Energy Powder |
|---|---|---|
| Sodium | 250mg | 500mg |
| Potassium | 200mg | 250mg |
| Magnesium | 60mg | 80mg |
| Calcium | - | 70mg |
| Caffeine | 60mg | 120mg + taurine & B vitamins |
| Natural sugars | From 0.3g | From 0.3g |
Both are sweetened with organic stevia and thaumatin, use Lake Deborah salt, and every batch is HASTA tested. Read why we launched Zuum Energy Powder.
Frequently asked questions
Is Zuum Energy Powder low in sugar?
Yes. It has no added sugar, and coconut water powder adds from 0.3g of natural sugars per sachet, depending on the flavour. It's sweetened with organic stevia and thaumatin.
Does sugar help you absorb electrolytes?
Yes, in the right amount. Glucose and sodium are absorbed together in your small intestine through a transporter called SGLT1, and water follows them. That's why oral rehydration solutions contain both.
How much sugar does a rehydration drink need?
Less than most people think. The WHO's oral rehydration solution uses about 13.5g of glucose per litre. Much more than that can make a drink too concentrated and slow fluid absorption.
Are sugar-free electrolyte drinks bad?
No. Sodium alone still helps your body hold on to fluid, and for most everyday situations a sugar-free drink plus normal meals is fine. You just miss the extra boost to absorption that glucose brings.
Are sports drinks good for hydration?
They can help in long or hot sessions, but many carry 60-80g of sugar per litre, much more than an oral rehydration solution. For shorter sessions that's often more sugar than you need.
Should I use an energy drink when I'm sick?
No. For dehydration from vomiting or diarrhoea, use a pharmacy oral rehydration solution and follow medical advice.
The bottom line
Sodium and glucose are absorbed together, and water follows. That's the science behind oral rehydration solutions, one of the most important medical advances of the last century. ORS is built for maximum absorption at any cost. Sports and soft drinks carry far more sugar than most sessions need. For everyday energy and hydration, balance wins: properly dosed electrolytes, a little natural sugar and no added sugar. Try Everyday Energy Powder for daily energy and hydration, or Performance Energy Powder for training and game day.
Read the research: Wright EM, Loo DD, Hirayama BA (2011), Biology of human sodium glucose transporters, Physiological Reviews 91(2):733-94. Abstract on PubMed.
Want to learn more about how Zuum works? Read the science behind Zuum, browse energy powder, or see our FAQs.
