Cucumbers, the cool truth: How the water-packed vegetable can improve your skin and digestion… and the plant power hiding within its dark green skin

Cucumbers are a staggering 95 per cent water, making them one of the most hydrating foods we can eat.

Millions of the salad vegetables – which are technically a fruit because they develop from a flower and contain seeds – are enjoyed by Britons every year.

They get added to salads, chopped into crudites to be dunked into hummus, and submerged in water or blitzed into juices to be enjoyed as a refreshing drink.

And of course, a huge number of cucumbers are sliced and added to sandwiches, including those of the late Queen Elizabeth, who insisted on jazzing them up with a sprinkling of fresh mint and a thin layer of yogurt. You could call it tzatziki, Windsor-style.

In the UK, we most commonly see long and slightly curved ‘English cucumbers’ with dark green skins, but of the 100 types of cucumber varieties, there are a huge array of different textures, lengths, girth and colours – some are yellow or brown.

And while they’re not a magic bullet for perfect health, cucumbers definitely have a place in a balanced diet – and could even help solve Britain’s dehydration crisis, Jenna Hope, nutritionist and author of How To Stay Healthy, tells the Daily Mail.

‘So many people simply don’t drink enough water, so if you can get some element of hydration through your food, then you’re one step closer to supporting your everyday fluid intake,’ she says.

But what else do cucumbers bring to the table? We asked Ms Hope to give us the juicy truth.

What’s actually in a cucumber? 

Due to their high water content, cucumbers are – unsurprisingly – very low in calories. There’s around 15 calories per 100g, a miniscule fraction of the NHS’ daily guidelines (2,500 calories for men, 2,000 for women).

They also contain almost no fat, contributing virtually nothing to the NHS’ recommended maximums of 30g (men) and 20g (women), minimal amounts of carbohydrates and sugar.

Cucumbers are a rich source of both Vitamin C – vital for a healthy immune system – and Vitamin K, which lowers cholesterol. 

It does this by decalcifying the arteries and relocating it to bones, making them stronger. Vitamin K is also needed for blood clotting.

Cucumbers also contain potassium, which regulates blood pressure, supports muscle and nerve function and balances salt levels.

They’re also a good source of antioxidants – notably flavonoids, lignans, and triterpenes – which tackle harmful molecules called ‘free radicals’ which are linked to inflammation within the body, ageing and diseases including cancer.

Fibre-wise, you can expect to get 0.5 to 1g per 100g, so they won’t move the needle much towards the NHS’ 30g daily goal.

‘Most of the fibre is in the skin,’ explains Ms Hope. ‘You get maximum fibre and antioxidants if you eat cucumber unpeeled, and ideally in its solid form rather than juiced. 

‘The seeds are tiny but they contain a lot of water,. They do also contain some fibre, but not as much as pumpkin or sunflower seeds. 

‘It’s the flesh that actually contains a lot of the more water soluble nutrients, so the Vitamin C, magnesium and potassium. Vitamin K is in found in the skin.’ 

Is cucumber good for digestion and can it reduce bloating?

Many people believe that cucumbers can reduce or relieve bloating, but Ms Hope says that this might be because they are a low FODMAP food and simply do not trigger that sort of reaction in the gut. 

FODMAPs – fermentable oligosaccharides, disaccharides, monosaccharides and polyols – are types of carbohydrates found in certain foods which can lead to IBS-like symptoms like bloating, cramping and flatulence in some people. 

She says: ‘From my understanding, there’s not a specific compound in cucumbers that would necessarily help digestion or bloating. 

‘Eating it doesn’t generally cause any discomfort and potentially, the high water content could help with digestion.’  

Does cucumber help lower blood pressure?

In 2018, a team from the Saveetha College of Nursing in India sought to find a connection between cucumber and blood pressure. 

They conducted a small study involving 60 adults with high blood pressure aged between 40 and 60, asking half of the group to eat 100g of cucumber everyday, mid-morning, for two weeks. 

Their blood pressure was taken at the start of the experiment and four weeks afterwards. 

The results, published in the medical journal Research Journal of Pharmacy and Technology, saw half who ate cucumber’s blood pressure fall significantly. 

Compared with pre-experiment measurements, their systolic blood pressure – the pressure the blood makes against the arteries when the heart beats – fell by 6.9 per cent. 

Similarly, their diastolic blood pressure – which measures the pressure the blood makes against the arteries between heartbeats – fell by 9.8 per cent.

In the control group, systolic blood pressure fell by 1.84 per cent and diastolic blood pressure by 3.67 per cent.

It suggests cucumber can play a helpful role in a blood-pressure-friendly diet, but it doesn’t position it as a cure for the condition. 

Scientists have suggested that cucumber’s richness in potassium also supports healthy blood pressure, as does its high water content. 

When you’re properly hydrated, you are able to maintain blood volume, which in turn supports stable blood pressure. Dehydration can cause blood vessels to constrict, which makes the heart work harder.

Good hydration also supports kidney function, helping the body regulate sodium levels more effectively. Excess sodium is one of the main catalysts behind high blood pressure. 

Does anyone need to be wary of eating cucumbers?

Research has suggested excessive Vitamin K can affect blood clotting meaning that people taking drugs such as warfarin shouldn’t suddenly increase the amount of cucumbers they’re eating on a daily basis.

A daily serving of 80g – which is what the NHS uses as a standard portion for all fruit and veg – is considered ‘safe’ for people on blood thinners. 

But, should they want to eat more, removing the cucumber’s skin can reduce the amount of Vitamin K they are ingesting.

Too much potassium may trigger hyperkalemia, which is when levels of the mineral in the blood are higher than normal.

Symptoms of hyperkalemia are usually mild and can include muscle weakness, numbness, tingling, nausea, according to the National Kidney Foundation.

More extreme symptoms are heart palpitations, shortness of breath, chest pain and vomiting.

Thankfully, experts previously told the Daily Mail that it is ‘very hard to overdose’ on cucumber, and you’d need to eat around 6 kg of it to reach dangerous potassium levels.

Registered nutritionist and author Rob Hobson said: ‘There is nothing wrong with eating cucumber and even if you ate a lot it is unlikely you would continue to do so for very long as the novelty would probably wear off.

‘It is very hard to overdose on nutrients from food as this normally happens with supplements.

‘Cases of too much potassium and Vitamin K are likely to occur in individuals with very specific health concerns rather than healthy individuals.

‘For instance, people on blood thinners like Warfarin would need to watch their intake of Vitamin K but this is a specific case and could be addressed by changing their dosage.’

What should you pair cucumber with for maximum nutrition? 

Healthy fats are a cucumber’s best friend. Pair them with olive oil, avocado or nuts to improve absorption of their fat-soluble nutrient Vitamin K.

But there are more creative ways to enjoy them. 

Back in 2024, the world went cucumber-mad after a spate of recipes went viral on TikTok.

Logan Moffitt – who became known as ‘Cucumber Guy’ – amassed millions of followers with his low-prep high-flavour salad pots which paired slices of cucumber with an array of creative ingredients like wasabi, soy sauce, cream cheese and egg.

It was reported at the time that the nation of Iceland actually sold out of cucumbers as people tried them out for themselves at home.

Since then, pickled cucumber recipes have gained traction online, with a copycat of Taiwanese restaurant chain Din Tai Fung’s Cucumber Salad Recipe – a simple dish of salted cucumbers marinated in soy, mirin, sesame oil, garlic, and chili – leading the charge.

Ms Hope says that many people get pickled and fermented cucumbers mixed up, and it’s actually the latter which is the key to great gut health.   

‘Pickled recipes involve more sugar so I would always say that you’re better to ferment the cucumbers,’ she explains. 

‘Fermenting is a slightly different process; pickling uses sugar and salt and is quite a quick process while fermenting uses salt and water, and you leave it for a much longer period of time.

‘When you pickling them you get an acidic taste, but the benefits aren’t necessarily there. But when you ferment cucumbers, that produces lactic acid which is very beneficial for feeding the gut bacteria.’ 

And of course, cucumbers had a different sort of pop culture moment in 2022 when Kendall Jenner revealed a very unique way of slicing one up.  

What about gherkins – are they good for gut health?

Many people are unaware that crunchy, slimy gherkins are merely a type of preserved cucumber – as are their smaller cousins, cornichons. 

If they’re fermented, they may contain beneficial probiotics that support gut health, but many supermarket versions are simply pickled in vinegar without live cultures, so they don’t offer the same benefit.

‘Gherkins are generally mass produced and heat treated which means the beneficial bacteria is destroyed,’ says Ms Hope. ‘However, gherkins that have been fermented using traditional methods can help to support a healthy gut and still taste fantastic.’