Latest news with #AlexRuani
The Independent
9 hours ago
- Health
- The Independent
Why eight glasses of water a day is a myth when it comes to hydration and heat stress
Last year was the hottest year on record and all the signs are that 2025 will be even hotter. Swathes of southern Europe have battled unseasonably hot temperatures and after months of frequently wet and cooler weather, temperatures are now hitting an annual high in the UK with temperatures soaring to 35 degrees in the South East. With this comes new health concerns. A recent analysis showed that heat-related deaths in Europe have increased by about 30% over the past 20 years. In 2023 alone, nearly 48,000 people died from heat-related causes — a huge rise from previous years as the human body struggles to cope with heat stress. 'Generally, humans die after a few days without fluid intake,' says Alex Ruani, a researcher in nutrition science at University College London (UCL) and chief science educator at the Health Sciences Academy. 'But in extreme heat where fluids and electrolytes [essential minerals, like sodium, calcium, and potassium, that are vital to many key functions in the body such as balancing blood pressure, regulating nerve and muscle function, and hydrating the body] losses are greater, death from dehydration comes a lot sooner.' At the less extreme end, Ruani says that chronic or severe dehydration can lead to urinary tract infections, kidney stones and a decrease in physical and mental performance. Add in constipation, delirium, seizures, and a drop in blood pressure (fluid loss leads to low blood pressure, which can lead to lightheadedness and fainting) and you can see why staying hydrated can not only help avoid heat exhaustion and heat stroke but is key to staying healthy. So, how much should we drink? Our body is composed largely of water (about 50 to 70 per cent) and this includes our cells, which need water to function properly. However, a 2023 study from the water bottle brand AirUp found that 45 per cent of British people drink the equivalent of just one glass of water per day, despite official NHS guidelines advising six to eight glasses. This needs to be increased in hot climates, during exercise, or when you're pregnant and breastfeeding. 'The benefits of staying properly hydrated include enabling your brain to work properly, regulating your body temperature, keeping a steady and rhythmic hormone production, fomenting cell longevity, aiding proper digestion, and helping to eliminate toxins,' says Ruani, who says that proper hydration should be given the same priority as our sleep and exercise habits. A 2023 study found that people who drink more water live longer and develop fewer chronic illnesses. The research, from the National Institutes of Health (NIH), studied 11,255 adults and found adults with the lowest fluid intake were more likely to develop chronic conditions and show signs of advanced biological ageing compared to those with healthy fluid intake. Natalia Dmitrieva, the study author at the Laboratory of Cardiovascular Regenerative Medicine at the National Heart, Lung and Blood Institute, which is part of the NIH, said: 'The results suggest that proper hydration may slow down ageing and prolong a disease-free life.' Ruani says many of us don't drink enough throughout the day to replenish the water we lose through urinating and sweating (roughly 2.5 to 3 litres per day, for a healthy adult). 'We tend not to think about drinking water, or even feel thirsty, until we are already a bit dehydrated.' By the time you feel thirsty, she says, you're probably already about 1 to 2 per cent dehydrated. She adds that while it's easy to treat a mild case of dehydration simply by drinking more water, as the recent European heatwave have shown, chronic or severe dehydration can be life-threatening. When someone experiences heat stroke, the body stops sweating and they may experience seizures or hallucinations. In these extreme cases, it is imperative the person gets an IV drip to rehydrate. Signs you are chronically dehydrated are feeling weaker and experiencing frequent headaches, she says, adding: 'But instead of drinking a large amount of water in one go, it's best to consume water throughout the day.' It is also possible to drink too much, she says, although this is more rare. 'Drinking too much water can dilute the blood while causing levels of sodium, potassium and other electrolytes to fall. This is called hyponatremia, or water poisoning, and can occur when you drink too much in a short space of time, or when there's an underlying medical condition where the kidneys can't process it all.' Several factors, like your weight, activity levels, and how hot it is will affect how much is too much but as a guide, a 2021 study published in the British Medical Journal suggested that drinking 5.3 litres of water over four hours can lead to water poisoning. When it comes to how much water we need to stay healthy, eight glasses – roughly two litres – is seen as the standard. However, a study in 2022 from the University of Wisconsin-Madison in the US found this may be a myth. Researchers measured the water intake of over 5,000 people from 26 countries, ranging in age from babies to 96-year-olds, and found the amount of water needed to stay healthy varied considerably. The body will tell you if you need to drink more and when Professor Tim Noakes 'The science has never supported the eight glasses thing, if only because it confused total water turnover with water from beverages and a lot of your water comes from the food you eat,' said Dale Schoeller, an emeritus professor of nutritional sciences who co-led the study. How much water we need depends on many factors. Professor Tim Noakes, emeritus professor in the Division of Exercise Science and Sports Medicine at the University of Cape Town and author of Waterlogged, says there is only one rule when it comes to fluid intake: if you're thirsty, drink. 'The body will tell you if you need to drink more and when,' he says. 'Men are generally larger so they will need to replace more fluid on a daily basis than smaller women. Any cause of fluid loss from the body, including menstruation, will increase the fluid requirements. But the body will indicate what it needs.' That said, some elderly people may have an impaired thirst mechanism and need to be encouraged to drink more than their thirst directs. 'As we get older, our sense of thirst is reduced, putting us at a higher risk of dehydration,' adds Alex Ruani. 'Some elderly adults may also be on medications that increase urine output, so they need to be more cautious.' Sam Rice, a nutritionist and author of Supercharge Your Diet: Ten Easy Ways to Get Everything You Need From Your Food, says it is worth remembering that 'tea, coffee, and milk all count' but adds that we should avoid shop-bought soft drinks as they can be very high in sugar, which has a hypernatremic effect, 'meaning it draws water from your tissues and so depletes your body of fluids'. As for coffee, while it's often thought to be a diuretic – a 2016 study found that the hydrating effects of water, coffee and tea were almost identical – it contains caffeine so it should be drunk in moderation. Rice says that water in food also counts, especially fruits and vegetables with a high water content, such as melon (especially watermelon), strawberries, cucumber, lettuce and celery. 'In truth, the simple rule to make sure you are getting enough is to drink a glass of water with every meal in addition to what you usually drink', says Rice. Another gauge is how often you pee, which should ideally be five to six times a day. Less than that and you probably need to drink more water.' Ruani suggests checking that your urine looks light and clear, like the colour of pale straw, throughout the day (the first urine of the day will be darker because you haven't consumed any water during the night). 'Another indicator is the 'skin turgor test',' she says. 'This might not work with older adults because their skin is less firm. But if you pinch a bit of skin on the back of your hand, does the skin go back down immediately after you release it, or does it stay up a bit? It may be a sign of dehydration if the skin stays up after you let it go.' In which case, go and pour yourself a large glass of water...
BBC News
11-05-2025
- Health
- BBC News
E dey bad for you to drink coffee wen you dey chop?
If dem don ever warn you say to dey drink coffee wen you dey chop, or straight afta am, fit be bad idea, some kain truth dey inside More dan 1000 chemical compounds dey inside coffee, and one handful, like caffeine, polyphenols, and tannins, fit interfere wit how you absorb nutrients from your food. Di good news be say for most pipo, dis effects dey small — e no dey serious enof to cause deficiencies. Nutrients na substances wey dem dey find inside our food and drink wey dey carry out certain vital jobs inside body. We need different nutrients to keep us healthy. "No be all absorption dey completely 'blocked' – some reduction fit just dey," Alex Ruani, University College London doctoral researcher in nutrition science education and chief science educator for The Health Sciences Academy tok. Di impact dey depend on di strength of di coffee; di amount of nutrients consumed, and individual risk factors such as age, metabolism, health status and genetics, Ruani explain. Di nutrients wey we dey tok about include calcium, iron, and B vitamins. No need to worry if your "nutrient levels don already dey enof, but for those wey don nearly hit deficiency or dey wit existing low levels, excessive coffee intake fit contribute to further depletion, Emily Ho, director of di Linus Pauling Institute and professor in di College of Health at Oregon State University tok. Who need to dey cautious about dia cappuccino? Since di 1980s, studies don associate coffee wit lower iron absorption. "Wen you drink coffee wit a food, di polyphenols inside am fit attach to certain minerals in your digestive system," Ho tok She explain say dis binding process fit make am dey harder for your body to absorb di iron - as minerals need to pass through di intestinal cells to enta di bloodstream. "If e dey tie to polyphenols, dey simply pass through your body and you poo-poo am." Dis dey especially important for iron, particularly di type wey dey inside plant-based foods, wey dem dey call'non-heme iron'. Non-heme iron from foods like fruit and vegetables dey harder for di bod to absorb. Polyphenols inside coffee - especially chlorogenic acid - fit attach to dis type of iron, stop am make e no absorb into bloodstream properly. Sake of result say, di iron remain tied to dis compounds as e dey move through di digestive system. You go eventually poo-poo am instead make di body use am. All dis means say pipo wit iron-deficiency anaemia suppose dey cautious about drinking coffee wey too close to iron-rich meals. "E fit dey best to enjoy your coffee at least one hour bifor or some hours afta you eat iron-rich foods so dem no go mix inside your belle," Alex Ruani tok. Women wey dey menstruate and di ones wey get belle often dey fall into dis category of pipo wey need to keep eye on dia iron levels. Dem typically need more iron and dey more prone to develop iron-deficiency anaemia so dem need to keep eyes on dia coffee intake. Calcium Calcium dey good for bone health, yet 9% of 16–49 year-olds in di UK dey consume less dan di Lowest Reference Nutrient Intake (LRNI) of calcium through dia food. Dis deficit dey put dem at risk of weak bones later in life. Our kidneys dey remove waste and extra water from di blood (as urine) and help keep chemicals (like sodium, potassium, and calcium) balanced inside body. E dey also dey make hormones. Studies suggest say caffeine fit make am harder for your body to hang on to calcium e go disturb how e dey processed in your kidneys and absorbed in di intestines. Again, dis effects dey minimal and more important for pipo wey already dey eat low calcium diet or dey at higher risk for bone-related health issues. "One popular study wey dem publish inside journal, Osteoporosis International, proposes say caffeine fit contribute to bone loss as e dey interfere wit bone metabolism," Ruani tok. "But more studies dey needed to determine di true impact of caffeine on osteoporosis risk." Calcium fit dey stored by di body, so you no need to consume di recommended amount daily – but over di period of months adults weydey di age of 19-64 suppose average out around 700mg of calcium a day. E also worth to get am for mind say caffeine get diuretic effect i.e. e dey increase how often you need to urinate. "Dis fit lead to di loss of water-soluble vitamins (like some B vitamins) and minerals (like iron and calcium), as excretion dey play key role to regulate dia levels in di body," Ho add. B Vitamins "Sake of coffee influence on kidney function and nutrient metabolism, to drink large amounts of coffee (like four cups a day or more), fit make you poo-poo too much and wit dat, di loss of water-soluble vitamins, including B vitamins," Ruani explain. B vitamins dey dissolve in water, so dem no dey stored in di body. Instead, any excess go comot for body through urine. Probiotics Probiotics na live bacteria and yeasts wey dey promoted to get various health benefits. Dem fit dey helpful to restore di natural balance of bacteria inside your gut in some cases according to di NHS site but na small evidence dey to support many health claims about dem. However, if you wan try probiotic supplements or probiotic-rich foods like yogurt and kimchi, e dey best to avoid to dey chop dem dem alongside hot drinks like coffee. "Live bacteria wey dey inside probiotics dey highly sensitive to heat, and exposure to high temperatures - like di heat in coffee - fit reduce dia survival rate in di gastrointestinal tract, make dem less effective," Ruani tok. Sometimes e dey prescribed by doctors to help ease diarrhoea wey antibiotic medication cause, to get di maximum benefit wait 30-60 minutes bifor you take probiotic if you don take a cup of coffee. E worth to swap out coffee for tea? If you dey consider to switch to tea, e dey important to sabi say some of di same concerns apply to tea too. "In fact, di polyphenols wey dey inside tea fit get similar effect on nutrient bioavailability, so e dey important to pay attention to di timing of your tea consumption if you dey worry about nutrient absorption," Ho warn.
