We know the importance of staying hydrated, especially in hot weather. But even for something as simple as a drink of water, conflicting advice and urban myths abound.

Is cold water really bad for your health? What about hot water from the tap? And what is “raw water”? Let’s dive in and find out.

Myth 1: Cold water is bad for you

Some recent TikToks have suggested cold water causes health problems by somehow “contracting blood vessels” and “restricting digestion”. There is little evidence for this.

While a 2001 study found 51 out of 669 women tested (7.6%) got a headache after drinking cold water, most of them already suffered from migraines and the work hasn’t been repeated since.

Cold drinks were shown to cause discomfort in people with achalasia (a rare swallowing disorder) in 2012 but the study only had 12 participants.

For most people, the temperature you drink your water is down to personal preference and circumstances. Cold water after exercise in summer or hot water to relax in winter won’t make any difference to your overall health.

Myth 2: You shouldn’t drink hot tap water

This belief has a grain of scientific truth behind it. Hot water is generally a better solvent than cold water, so may dissolve metals and minerals from pipes better. Hot water is also often stored in tanks and may be heated and cooled many times. Bacteria and other disease-causing microorganisms tend to grow better in warm water and can build up over time.

It’s better to fill your cup from the cold tap and get hot water for drinks from the kettle.

Myth 3: Bottled water is better

While bottled water might be safer in certain parts of the world due to pollution of source water, there is no real advantage to drinking bottled water in Australia and similar countries.

According to University of Queensland researchers, bottled water is not safer than tap water. It may even be tap water. Most people can’t tell the difference either. Bottled water usually costs (substantially) more than turning on the tap and is worse for the environment.

What about lead in tap water? This problem hit the headlines after a public health emergency in Flint, Michigan, in the United States. But Flint used lead pipes with a corrosion inhibitor (in this case orthophosphate) to keep lead from dissolving. Then the city switched water sources to one without a corrosion inhibitor. Lead levels rose and a public emergency was declared.

Fortunately, lead pipes haven’t been used in Australia since the 1930s. While lead might be present in some old plumbing products, it is unlikely to cause problems.

Myth 4: Raw water is naturally healthier

Some people bypass bottled and tap water, going straight to the source.

The “raw water” trend emerged a few years ago, encouraging people to drink from rivers, streams and lakes. There is even a website to help you find a local source.

Supporters say our ancestors drank spring water, so we should, too. However, our ancestors also often died from dysentery and cholera and their life expectancy was low.

While it is true even highly treated drinking water can contain low levels of things like microplastics, unless you live somewhere very remote, the risks of drinking untreated water are far higher as it is more likely to contain pollutants from the surrounding area.

Myth 5: It’s OK to drink directly from hoses

Tempting as it may be, it’s probably best not to drink from the hose when watering the plants. Water might have sat in there, in the warm sun for weeks or more potentially leading to bacterial buildup.

Similarly, while drinking water fountains are generally perfectly safe to use, they can contain a variety of bacteria. It’s useful (though not essential) to run them for a few seconds before you start to drink so as to get fresh water through the system rather than what might have been sat there for a while.

We are fortunate to be able to take safe drinking water for granted. Billions of people around the world are not so lucky.

So whether you like it hot or cold, or somewhere in between, feel free to enjoy a glass of water this summer.

Just don’t drink it from the hose.

Oliver A.H. Jones, Professor of chemistry, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Hundreds of thousands of people worldwide are taking drugs like Ozempic to lose weight. But what do we actually know about them? This month, The Conversation’s experts explore their rise, impact and potential consequences.

You’ve no doubt heard of Ozempic but have you heard of Wegovy? They’re both brand names of the drug semaglutide, which is currently in short supply worldwide.

Ozempic is a lower dose of semaglutide, and is approved and used to treat diabetes in Australia. Wegovovy is approved to treat obesity but is not yet available in Australia. Shortages of both drugs are expected to last throughout 2024.

Both drugs are expensive. But Ozempic is listed on Australia’s Pharmaceutical Benefits Schedule (PBS), so people with diabetes can get a three-week supply for A$31.60 ($7.70 for concession card holders) rather than the full price ($133.80).

Wegovy isn’t listed on the PBS to treat obesity, meaning when it becomes available, users will need to pay the full price. But should the government subsidise it?

Wegovy’s manufacturer will need to make the case for it to be added to the PBS to an independent advisory committee. The company will need to show Wegovy is a safe, clinically effective and cost-effective treatment for obesity compared to existing alternatives.

In the meantime, we asked five experts: when supplies resume, should governments subsidise drugs like Ozempic for weight loss?

Four out of five said yes

This is the last article in The Conversation’s Ozempic series. Read the other articles here.

Disclosure statements: Clare Collins is a National Health and Medical Research Council (NHMRC) Leadership Fellow and has received research grants from the National Health and Medical Research Council (NHMRC), the Australian Research Council (ARC), the Medical Research Future Fund (MRFF), the Hunter Medical Research Institute, Diabetes Australia, Heart Foundation, Bill and Melinda Gates Foundation, nib foundation, Rijk Zwaan Australia, the Western Australian Department of Health, Meat and Livestock Australia, and Greater Charitable Foundation. She has consulted to SHINE Australia, Novo Nordisk (for weight management resources and an obesity advisory group), Quality Bakers, the Sax Institute, Dietitians Australia and the ABC. She was a team member conducting systematic reviews to inform the 2013 Australian Dietary Guidelines update, the Heart Foundation evidence reviews on meat and dietary patterns and current co-chair of the Guidelines Development Advisory Committee for Clinical Practice Guidelines for Treatment of Obesity; Emma Beckett has received funding for research or consulting from Mars Foods, Nutrition Research Australia, NHMRC, ARC, AMP Foundation, Kellogg and the University of Newcastle. She works for FOODiQ Global and is a fat woman. She is/has been a member of committees/working groups related to nutrition or food, including for the Australian Academy of Science, the NHMRC and the Nutrition Society of Australia; Jonathan Karnon does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment; Nial Wheate in the past has received funding from the ACT Cancer Council, Tenovus Scotland, Medical Research Scotland, Scottish Crucible, and the Scottish Universities Life Sciences Alliance. He is a fellow of the Royal Australian Chemical Institute, a member of the Australasian Pharmaceutical Science Association and a member of the Australian Institute of Company Directors. Nial is the chief scientific officer of Vaihea Skincare LLC, a director of SetDose Pty Ltd (a medical device company) and a Standards Australia panel member for sunscreen agents. Nial regularly consults to industry on issues to do with medicine risk assessments, manufacturing, design and testing; Priya Sumithran has received grant funding from external organisations, including the NHMRC and MRFF. She is in the leadership group of the Obesity Collective and co-authored manuscripts with a medical writer provided by Novo Nordisk and Eli Lilly.

Fron Jackson-Webb, Deputy Editor and Senior Health Editor, The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.