You've probably asked yourself too if that old bottle of water in your pantry is still good to drink? Water is life, yet there are remaining questions about the shelf life. Whether you are stockpiling for emergencies or wondering if that bottled water left in a heated car is safe to drink, understanding if and how water "expires" is essential. This article goes into the science behind water storage and its potential risks and practical tips to ensure your water will remain safe and consumable.

Water itself does not spoil or degrade. Chemically, pure water (H₂O) remains unchanged indefinitely. However, there are issues that arise due to the containers in which it is stored and the environmental conditions surrounding the storage.

In the United States, most bottled water has an expiration date. This labeling is often misunderstood as being an indication of the water's safety, but it mainly has to do with quality. The U.S. Food and Drug Administration (FDA) confirms that commercially sealed bottled water is safe to drink indefinitely if stored properly. Over time, though, the taste, smell, and even the appearance of water may change due to interactions with its packaging.

Role of Packaging in Water Safety

Plastic Bottles and Chemical Leaching

Bottled water is mostly packed in polyethylene terephthalate, PET plastic. Even though it is light in weight, resistant, and recyclable, this material is limited in other aspects. It leaches chemicals in trace amounts in the water if heated or placed under direct sunlight. For instance, do not leave your bottled water in the hot car for an extended period.

The next is bisphenol A or BPA. This chemical has been used to soften some plastics and is known for its hormone disruption. Many producers have shifted toward BPA-free materials, but older bottles and improper storage still pose risks. Bottles carrying recycling code #7 may be BPA-contaminated. There are also concerns over microplastics and long-term storage.

Microplastics and Long-Term Storage

Over time, the plastic in the bottle may leach into the water, causing some to question health risks. In 2019, one article published in the International Journal of Environmental Research and Public Health noted that these particles exist but are usually not at high enough concentrations to pose a problem if the water is properly stored.

Also Read: What Happens When You Drink Too Much Water?

How Long Can Water Be Stored Safely?

Bottled Water

Unopened bottled water, kept in a cool, dark place, remains safe to drink for years. But manufacturers often advise that it should be consumed within two years of its manufacture date for best quality. After this period, it may start showing off-flavors or odors due to contact with the plastic.

Tap Water

Tap water, under the Environmental Protection Agency (EPA), undergoes strict standards for safety. It can be kept in pure, BPA-free bottles up to six months. Afterward, it loses its fresh flavor or becomes dirty if not properly sealed.

Rainwater

Don't drink rainwater unless treated first. It usually contains contaminants that should not reach the human stomach. It should be used to water plants if not filtered and sterilized first.

Signs That Water Has Gone Bad

Water itself doesn't go bad, but extrinsic factors make it unsafe. Always discard water that has:

An off smell: An earthy, metallic smell indicates contamination.

Coloration: Greenish or bluish coloration signifies microbial growth or rust.

Unpleasant taste: A metallic or stale taste is a hallmark of degradation.

Froth or particles: Indicate dirt, germs, or other impurities.

How to Store Water Safely?

Avoid Heat and Sunlight

Store water in a cool, dark place and out of direct sunlight. Heat breaks down the plastic, allowing chemicals to leach out more easily.

Choose the Right Containers

For long-term storage, select BPA-free or food-grade plastic containers. The best alternatives are stainless steel and glass containers, which avoid all the risks that plastic poses.

Hygiene Maintained

Wash and sanitize the container before refilling. Always seal the lids so that no bacteria get inside.

Rotate Your Stock

Use a first-in, first-out rotation system with stockpiled water. This will mean that you will use the oldest water first to keep your water supply fresh.

Is It Safe to Drink Water Past Its Expiration Date?

The expiration date on bottled water is a mark of its quality, not safety. Although the water is safe to drink past this date, it is sensible to check it for any signs of spoilage as mentioned above. Tap water that has been stored for longer periods should be checked for clarity and odor before consumption.

Plastic bottles, although convenient, degrade the environment. Only a few percent of PET bottles are recycled, while the rest remain in landfills or oceans. Choose reusable containers and tap water whenever possible to minimize plastic waste and environmental damage.

Water is one of the most precious resources in this world, yet it can be safe only if it is kept appropriately. People may tell you that water does not expire, but the fact is that packaging materials, exposure to the environment, and storage conditions may affect the quality of the water. Proper storage techniques, opting for BPA-free containers, ensure that water remains fresh, safe, and ready for consumption at any time.

Vitamin D, better known as the sunshine vitamin, is not only important for bone health but also plays a role in maintaining muscle and cardiovascular function.

An animal study led by researchers at the ICMR-National Institute of Nutrition (ICMR-NIN), Hyderabad, found that Vitamin D3 was more effective than Vitamin D2 in maintaining and restoring skeletal muscle and heart function in male rats.

Vitamin D2 Vs Vitamin D3: What’s The Difference?

Vitamin D occurs naturally in two forms: Vitamin D3 (cholecalciferol) and Vitamin D2 (ergocalciferol). Vitamin D3 is produced in the skin following exposure to sunlight and is also obtained from animal-based foods such as eggs, fish and organ meats, as well as supplements.

Vitamin D2 is derived from wild, cultivated or sun-dried mushrooms, UV-B-irradiated yeast, plant-based sources and some dietary supplements.

Amid increasing vitamin D deficiency, both forms are used for food fortification. However, D2 is preferred in some countries because of widespread vegetarianism and among people following strict vegan diets.

Also read: India Gets Its First Plant-Based Vitamin D3: What You Need to Know

How Was The Study Conducted?

Researchers compared the effects of Vitamin D2 and Vitamin D3 on skeletal muscle and cardiac parameters in rats during both maintenance and recovery from vitamin D deficiency.

The study used weaning male Sprague-Dawley rats, which were given diets containing Vitamin D2, Vitamin D3, a combination of both forms, or a vitamin D-deficient diet.

Researchers assessed several parameters, including body composition, muscle strength, skeletal muscle structure and metabolism, along with markers associated with cardiac function.

Vitamin D3 Showed Greater Benefits

The study found that Vitamin D3 produced greater improvements in muscle mass, muscle fibre size and grip strength compared with Vitamin D2.

Vitamin D3 also showed stronger effects on markers associated with muscle development and energy metabolism.

Similar differences were observed in cardiac parameters, with Vitamin D3 showing greater effects on markers related to cardiac contractility and metabolism.

The differences between the two forms were particularly pronounced during the recovery phase following vitamin D deficiency, according to the researchers.

Dr Ayesha Ismail, Scientist F at ICMR-NIN and corresponding author of the study, said both forms were effective in improving calcium-related parameters, but Vitamin D2 was less effective on several measures linked to muscle and heart structure and energy metabolism.

“Although both forms of vitamin D were effective in improving calcium-related parameters, vitamin D2 was less effective than vitamin D3 in several parameters related to muscle and heart structure and energy metabolism,” Ismail said, ANI news agency reported.

Read More: Sweetener In Sugar-Free Gum Linked To 57% Higher Heart Attack And Stroke Risk: What Is Xylitol?

Can The Findings Be Applied To Humans?

Dr Bharati Kulkarni, Director, ICMR-NIN, stressed that further research would be required before drawing conclusions about the effects of the two forms of vitamin D in humans.

“Further studies are needed to establish the effects of the two forms of vitamin D on skeletal and extra-skeletal functions and their implications for supplementation and fortification programs,” she told ANI.

The findings suggest that Vitamin D3 may have stronger effects than Vitamin D2 on skeletal muscle and cardiac function. However, the study was conducted in male rats, and whether the same effects occur in humans remains to be established.

The researchers said the study provides additional evidence of differences between Vitamin D2 and D3 beyond their established roles in calcium regulation and bone health.

Researchers have developed a form of Spirulina containing biologically active vitamin B12 at levels comparable to beef. By carefully controlling the light used during cultivation, they overcame a key limitation of conventional Spirulina, which mainly contains a form of B12 that the human body cannot use.

The carbon-neutral system could offer a more sustainable, vegan-friendly source of vitamin B12, particularly for people who avoid meat and dairy.

A New Source Of Active Vitamin B12

Researchers from Reichman University in Israel, along with scientists from Iceland, Denmark and Austria, found a way to grow Spirulina that produces biologically active B12.

Published in Discover Food, the study used biotechnology and controlled light conditions to produce nutrient-rich, carbon-neutral Spirulina biomass. The researchers say this is the first reported production of biologically active B12 in Spirulina.

The cultivated biomass contained 1.64 µg of active B12 per 100 grams, compared with 0.7–1.5 µg per 100 grams in beef.

Spirulina, a blue-green cyanobacterium, is already valued for its protein and nutrient content and can be cultivated with a relatively small environmental footprint.

Why Conventional Spirulina Falls Short

Vitamin B12 is essential for functions including red blood cell formation and normal nervous system function. More than a billion people worldwide are estimated to have low levels of the vitamin.

Although Spirulina has long been promoted as a sustainable food source, conventional varieties largely contain pseudo-vitamin B12. While chemically similar to the vitamin humans need, this form is not bioavailable and cannot be effectively used by the body.

That has limited conventional Spirulina as a reliable alternative to animal-derived sources of B12.

Using Light to Change Spirulina’s Nutrition

The researchers studied a biotechnology platform developed by VAXA Technologies in Iceland. Its key feature is photonic management, which involves precisely adjusting the light environment in which Spirulina grows.

The controlled conditions encouraged the production of biologically active B12 while generating carbon-neutral biomass. The cultivated Spirulina also contained other bioactive compounds associated with antioxidant, anti-inflammatory and immune-related properties.

Potential for Large-Scale Production

The researchers modelled possible large-scale production scenarios. In one scenario, reallocating electricity currently used by heavy industry in Iceland could support the production of 277,950 tonnes of Spirulina biomass annually.

They estimate this could contain about 4,555 grams of active B12—enough, based on their calculations, to provide the recommended dietary allowance for more than 13.8 million children aged 1–3.

More ambitious scenarios could potentially meet the B12 RDA for more than 26.5 million children aged 1–3 and more than 50 million infants aged 0–6 months.

These figures are projections rather than current production levels.

A Sustainable B12 Alternative

The findings suggest that photosynthetically controlled Spirulina could become a sustainable, vegan-friendly source of active vitamin B12, potentially reducing some reliance on animal-based foods.

However, further research, validation and large-scale production are needed to determine whether the technology can become a practical dietary solution for vitamin B12 deficiency.

A piece of sugar-free chewing gum may seem like a healthier choice. But new research is putting one of its most excessively used ingredients under the microscope: xylitol. It is a sugar alcohol used in sugar-free chewing gum, mints, toothpaste, jam, yoghurt, and other products.

Also Read: Trump Strikes Drug Pricing Deals With 9 More Drug makers: Will Americans Finally Pay Less For Medicines?

The sugar-free sweetener has been linked with a significantly higher risk of heart attack, stroke and cardiovascular death in a large new study.

Researchers found that people with the highest blood levels of xylitol had a 57% higher risk of a major cardiovascular event over six years than those with the lowest levels.

The findings were presented at the European Society of Cardiology (ESC) Congress 2026. It was based on 17,710 people from two long-running population studies. The researchers also found an 18% higher risk over 30 years in the European group.

Also Read: Fifth Universal Definition of Myocardial Infarction: What the 3 New Heart Attack Categories Mean

But before you throw every packet of sugar-free gum into the bin, remember that the study only found an association, not definitive proof that consuming xylitol directly increases the risk of heart attacks or strokes.

What Is Xylitol?

Xylitol is a sugar alcohol, also known as a polyol. It occurs naturally in tiny amounts in some foods and is also produced by the human body while metabolising glucose.

Xylitol tastes almost the same as sugar but contains fewer calories, and it does not promote tooth decay in the same way ordinary sugar does. That's why it has become a popular ingredient in sugar-free gum, mints, and other oral-care products.

According to the ESC, the concerning part is that commercially added amounts of xylitol can be more than 1,000 times higher than the tiny quantities naturally present in foods and the body.

Also read: Eli Lilly Moves Beyond GLP-1 Drugs, To Spend 2.88 Billion On Autoimmune Drug Development

How Was Study Conducted?

Researchers divided participants according to their blood xylitol levels and compared the highest quarter with the lowest quarter.

In the Canadian cohort, those with the highest levels had a 57% greater risk of major adverse cardiovascular events over six years after adjusting age, sex, smoking, diabetes, blood pressure and cholesterol.

In the European cohort, the association remained visible over a much longer period, with an 18% higher risk over 30 years.

One of the most important findings is that 57% does not mean that eating a piece of xylitol gum makes your personal risk of a heart attack jump by 57%. The researchers measured xylitol circulating in the blood, rather than asking participants how much xylitol-containing food they consumed.

Xylitol May Enable The Formation Of Blood Clots

The researchers had previously investigated how xylitol might influence blood clotting. Their laboratory work suggested that xylitol can make platelets more reactive, equipping them to form clots.

Dr Marco Witkowski of Charité University Hospital in Berlin, who presented the research, said, "Xylitol can enhance the ability of platelets to form clots."

When a blood clot blocks an artery supplying the heart, it can trigger a heart attack. If a clot blocks blood flow to part of the brain, it can cause an ischaemic stroke.

Witkowski added, "Our long-term findings highlight how little we know about the cardiovascular safety of xylitol."

The study does not establish that ordinary consumption of products containing xylitol causes heart attacks or strokes, and it does not mean that replacing sugar with xylitol is automatically dangerous.