Alkaline water has gained popularity in recent years, but does it have any benefits over regular water? Live Science reached out to experts to find out. (Image credit: UCG via Getty Images)
Drinking alkaline water has become a trendy beverage, with many companies claiming it offers a variety of benefits, from improved hydration to the prevention of chronic diseases.
But what is alkaline water and does it really have any benefits?
“These claims are not supported by evidence,” Salome Kruger, a professor of nutrition at the North-West University Centre of Excellence in Nutrition in Potchefstroom, South Africa, told Live Science.
Alkalines are bases, or the opposite of acids—they have a high pH, while acids have a low pH. Lower pH values indicate more positively charged particles. Alkaline water typically has a pH of 8 to 9, which is higher than regular drinking water, which is generally considered “neutral,” at around 7.
Water can become alkaline by passing through rocks and accumulating alkaline minerals, or it can be made artificially through electrolysis, a process in which filtered water is passed through a device that separates the water into alkaline and acidic streams. The alkaline stream contains minerals such as calcium, magnesium, and potassium.
When consumed, alkaline water is unlikely to have a long-term effect on the body. This is because when it enters the stomach, its pH is neutralized by the acidity of gastric juice, which has a pH level of between 1.5 and 3.5.
The bicarbonate in the water reacts with stomach acid to form water and carbon dioxide, which is then excreted. Minerals from the water are absorbed in the small intestine and enter the bloodstream, where the pH is strictly maintained between 7.35 and 7.45 by the lungs and kidneys. Excess minerals in the blood are filtered by the kidneys and excreted.
So drinking alkaline water is unlikely to significantly “alkalize” the body. Moreover, scientific research on the possible health effects of alkaline water is limited and often inconclusive, Krueger said.
Test-tube studies show that alkaline water can inactivate human pepsin, a digestive enzyme. In acid reflux, pepsin reaches the throat and damages tissue, so inactivating pepsin may seem beneficial in this context. However, in the stomach, it could potentially disrupt the digestive process, which would be undesirable, Krueger explained.
Animal studies have shown potential benefits, such as increased lifespan and weight loss, in animals that consumed alkaline water over a long period of time. However, researchers have not been able to clarify the mechanisms behind these effects, so it is unclear whether they apply to humans.
One observational study of more than 300 women found that those who regularly drank alkaline water had lower body mass index (BMI), blood sugar levels, and blood pressure than those who drank plain water. But the former group also had higher incomes, better nutrition, and more physical activity. “These lifestyle factors are known to have a much greater impact on chronic disease risk than simply drinking alkaline water,” Krueger said.
Additionally, there’s no strong evidence that alkaline water hydrates better than regular water. In a 2016 study, researchers noted a decrease in blood viscosity — the thickness and stickiness of blood — in people who drank alkaline water, and speculated that this might be due to improved hydration. However, other studies that tracked direct markers of hydration found no significant differences between alkaline and regular water.
Overall, methodological issues in some of these human studies, such as limited sample sizes and lack of baseline measurements, make it difficult to draw firm conclusions, said Liz Havemann-Nel, an associate professor at the Centre of Excellence in Nutrition at North-West University in Potchefstroom, South Africa.
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