Diet Soda Causing Dementia? The Harmful Costs of This Beloved Beverage

Soda in general is not ideal for good health. This beverage, and other similar sugary drinks, can lead to numerous health issues like diabetes and obesity. But diet soda has been found to have even more adverse effects, from weight gain and insulin resistance to altering the brain's response to sugar treats. It can be difficult to link low- or zero-calorie soft drinks to precise illnesses, which is why researchers use caution in labeling them dangerous.

While the cause of certain health factors may not be explicitly clear, health experts will still recommend refraining from drinking soda and sticking to a healthier option like water or herbal teas. There is still no denying that soda has no nutritional value to offer.

24/7 Tempo reviewed scores of medical studies and meta-analyses in journals published by nonprofit health organizations, such as the American Heart Association and the American Diabetes Association, to identify 10 surprising ways diet soda harms your body. These studies and journals examine the health effects of artificially sweetened beverages.

This post was updated July 4th, 2025, to reflect additional information.

Here are surprising ways diet soda harms your body.

Researchers from Columbia University College of Physicians and Surgeons and the University of Miami Miller School of Medicine followed more than 2,500 adults for a decade. One group of people frequently drank regular soda, and the other dieted.

At the end of the study, which was conducted in 2012, those who consumed diet soda had a 43% higher chance of cardiovascular disease, such as a heart attack, than those who drank regular soda. A 2014 study found that women who had two or more diet sodas had a 30% higher risk of heart attack and were twice as likely to die than women who rarely drank diet soda.

Artificial sweeteners may cause increased consumption of high-calorie foods — they simply make you crave fatty foods — leading to glucose intolerance and weight gain. Artificial sweeteners may not be natural but they are sweet, and as such they encourage sugar cravings and sugar dependence.

A 2015 study by the American Geriatrics Society of nearly 800 people over the age of 65 found that diet soda intake was related to increasing abdominal obesity. Separate research that followed people for over eight years found that those who drank artificially sweetened beverages were more likely to report increased BMIs.

According to a Gallup survey, 32% of overweight Americans say they drink diet soda, compared to 19% of those with normal weight.

A 2017 study of almost 3,000 people over 60 found that diet sodas sweetened with artificial ingredients — unlike sugar-sweetened beverages — lead to a higher risk of dementia. People who drank at least one diet beverage a day were almost three times more likely to develop dementia. The results were the same after accounting for gender, general diet, smoking, and level of physical activity.

The same study of nearly 3,000 people found that daily consumption of diet beverages was associated with an increased risk of stroke and dementia over a 10-year period. Older studies have also shown a connection between low-calorie sodas and a significantly higher risk of stroke.

Researchers are not sure how exactly artificial sweeteners may increase the risk of stroke, but this is not a reason to keep them in your diet. Researchers following 127,000 people for 20 years concluded that those who consumed more than one soda per day had a higher risk of stroke, regardless of whether the soda contained sugar or was artificially sweetened.

Hypertension increases the risk of heart attack and stroke, among other chronic health conditions. Diet sodas are linked to high blood pressure possibly because people who drink artificially sweetened beverages tend to be overweight or obese.

Another possible explanation is the sodium content. One can of soda contains 40mg of sodium. Even though the recommendation is 1,500 mg per day for most adults, drinking more than one can a day really adds up, especially considering that almost all foods we consume have salt.

Daily consumption of diet soda was linked to a 67% higher risk of developing type 2 diabetes, which nearly 10% of Americans have. Diabetes was the seventh leading cause of death in the United States in 2015. Artificial sweeteners in diet soda may lead to insulin spikes, which worsen insulin sensitivity over time. They can also increase appetite, encouraging a sweet tooth.

A study of more than 600 people, published last year in the Clinical and Experimental Ophthalmology journal, found that diabetics who consumed more than four cans of diet soda a week were twice as likely to have vision problems, including blindness.

Research in mice suggests that non-caloric artificial sweeteners may be harmful to the gut microbiome. Gut changes that were noted included higher systemic fatty acid levels, which have been linked to obesity and gluconeogenesis (the body's synthesis of sugar from non-carbohydrate sources).

A recent study published in the journal Molecules concluded that artificial sweeteners in general cannot be tolerated by the human body. They were found to have an adverse effect on the gut microbiota and in some tests induced glucose intolerance.

There is some evidence diet sodas are linked to a higher risk of non-alcoholic fatty liver disease, which close to 100 million Americans have. One study found that people suffering from moderate to severe fatty infiltration were drinking mostly regular Coca-Cola and Diet Coke.

The artificial sweetener commonly used in diet soft drinks, Aspartame, seems to be one of the big culprits. The intestines absorb it and then the liver metabolizes it, but the process is shown to cause mitochondrial dysfunction, which is the root of many diseases, and ATP depletion, which can lead to fat buildup in the liver.

Both regular and diet soft drinks hurt your bones because they contain phosphoric acid. The National Osteoporosis Foundation has stated that people with the condition should not drink more than five soft drinks a week.

Some research suggests that too much phosphorus in your body can decrease calcium absorption, weakening the bones. A study found that women who drank three or more cola-based sodas a day had nearly 4% lower bone mineral density in the hips, even with levels of calcium and Vitamin D controlled.

Studies are not conclusive when it comes to identifying Aspartame as a carcinogen. Research has found that the sweetener can cause several cancers in both male and female rats, but only male mice. In 2016, the Center for Science in the Public Interest downgraded sucralose (known as Splenda), which is used in some diet sodas, from "caution" to "avoid," because it was found to cause leukemia and other blood cancers in male mice.