By Dr. Mercola
At the peak of its popularity in 2005, 3 billion cases of diet soda were sold in one year. This beverage has since fallen out of favor, falling by 27 percent (or 834 million cases) as of 2016. Still, diet soda still makes up 25 percent of the carbonated beverages sold in the U.S.1 (by volume), which means many Americans are still partaking — undoubtedly many of them because they believe they're making a healthier choice than regular soda.
This — the idea that diet soda is in any way healthy — is one of the biggest prevailing myths in the nutrition realm today. If you're one of the nearly half of U.S. adults who consume artificial sweeteners, mostly in the form of diet soda, daily (even one-quarter of kids do so as well),2 it's important you're let in on the truth: If you drink a lot of diet soda, you're putting your health at risk.
What Are the Health Risks of Diet Soda?
A number of studies have been published recently that cast serious doubt on the safety of drinking diet soda. The health risks revealed include:
Stroke and Dementia
Drinking one artificially sweetened beverage a day may increase your risk of stroke and dementia by three-fold compared to drinking less than one a week.3 Even drinking one to six artificially sweetened beverages a week was linked to a 2.6 greater risk of stroke compared to not drinking any.
A 2012 study similarly found that people who drank diet soft drinks daily were 43 percent more likely to have suffered a vascular event, including a stroke.4 This significant association persisted even after controlling for other factors that could increase the risk, such as smoking, physical activity levels, alcohol consumption, diabetes, heart disease, dietary factors and more.
As for the dementia link, this one is new and no one knows for sure how diet drinks may affect your brain. Forbes compiled some plausible theories, however, including perhaps via the disruption artificial sweeteners pose to your gut health, via the corresponding gut-brain axis. Alternatively:5
"Diet sodas are designed to trick the brain into thinking it's getting an extra dose of glucose (the brain's fuel), but eventually the trick is on us because the brain adapts to not receiving the added glucose by overcompensating in other ways (leading to a variety of effects still under investigation)."
Research that included nearly 60,000 post-menopausal women who were followed for about 10 years found that drinking just two diet drinks a day can dramatically increase your risk of an early death from heart disease.6
Metabolic Syndrome and Type 2 Diabetes
People with type 2 diabetes are often advised to consume artificial sweeteners in lieu of sugar, but research shows consumption of diet soda at least daily is associated with a 36 percent greater relative risk of metabolic syndrome and a 67 percent greater relative risk of type 2 diabetes compared with not consuming any.7
According to a study that included nearly 264,000 U.S. adults over the age of 50, those who drank more than four cans or glasses of diet soda or other artificially sweetened beverages daily had a nearly 30 percent higher risk of depression compared to those who did not consume diet drinks.8
Diet Soda May Make You Gain Weight
If you're drinking diet soda to avoid all the calories in sugar-sweetened soda, you may be surprised to learn that, like regular soda, diet soda is linked to weight gain. In April 2017, research presented at ENDO 2017, the Endocrine Society's 99th annual meeting in Orlando, Florida, once again found that artificial sweeteners promote metabolic dysfunction that may promote the accumulation of fat.9
The study tested sucralose (brand name Splenda) on stem cells taken from human fat tissue, which revealed that a dose similar to what would be found in the blood of someone who drinks four cans of diet soda a day increased the expression of genes linked to fat production and inflammation, as well as increased fat droplets on cells.10 The study's lead author, Dr. Sabyasachi Sen, an endocrinologist at George Washington University Hospital, noted in a press release:11
"From our study, we believe low-calorie sweeteners promote additional fat formation by allowing more glucose to enter the cells, and promotes inflammation, which may be more detrimental in obese individuals."
The fact that the artificial sweetener was associated with increased glucose uptake in the cells was particularly concerning, as it could have detrimental effects for people with elevated blood sugar levels, like those with diabetes or pre-diabetes.12
Aspartame in Diet Soda Linked to Obesity
Aspartame is one of the most popular artificial sweeteners used in diet soda, and research has also linked it to weight gain and obesity. A study on mice revealed that animals fed aspartame-laced drinking water gained weight and developed symptoms of metabolic syndrome while mice not fed the artificial sweetener did not. Further, the researchers revealed that phenylalanine, an aspartame breakdown product, blocks the activity of a gut enzyme called alkaline phosphatase (IAP).
In a previous study, IAP was found to prevent the development of metabolic syndrome (and reduce symptoms in those with the condition) when fed to mice.13 Aspartame likely promotes obesity by interfering with IAP activity. Mice in the study were fed either plain water or water infused with the equivalent amount of aspartame found in two to 3.5 cans of diet soda, along with a normal diet or a high-fat diet.
Mice in the high-fat group that drank aspartame-infused water gained more weight than those eating the same diet without aspartame in their water. Further, all the mice fed aspartame had higher blood sugar levels — an indicator of glucose intolerance — and higher levels of inflammatory protein TNF-alpha, which is suggestive of systemic inflammation. Given aspartame's inhibition of IAP, the researchers suggested its use is counterproductive.
Diet Soda May Harm Fertility
According to Dr. Arvind Vaid, an IVF expert at Indira IVF in India, "Almost all of the soft drinks and sodas contain aspartame which is linked to many health problems including infertility, malformations and miscarriages." He told the Kashmir Monitor, "Excess consumption leads to hormonal imbalance and fluctuation that causes ovulatory disorders and even worsens PMS (premenstrual syndrome)."14
In addition, Vaid said, the phenylalanine and aspartic acids in aspartame may lead to the production of free radicals that may kill cells, including sperm and ovum cells. Indeed, a 2017 animal study revealed that aspartame consumption was linked to oxidative-stress-related damage to rat sperm.15 Further, the acidic nature of the soda may alter the pH level of your body, which may further harm sperm cells.
Adding to the problems, the caffeine in diet soda is linked to increased ovulatory disorders and infertility in women.16 If you're pregnant, you'll also want to steer clear of artificial sweeteners. In 2016, a study found that women who consumed artificially sweetened beverages daily during pregnancy had babies with a two-fold higher risk of being overweight at the age of 1 year.17
Adding Fiber to Poison
In an effort to revamp Diet Coke's increasingly negative reputation, Coca-Cola has rolled out artificially sweetened zero-calorie Coca-Cola Plus, which has added fiber. It's currently only available in Japan, where it's even being marketed as able to help "suppress fat absorption." As registered dietician Cynthia Sass wrote in Time:
"When I heard about Coca-Cola Plus, a zero-calorie Coke with added fiber, I thought it was an April Fool's joke I somehow missed. Especially when the company claimed this ridiculous product is meant for a 'health-conscious consumer.' No sugarcoating here: Adding fiber to soda of any kind, regular or diet, doesn't make it healthy."18
Many people could benefit from increasing their fiber intake, but drinking diet soda to do so is defeating the point. To get more fiber, eat more vegetables — they're among the best sources — along with seeds and psyllium husk, and forget about fiber-enhanced soft drinks, if and when they become available in your area.
Ditching Diet Soda Is Essential for Your Health
Eliminating diet (and regular) soda from your diet is an excellent step toward better health. As you wean yourself off artificial sweeteners, keep something sour nearby. Sour taste, such as that from fermented vegetables or water spruced up with lemon or lime juice, helps to reduce sweets cravings. If that doesn't appeal to you, try a cup of organic black coffee, an opioid receptor that can bind to your opioid receptors, occupy them and essentially block your addiction to other opioid-releasing food.19,20
I also recommend addressing your cravings on an emotional level. Turbo Tapping, which is a version of the Emotional Freedom Techniques (EFT), is specifically useful for diet soda addiction. And if you're missing the carbonation element of diet soda, try a sparkling mineral water instead. Spruce it up with fresh lemon or lime juice, a drop or two of natural peppermint extract, liquid stevia, cucumber slices or a few crushed mint leaves for a refreshing treat that will support your health instead of sabotage it.