Artificial sweeteners are toxic, manmade molecules that are dangerous to your health and can even cause you to gain weight. Adding to the warnings about artificial sweeteners, a 2014 study in the journal Nature found that they alter the composition of gut bacteria in those who use them.

The bacteria in your gut play a fundamental role in your health. Disrupting them can have a devastating effect, depressing your immunity, generating toxins and causing many diseases from autoimmune syndromes to cancer and mental problems. The study in Nature showed that the gut bacteria in those using artificial sweeteners were fundamentally altered.

In addition, sweeteners such as aspartame, saccharin and sucralose caused spikes in blood sugar levels. More than half of the human subjects developed dramatic increases in glucose intolerance, contributing to diabetes and obesity—problems these sweeteners are supposed to be preventing.

The aspartame, used in most diet sodas, is known to be particularly toxic. One of the breakdown products of this molecule is formaldehyde. Formaldehyde accumulates in our cells, where it damages DNA and causes cancer. Drinking even one can of diet soda can cause DNA damage that leads to cancer, and your risk increases with each can consumed. It is now well established that aspartame, an excitotoxin, causes brain cancer, lymphomas, and leukemias in experimental animals. Aspartame can penetrate the blood-brain barrier and damage the brain and nervous system. Aspartame also increases your risk of strokes and heart attacks. The FDA once listed 92 side effects from consuming aspartame, including seizures, sexual dysfunction, and sudden cardiac death. The FDA has received more complaints about aspartame than any other substance.

Another common sweetener is Splenda. Splenda is another manmade chemical that affects the body in numerous ways. The side effects of Splenda include skin rashes/flushing, panic-like agitation, dizziness and numbness, diarrhea, swelling, muscle aches, headaches, bladder issues, and severe gastrointestinal problems. Animal studies show that Splenda reduces the amount of good bacteria in the intestines by 50 percent, and we now know this happens in humans as well. Splenda also increases the pH level in the intestines, and contributes to increases in body weight. If you care about your health, don’t consume artificial sweeteners.