A study suggests that a common gut bacteria, Helicobacter pylori (H pylori), which is present in two-thirds of the world's population, may be linked to a higher risk of Alzheimer's disease. The research examined the health information of over 4 million adults in the UK aged 50 and older and found that individuals with a symptomatic H pylori infection had an 11% increased risk of Alzheimer's disease. H pylori is known to cause stomach cancer, gastritis, ulcers, and indigestion. The findings highlight the potential role of H pylori in the development of Alzheimer's and the need for further research.