The full answer
Yes — many people describe this as one of the most disruptive symptoms
Difficulty concentrating, mental fatigue, and general “brain fog” are widely reported by people with celiac disease, and are thought to relate to a combination of intestinal inflammation, nutrient deficiencies, and disrupted sleep from other symptoms.
It often improves with a gluten-free diet
Many people report noticeable improvement in mental clarity within weeks to months of starting a strict gluten-free diet, alongside improvement in fatigue — though, as with other symptoms, timelines vary from person to person.
Important context
Individual symptoms, reactions, medical histories, food products, and local labeling rules can vary. Community experiences are not medical evidence.
For personal medical decisions, diagnosis, testing, or treatment, consult a qualified healthcare professional.