5 Health Foods , That Can Make IBS Worse.br Irritable bowel syndrome affects br 10 to 15 of the population.br These 5 healthy foods br could trigger a flare-up.br 1. Garlic is known to rapidly ferment br in the gut without getting absorbed properly.br 2. Avocados should be avoided br to better manage IBS symptoms. .br 3. Whole wheat, high in insoluble fiber, br can worsen symptoms.br 4. The milk sugar lactose and the protein casein should be avoided, which rules out most dairy.br 5. Cruciferous vegetables such as kale, Brussels sprouts and cauliflower may worsen gas and bloating.