Atlanta Gastroenterology Associates | 1,602 followers on LinkedIn. Now part of United Digestive -- comprehensive digestive healthcare for the whole family | Atlanta Gastroenterology Associates (AGA), now part of United Digestive, is one of the largest gastroenterology practices in the country. For more than 40 years, AGA has been a leading provider of gastroenterology services in Georgia – and throughout the southeast. Our goal remains the same: make high-quality, comprehensive digestive healthcare services more accessible to our patients.