Soy protein meals stimulate less gastric acid secretion and gastrin release than beef meals

Soy protein is a widely used, inexpensive, and nutritious source of dietary protein. In contrast to beef protein, the effects of soy protein on gastric acid secretion and serum gastrin concentration have not been evaluated. We compared the effects of meals containing the same amounts of either isolated soy or beef protein on acid secretion and serum gastrin concentration in normal humans. Acid secretion measured by in vivo intragastric titration was 30%-40% less with soy than beef protein (p less than 0.05), whether isolated soy protein alone was compared with a mixed beef meal containing carbohydrate and fat or whether soy or beef meals containing similar amounts of fat were compared. Average gastrin rises were 65%-75% less with soy than with beef (p less than 0.01). The explanation for less gastrin release with soy than with beef is unclear, but lower serum gastrin concentrations with soy probably accounted for reduced acid secretion. These results indicate that the source of dietary protein in a meal may be an important determinant of gastric acid secretion and gastrointestinal hormone release.