Low-protein vegetarian diet does not have a short-term effect on blood acid-base status but raises oxygen consumption during submaximal cycling

• Published in: Journal of the International Society of Sports Nutrition 2012-11, Vol.9 (1), p.50-50
• Main Authors: Hietavala, Enni-Maria, Puurtinen, Risto, Kainulainen, Heikki, Mero, Antti A
• Format: Article
• Language: English
• Subjects: Acid–base balance; Aerobic performance; Blood; Body fluids; Carbohydrates; Carbon dioxide; Consumption; Cycling; Diet; Exercise; Food; Fruits; Insulin-like growth factors; Low-protein diet; Medical examination; Nutrition; Nutrition research; Oxygen consumption; Physical fitness; Physiological aspects; Proteins; Studies; Vegetarianism
• ISSN: 1550-2783; 1550-2783
• DOI: 10.1186/1550-2783-9-50

Acid-base balance refers to the equilibrium between acids and bases in the human body. Nutrition may affect acid-base balance and further physical performance. With the help of PRAL (potential renal acid load), a low-protein vegetarian diet (LPVD) was designed to enhance the production of bases in body. The aim of this study was to investigate if LPVD has an effect on blood acid-base status and performance during submaximal and maximal aerobic cycling. Nine healthy, recreationally active men (age 23.5 ± 3.4 yr) participated in the study and were randomly divided into two groups in a cross-over study design. Group 1 followed LPVD for 4 days and group 2 ate normally (ND) before performing a cycle ergometer test. The test included three 10-min stages at 40, 60 and 80% of VO2max. The fourth stage was performed at 100% of VO2max until exhaustion. After 10-16 days, the groups started a second 4-day diet, and at the end performed the similar ergometer test. Venous blood samples were collected at the beginning and at the end of both diet periods and after every stage cycled. Diet caused no significant difference in venous blood pH, strong ion difference (SID), total concentration of weak acids (Atot), partial pressure of CO2 (pCO2) or HCO3- at rest or during cycling between LPVD and ND. In the LPVD group, at rest SID significantly increased over the diet period (38.6 ± 1.8 vs. 39.8 ± 0.9, p=0.009). Diet had no significant effect on exercise time to exhaustion, but VO2 was significantly higher at 40, 60 and 80% of VO2max after LPVD compared to ND (2.03 ± 0.25 vs. 1.82 ± 0.21 l/min, p=0.035; 2.86 ± 0.36 vs. 2.52 ± 0.33 l/min, p