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lactate's role in the body, further refuting the notion that lactate is a sign of oxygen deprivation in the muscles.
In a paper published in February in the journal Nature Metabolism, Leija, Brooks and their colleagues showed conclusively that lactate is produced normally in humans after ingestion of carbohydrates. Lactate rapidly enters the bloodstream, even before glucose shows up. Far from being a toxic byproduct to be eliminated during hard exercise, dietary glucose is converted so rapidly to lactate that it preempts or shares top billing with glucose as the two main carbon-energy carriers in the body.
The results show that the rapid conversion of glucose to lactate, starting initially in the intestines, is a way for the body to deal with a sudden dose of carbohydrates. Lactate, working with insulin, buffers the appearance of dietary glucose in the blood.
Instead of a big glucose surge, we have a lactate and glucose surge after eating. And the more of it that is converted into lactate from glucose, the better it is to manage glucose. Lactate is a carbohydrate buffer."
George Brooks, UC Berkeley professor of integrative biology
Brooks and his colleagues had earlier shown this to be true during intense exercise. The new study confirms that lactate plays the same role during normal non-exercise activity and resting.
"It's evidence to show that lactate shouldn't be associated with anaerobic metabolism -; that is oxygen-limited metabolism. It's just a normal response to consuming carbohydrates or to exercise," Leija said. "In exercise, lactate is utilized as the dominant fuel source. That's why your blood lactate increases as you exercise a little harder. It's not that you're making it as a waste product. It's getting into the blood because it needs to go to tissues that need it to continue their physiological performance."
