Sucrose/fructose intake raises lactate in humans, glucose intake doesn't

cs3000

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Feeding decently high amounts of sugar water vs "glucose" (as 60% dextrose/40% maltodextrin) to people.
post-exercise. 1.5g/kg per hour

Plasma glucose is similar for both. insulin is a lot higher from the 60% dextrose.
100% sucrose works better than 60% glucose/40% maltodextrin to raise liver glycogen stores. 66g vs 87g stored. (wonder if 100% dextrose would be equal though)

But with glucose there's no increase in plasma lactate from baseline,
there's a massive surge in plasma lactate from sucrose, (sustained over the 5 hours tested because the sugar intake was kept up)

zdg0101618140004.jpeg

Plasma lactate concentrations increased significantly after 15 min in the SUC trial compared with GLU and remained significantly higher over the entire postexercise recovery period
Fructose is primarily taken up by the liver, where it can be phosphorylated and converted to glycogen or metabolized to lactate and glucose (28, 29).
Lactate will subsequently be released into the bloodstream for oxidation in extrahepatic tissues or can be used as substrate for muscle glycogen synthesis (via gluconeogenesis) (45).
In agreement, we observed substantial differences in circulating plasma lactate concentrations between treatments



What this lactate surge means in health & in terms of performance terms though i don't know.
maybe someone else can chime in on this

in terms of exercise performance does this mean we should avoid high sucrose / fruit juice intake close to exercise? or is lactate a biomarker of reduced exercise tolerance instead of a direct cause?

is the elevated lactate from drinking fruit juice / high sucrose detrimental in terms of health / functioning when this lactate response can be eliminated with dextrose instead?
or does lactate have benefits?
 
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GTW

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As physiologist George Brooks discovered, lactate plays a beneficial role in exercise via the Lactate Shuttle. The lactate produced by anerobic glycolysis in fast twitch muscles is taken up and used by slow twitch muscles directly from the blood (without conversion back to glucose in the liver) and used for energy.
Some studies show that post-exercise carbs for muscle glycogen repletion comes at a cost, reduced GH secretion in the following diurnal cycle.
 
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