|Image 1: Ex-Mr. Universe, Manohar Aich, turns 100 and swears by milk and other whole foods (NYDaily)|
Whey + casein + lactose = almost milk
In order to quantify the quantity and time course of the total body, splachnic (hepatic) and leg protein flux of whey and casein, Mattias Soop, Vandana Nehra, Gregory C. Henderson, Yves Boirie, G. Charles Ford, and K. Sreekumaran Nair conceived a clever experiment. They used differently labeled whey and casein proteins to determine the individual metabolic fate of the two dairy proteins over 7 hours after their ingestion. To this ends, their 18 healthy subjects (6 men, 12 women) who had been consuming a weight-maintaining diet (20% protein, 50% carbohydrate and 30% fat) for three days before the experiment and had reported to the lab the evening before the actual testing procedure took place, ingested one of the following test meals
- 0.625 g/kg LBM whey + casein + 0.9g/kg LBM lactose, or
- 1.85g/kg LBM lactose
|Figure 1: Mean rates of appearance (left) and disappearance (right) of radiolabeled phenylalanine via the hepatic vein and portal vein, respectively (Soop. 2012)|
Surprise?! Lactose is not the working ingredient in milk
Similarly unsurprising as the different amino acid kinematics of whey and casein are is probably that lactose alone did not elevate the protein synthesis in the legs of study participants to a similar level as the ~25g of whey + casein test meal (mixed, mitochondrial and sarcoplasmic FSR were elevated to the same roughly the same degree; data not shown).
|Figure 2: Insulin, glucagon and glucose increases (peak at ~60min) after ingestion of the test meals (Soop. 2012)|
Scientists put the pieces back together, yet not without making a fat mistake
|Image 2: I wonder if those are the physical consequences of drinking skimmed milk - I mean, David looks like he had a hell lot of glucagon going on, right? ... what? You mean David did not even drink milk, just took the money, no - impossible!|
If you will, you could however argue that nature must have a design flaw in its muscle builder #1, after all the amount of carbs appears to be insufficient to fully negate the release of glucagon; yet while the lactose to protein ratio was 1.44 and thus identical to milk, there was one essential component of milk scientists tend to forget missing: fat! And you know what - an increase in free fatty acids as the one that follows the ingestion of the allegedly bat saturated fats blunts the release of glucagon. What? Yeah, nature is actually pretty smart, you are right!