and why cholesterol is helpful, they didin't know where it came from in the blood !
“When we eat more polyunsaturated fat, the cells collect cholesterol from the blood, and build it into the cell membranes to ensure that they become rigid enough. This is where the cholesterol has gone when we measure less cholesterol in the blood!”
And the opposite holds true as well – when we eat more saturated fat, the cell membranes become stiffer. The cells have less need to bring in stabilizing cholesterol and instead send it into the bloodstream. The cells also stop absorbing cholesterol, thus raising the blood cholesterol level.
In the second instance, Zinöcker arrived at another understanding:
The increase in blood cholesterol level as a result of more saturated fat in the diet may not be a sign of disease at all. On the contrary.
"The increased blood cholesterol level is probably a sign that the regulatory mechanisms in the body are working the way they should," says Zinöcker.
Perhaps the cholesterol in the blood of healthy people is simply a kind of emergency stockpile, which the body has at its disposal when the fluidity of the cell membranes needs to be adjusted.
“Cell stiffness is probably so important that the body doesn’t take a chance on covering the need exclusively through food,” says Zinöcker.
https://sciencenorway.no/cholesterol-fat-heart-attacks/new-model-could-explain-old-cholesterol-mystery/1810159