Just got my total cholesterol results back and, not believing them, went and did a Boots test too for a "second opinion", which got the same result, or near as dammit.
5.6 thingies per thingie wotsit is regarded as borderline for high.
So when mine came back at 1.6 I thought "woohoo, how good is that?"
Elation lasted all of a few seconds before the doctor frowned and started reeling off problems associated with overly LOW cholesterol (as mine would need to double to be in reference range).
Stroke (!), heart disease and all those nasties are, apparently, also associated with overly low cholesterol. Joint problems are another (which I'm getting but maybe not from this), impotence

(not arrived yet, honest), and a host of other malaises.
And it has an effect on growing and thyroid efficiency, too.
With the fat intake I have, total cholesterol should be higher.
I get very little saturated fat and mostly "good" fats - from flax, peanut butter, various other cold-pressed oils, fish, etc.
Back in for more bloodwork to determine what's up but if she saw my family she'd understand why - we're all built like shredded marathon runners by default. Still, no harm in ruling out liver disease, etc, which can cause low cholesterol levels. I think knackered intestines cause it too through malabsorption of food. That, however, isn't an issue in me - I know that already from other things I've had done.
Need more fats....