No worries man, just glad you made it through the whole thing without falling asleep.
I’ve read one study that indicated high carb diets affected liver panel results to a greater extent than caloric load, but typically that sorta thing is influenced by medications and herbal supplements more than food. Given that you exercised shortly (more or less) before, that seems to be the much more likely culprit. Try not to exercise the day or two before the test to see what happens to the liver function panel; given how hard/often you train, it might not be able to hit “optimal” within that time period, but even a sharp downward trend would help suggest no dire pathological process is at play. Try to avoid acetaminophen (Tylenol) before, too.
As far as TG levels are concerned: the reason why many feel it is important to fast before testing is because TG are the predominant fat in the diet. So, obviously, eating a meal containing fat shortly before the test will show the transient, largely chylomicron-mediated elevation in TG that, when interpreted under fasting guidelines (the most routinely utilized kind), indicates the need for treatment.
As far as the rest of the lipid panel is concerned: most laboratories do not currently test for LDL (specifically, LDL cholesterol; LDL-C) directly; rather, they calculate it from TG using an equation called the Friedewald formula (i.e., Total Cholesterol (TC) - HDL - VLDL = LDL). So, anything that affects the left side of the equation will be seen on the right side. This is important to remember because labs that use this equation ALSO do not even directly calculate VLDL, either, but instead usually obtain it by dividing the measured TG level by 5. The logic behind this is that, in fasting conditions, most all chylomicrons (which carry the fat you’ve eaten) are out of the bloodstream, so that virtually all the TG detected will be from VLDL (though incidentally, even in the non-fasted state VLDL still outpaces chylomicrons about 10-fold or so). The reason why they choose to divide by 5 is because normal VLDL particles are considered to have about 5 times more TG than cholesterol.
So, the Friedwald formula “more correctly” can be shown as: TC - HDL - TG/5 = LD (I should be saying HDL-C, LDL-C, etc, so just remember we’re discussing the cholesterol portion here)
Note that this method has been observed to become increasingly prone to error when TG levels start to exceed 200 mg/dl, or so (the cutoff point for hypertriglyceridemia)… another reason why fasting is important. This is due to the way most assays are designed to detect TG: the sample TG is broken down (typically with a lipase enzyme but alkaline conditions may be used) into the glycerol molecule and the three fatty acids. The glycerol is then oxidized through a few steps to produce hydrogen peroxide as a byproduct, which is then commonly exposed to a reagent which induces either a color change in the sample or causes it to fluoresce at a certain wavelength. Probes may also be used for similar effect.
These assays are designed to be linear (a certain color/fluorescence intensity = a certain TG level), but obviously this can only proceed to a certain point before TG concentrations reach a point where the reaction kinetics or the instrument’s ability to accurately determine the change is compromised (or both). This is one reason why you might get a result that simply says “above range” or whatever (we see this with steroid users who check their T levels quite often)… the machine’s not lazy, it just can’t do it.
Again, another reason why fasting is advised. Normally, the sample can simply be diluted and rerun, with the adjustment taken into consideration for determining the final value, but I don’t work in that kind of lab so I don’t know how common it is. This is probably routinely performed for non-fasting tests, where above-range values are expected.
Now, labs CAN directly measure LDL-C/VLDL-C, but it is not hugely common because a) the Friedwald equation works fairly well under proper conditions in most individuals and b) using the Friedwald equation is faster and, most importantly, CHEAPER!
But, there is some evidence that suggests non-fasting conditions are just as good as fasting ones for predicting the risk of cardiovascular disease, provided the proper things are looked at. There is a bit of research emerging that indicated total cholesterol and “non-HDL” particles (LDL, VLDL) are more accurate predictors when measured in a fasted state (using the current protocols), whereas HDL, the TC:HDL ratio and TG seem to work quite well non-fasted for predicting CVD risk.
That last part is because HDL isn’t really acutely impacted by diet and non-fasted TG show how what our bodies are exposed to over the course of the entire day (fasting blood lipids are an uncommon, largely artificial thing in most societies – great for standardizing tests, but a poor reflection of what our bodies routinely have to deal with). Note, though, that “non-fasting” does NOT equal “postprandial” (after meals)… so while you can theoretically get a decent assessment without fasting 12+ hours, remember that TG content rises steadily after meals and tends to peak around 4 - 5 hours and is dependent upon the amount you’ve eaten as well as what you’ve eaten.
Another thing I might as well mention is that persistently elevated postprandial TG levels STRONGLY influence atherosclerotic progression and CVD (probably by promoting the formation of small dense LDL particles which can easily infiltrate vascular tissue; a +1 for non-fasted testing), and that higher carbohydrate diets, while causing higher TG values in the fasted stated, actually have lower postprandial TG measurements than fatty meals (because it gets burned/stored right off the bat rather than getting converted to fat and sent otu). Also consider that using non-fasted TG measurements is a fairly new practice; most information available on assessing risk is based around results obtained from fasting conditions.
So… basically it’s all VERY complicated stuff that a whole lotta people much smarter than I am are STILL tryign to figure out.
) to confirm that I don’t have any bad thing like cirrhosis, hepatitis, or cancer.