Most doctors don't interpret this test correctly
And it's the most important lab test that we get
A test is only as useful as our ability to understand what it means.
After all, if you don’t know what the results mean, how can you act on it correctly?
And if you can’t act on it correctly, why did you even order it in the first place?
I’m sure that basically everyone reading this has had a lipid panel done before, which most people think of as a cholesterol test.
A lipid panel is one of the most commonly ordered lab tests - we all get one as part of generalized health assessment, I order them about a dozen times a day.
A standard one looks like this:
A fancier one looks like this:
But while a lipid panel is incredibly valuable, it is unfortunately also an almost universally misinterpreted lab test.
Many of my patients focus on the total cholesterol number, which is a metric that isn’t quite meaningless, but certainly close.
Most doctors focus on the LDL portion of the lipid panel - they look at the “bad cholesterol” numbers and then decide whether or not to prescribe a statin. [As an aside, the terms “good cholesterol” and “bad cholesterol,” make an already confusing topic even more confusing by adding misnomers, which is a conversation for another day.]
And while LDL is certainly important, it’s not the only part of a lipid panel that helps us make a cardiovascular risk assessment. And LDL-cholesterol - which is what’s reported in this test - isn’t even the best marker for LDL-mediated risk (the best marker there is apolipoprotein B, which I’ve written about before and will write about again).
But a lipid panel gives you a ton of useful information beyond just LDL - it’s a really important window into our overall health.
When it comes to overall health, I would argue the most important part of the lipid panel is the ratio of triglycerides to HDL-cholesterol (TG/HDL).
And most doctors either don’t look at this or don’t understand what it means.
Your ratio of triglycerides to HDL-cholesterol is the most direct window into your metabolic health
The triglyceride to HDL ratio tells you almost everything that you need to know about your risk for metabolic syndrome.
An ideal TG/HDL ratio is under 1:1.
When you start getting over 2:1, I become a little bit worried. When that goes over 3:1, it’s frankly quite alarming.
The higher than ratio is, the most confident we can be that you have metabolic dysfunction.
For many people, the triglyceride to HDL ratio is the canary in the coal mine of metabolic syndrome and the onset of chronic disease.
Understanding your metabolic health is important, because if you aren’t healthy from a metabolic perspective, that means you aren’t healthy
There are a lot of metrics that we use to track metabolic health because it’s so important, and the newfound attention it’s getting is leading to a lot of buzz and a lot of money.
But unfortunately, explaining metabolic health in plain English is really hard.
It makes sense to think of bad metabolic health as leading to metabolic syndrome, which is a tiny bit easier to communicate about.
You lose your audience when you start talking about intramuscular diacylglycerol accumulation and impaired skeletal muscle response to insulin, which is why there’s a formal definition of what metabolic syndrome means.
Metabolic syndrome is defined as having 3 out of 5 of the following findings:
Abdominal obesity
Elevated triglycerides
Low HDL cholesterol
High blood pressure
High blood sugar
This is just so damn important because of the link between metabolic syndrome and illness.
For all intents and purposes, if you have a chronic disease, chances are it’s because of metabolic syndrome and that’s why readers of this newsletter have heard me drone on and on about it.
I’m not exaggerating when I say that metabolic syndrome does almost everything bad in medicine.
The list of diseases caused or worsened by metabolic syndrome includes almost everything that people take daily medications to treat: high blood pressure, abnormal blood lipids (cholesterol), diabetes/prediabetes, fatty liver, GERD, gout, obesity, and a significant amount of heart disease, heart failure, cancer, Alzheimer’s, and even depression.
Seriously: metabolic syndrome makes all chronic disease worse
If you are prescribed any medicine to take every day, it’s almost certainly treating a manifestation of metabolic syndrome.
It’s common to think of high blood pressure, high cholesterol, diabetes, acid reflux, heart disease, and the like as different medical problems.
And while that’s technically accurate, I think it misses the point, since many of these things have similar underlying causes.
You can think of metabolic syndrome as overlapping with insulin resistance, one of the hallmarks of type 2 diabetes.
But you don’t just wake up one morning and all of a sudden have type 2 diabetes - it’s a spectrum of disease that takes a long time to develop.
And if your pancreas can keep pumping out enough insulin to keep your blood sugar from spiraling out of control, you might never get full blown diabetes, even if you have awful metabolic syndrome.
Fortunately, the signs are there in our bloodwork that we might be going down that path many years before we get there.
One of the world experts on this topic is Gerald Shulman, an endocrinologist at Yale. If you’re really into this stuff and want to dive deep (and I mean really deep), this talk from him is worth an hour of your time:
But the average person doesn’t have to worry about diving deep, because the information you need here comes in your standard bloodwork.
It may help to think about an abnormal TG/HDL ratio as pre-pre-diabetes
My patients hear me harp on this all the time. I often get puzzled looks when I use the term pre-pre-diabetes, because you need to understand a lot of physiology to really get the connection.
But you don’t need a lot of understanding about physiology to act on the warning signs.
Metabolic dysfunction shows up in bloodwork well before it starts to cause major medical issues, so understanding the leading indicators is of vital importance.
It’s much easier to check a lipid panel and look at the triglycerides and HDL than to do something like an oral glucose tolerance test (OGTT) with serial insulin measurements. An OGTT that also measures insulin to detect an abnormal spike in insulin in response to a carb load may be the gold standard test to detect metabolic dysfunction, but it’s also onerous and not done by most labs.
The TG/HDL ratio isn’t just simpler, it’s also way more widely available, cheaper, and easier to interpret.
So if you see that your lab tests here are abnormal, it’s a sign that something isn’t optimized in your lifestyle. The causes here are myriad, but it’s likely some combination of imperfections in the following:
Diet (meaning too many calories)
Physical activity (or lack thereof)
Stress
Sleep
Excess weight (particularly visceral fat)
As with any problem, it’s much easier to identify what’s wrong than it is to act on it. When you see that your TG/HDL ratio is abnormal, the action steps tend to be straightforward, but not always easy to execute.
We’ll save the what-to-do-about-this advice for another day.