*This article is intended for entertainment and educational purposes only and should not be considered medical advice.

I recently switched primary care physicians and decided to get a basic check-up. It had been a while, and I was interested in getting a blood draw for total cholesterol, LDL, HDL, triglycerides, A1C, etc., the usual panel. As I mentioned in previous articles, in the months leading up to the appointment, I had made some changes. I was eating considerably less, drinking much less beer (begrudgingly), almost never eating fast food, consuming tons of non-starchy vegetables, and exercising almost daily. I had lost 18 pounds and was feeling great. Based on my experience, both personally and professionally, I suspected my lab numbers would be well within healthy limits.

The night before the appointment to get my lab work, I stopped eating after dinner, about 6:30 p.m., knowing they would ask if I was fasting. While not necessary for certain tests, it is required for an accurate blood glucose test. This wasn’t difficult, as it had been my nightly practice for months. The next morning, I skipped my usual black coffee even though the typical thinking is that black coffee won’t affect results. Anecdotally, I have observed short-term blood sugar spikes in people who drank beverages with caffeine, even black coffee. I looked into it and found research to back this up. While it’s not usually a big deal, I wanted the most accurate reading possible. Unfortunately, this came with a blinding caffeine headache.

The appointment went generally as I expected (good and bad), though I was pleasantly surprised to get my lab results back very quickly. My numbers looked healthy except for my total cholesterol and LDL. I have never had high cholesterol. How could this possibly be? I was eating well, exercising, and had lost weight. It should have been outstanding. The interesting thing was that my triglycerides and other numbers were fine.

So, I said to myself, “Dave, what was different? Why would your LDL go up?” (I didn’t really say this out loud. People would have stared.) The only thing that I could come up with was my coffee consumption. I like coffee. I mean, I really like coffee. I reflected on how much I thought I drank versus what I actually drank, and I realized that between what I made at home and what I consumed on the road and at coffee shops, I was drinking about a pot a day. Much more than I had drank in past years. OK, so what does that have to do with high LDL levels? Well, I happened to remember some articles I had read a while back about the relationship between coffee and high cholesterol.

First, let’s take a step back and talk about serum lipids, specifically LDL. When your doctor’s office sends your blood to a lab, they test total cholesterol, LDL, HDL, and triglyceride levels, among other things. LDL (high-density lipoprotein) is sometimes called the “Bad Fat” because it is associated with plaque build-up in your arteries. (Please don’t use this term around me.) So, the bottom line is that you want this number, along with triglycerides, to be lower, ideally below 100.

So, where does the cholesterol in your body come from? Generally, not from eating fat. Only about 20% comes from food. Most cholesterol is produced by the liver and intestines. Back in the 1960s, it was thought that consuming fat and cholesterol raised your serum cholesterol levels. It wasn’t until the 1990s that researchers challenged that. It was found that consuming things like eggs wasn’t so bad after all and had some benefits if not eaten to excess. In 2015, the USDA removed the 300 mg/day upper limit consumption guideline for cholesterol. Unfortunately, this is NOT a license to eat bacon at every meal. While eating some eggs and the occasional steak is not necessarily bad for your health, eating loads of saturated fat in combination with trans-fat can, however, raise your LDL and lower your HDL (you want this number higher), neither of which is beneficial. Remember, trans-fats are manufactured by adding hydrogen to an unsaturated fat, thereby “saturating” it and turning it from liquid to solid. You’ll see these in packaged food, fast food, and processed food. Yuk!

Here’s the thing. I wasn’t eating processed or fast foods. I ate very well. I was back to coffee as a culprit. So, is coffee actually bad for you? Please say it isn’t so. My regular readers might remember an article I wrote a while ago about the health benefits of coffee, one of the world’s most popular drinks. Coffee consumed in moderation, four cups or less, can be good for most people and has all sorts of health benefits. However, it turns out coffee may also have a bit of a dark side under certain circumstances. Coffee doesn’t contain any cholesterol, but it does contain oils called diterpenes, specifically cafestol and kahweol. Research has shown that these two substances may actually raise your LDL and total cholesterol numbers by interfering with how your body naturally processes cholesterol. Not to worry, at least in the US, as most American coffee makers use paper filters, which remove most of the diterpenes. In addition, even if you consume unfiltered coffee such as espresso or if you are like me and use a wire basket, you will be glad to know that as long as you are consuming coffee in moderation, your lipid levels should be unaffected. So, my hypothesis is that if I reduce my coffee consumption in general and use a paper filter, my LDL and total cholesterol should go down. Stay tuned; I’ll keep you posted on my results in a few months.