Dietary Cholesterol & Heart Disease: What’s The Link?
Arko Provo Ghosh
A few decades ago, the health industry was rocked by claims that dietary cholesterol leads to an increase in serum cholesterol and is responsible for an elevated risk of cardiovascular diseases. Cut to 2020 and followers of the Low Carb movement can’t stop adding butter into their coffee. So, what’s the truth? Let’s see what research has to say. What is Cholesterol? Cholesterol comes under the sterol type of lipids and has a multi-ringed structure which makes it different from other lipids. It has several functions in the body and it is the major component required to form and sustain some hormones. In addition, it supports brain health and the functioning of the nervous system. Cholesterol has often been linked to cardiovascular diseases. But here’s the problem: it’s always the total cholesterol count which is taken into consideration. The facts are a little more nuanced. It’s important to consider the ratio between the two lipoproteins, HDL (High-Density Lipoprotein) and LDL (Low-Density Lipoprotein). The HDL cholesterol particle is dense compared to other cholesterol particles, so it’s called high density. It helps scavenge and remove LDL, and even recycles LDL by transporting them to the liver where they can be reprocessed. This is important since LDL collects on the walls of blood vessels and increases the chance of heart diseases. That’s why HDL is called “Good Cholesterol” while LDL is labelled “Bad Cholesterol”. We’re interested in science and not labels. Science tells us to look at the ratio between HDL and LDL while considering the cholesterol levels. This ratio of low serum levels of LDL and high serum levels of HDL is known to support the concept of a good cholesterol level. Food & Cholesterol: Before dietary fats came back into vogue, all of us were told to discard egg yolks because they contain cholesterol. In fact, many people still hold this belief and impose arbitrary restrictions such as “Don’t eat more than 2 eggs a day”. A meta-analysis organized by Missimer et al found that the intake of two eggs a day doesn’t harm the heart disease biomarkers. While considering the cholesterol level, we need to consider the ratios between HDL and LDL. The study found that the ratio remained constant even in those people who consumed more than 2 eggs a day. In another study, a 6-week trial was conducted to investigate the effects of eggs on patients with coronary heart diseases. One group ate breakfast consisting of 2 eggs while the other group consumed a breakfast that was high in carbohydrates. The results indicated that there was no difference in the lipid profiles of these two groups. Similarly, in another year-long study, groups were served with egg-enriched meals and the results reported that total cholesterol, LDL, and HDL cholesterol, as well as the total cholesterol to HDL cholesterol ratio, were not different between the two groups. What does this tell us? Food items that are high in cholesterol include eggs, meats, shrimps, and cheese. Egg yolk contains around 210 mg of cholesterol and many other important micronutrients. People often blame eggs for causing elevated serum cholesterol while the fact is that research does not support this claim. Multiple meta-analyses have proven the fact that dietary cholesterol does not increase serum cholesterol nor the risk of cardiovascular diseases. So, the next time someone tells you not to eat egg yolks, you know what to do! Sources: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6024687/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520795/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5946211/ https://www.webmd.com/heart-disease/ldl-cholesterol-the-bad-cholesterol#1 https://www.webmd.com/cholesterol-management/guide/hdl-cholesterol-the-good-cholesterol