With the ongoing talk about cholesterol, it’s important to remember that the human body requires the stuff just to survive. As with many things in life, the issue is one of balance.
Cholesterol: What’s It Good For?
When some tissues are damaged, it is cholesterol that is needed for repair. The high-density lipoproteins (HDLs) are released by the liver into the bloodstream to assist with the cleanup of excess low-density lipoproteins (LDLs) and very low-density lipoproteins (VLDLs).
Since there was little cholesterol in the early human diet, humans adapted to produce their own cholesterol, with the liver as the factory. Flash forward a few thousand years, and cholesterol is present just about everywhere we as a society turn for food; from the church pot luck dinner to the acres of aisles at the local mega mart, to the express lane at just about any fast food place. With that in mind, it’s understandable why talk of cholesterol has remained a hot topic in mass culture over the past few decades.
As with blood pressure, it’s a good idea to “know your numbers” when it comes to cholesterol in the form of a blood cholesterol profile. The blood cholesterol profile is a combination of several factors, including the high-density lipoprotein (HDL), the low-density lipoproteins (LDL), triglycerides (TG), and total cholesterol, which is a combination of the previous factors.
Having a high overall cholesterol (>200 mg/dl) is a risk factor for developing cardiovascular disease, as is having a high LDL, a low HDL, or a low total-to-HDL ratio are all used to calculate risk of cardiovascular disease.
Putting the Pieces Together
If a triglyceride level is known, for example, it’s easy to calculate total cholesterol using these three variables. Simply divide the triglyceride level by 5 (or multiply it by 0.2) and then add the HDL and LDL to the product.
It is possible also to calculate a triglyceride level (for example, if there has been no blood test for triglycerides), by rearranging the equation to multiply the difference between lipoprotein levels and total cholesterol by 5.
For example, assume a total cholesterol of 200, and HDL of 50, and an LDL of 120. Summing the the HDL and LDL yields 170, which subtracted from the total cholesterol level of 200 yields 30. So, 30×5 reveals a triglyceride level of 150.
Cholesterol: Nature vs. “Nurture”
In general, serum cholesterol levels over 200 mg/dl are associated with an inherited tendency to produce excess amounts of LDLs, and/or an overconsumption of LDLs in the diet.
In the case of the inherited tendency toward high production of LDLs, the liver is overproducing cholesterol. Reducing the dietary intake of cholesterol by itself may not be enough produce optimal results. Because resistance exercise has a positive effect on lowering LDL levels and raising HDL levels, it is often encouraged for people who overproduce cholesterol. So even if we can’t direct the wind, we can still trim the sails.
On average, only about 25% of our cholesterol comes through dietary intake. But even if a person has no particular tendency to producing excess amounts of cholesterol on his or her own, food selection can often lead to higher than desirable levels of cholesterol. A preliminary dietary review can be enough to identify a client’s food choices as a potential cause of high serum cholesterol levels. In terms of a personal trainer’s practice, if a client’s food selections contain a considerable amount of saturated fat, recommending that he or she consult with the appropriate healthcare professional, as well as having a complete blood profile performed with an emphasis on total cholesterol and LDL levels, is warranted.
Both genetics and everyday choices play major roles in our cholesterol numbers. Fortunately, positive changes in exercise, diet and medication can control levels in most people in order to steer clear of cardiovascular complications.