Statins are one of the top medications recommended, as many people take it to lower cholesterol levels. While many doctors are concerned about high cholesterol levels, very rarely do medical doctors express any concern over low cholesterol levels. But it is possible for your cholesterol to get too low. In this blog post I’ll discuss some of the common causes of low cholesterol, the risks associated with low cholesterol, and what you can do to increase it.
But what level of total cholesterol is considered to be optimal? Before revealing this, I’d like briefly discuss what cholesterol is, and why it’s important. Cholesterol is a waxy substance that is manufactured by the liver, although we obtain some cholesterol from certain foods, including meat, poultry, and full-fat dairy products. Cholesterol has many important functions, as it is a vital component of cell membranes, it’s a precursor to all of our steroid hormones, as well as to vitamin D and bile acids, and it has other important functions. But even if we focus on the roles I specifically mentioned here, it should be easy to understand why having healthy cholesterol levels is important, and why it can be harmful if your cholesterol gets too low.
For example, regarding the steroid hormones, pregnenolone is a precursor to both progesterone and DHEA. As a result, if pregnenolone is low, then both progesterone and DHEA will also be low. Progesterone in turn is a precursor of 17-OH progesterone, which is a precursor of cortisol, whereas DHEA is a precursor of testosterone, which converts into estradiol. So if someone has low or deficient pregnenolone levels, then they can be deficient in all of these hormones I mentioned.
The reason why I’m bringing this up here is because cholesterol is converted to pregnenolone in the mitochondria. Thus, if someone has very low cholesterol levels, they very well might have low pregnenolone levels. And while having the person take pregnenolone may help to increase the other hormones, the primary goal should be to increase the cholesterol levels.
Why Are Many People Concerned About High Cholesterol Levels?
Although the focus of this blog post is on the risks associated with low cholesterol levels, I think it’s important to discuss why many people, including most medical doctors, are concerned with cholesterol being too high. Of course the answer is that many are concerned about high cholesterol causing cardiovascular disease. Keep in mind that elevated levels of total cholesterol and LDL alone aren’t strongly associated with heart disease. On the other hand, low HDL levels are a concern, and LDL particles (LDL-P) and lipoprotein a LP(a) are superior markers for determining if someone is at risk for cardiovascular disease. The point here isn’t to completely dismiss high total cholesterol and LDL as being risk factors, but if these are high you should consider additional testing.
Other Risks of Low Cholesterol
Earlier I mentioned the important role cholesterol plays, and thus the consequence of having low cholesterol levels. However, I also want to dive into some of the research. Cholesterol seems to play a role in the neuron membranes, specifically regarding the function of the 5-HT1A serotonin receptor (1) [1]. The significance of this is that a large decrease in total cholesterol and other lipid markers (LDL, VLDL, and triglycerides) is associated with depression and suicide attempt (1) [1]. Another study looked at the relationship between low cholesterol and mortality, and found that low cholesterol was related to high mortality, while high cholesterol was not a risk factor for mortality (2) [2]. A case-control study showed that low cholesterol is a risk factor for primary intracerebral hemorrhage (3) [3]. Yet another study showed that low cholesterol was strongly associated with criminal violence, as violent criminals had significantly lower cholesterol than others identical in age and sex (4) [4].
What Are The Causes of Low Cholesterol?
There are two main types of hypocholesterolemia. Primary hypocholesterolemia is due to genetic factors, as there can be genetic defects that affect cholesterol absorption, as well as genetic defects affecting cholesterol biosynthesis or metabolism (5) [5]. If you have always had low total cholesterol and LDL-C levels on a lipid panel, then there is a good chance that genetics is the main factor.
Secondary hypocholesterolemia is acquired, and here are some of the common causes (1) [1]:
- Hyperthyroidism. It is very common for people with hyperthyroidism and Graves’ disease to have low total cholesterol and LDL levels. Cholesterol 7 alpha hydroxylase is an enzyme that plays a role in the metabolism of cholesterol. In hyperthyroidism this enzyme is increased, which is what leads to lower serum cholesterol levels (6) [6].
- Statins. Not surprisingly, taking statins can lead to low cholesterol levels. This of course is the main reason why statins are prescribed.
- Liver disease. Since cholesterol is manufactured by the liver, it makes sense that liver disease can result in low cholesterol levels.
- Malabsorption. The intestine plays an important role in the regulation of cholesterol absorption. Pancreatic insufficiency is one condition that can cause cholesterol malabsorption (7) [7]. Bile acid malabsorption can also lead to lower cholesterol levels (8) [8]. Celiac disease is also associated with hypocholesterolemia, although if someone has Celiac disease then a gluten free diet can help to normalize cholesterol levels (9) [9].
- Acute or chronic infection. Acute and chronic bacterial, viral, and parasitic infections all might induce hypocholesterolemia due to the chronic effect of proinflammatory cytokines on lipoprotein metabolism (10) [10]. In addition, parasites feed on host cholesterol, which is another way that parasitic infections can cause low cholesterol levels (10) [10] (11) [11].
- Anemia. Although I can’t say that every patient I’ve worked with who had anemia also has had high cholesterol levels, the research does show a correlation (12) [12] (13) [13].
How Is Hypocholesterolemia Diagnosed?
Both high and low cholesterol levels are typically measured through a standard lipid panel. This looks at the following markers:
- Total cholesterol
- Low-density lipoprotein (LDL)
- High-density lipoprotein (HDL)
- Very low-density lipoprotein (VLDL)
- Triglycerides
Regarding high cholesterol levels, keep in mind that an elevated total cholesterol and/or LDL doesn’t mean that you are at an increased risk of developing cardiovascular disease. There are other “advanced” lipid markers that can help with this, and I discussed this in an article entitled “LDL Particles, Lipoprotein A, and Thyroid Health [14]”. On the other hand, a standard lipid panel can help determine if your cholesterol levels are too low.
What Is The Optimal Level of Total Cholesterol?
For total cholesterol, most labs have a reference range of <200 mg/dL. Because they don’t give a lower limit, this gives many people (including doctors) the impression that the lower their cholesterol levels the better. But as I presented in the research earlier, there are risks of cholesterol being too low. Many natural healthcare practitioners, including myself, don’t want to see the total cholesterol below 150 mg/dL. And I’d say that the “optimal” reference range is around 180 to 200 mg/dL. I should also add that I don’t get too concerned when someone’s total cholesterol is above 200 mg/dL, especially if it’s less than 250 mg/dL.
Can Cholesterol Levels Be Increased Through Diet?
Many people still believe that eating foods high in cholesterol (i.e. red meat, eggs) will have a big impact on our cholesterol levels, and perhaps even lead to elevated cholesterol. The truth is that the body does a great job of regulating cholesterol production, as if we consume a lot of dietary cholesterol the liver will make less, and vice versa. So for someone who has low cholesterol levels, eating foods that are higher in cholesterol may slightly increase total cholesterol levels, but it usually won’t have a significant impact.
So what can help to increase low cholesterol levels? Assuming primary hypocholesterolemia isn’t the main culprit, then the goal should be to address the cause of the problem. For example, if I’m working with a hyperthyroid patient who has low cholesterol levels, then we of course would want to decrease the thyroid hormone levels, and this in turn will usually result in the cholesterol levels increasing. If malabsorption is the problem then the cause of the problem needs to be addressed, whether this is due to an infection, Celiac disease, or another factor.
In summary, cholesterol has many important functions, which is why you don’t want it to be too low. Some of the causes of low cholesterol include hyperthyroidism, statins, liver disease, malabsorption, infections, and anemia. Eating foods high in cholesterol may slightly increase cholesterol levels, but if someone has low cholesterol they ultimately need to address the cause of the problem.