Can My Cholesterol Be Too Low?

It is possible for cholesterol to be too low, but it is very rare for low cholesterol to lead to health problems. 

Most cholesterol problems are associated with high low-density lipoprotein (LDL), or "bad" cholesterol, but some people can also have very low levels of LDL cholesterol. Some health experts believe that low LDL can cause can cause problems like anxiety, nervousness, or sleep problems. Others believe that for LDL, lower numbers are always better.

It is also possible to have levels of high-density lipoprotein (HDL) cholesterol or "good" cholesterol that are too low.

This article explores the role of HDL and LDL, what happens if either number drops "too low," and what you can do to keep your cholesterol levels in the right place.

Can Cholesterol Be Too Low?

Low levels of HDL cholesterol can put you at risk for certain health conditions, but some researchers also believe your LDL cholesterol can be too low.

LDL is a lipoprotein whose role it is to deliver lipids to every cell in the body. Cholesterol is a critical component of cell membranes, serves as a brain antioxidant, and is used by the body to create the hormones estrogen, progesterone, and testosterone. It is also important for making certain vitamins and plays a role in digestion and metabolizing nutrients.

When LDL cholesterol is too low, some of these important functions may not work as well as they should.

What Causes Low Cholesterol?

It is possible to have levels of both "good" cholesterol (HDL) and "bad" cholesterol (LDL) that are too low.

Low HDL Cholesterol

There are many reasons why your HDL levels may be low. Chief among these is a high-carbohydrate diet. A diet of this sort not only affects your blood sugar, increasing the risk of insulin resistance. It can also lower your HDL while raising both your LDL and triglycerides by 30% to 40%.

Other factors associated with low HDL levels include:

• Elevated triglycerides
• End-stage kidney disease
• High-dose beta blockers
• High-dose thiazide diuretics
• Obesity and metabolic syndrome (which can lead to cardiovascular problems, heart attack, stroke, and diabetes)
• Sedentary lifestyle
• Severe liver disease
  
• Smoking
• Tangier disease, a rare genetic disorder associated with a severe, chronic reduction of HDL
• Type 2 diabetes

Malnutrition can also contribute to chronically low HDL levels.

Low LDL Cholesterol

Most of the time, lifestyle changes that lead to lower LDL levels are good for your health. However, when cholesterol levels drop in the absence of these efforts (hypobetalipoproteinemia), it can indicate a health problem such as:

• Thyroid disease
• Cancers of the blood
• Infections such as hepatitis C
• Malnourishment or poor nutrition
• Chronic inflammation
• Genetic disorders
• Cholesterol-lowering medication
• Wasting disorders

These are uncommon occurrences. Far more commonplace is the likelihood of people taking medication to lower their cholesterol. This may be an option if someone's LDL level is 190 mg/dL or higher. There has been some concern that these medications may drop LDL too low.

In two large medical trials, though, researchers found that low LDL isn't an issue. Some participants recorded LDL levels of 25 mg/dL or even lower—and reported no negative side effects.

What Are the Risks of Low Cholesterol?

From the standpoint of heart health, a total cholesterol level can never be too low. However, HDL and LDL cholesterol levels can be too low, and may cause different kinds of health problems.

Risks of Low HDL

HDL that drops below 40 mg/dL is considered too low. Quite simply, the less HDL there is in your blood, the less cholesterol you can clear from the body. This, in turn, increases the risk of atherosclerosis (hardening of the arteries), heart attack, and stroke.

Risks of Low LDL

While it would be fair to assume that low LDL is a good thing, there are circumstances in which chronically low levels may not be desirable.

Very low LDL levels during pregnancy may trigger hormonal imbalances that contribute, at least in part, to premature birth.

Some studies suggest that people who have very low cholesterol may experience anxiety, depression, and other mental health conditions.

Some studies have also found that people who have very low cholesterol are at greater risk for developing certain kinds of cancer. Others have found that low cholesterol may be associated with depression and risk of suicide.

However, it is important to note that more research is needed to determine whether these effects are caused by low cholesterol or by other things like side effects of drugs used to treat high cholesterol.

What Are the Symptoms of Low Cholesterol?

Research into the health effects of low LDL cholesterol are ongoing. If low LDL contributes to a condition like depression or anxiety, you may experience:

• Feelings of hopelessness and despair
• Changes in sleeping or eating habits
• Confusion and agitation
• Difficulty making decisions
  

Normal Cholesterol Levels

HDL and LDL levels can (and should) be measured with a simple blood test. For the average American adult, the values, measured in milligrams per deciliter (mg/dL), can be put in perspective as follows:

• HDL values of 60 or higher are considered "good" while anything less than 40 is considered "low." Levels above 80 are considered too high and may increase all-cause mortality.
• LDL values under 100 are considered "optimal," between 100 and 129 are "near optimal," between 130 and 159 are "borderline," and 160 and over are "high." For people who have had a heart attack, stroke, coronary artery disease, the optimal LDL should be less than 70.
  

Meanwhile, the American Heart Association and the American College of Cardiology support LDL levels of 100 mg/dL or less. People who are in this range tend to have lower rates of heart disease and stroke.

Other measurements on a cholesterol test include triglycerides, a type of fat in the blood, and total cholesterol, the total amount of LDL, HDL, and triglycerides.

How to Keep Cholesterol at a Normal Level

It's often difficult to manage low cholesterol with anything other than diet or lifestyle. There are currently no medications able to raise HDL (with the exception of hormone replacement therapy in people who have gone through menopause).

Beyond this, the best ways to get your cholesterol within normal limits is to:

• Avoid saturated fat and trans fat
• Eat plenty of fruits, vegetables, whole grains, and nuts
• Exercise regularly
• Limit red meat, processed foods, sugar, and processed flour
• Lose weight if you're overweight
• Stop (or don't start) smoking
• Take statin medications, if prescribed
  

Aim to keep your total cholesterol within the middle range, or somewhere between 150 and 200 mg/dL. And continue monitoring your levels as directed by your healthcare provider.

Cholesterol Healthcare Provider Discussion Guide

Get our printable guide for your next healthcare provider's appointment to help you ask the right questions.

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Current Dietary Recommendations

You may have formed the idea that you need to avoid all dietary cholesterol. But that's not necessarily so. Specific daily cholesterol limits were removed from dietary guidelines because there isn't much evidence that cholesterol from diet affects blood cholesterol levels.

Cholesterol is a fat, and you need fat in your diet. It's the type of cholesterol-containing foods we eat that influence our risk for cardiovascular disease and cardiovascular-related illnesses. Unfortunately, most foods that are high in cholesterol are also high in unhealthy fats.

Cholesterol is just one measure of heart health. So put the full picture into perspective and choose foods with “good” unsaturated fats, avoid “bad” trans fats, and limit foods high in saturated fats:

• “Good” unsaturated fats are the monounsaturated and polyunsaturated fats that can lower your risk for heart disease. You can find these good fats in oils like olive, canola, sunflower, soy, and corn oil. Good fats are also present in fish, nuts, and seeds.
• Trans fats are "bad" fats that can increase your risk for disease even when they're consumed in small amounts. They've mostly been removed from packaged processed foods, but fried foods may contain them.
• Saturated fats aren't as unhealthy as trans fats, but they should be consumed in small doses. You should limit saturated fats from sources like red meat, fast food, and pizza.

By and large, foods that are high in cholesterol tend to be high in saturated fat, the latter of which significantly increases the risk of cardiovascular disease (CVD).

On the other hand, eggs and shellfish are high in cholesterol but low in saturated fat, making them an ideal source for the cholesterol our bodies need.

Summary

It can be tricky to keep "good" (HDL) and "bad" (LDL) cholesterol straight. HDL values of 60 or higher are considered "good" while anything less than 40 is considered "low." Meanwhile, LDL values under 100 are considered "optimal," between 100 and 129 are "near optimal," between 130 and 159 are "borderline," and 160 and over are "high."

Low HDL levels can lead to heart disease, but researchers often disagree whether it's possible for LDL levels to fall too low. A growing pile of research suggests that "lower is better" when it comes to LDL levels.