High Levels of ‘Bad Cholesterol’ Associated With Greater Dementia Risk, New Study Finds

If you want to live a long, healthy life, one of your top priorities should be taking good care of your heart and brain. While it's no secret that these organs are critical for overall health and nearly every bodily function, many people, unfortunately, have lifestyles that are not only detrimental to their heart and brain health but also spike their risk of developing chronic diseases that afflict these essential organs, like heart disease and dementia. In fact, heart disease has been the top killer in America since 1950, and Alzheimer's disease (the most common form of dementia) ranks in the top 10 causes of death in the U.S. While some common dementia risk factors like age, genetics, and family history are out of your control, most of them are modifiable lifestyle factors. Translation? You have the power to adopt healthy lifestyle habits that lower your risk of developing these devastating diseases.

Healthy lifestyle habits that slow aging (e.g., regular exercise, healthy diet, proper sleep, avoiding alcohol and tobacco) can improve several biomarkers linked to higher disease risk. For example, your cholesterol levels are biomarkers associated with atherosclerosis—plaque formation in your arteries that sends your risk of cardiovascular disease soaring. Now, a November 2022 study published in Scientific Reports, found that having high levels of LDL cholesterol (the "bad" cholesterol) can elevate your risk of not only Alzheimer's disease but all types of dementia (of which there are over 100).

To find out how you can keep your cholesterol in check and help prevent cognitive decline as you age, we spoke with Kelsey Lorencz, RDN, registered dietitian nutritionist and nutrition advisor for Fin vs. Fin, who weighs in on how cholesterol can impact dementia risk. Plus, she shares some nuggets of wisdom on ways to boost your heart and brain health and add years to your life.

High LDL cholesterol increases dementia risk.

To arrive at these findings, researchers conducted a nationwide cohort study that examined the connection between cholesterol levels and dementia risk in the "presence of diabetes and statin use." The researchers evaluated Korean National Health Insurance Services data that included a whopping 6,883,494 people. All individuals included in the study had undergone health exams in 2009 and were 40 or older. Among the dataset, researchers found that 4% of the cohort developed dementia. In addition, those with high levels of LDL cholesterol displayed the greatest risk of dementia.

It's not just having high LDL cholesterol that's bad for you. Low levels of HDL cholesterol (the "good" cholesterol) can also lead to dementia. Lorencz says, "A March 2022 study found a link between low HDL cholesterol, high triglycerides, and high glucose levels from age 35 and dementia later in life. In the study, increasing HDL by 15 points between the ages of 35 and 50 decreased the risk of dementia by 15%."

This One Habit Can Help Fight Your Brain's Aging, New Study Says

Taking statins and having diabetes can affect brain health.

If you're one of the over 200 million people worldwide who take statin drugs for heart health, you could be at an increased risk of developing dementia. Besides high LDL cholesterol boosting dementia risk, the study also found that individuals who took statin drugs (cholesterol-lowering medication) were more likely to develop dementia. These findings aren't surprising, says Lorencz.

"Studies have found that high cholesterol is linked to developing vascular dementia and Alzheimer's, two of the most common forms of this debilitating disease."

Additionally, having diabetes can up your chances of cognitive decline—especially if it's type 2. "Type 2 diabetes is a risk factor for Alzheimer's, most likely because of its relationship to heart disease," says Lorencz. Past research has concluded that having diabetes is associated with significantly higher dementia risk.

Ways to boost your heart and brain health.

The best way to improve your heart and brain health while helping prevent dementia is to adopt a myriad of healthy lifestyle habits. Taking the following daily actions can slash your risk of chronic disease and boost overall health:

Eat a healthy, well-balanced diet: More whole foods, less processed junk.
Exercise regularly: Do both cardio and strength training exercises.
Get at least seven hours of sleep each night: Getting enough Zs is essential for healthy aging.
Keep a healthy weight: Carrying extra weight can impact your heart health and increase your risk of chronic diseases like dementia.
Watch your cholesterol: Keep your LDL cholesterol down and your HDL cholesterol up.
Manage your blood sugar: Eating a poor diet that consistently spikes your blood sugar can lead to diabetes, significantly increasing your risk of heart disease and dementia. Avoid smoking and limit alcohol consumption; need we say more?

Ultimately, diet and exercise are critical factors in reducing your risk of heart disease, dementia, and diabetes. "Eating a diet high in fiber and low in processed, sugary foods can encourage a healthy heart, blood sugar levels, and a healthy brain. In addition, making exercise a daily part of your routine can make a big difference in brain and heart health," says Lorencz. "Researchers analyzed 11 studies and found that regular exercise can decrease dementia risk by up to 30 percent. Additionally, the American Heart Association recommends 150 minutes of moderate-intensity aerobic exercise or 75 minutes of vigorous aerobic activity per week, which can lower the risk of heart disease by 20%."