What is a healthy cholesterol level and when should I be concerned?
A normal LDL value does not give a complete picture of your cardiovascular risk. Ask your doctor about your remnant cholesterol as well, especially if cardiovascular disease or Alzheimer's disease runs in your family.
Cholesterol is essential for cell membranes, hormones and nerve tissue. Most attention goes to LDL ('bad') and HDL ('good'), but there is a third fraction that is often overlooked: remnant cholesterol. This is calculated as total cholesterol minus LDL minus HDL. Research in humans shows that it is an independent risk factor for atherosclerosis, even when your LDL is normal.
Concretely: people with a normal LDL but an elevated remnant cholesterol had their carotid artery wall thickened almost twice as often, an early sign of atherosclerosis1. A normal LDL figure on your blood test therefore does not tell the whole story.
In addition to the amount of cholesterol, how your body transports it also matters. The genetic variant APOE4, which increases the risk of Alzheimer's disease, clears cholesterol from brain cells less efficiently. In cell studies, this leads to an accumulation of cholesterol and higher levels of proteins associated with Alzheimer's disease2. This is cell research, not evidence in humans. If you have a family history of Alzheimer's disease or carry APOE4, that is an additional reason to discuss this with your doctor.
In mouse studies on ALS, an excess of cholesterol in the nervous system led to poor protection of nerve fibres. Treatment with a cholesterol-binding agent extended lifespan in female but not male mice3. It was also found that immune cells tasked with clearing cancer cells have a cholesterol deficiency, while tumour cells themselves are cholesterol-rich4. Neither finding has yet been translated into treatments in humans.
The evidence for a link between cholesterol and anxiety or depression is extremely thin. In a study of 85 patients with panic attacks, anxiety disorder or depression, no meaningful differences in total cholesterol were found5. This is therefore not something you need to worry about.
All claims are based on the provided PMIDs. Most studies are observational or experimental (cell and mouse research). There is no randomised controlled trial in this set. The study on carotid artery plaques includes only 63 patients. Causal relationships cannot be established on the basis of this material.
Should I be worried about a mildly elevated cholesterol if everything else looks fine?
A mildly elevated cholesterol is not automatically harmless: the overall picture, including triglycerides and lipoprotein(a), determines your risk. Have those values measured and discuss them with your doctor if cardiovascular disease runs in your family.
What is a healthy HDL (good cholesterol) level, and can I raise it?
Raising HDL through lifestyle is possible, but your genes set the ceiling. Lowering triglycerides through less sugar and alcohol, more exercise, and weight reduction has the greatest effect.
Are eggs bad for your cholesterol?
Eggs are not automatically bad for your cholesterol; the rest of your diet, especially the amount of saturated fat, carries more weight. If you have high LDL, diabetes or a family history of cardiovascular disease, discuss your egg consumption with your doctor.
What is a healthy waist circumference and why does it matter?
A larger waist circumference is associated with a greater risk of diabetes, bone fractures, gum disease and premature death. That risk is greatest when other risk factors are also present, such as high blood pressure or elevated blood sugar.
What does high cholesterol do to your brain as you age?
High cholesterol in middle age likely increases the risk of dementia, but at older ages the relationship is less clear and cholesterol-lowering drugs have not been proven effective for the brain. Stable cholesterol appears wiser than strongly fluctuating values; discuss your risk profile with your doctor if you are concerned.
Can your gut microbiome affect your cholesterol?
Your gut microbiome influences your cholesterol through bile acid conversion and the fermentation of fibres. Eating more fibre is the most concrete and safe step to take; supplements such as berberine are not yet sufficiently substantiated for daily use.