High Cholesterol but Eat Healthy? When It's Genetic

You eat well, you move, and your LDL is still above the range on your lab report. That may have little to do with your plate: your body makes most of its cholesterol itself. You can keep your reports in a folder, or add them to the Health Vault in Sam, which reads the lipid values once you agree and, if both reports print the same unit, shows the three biggest changes since your previous report.

For what each line on the report means, see cholesterol results explained. This post is about the cause: why the number stays high, and how doctors check for an inherited form. What Sam keeps for high cholesterol is on the high cholesterol page.

Why is my LDL high when I eat healthy?

The German Heart Foundation says the body takes in only about a third of its cholesterol from food. It makes the other two thirds itself, mainly in the liver.

How much of that stays in your blood also depends on your genes. Cardiologist Ulrich Laufs, of the foundation's advisory board, calls cholesterol metabolism largely genetic and inherited. Slim, active people who eat well can still have high levels, notes the German pharmacy portal aponet.de.

IQWiG weighs it differently. It says cholesterol levels are mainly influenced by lifestyle: eating a lot of saturated and trans fats and not getting enough exercise, and very overweight people also often have high cholesterol. Whether genes play the bigger part for you is for your doctor to assess.

Some conditions and medicines also push cholesterol up. And some people have a clearly inherited form, familial hypercholesterolemia.

How much can diet really lower LDL?

Diet works, but by less than many people expect. Three German patient sources give a sense of scale. They are estimates from patient information and do not apply to everyone.

The starting point matters. People who eat a lot of fried food and are overweight see bigger changes, aponet notes. People who already eat well see smaller ones. For very high levels, diet often does not reach the target range.

A made-up calculation shows the scale. If LDL is 200 mg/dL, 10% is about 20 mg/dL. That is arithmetic, not a benchmark and not a forecast for you. Do not put off an appointment because a number looks fine.

Lifestyle still matters. IQWiG, Germany's independent health institute, lists not smoking, less saturated and trans fat and regular exercise. It says a healthy lifestyle can lower the risk of heart disease and stroke even with familial hypercholesterolemia. With FH, lifestyle alone is usually not enough, IQWiG says. What fits you is something to agree with your doctor.

Is high cholesterol genetic?

Partly, for many people, and strongly for some. The clearly inherited form is called familial hypercholesterolemia, or FH. A gene fault usually means the body makes too few LDL receptors, IQWiG explains. Cholesterol can then build up in the blood from childhood.

Estimates of how common it is vary.

• IQWiG puts the common form, inherited from one parent, at about 3 in 1,000 people.
• MedlinePlus (US National Library of Medicine) and the European guideline (ESC/EAS) both give 1 in 200 to 250.
• The guideline adds that only a small fraction of people with FH are identified and treated.

If one parent has FH, each child has at least a 50% chance of inheriting it, says IQWiG. Untreated, LDL in the common form is often above 190 mg/dL (4.9 mmol/L). The rare form, inherited from both parents, affects fewer than 1 in 100,000 people.

That 190 figure describes what is typical in FH. It is not a cut-off to check yourself against. A lower result does not rule out an inherited form, and a higher one does not prove it.

A second inherited blood fat is lipoprotein(a), or Lp(a). The European guideline says about 90% of a person's Lp(a) level is inherited. The German Lipid League adds that diet and exercise barely change it. Guidelines disagree on who should have it measured; the cholesterol results post covers that debate.

High cholesterol in your 30s: when do doctors think of FH?

A high result at a young age is not a diagnosis on its own. But it is a reason to look closer, because FH raises cholesterol from childhood. The European guideline lists situations in which doctors should look for FH.

• Very high total cholesterol without treatment, in you or an adult relative.
• Early coronary heart disease in you or a family member.
• Fatty lumps on tendons (tendon xanthomas) in you or a family member.
• Sudden early cardiac death in a family member.

The German GPs' guideline (DEGAM) recommends a one-off cardiovascular risk consultation between 18 and 35 when family risk is high.

These are tools for doctors. They are not a test you can run on yourself, and none of them applying is not an all-clear.

How do doctors check for familial hypercholesterolemia?

IQWiG says FH is usually diagnosed by a doctor, using these criteria.

• How high LDL is: the higher it is, the more likely FH becomes.
• Your own history, such as early heart or blood vessel disease.
• Close relatives with very high cholesterol or early cardiovascular disease.
• Visible fatty deposits on tendons or in the eye.

Doctors often combine these findings into a score. The European guideline describes the Dutch Lipid Clinic Network criteria. Points come from family history, personal history, examination, untreated LDL and a genetic test. DEGAM advises referral for specialist assessment above 5 points or when the Simon Broome criteria are met. Your doctor works out the score; a missing point is not an all-clear.

A genetic test can also confirm FH. IQWiG says it is mainly needed when the other criteria are not enough. It also cannot find every gene fault. Whether it makes sense for you is your doctor's call.

FH runs in families, so a diagnosis reaches beyond you. IQWiG says children of a parent with known FH are offered testing. First- and second-degree relatives are advised to get checked too. This is called cascade testing, and the European guideline says a lipid clinic is the best place for it. IQWiG says people with FH are advised to have treatment. Which treatment is a decision for you and your doctor.

Who should you see about inherited high cholesterol?

Start with your GP or primary care doctor. The NHS suggests asking your GP for a test if you have never had one and high cholesterol or heart problems run in your family. Your doctor looks at your overall risk of heart attack and stroke. Smoking, blood pressure and diabetes all count. The post on the first weeks after a high blood pressure diagnosis covers that side.

If FH looks possible, DEGAM recommends referral for specialist assessment. Two kinds of places specialise in this:

• A specialist lipid clinic, for example at a university hospital. In Leipzig, for example, cardiology, endocrinology and laboratory medicine run one together.
• A lipid specialist (lipidologist), a doctor with extra training in blood fat disorders.

Yellow patches on the eyelids or a ring around the iris: what do they mean?

You can't feel high cholesterol. At very high levels, though, it can leave deposits. IQWiG describes yellowish lumps around the Achilles tendons or above the eyelids, called xanthomas. A pale ring can also form at the edge of the iris.

Visible deposits on tendons or in the eye are a strong sign of FH, IQWiG says. They are most common in the rare form inherited from both parents. In the common form they only appear sometimes.

Not every patch or ring means high cholesterol, though.

• Yellow patches on the eyelids (xanthelasma): lipid levels are within the lab's range in about half of people with them, says the UK clinical reference GPnotebook. High cholesterol is more common when they appear young. GPnotebook says lipids should be checked in everyone who has them.
• A pale ring at the edge of the cornea (arcus): it is common with age. In children and young adults it can be a sign of high cholesterol, and the American Academy of Ophthalmology advises an eye exam. The Dutch Lipid Clinic Network score counts arcus before age 45.

If you notice any of these, mention them to your doctor.

Thyroid, kidneys, medicines: what else raises cholesterol?

Not every high result is inherited. IQWiG names diabetes, rheumatoid arthritis, an underactive thyroid and kidney or liver disease as possible causes. Some medicines can raise cholesterol slightly. In women, LDL may rise a little after menopause.

DEGAM asks doctors to consider these causes before starting treatment. It names an underactive thyroid, heavy drinking, poorly controlled diabetes, liver and kidney disease and medicine effects. So your doctor may order more blood tests, such as TSH, creatinine, eGFR or HbA1c.

The post on TSH results and hypothyroidism explains the thyroid values. Kidney test results covers creatinine and eGFR. For the medicines question, a full list helps, including anything bought over the counter. The post on what to put on a medication list sets it out.

The Health Vault in Sam also keeps TSH, fT4, creatinine, eGFR, HbA1c and ALT by name. You can keep your medicines in Sam's medication list.

Family history and old results: what helps at the assessment?

Much of what counts is not on your latest report.

• Your oldest lab report from before any treatment. The Dutch Lipid Clinic Network score uses untreated LDL.
• Your family history: whether a parent or sibling had a heart attack or stroke early in life. Very high cholesterol in a relative counts too.
• A list of everything you take.
• A photo, if you have noticed lumps on tendons, eyelid patches or a ring in the eye.
• Letters from earlier appointments or tests.

In Sam, older reports go into the Health Vault the same way as new ones. Letters from a lipid clinic can sit in the same place. Sam does not chart your lipid values over time. Some labs print separate ranges for women and men; then the range label in Sam can be wrong, so check the original report.

Sam keeps 33 lab values by name, including total cholesterol, LDL, HDL and triglycerides. Sam does not keep Lp(a) as a named value. If a report prints that line, Sam usually keeps it under its printed name. If one lab prints mg/dL and the other mmol/L, Sam does not compare that line. Sam files some rows under the wrong value, for example VLDL cholesterol under total cholesterol, so check the name and number of every row against the original report.

When to call an emergency number

High cholesterol does not usually cause symptoms. Chest pain or pressure, though, is always an emergency. Call your local emergency number straight away (112 in the EU, 999 in the UK, 911 in the US). The pain can feel tight or squeezing and spread to your arm, back, neck, jaw or upper abdomen. Shortness of breath, sweating or feeling sick can come with it.

The same applies to possible stroke signs. These include sudden weakness or paralysis, one side of the face drooping, slurred speech or other speech problems, and loss of sight or a gap in your field of vision. Call even if the signs have stopped. Do not wait for symptoms to pass. For urgent but not life-threatening problems when your practice is closed, use the out-of-hours service where you live.

Gather lab reports and letters for your appointment in Sam

You walk into the appointment with all your results, old ones included, instead of digging through folders.

• Instead of a folder: photograph each lab report or upload the PDF to the Health Vault. Once you agree, Sam reads total cholesterol, LDL, HDL and triglycerides. You check the name and number of every row before saving, because Sam files some rows under the wrong value.
• Instead of flicking through pages: if both reports print the same unit, Sam shows the three biggest changes between your last two reports. You see whether a value sits above or below your lab's printed range.
• Instead of loose letters: letters and results from a lipid clinic sit in the same place as your lab reports.

Sam doesn't measure cholesterol or calculate cardiovascular risk or an FH score. More on the high cholesterol page.

Try Sam for free

Sam is a wellness companion, not a medical device. The app does not diagnose, treat, cure or prevent any disease or health condition. Always consult qualified professionals for medical decisions.

Related reading

• Cholesterol results explained: LDL, HDL, triglycerides
• TSH results explained: hypothyroidism and your doctor visit
• Medication list for your doctor: what to include
• Kidney test results explained: creatinine, eGFR, albumin
• Doctor appointment checklist for a chronic condition

Sources

Updated: October 2026

• IQWiG (InformedHealth.org): Familial hypercholesterolemia (FH) (created 24 September 2025) and High cholesterol (updated 24 September 2025)
• MedlinePlus Genetics: Familial hypercholesterolemia
• Mach F et al.: 2019 ESC/EAS Guidelines for the management of dyslipidaemias, Eur Heart J 2020;41:111-188, sections 5.3.4, 5.5 and 9.1.2
• DEGAM: S3 guideline on GP cardiovascular risk counselling, version 2.1, short version (2025, in German)
• aponet.de: High cholesterol: why diet often does less than expected (16 July 2026, in German)
• German Heart Foundation via idw: Eggs and cholesterol (28 March 2024, in German)
• German Lipid League (DGFL): Information for patients (in German)
• Deutsches Ärzteblatt: Hamburg City Health Study on FH (5 May 2025) and Leipzig lipid clinic (22 January 2018), in German
• NHS: Getting tested for high cholesterol (13 March 2026), Heart attack (31 March 2026) and Stroke symptoms (12 September 2024), dates of last review
• GPnotebook: Xanthelasma (last reviewed 9 June 2026)
• American Academy of Ophthalmology: What is arcus senilis? (26 April 2019)