8 surprising facts about cholesterol
There's more to cholesterol than just diet. From hormones to menoapuse, here's eight surprising ways your health can affect your cholesterol levels.
Thinking about checking your cholesterol levels?
High cholesterol doesn’t come with symptoms but is one of the leading risk factors for stroke and heart disease. The best way to keep an eye on your levels is with a blood test, such as our Cholesterol Blood Test, which gives you a full cholesterol profile.
For an even more in-depth look at your health, you could try our Optimal Health Blood Test which, besides a full cholesterol panel, checks advanced heart health markers, hormones, thyroid, and more.
Cholesterol. It’s a word we hear often, bringing thoughts of ‘good’ or ‘bad’, fatty foods, and heart health. We know that high cholesterol is a major risk factor for heart disease, but did you know most cholesterol in our bodies doesn’t actually come from food? Or that your hormones can affect your cholesterol levels?
Read on for eight surprising facts about cholesterol and what they could mean for you.
1. Most of the cholesterol in your body doesn’t come from your diet
We often think of food choices when we hear about having healthy cholesterol levels. But only about 20% of the cholesterol in our bodies comes from the food we eat [1,2].
The remaining 80% of the cholesterol in the body is produced by the liver. So, what’s the link with food? Well, diets high in saturated and trans fats affect how the liver handles cholesterol, leading to higher levels in the blood. In fact, trans fat increases the risk of heart disease by increasing levels of ‘bad’ cholesterol, known as low density lipoprotein or LDL cholesterol, and lowering levels of ‘good’ or high density lipoprotein (HDL) cholesterol in the blood.
You can read more about the different types of cholesterol and what they mean for your health, in our blog.
Top tip: Where possible swap saturated fats such as fatty meat, butter, and cakes, for unsaturated fats like nuts and oily fish, and include lots of fibre-rich foods like wholegrains, legumes and veggies. The Mediterranean diet is a good set of guidelines to follow.
2. Your brain can make its own cholesterol
The brain has a higher cholesterol content than any other organ. Most of the cholesterol is in the myelin sheaths that surround the axons of nerve cells (a fatty coating that protects your nerve cells), which helps the transmission of electrical impulses that control our thoughts, actions and movement. Because cholesterol is too big a molecule to cross the blood-brain barrier, the brain can make all its own cholesterol in situ.
That doesn’t mean blood cholesterol is irrelevant to brain health. Research suggests that high LDL cholesterol is linked to declining cognitive health, although exactly how isn’t fully understood. However, it’s likely to involve damage to the blood vessels that supply the brain, and potentially cause changes in the way the brain handles cholesterol. Studies have shown that abnormal cholesterol levels are linked to conditions such as Alzheimer’s, Parkinson’s, and Huntington’s [1].
3. Taking steroids can affect cholesterol levels
One of the side effects of taking anabolic steroids or too much testosterone replacement is the impact on heart disease risk. There are a few direct and indirect ways use of steroids can contribute to the development of heart disease.
Anabolic steroids can cause abnormal cholesterol, increasing your LDL levels and decreasing good HDL cholesterol levels. Not only is it the unfavourable movement of HDL and LDL that is important, but how this affects the ratio of total cholesterol to HDL. This ratio is an indicator of cardiovascular disease risk and although this ratio can return to normal levels after stopping steroids, atherogenesis (fat deposition in the vessel walls) may have already occurred.
Top tip: If you’re on testosterone replacement, it’s a good idea to check your cholesterol levels regularly. The experts at Leger Clinic have good resources for people on TRT or considering it.
If you’re using anabolic steroids, it’s also important to keep an eye on your cholesterol and general health and be open with your doctor about what you’re taking.
4. Almost half of the UK have raised cholesterol levels
According to HEART UK over half of all adults in England have raised cholesterol, a major risk factor for the development of heart disease and stroke. There are no obvious telltale signs of high cholesterol in the body. Because of this, it is very important to regularly monitor your levels to make sure you are not at risk.
Top tip: Medichecks' Cholesterol Blood Test is a good way to measure triglycerides, LDL and HDL cholesterol levels as well as determining your risk of heart disease based on the ratio of HDL to total cholesterol.
5. Your hormones can affect your cholesterol levels
Hormonal imbalances in the body can negatively affect cholesterol levels. Conditions such as PMOS (polyendocrine metabolic ovarian syndrome, formerly known as PCOS), diabetes, and hypothyroidism can all affect your lipid health.
PMOS
PMOS is a common condition that affects how a woman's ovaries work. The exact cause of PMOS is unknown but it is related to abnormal hormone levels in the body. Approximately 70% of women with PMOS have dyslipidaemia (abnormal blood fats), which commonly includes high levels of triglycerides and low levels of HDL cholesterol.
You can learn how to calculate your triglyceride to HDL cholesterol ratio in our blog.
Diabetes
According to Heart UK, having diabetes is considered a risk factor for heart and circulatory disease because those with diabetes are less efficient at processing cholesterol. Diabetes tends to lower 'good' cholesterol levels and raise triglyceride and 'bad' cholesterol levels, which increases the risk of heart disease and stroke.
Hypothyroidism
An underactive thyroid (hypothyroidism) occurs when the thyroid gland does not produce enough of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Thyroid function significantly affects lipoprotein metabolism and hypothyroidism has an unfavourable effect on lipids as well as several other cardiovascular risk factors. If thyroid levels are low, the body isn’t able to break down and remove LDL cholesterol as efficiently as usual. LDL cholesterol can then build up in your blood.
Top tip: If you are living with one of these conditions, it is a good idea to make cholesterol checks part of your annual healthcare routine. Ask your GP or take a Cholesterol Blood Test from the comfort of your home.
6. You can be young and fit, and still have high cholesterol
High cholesterol isn't just a lifestyle problem. Around 1 in 250 people have familial hypercholesterolaemia (FH), an inherited condition that raises cholesterol from birth. People with FH can have very high cholesterol even if they eat a healthy diet.
Like other types of high cholesterol, FH usually has no symptoms, so many people don't know they have it [23]. Left untreated, it significantly raises the risk of heart disease at a young age, but with treatment, life expectancy can be normal [21, 23].
Because FH runs in families, if one person is diagnosed, their close relatives are usually offered testing too [21].
Additionally, even if you are young and exercise regularly, eating a diet high in saturated fats can cause raised cholesterol.
Top tip: Get your cholesterol checked and tell your GP about your family history if a close relative had heart disease before the age of 55 has very high cholesterol, or FH.
7. Menopause and cholesterol changes often go hand in hand
The risk of heart disease increases with age in men and women, but after menopause the risk for women is higher than men.
As your oestrogen levels naturally fall around menopause, you might find your levels of LDL and total cholesterol rise. Oestrogen helps keep LDL in check, so as it drops, your LDL and total cholesterol often go up, and the biggest jump tends to happen in the year either side of your last period.
HRT can improve cholesterol for some women, with oestrogen tending to lower LDL. The effect depends on the type and how it's taken, and HRT isn't prescribed to treat cholesterol alone. If you're going through perimenopause or menopause, it's worth checking your cholesterol and discussing the full picture with your doctor, or menopause specialist
Top tip: Lifestyle changes such as exercise, stopping smoking, and eating a healthy diet can decrease your risk factor. If you’re concerned about your heart risk reach out to your GP.
For specialist advice about menopause, the experts at My Menopause Centre have a wealth of resources, or you can book a consultation for personalised care.
8. There’s more to cholesterol than just a number
While healthy cholesterol levels is certainly a good goal, it’s not the only factor to consider – cardiovascular conditions are closely associated with other markers, such as inflammation and lipoproteins.
Some key markers to keep an eye on:
- Apolipoprotein B (ApoB)
- Lipoprotein(a) (Lp(a))
- Hs-CRP
Top tip: If heart conditions run in your family ask your GP about checking the markers above. Or if you feel like taking your health into your own hands, our Advanced Heart Disease Risk Blood Test can give you an in-depth review of your heart markers.
Take control of your heart health
You can't feel high cholesterol, but you can measure it. Knowing your numbers is the first step to lowering your risk, and small changes to diet, activity, and sleep can make a real difference.
References
- HEART UK – The Cholesterol Charity. What is cholesterol? [Internet]. Maidenhead (UK): HEART UK; [cited 2026 Oct 14].
- Corliss J. How it’s made: Cholesterol production in your body [Internet]. Boston (MA): Harvard Health Publishing; 2017 Feb 6 [cited 2026 Oct 14].
- NHS. Fat: the facts [Internet]. London: NHS; 2023 Apr 14 [cited 2026 Oct 14].
- Jin U, Park SJ, Park SM. Cholesterol metabolism in the brain and its association with Parkinson’s disease. Exp Neurobiol. 2019;28(5):554–567. doi: 10.5607/en.2019.28.5.554
- Shin KC, Ali Moussa HY, Park Y. Cholesterol imbalance and neurotransmission defects in neurodegeneration. Exp Mol Med. 2024;56(8):1685–1690. doi: 10.1038/s12276-024-01273-4
- British Dietetic Association. Cholesterol: Food Fact Sheet [Internet]. Birmingham (UK): BDA; 2026 Jul [cited 2026 Oct 14].
- Bond P, Smit DL, de Ronde W. Anabolic–androgenic steroids: How do they work and what are the risks? Front Endocrinol (Lausanne). 2022;13:1059473. doi: 10.3389/fendo.2022.1059473
- HEART UK. HEART UK – The Cholesterol Charity [Internet]. Maidenhead (UK): HEART UK; [cited 2026 Oct 14].
- Song DK, Lee H, Sung YA, Oh JY. Triglycerides to high-density lipoprotein cholesterol ratio can predict impaired glucose tolerance in young women with polycystic ovary syndrome. Yonsei Med J. 2016;57(6):1404–1411. doi: 10.3349/ymj.2016.57.6.1404