Understanding cholesterol: What is it, why it matters, and how to control it
Understanding cholesterol: beyond the basics
You’ve had your results. Maybe you’ve been told your cholesterol is “a little high” – or you’re already on statins and wondering if there’s more to the picture. Perhaps you have a family history you’d rather not repeat, and you want to understand what’s actually going on before it becomes a problem.
Whatever brought you here, you’re asking the right questions. Because cholesterol is one of the most talked about health markers and one of the most misunderstood.
The standard conversation goes like this: LDL is bad, HDL is good, keep your total number below 5, take a statin if needed. And while that’s not wrong exactly, it misses most of what actually matters.
Rarely, in a GP appointment are you discussing particle size, oxidation, inflammation, insulin resistance, or nutrigenomics (how food and nutrients influence gene expression). The things that explain why two people with identical LDL readings can have completely different cardiovascular risk.
This page gives you the foundation: what cholesterol really is, what drives it, and what the numbers on your blood test are – and aren’t – telling you.
What is cholesterol?
Cholesterol is a waxy, fat-like substance found in your blood and cells. It’s essential for the body to function as it helps make cell membranes, hormones, and vitamin D.
It also produces bile, which enables the body to digest fats.
However, too much cholesterol can increase your risk of heart disease and stroke.
The different types of cholesterol
This is where things can get a little confusing! Cholesterol is largely misunderstood because there are several different types that can affect the body in different ways, including:
- Low-Density Lipoprotein (LDL) – “Bad” Cholesterol
- High-Density Lipoprotein (HDL) – “Good” Cholesterol
- Triglycerides – the one that really matters
- Very Low-Density Lipoprotein (VLDL)
- Non-HDL Cholesterol
Let’s look at these a little more closely…
Low-Density Lipoprotein (LDL) – "Bad" Cholesterol
Firstly, let’s clarify what a lipoprotein is. It’s not cholesterol but a carrier of fats (lipids) and cholesterol, through the bloodstream, and its name identifies its role as a carrier.
You’ve likely heard LDL cholesterol referred to as “bad” cholesterol. This is because LDL is the form that carries fats and cholesterol from the liver to cells, tissues, and organs like the adrenals, gonads, muscle, etc. It’s this direction of transfer that classes LDL as “bad” but it’s more nuanced than that. Whether LDL is genuinely harmful depends on particle size, oxidation, and inflammatory context – not the number alone.
High-Density Lipoprotein (HDL) – "Good" Cholesterol
HDL cholesterol is often referred to as “good” cholesterol. It’s given this name because it is the carrier of cholesterol from the bloodstream to the liver, where it is processed and eliminated from the body.
Higher levels of HDL are associated with a lower risk of heart disease, but as with everything, there is an upper limit.
Non-HDL Cholesterol
Non-HDL cholesterol is a calculated value derived by subtracting your HDL (good) cholesterol level from your total cholesterol level, providing a more comprehensive picture of atherogenic cholesterol particles, including LDL, VLDL, and IDL (Intermediate-density lipoprotein), which are linked to an increased risk of heart disease.
Triglycerides
Triglycerides are a type of fat created from over-consumed energy (food) that can be stored in your fat cells as stored energy. They are the most common type of fat in the body.
High triglyceride levels can increase the risk of cardiovascular diseases, especially when combined with high LDL and low HDL levels.
Very Low-Density Lipoprotein (VLDL)
Very Low-Density Lipoprotein (VLDL) is a type of lipoprotein produced by the liver that carries triglycerides through the bloodstream to fat cells. It’s considered an unhealthy cholesterol because high levels can contribute to plaque buildup in arteries.
What is considered high cholesterol?
Tests to measure cholesterol are routinely carried out by a doctor; however, private home tests are also available and can provide more detailed information to uncover the nuances behind cholesterol.
Each cholesterol type is categorised as follows:
- Total Cholesterol: Below 5.1 mmol/L is desirable, 5.2-6.1 mmol/L is borderline, and 6.2 mmol/L or higher is considered high.
- LDL Cholesterol: 2.5-3.3 mmol/L is classed as ideal, 3.4-4.1 mmol/L is borderline, 4.2-4.8 mmol/L is considered high mmol/L, and 4.9 mmol/L or above is seen as very high.
- HDL Cholesterol: 1.5 mmol/L or higher is considered protective against heart disease, 1.1-1.4 mmol/L is moderate, and below 1 mmol/L is considered unsupportive of good health.
- Triglycerides: The expected range is less than 1.7 mmol/L, but a value under 1 mmol/L is more beneficial. A level between 1.8-3.3 is borderline, and 3.3-5 mmol/L is considered high. Above 5 mmol/L is very high, with a level of 8 mmol/L or higher posing a significant health risk.
Beyond the ranges...
These ranges are designed to flag significant risk across a broad group of people – not to identify your actual risk as an individual.
A result that sits within the “acceptable” band isn’t necessarily a green light, and a result slightly outside it isn’t necessarily cause for alarm.
What matters more than where your number lands on a chart is the context around it: what type of LDL particles you have, whether inflammation is present, how your blood sugar and insulin levels look, and whether your cholesterol is being efficiently produced, transported, and cleared by your body.
Importantly, the question is, why is your body metabolising cholesterol in this way?
That’s where we come in.
What causes high cholesterol?
There are lots of factors that contribute to high cholesterol, including lifestyle, genetics, and underlying health conditions.
Some people may have naturally higher cholesterol due to hereditary factors, while others may develop it due to poor diet, inactivity, and other habits.
Let’s explore all of the contributing factors…
Diet
It may not come as a surprise that diet is a significant contributing factor to high cholesterol levels.
High amounts of saturated fats (found in processed red meat and ultra-processed foods) and trans fats (found in fried and commercially baked goods) can increase cholesterol levels.
This is because saturated fats stimulate the liver to produce more cholesterol, while trans fats interfere with normal cholesterol metabolism by increasing LDL and decreasing HDL levels.
Physical inactivity
Being physically active helps maintain a healthy balance of cholesterol by increasing HDL levels and reducing LDL and triglyceride levels.
Exercise stimulates enzymes that help move LDL from the bloodstream to the liver, where it is processed and eliminated.
A sedentary lifestyle, however, reduces this cholesterol-clearing process, contributing to higher LDL and triglyceride levels over time.
Gallbladder
The gallbladder plays a crucial yet subtle role in maintaining cholesterol balance.
It stores and concentrates bile, which is made in the liver and contains bile salts derived from cholesterol. When fat is eaten, the gallbladder releases bile into the small intestine to help emulsify and absorb fats, including dietary cholesterol.
If bile flow is sluggish or the gallbladder isn’t functioning well (as in gallstones or after removal), cholesterol may not be eliminated efficiently through bile, which can lead to an increase in circulating cholesterol.
Gallstone formation is also linked to cholesterol metabolism; most stones are composed of hardened cholesterol due to an imbalance in bile composition, and this may also be related to low-fat diets.
Microbiome
Certain gut bacteria help break down bile salts and recycle them, a process called enterohepatic circulation. This regulation controls how much cholesterol the liver removes from the blood to produce more bile. An imbalance in gut bacteria (dysbiosis) can disrupt this process, reducing bile acid conversion and leading to higher cholesterol levels.
Some microbial strains can even convert cholesterol into a compound that’s excreted rather than reabsorbed, helping to lower blood cholesterol. A diverse and healthy microbiome, supported by a diet rich in fiber, may contribute to better cholesterol regulation.
Genetics
Cholesterol levels can also be significantly influenced by genetics — and not just in the obvious ways.
Mutations in genes such as LDLR, APOB, or PCSK9 affect how well LDL receptors function, which directly determines how efficiently LDL is cleared from the bloodstream. Variants in APOE influence how you absorb and process cholesterol, with some variants associated with naturally higher LDL and greater cardiovascular sensitivity to dietary fat.
Genetics also shape the methylation cycle – the biochemical process that manages homocysteine, an amino acid that, when elevated, can damage artery walls and increase cardiovascular risk. Variants in genes like MTHFR affect how efficiently your body processes B vitamins to keep homocysteine in check. It’s a layer of risk that rarely appears on a standard blood test, but can be highly relevant, particularly if you have a family history of early cardiovascular disease.
At Integral Wellness, the team are trained in nutrigenomics and use DNA testing to understand how your individual genetic profile influences cholesterol metabolism, methylation, and nutrient needs, so recommendations are built around your biology, not a population average.
Insulin resistance and blood sugar
Insulin resistance is one of the most significant (and most overlooked) drivers of an unfavourable cholesterol profile. Yet it rarely comes up in a standard GP cholesterol conversation – and it certainly isn’t tested!
When cells stop responding efficiently to insulin, the pancreas compensates by producing more of it. Those chronically elevated insulin levels send a direct signal to the liver to produce more triglycerides and VLDL (the lipoprotein that carries fat through the bloodstream). As VLDL rises, HDL tends to fall, and LDL particles shift toward the smaller, denser subtype that is more likely to contribute to arterial damage.
The result is a lipid pattern that looks unfavourable on a blood test, but the drivers have nothing to do with dietary fat and everything to do with how the body is handling blood sugar. This is also where fatty liver can come into play as a metabolic issue.
Insulin resistance can be present long before blood sugar levels become abnormal, which is why fasting insulin is one of the markers we assess as part of a comprehensive cholesterol review. Addressing blood sugar balance – through diet, movement, sleep, and stress management – is often the most powerful single intervention for improving the overall lipid picture.
Body weight and visceral fat
Excess body fat, particularly visceral fat stored around the abdomen, directly affects how your body handles cholesterol. It raises LDL and triglycerides, lowers HDL, and impairs the liver’s ability to clear cholesterol from the bloodstream efficiently.
Visceral fat is also metabolically active, meaning it releases inflammatory signals that damage LDL receptor function and contribute to a less favourable lipid profile. Importantly, you don’t have to be significantly overweight for visceral fat to be a factor – it can accumulate in people who appear a healthy weight, particularly with a sedentary lifestyle or poor dietary pattern.
Even modest weight loss of 5-10% has been shown to produce meaningful improvements in cholesterol and other cardiovascular risk markers.
Smoking
Smoking negatively impacts cholesterol by lowering HDL (“good”) cholesterol and promoting LDL (“bad”) cholesterol accumulation.
The harmful chemicals in cigarette smoke decrease HDL production and impair its function, making it less effective at removing LDL from arteries.
Add to that, smoking damages blood vessel linings, allowing more LDL to infiltrate arterial walls and contribute to plaque buildup. This increases the risk of atherosclerosis and cardiovascular disease.
The good news is that quitting smoking can improve HDL levels. In fact, research has found that HDL levels increased by approximately 10% to 15% within three months of quitting smoking.
Medical conditions
Medical conditions like diabetes, hypothyroidism, and liver disease significantly impact your cholesterol levels too.
In particular, diabetes is associated with elevated LDL (“bad”) cholesterol and reduced HDL (“good”) cholesterol.
This is down to insulin resistance, which you’ve just learned about. If you have insulin resistance, it can lead to increased production of LDL cholesterol and decreased uptake of HDL cholesterol.
On top of that, high blood sugar levels can damage blood vessels, promoting inflammation and plaque buildup.
Age and gender
Your age and gender can affect your cholesterol levels as well.
Cholesterol levels tend to rise with age. Research finds that in older adults, particularly those over 60, cholesterol levels, especially LDL, often exceed recommended thresholds.
As for gender, women typically have lower cholesterol levels than men during their reproductive years.
This is largely down to the protective effects of oestrogen, which helps maintain higher levels of HDL (“good”) cholesterol and lowers LDL (“bad”) cholesterol.
However, after menopause, women’s oestrogen levels decline, they are less insulin sensitive, and their gallbladder and microbiome can also change, resulting in an increase in LDL cholesterol and a decrease in HDL cholesterol.
Symptoms of high cholesterol
How can you tell if you have high cholesterol? High cholesterol is often referred to as a “silent condition” as it tends not to have any symptoms.
Often, you won’t know you have high cholesterol until you have a blood test.
However, if you have developed atherosclerosis (hardening of the arteries), you may experience symptoms related to reduced blood flow, such as pain, cramping, or numbness in the legs or arms, chest pain, or, in extreme cases, heart attack or stroke.
How to lower cholesterol with lifestyle changes
1. Follow a heart-healthy diet
Diet plays a major role in cholesterol levels by influencing lipid absorption, hepatic cholesterol synthesis, and inflammation.
Increasing your soluble fibre intake is one way to positively impact your cholesterol. It’s found in oats, beans, lentils, flaxseeds, and psyllium husk.
Soluble fibre reduces LDL cholesterol by inhibiting cholesterol absorption and preventing bile acid reabsorption.
Research shows that consuming 5–10 grams of soluble fiber per day can reduce LDL cholesterol by 5–10%.
Eating monounsaturated and polyunsaturated fats is also helpful. These fats enhance LDL receptor activity and reduce cholesterol synthesis,
Reducing processed foods and added sugars in your diet may also reduce your cholesterol levels.
This is because diets high in processed carbohydrates, refined sugars, and trans fats contribute to Increased triglycerides, insulin resistance, and the promotion of small LDL particles.
2. Increase Physical Activity
Exercise is one of the most effective ways to optimise your cholesterol levels because it influences lipoprotein metabolism, insulin sensitivity, and endothelial function.
How Exercise Affects Cholesterol
- Increases HDL (“Good” Cholesterol): Physical activity activates lipoprotein lipase (LPL), an enzyme that helps clear triglycerides from the blood and facilitates HDL production.
- Enhances LDL clearance: Exercise upregulates LDL receptors in the liver, increasing the removal of LDL from circulation.
- Reduces Hepatic Lipogenesis: By improving insulin sensitivity, exercise lowers hepatic triglyceride synthesis, decreasing VLDL secretion.
So, what kinds of exercise should you be focusing on for cholesterol management?
Finding something you enjoy is key.
Activities like running, cycling, swimming, and brisk walking increase HDL levels while reducing LDL and triglycerides. Aim for at least 150 minutes per week of moderate-intensity aerobic exercise.
Meanwhile, strength training increases insulin receptor sensitivity and improves lipid metabolism. Aim for 2–3 sessions per week targeting major muscle groups.
Finally, short bursts of intense activity (known as high-intensity interval training (HIIT)) trigger AMPK enzyme activation, an enzyme that reduces cholesterol synthesis in the liver.
3. Maintain a healthy weight
Maintaining a healthy weight can improve insulin sensitivity, which in turn, lowers triglyceride levels and improves HDL cholesterol levels.
Reducing visceral fat may be particularly beneficial as it secretes inflammatory signals that can impair LDL receptor function and contribute to high levels of LDL cholesterol.
Additionally, people with obesity have lower adiponectin hormone levels, which correlate with higher cholesterol.
Weight loss can be challenging for many people. However, modest weight losses of 5 to 10% have been linked to significant improvements in cardiovascular disease risk factors over a one-year period.
4. Quit smoking
If you smoke, it’s time to stub it out. Smoking affects cholesterol metabolism by increasing LDL oxidation, reducing HDL, and promoting endothelial dysfunction.
But some good news: you can experience some notable improvements in a short period of time after quitting.
Research has found that quitting smoking is associated with an increase in HDL cholesterol and that the increase occurs rapidly in less than three weeks.
5. Limit your alcohol intake
Drinking heavily can negatively impact your cholesterol levels and heart health.
Alcohol is processed in the liver, where it’s converted into triglycerides, and as you’ve just learned, high triglyceride levels are a risk factor for heart disease. Heavy alcohol consumption can also contribute to weight gain and increased LDL cholesterol.
Additionally, over time, heavy drinking can lead to fatty liver disease, which impairs the liver’s ability to regulate cholesterol levels. The NHS recommends that men and women drink no more than 14 units of alcohol per week, spread out over three or more days.
But remember this is a limit, not a target.
Medications for high cholesterol
Lifestyle changes can make a huge difference to your cholesterol levels.
However, if you have high cholesterol, you may be prescribed medication. Common cholesterol-lowering medications include:
- Statins: These medications reduce the production of cholesterol in the liver and help lower LDL levels.
- Bile Acid Sequestrants: These drugs help remove cholesterol from the bloodstream by binding to bile acids in the intestine.
- Cholesterol Absorption Inhibitors: These medications decrease the absorption of dietary cholesterol in the intestines.
If you’re already on a medication, lifestyle and nutritional work still matters. Medications manage a number, they do not address the underlying drivers that may still be at play and increasing your risk factors.
Not to mention, all medications come potential side effects, including reduced nutrient levels (such as Vitamin D, B12, CoQ10, and Selenium), and for statins, a risk of higher blood sugar levels.
Taking control of cholesterol
High cholesterol typically doesn’t have any symptoms; however, it can increase your risk of serious health concerns like heart disease and stroke.
The good news is that you have the power to manage your cholesterol levels through diet, exercise, weight management, and other healthy lifestyle choices.
By eating heart-healthy foods, staying active, quitting smoking, limiting alcohol intake, and maintaining a healthy weight, you can lower your LDL cholesterol, raise your HDL cholesterol, and improve your overall heart health.
The choices you make today can lead to a healthier tomorrow – and Integral Wellness is here to support you with the knowledge and tools you need to get there.
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