Many of us know someone who’s been told to “watch their cholesterol”. It’s one of the most common health conversations in the UK — and for good reason.

According to NHS Digital’s Health Survey for England 2021, 59% of adults had raised total cholesterol levels (5 mmol/L or above).¹ That means over half of UK adults live with a key risk factor for heart disease and stroke.

So, can what you eat really make a difference? Or are your cholesterol levels mostly down to age and genetics? Let’s explore what cholesterol actually is, how food can help — and the limits of diet alone.

What Exactly Is Cholesterol?

Cholesterol is a waxy, fat-like substance found in every cell of your body. Despite its bad reputation, it’s essential for life — used to make hormones (including oestrogen and testosterone), vitamin D, and bile acids that help digest fats.

Your liver produces around 80% of your body’s cholesterol. The remaining portion comes from food, such as meat, eggs, and dairy.

Types of Cholesterol: LDL, HDL, and Triglycerides

• LDL (Low-Density Lipoprotein) – often labelled “bad” cholesterol because it can deposit on artery walls, forming fatty plaques.

• HDL (High-Density Lipoprotein) – known as “good” cholesterol, as it helps remove excess LDL from the bloodstream and transports it back to the liver.

• Triglycerides – another type of blood fat. High levels can also raise your risk of heart disease and stroke.

  
  

When LDL builds up, it can narrow and stiffen arteries — a condition called atherosclerosis — increasing the risk of heart attack and stroke.

Does Dietary Cholesterol Matter?

For decades, cholesterol-rich foods like eggs and shellfish were seen as villains. We now know that dietary cholesterol has only a small impact on blood cholesterol for most people.

The body cleverly adjusts: when you eat more cholesterol, the liver usually makes less. What matters far more is the type of fat in your diet:

• Saturated fats (found in butter, cheese, cakes, and fatty meats) raise LDL.

• Unsaturated fats (found in olive oil, nuts, seeds, and oily fish) lower LDL and help maintain healthy HDL levels.

NHS guidance: “It’s much more important to cut down on saturated fat than the cholesterol found in food.”²

Cholesterol and the Brain: Does Lowering It Affect Memory?

The brain contains large amounts of cholesterol — it’s vital for nerve function and cell membranes. But the brain’s cholesterol is made locally inside the brain and does not come directly from blood cholesterol, thanks to the protective blood–brain barrier.

That means lowering blood cholesterol — through diet or medication — does not reduce brain cholesterol or damage brain function.

A large Lancet Neurology meta-analysis (2019) found that statin use was not linked to cognitive decline in over 18,000 adults.³

However, there’s another side to the story. According to the Alzheimer’s Society, high blood cholesterol — especially high LDL — can increase the risk of dementia later in life.⁴

“Research suggests that high cholesterol is linked to increased risks of dementia.” — Alzheimer’s Society

Studies indicate that maintaining healthy blood cholesterol levels in mid-life may reduce dementia risk by as much as 25–30%.⁵

So while lowering cholesterol doesn’t deplete the brain, it likely protects it over time.

How Cholesterol Affects the Heart

When LDL levels stay high, cholesterol can accumulate in artery walls, forming plaques that restrict blood flow.

If a plaque ruptures, it can trigger a blood clot, blocking an artery and causing a heart attack or stroke.

HDL helps counteract this process by carrying excess cholesterol away for disposal in the liver.

“High cholesterol itself doesn’t cause symptoms, but it can lead to serious heart and circulatory diseases.” — British Heart Foundation⁶

Can Diet Really Lower Cholesterol — and by How Much?

For many people, diet can meaningfully reduce cholesterol — especially LDL — but results vary. Research shows that dietary changes can typically reduce LDL by 10–15%, while medication such as statins may lower it by 30–50%.

That means dietary change alone may bring meaningful improvements for many people, though medication can achieve greater reductions when needed.

Oats: The UK-Approved Food Claim for Cholesterol

The UK’s Nutrition and Health Claims Register recognises beta-glucans from oats and barley as having a proven cholesterol-lowering effect.

“Oat beta-glucan has been shown to lower/reduce blood cholesterol. Blood cholesterol lowering may reduce the risk of (coronary) heart disease.” — Regulation (EU) No 432/2012; EFSA Journal 2010; 8(12):1885

For this cholesterol-reducing benefit a food must provide at least 3 g of oat beta-glucans per day. This can come from one or several portions of oat-based foods, such as

• A large bowl of porridge oats (70–80 g dry weight)

• Oat bran or oat-based drinks enriched in beta-glucans

How it works: Beta-glucans form a gel in the gut that binds bile acids. The body then draws cholesterol from the blood to make more bile acids, helping reduce LDL (“bad”) cholesterol.

Regular intake of 3 g/day can lower LDL by 5–10% within 4–8 weeks.

“Oats are rich in beta-glucans, a soluble fibre that helps reduce cholesterol when eaten regularly.” — British Heart Foundation, 2024

Factors Diet Can’t Fully Control

Even with an ideal diet, several other factors influence cholesterol levels:

1. Age: LDL tends to rise naturally as liver function changes with age. The 2021 NHS survey found **the highest prevalence (72%) of raised cholesterol among adults aged 45–64.**¹

2. Genetics: Familial hypercholesterolaemia causes high cholesterol regardless of diet.

3. Body weight: Excess body fat can raise LDL and triglycerides.

4. Physical activity: Regular exercise boosts HDL (“good” cholesterol).

5. Smoking and alcohol: Both lower HDL and increase triglycerides.

“Lifestyle and age are key factors — diet alone may not always be enough.” — British Heart Foundation, 2024

When Diet Isn’t Enough

If cholesterol remains high after several months of dietary and lifestyle changes, your GP may suggest statins. Statins work by slowing cholesterol production in the liver, often cutting LDL levels by a third or more.

Combining diet, exercise, and medication — where necessary — gives the best long-term protection for heartand brain health.

Key Takeaway

Diet is one of the most effective natural tools for improving cholesterol — but it isn’t the only one.

For most people, the best results come from:

• A balanced, high-fibre diet low in saturated fat.

• Regular physical activity.

• Maintaining a healthy weight.

• Avoiding smoking and limiting alcohol.

• Following medical guidance where needed.

You can absolutely make a real difference through food — but lasting heart and brain protection comes from the bigger picture of healthy living. Even small changes — like swapping butter for olive oil or adding a bowl of oats each morning — can start moving your cholesterol in the right direction.