There’s a new incentive for tackling your cholesterol levels – it could reduce your risk of dementia, based on new research that has been presented at the Alzheimer’s Association International Conference in Philadelphia.

Growing evidence has shown excessive cholesterol, clogging up your arteries with fatty deposits, now officially recognised as one of 14 modifiable dementia risk factors.

It is also, of course, a risk factor for heart attack and stroke.

Julie Ward, senior cardiac nurse at the British Heart Foundation describes high cholesterol as being a common “hidden risk factor” for disease. “It can be present without anyone knowing until it’s too late,” she says. “That’s why it’s so important to get checked. You can ask your GP to check your cholesterol levels, which are measured using a simple blood test. Alternatively, a finger-prick cholesterol test is available in some pharmacies, or as part of the free NHS Health Check in England.”

So what exactly is cholesterol, what role does it play in the body, and what can you do to reduce it?

What is cholesterol?

Cholesterol is a waxy-like substance which occurs in two main forms – LDL cholesterol and HDL cholesterol. While it’s usually described in a negative context, we do actually need cholesterol in our bodies, which is synthesised naturally by the liver.

“It is essential for human health due to its varying roles in the body including nerve insulation, cell membrane structuring and the production of hormones,” says Matt Taylor, health and wellbeing physiologist at Nuffield Health.

An excessive intake of LDL cholesterol can lead to fatty deposits within arteries forming plaques. This can obstruct blood flow to the brain, which is one of the reasons why cholesterol is linked to dementia. HDL cholesterol has long been regarded as “good cholesterol” because while still a type of fat in your blood, it doesn’t actually clog your arteries. However, research examining drugs that increase HDL cholesterol have yet to find any reduction in heart problems. As such, the NHS still recommends examining your total cholesterol score as an indication of whether you’re at heightened risk.

According to the NHS, around 220,000 people have so-called familial hypercholesterolaemia, an inherited condition which leads to high cholesterol levels from birth. While it can be treated with statins, fewer than eight per cent of these people realise they have the condition.

“There can be visible signs including swellings made from cholesterol on the knuckles of your hands, your knees or the Achilles tendon at the back of your ankle,” says Ward. “Other signs include small yellow lumps of cholesterol near the inner corner of your eye, or a pale white ring around your iris, the coloured part of your eye.”

But for the vast majority of people, the major cause of elevated cholesterol is diet. According to nutrition experts, the below six foods tend to be the major culprits.

Foods that can raise your cholesterol

Fizzy drinks

While Coca-Cola and other fizzy drinks are well-known for not being the best for our health, you might be surprised to know that they can also impact your cholesterol. This is due to how the body metabolises and stores excess sugar, especially fructose which is present in fizzy drinks in high quantities due to its low cost.

“When we drink calories, the body uses [different] pathways within the liver to store this excess energy for later use by making new cholesterol,” says registered nutritional therapist Katherine Paton.

Drinking fructose is much worse for the body compared to eating it, as it’s present in higher concentrations. A lack of solids to slow down the metabolism means that it reaches the bloodstream much faster, meaning it’s easier to drink larger amounts. In turn, this leads to a greater accumulation of cholesterol.

Alcohol

Drinking alcohol – which is also broken down in the liver and reconstructed as cholesterol – in excess can also raise your total cholesterol levels.

Saturated fat

One of the problems with consuming foods high in saturated fat, is that like fructose, the body then converts it into cholesterol. Consultant dietitian Orla Walsh recommends that we consume less than 30 grams of saturated fat per day, and one surprising contributor is coconut oil.

According to the British Heart Foundation, coconut oil is 86 per cent saturated fat, a third more than butter. Walsh says the same is true for coconut milk. “One tin of coconut milk has double the recommended amount of saturated fat you should eat in a day,” she says. “It contains [around] 66g per tin.”

James Vickers, nutritionist at Vitality, says that while coconut oil is typically regarded as healthy, it’s best to use only in moderation. “Only use small amounts and go for alternative unsaturated oils [such as olive or sunflower oil] on a day-to-day basis instead,” he says.

At the same time, the jury still remains out on coconut oil. The Mayo Clinic is firmly in agreement with Walsh and Vickers, describing coconut oil as raising both LDL and HDL cholesterol more than olive or canola oil. But a 2018 clinical trial published in the British Medical Journal seemed to show that coconut oil had less of an impact on LDL cholesterol compared to butter, and overall was more comparable to olive oil.

As ever in nutrition, the evidence is blurry.

Fried foods

Perhaps less controversially, Vickers says that kinds of any fried foods such as french fries, battered onion rings, fried chicken, spring rolls and doughnuts tend to be particularly rich in both saturated fat as well as so-called trans fats. The latter are formed through an industrial process that adds hydrogen to vegetable oil, causing the oil to become solid at room temperature, and can be converted into LDL cholesterol.

Ultra-processed ice cream

One of the differences between many tubs of ultra-processed ice cream compared to the fresh versions made by independent vendors is that they typically contain combinations of added milk fat, high fructose corn syrup, multiple sources of liquid sugar, and coconut fat. All of these additives make it more palatable but ultimately increase your cholesterol.

“These UPF ice creams are easy to spot if you read the ingredients label,” says nutritionist Rhian Stephenson, founder of supplement brand ARTAH. “Some of them will have added baked goods like cookie dough and brownie bites which contribute as well.”

Coffee

Overall, coffee is pretty good for your health unless you’re regularly adding spoonfuls of extra sugar, milk and cream as in many common barista coffees like a frappuccino. 

However, when it comes to black coffee, it seems that filter or instant coffee is best. Increasing evidence has indicated that coffee made using a cafetiere, Turkish coffee or an espresso machine, can raise your LDL cholesterol. 

“The effect seems to be due to a compound in unfiltered coffee called cafestol, which interacts with genes that maintain cholesterol balance in the body,” says Federica Amati, the head nutritionist at Zoe. “In particular, cafestol reduces the production of bile acids, which normally help the body eliminate cholesterol. So, when their production is interrupted, it can throw the balance off, leading to increases in LDL cholesterol.”

At the same time, experts have pointed out that this only seems to be relevant if you’re drinking an excessive amount of coffee, such as six or more cups per day. “It doesn’t really matter what type of coffee you drink if you only have one or two cups a day,” says Tom Sanders, emeritus professor of nutrition and dietetics at King’s College London.

Other foods to avoid

Just like fried foods, many processed meats are typically high in saturated fats, and Vickers particularly suggests keeping bacon to a minimum. “You should limit how much you eat,” he says. “Only eat it occasionally, in small quantities and grilled not fried. But if you already have high cholesterol, high blood pressure or you’re at risk of cardiovascular disease, you should consider avoiding eating it completely.”

Who doesn’t enjoy a morning croissant? The problem though, according to Jess Willow, a registered dietitian at Willow Nutrition, is that such delicacies tend to be high in trans fats. Artificial trans fats are thought to be even worse than saturated fat for raising cholesterol levels with research showing that they increase the risk of heart disease.

“We typically find trans fats in pastries and baked goods, so limiting things like croissants and other pastry type foods, cakes and biscuits is a good idea,” she says.

Other saturated-fat rich foods that can have a potent effect on cholesterol, include red meats and butter. Hence experts suggest eating these in moderation.

Foods that are actually good for you

There are many foods which are naturally high in cholesterol, but rather than shying away from them, they’re actually good for us. This might sound counterintuitive, and as the dietitian Duane Mellor explains, it once led to some dubious nutrition advice.

However, we now know that it isn’t the cholesterol within food that causes us problems, but the excess fructose, saturated and artificial fats that our body then uses to make LDL cholesterol which ends up in our blood vessels.

“Eggs containing cholesterol previously led to them being discouraged for people with a higher risk of heart disease,” says Mellor. “But they are a great source of protein and not that high in saturated fats, so the cholesterol is not a problem.

Shellfish, unless dipped in batter and fried, are generally low in fat, and the cholesterol they contain is chemically different and has very little effect on our own cholesterol levels.”

Research has since found that while foods like full-fat yoghurt and milk contain their own cholesterol, they might actually reduce risk of cardiovascular diseases because they contain different fats called odd chain fatty acids and conjugated linoleic acid which are thought to be protective. “Many studies suggest that people who eat more unflavoured yoghurts have a reduced risk of these diseases,” says Mellor.

Other tips for lowering cholesterol

Stephenson describes overall diet quality and particularly fibre intake as crucial to reducing and maintaining healthy cholesterol levels.

“An overall dietary pattern that is lacking in fibre, with regular or heavy alcohol consumption, red and processed meats, and higher in added sugar, will likely be troublesome if cholesterol is a concern,” she says.

Mellor recommends trying to include aspects of the so-called Portfolio Diet, which was developed at the University of Toronto as a way of improving cholesterol levels. The four main recommendations of the Portfolio Diet are:

• Eat plenty of soluble fibre: This type of fibre is found in foods like oats, beans, lentils, and apples. It helps to bind with cholesterol in the gut and remove it from the body.
• Choose plant-based protein sources: Plant-based protein sources, such as beans, lentils, tofu, and nuts, are typically lower in saturated fat than animal products.
• Include nuts and seeds: Nuts and seeds are a good source of healthy fats and fibre, which can help to lower cholesterol levels.
• Limit saturated and trans fats: As we discussed earlier, saturated and trans fats are the main culprits for raising cholesterol.

Conclusion: A healthy heart and brain

Maintaining a healthy cholesterol level is essential for a healthy heart and brain. By avoiding the foods that can raise your cholesterol and incorporating more heart-healthy options into your diet, you can lower your risk of dementia, heart disease, and other health problems.

It’s important to remember that everyone’s body is different, and what works for one person may not work for another. If you are concerned about your cholesterol levels, talk to your doctor to get personalized advice and a plan that’s right for you.