For many, the results of their first midlife health check are reassuring. Their cholesterol, they learn, is below 5mmol/L, well within the “healthy” range.
So when within a few years their numbers begin to soar, despite their diet and exercise habits remaining largely unchanged, it can come as something of a shock.

“Around the age of 50, LDL cholesterol – the “bad” cholesterol which contributes to cholesterol building up in the artery walls – starts to rise,” says Dr Negar Maghsoodi, consultant chemical pathologist and lipid specialist at University Hospitals Sussex NHS Foundation Trust and The London Welbeck Hospital. “But because high cholesterol doesn’t cause any symptoms, people usually have no idea their numbers have changed, and neither do their GPs, who also panic when they see the test results and refer the patient to me.

“Therefore, it’s not uncommon at all for me to see ladies aged 52, or gentlemen who are around 50, in my clinics, who have been astonished to discover that they now have cholesterol of around 8mmol/L or 9mmol/L, even if they are still relatively slim and fit.”

So what causes this sudden spike in midlife – and what can you do to protect your heart health?

Midlife hormonal changes

Like puberty, the hormonal shift that happens in midlife affects almost every part of the body, and the effect on our heart health can be hugely detrimental.

Sex hormones and cholesterol are intrinsically linked. Our bodies use cholesterol (a waxy fat-like substance that is produced naturally in our livers) to synthesise both oestrogen and testosterone, “which in turn are both important in regulating cholesterol production and cholesterol clearance from our blood”, explains Maghsoodi. “Therefore, we can see huge changes in our cholesterol readings around the age of 50, when our levels of these sex hormones start to drop.”

Dr Francesco Lo Monaco, a cardiologist at The National Heart Clinic on Harley Street, goes on to explain that, for women, “oestrogen helps the liver clear LDL cholesterol from the bloodstream, supports healthy blood vessel function, and improves insulin sensitivity [how effectively you clear glucose from your bloodstream]”.

These protective benefits explain why women tend to have healthier cholesterol profiles than men between the ages of 16 and 44 (46% of women in the UK have raised cholesterol compared with 53% of men).

“Then, around the age of 50, the average woman goes through menopause, causing a huge drop in their sex hormones,” explains Maghsoodi, with oestrogen levels falling between 65% and 80%. With its protective qualities gone, 77% of women aged 45 to 64 will have high cholesterol, compared to 67% of men. “When oestrogen levels drop in midlife, the blood vessels become much tighter, LDL cholesterol starts rising and is more likely to be deposited into the coronary arteries,” says Lo Monaco.

Midlife hormonal changes also affect men, though they are less dramatic in their symptoms as they happen more slowly. “Men have gradually been losing about 1% of their testosterone every year since they were 40, so by the time they are 50, the impact on their cholesterol levels can be significant,” explains Maghsoodi.

“With men, as the testosterone goes down there is a loss of muscles and an accumulation of visceral fat, which can increase insulin resistance [a sign that your body is having difficulty metabolising glucose], which changes how your body processes fats,” adds Lo Monaco. “Again, this is why I will often send men who come to see me to andrologists, who will treat issues with male hormones.”

Even those who believe they are doing all the right things can find their cholesterol levels become problematic as they age. “I often see patients who will say ‘but I haven’t changed anything – I still eat well and go to the gym’,” says Maghsoodi. “But when these hormonal changes happen, you will often see LDL levels rising. So although it’s important we need to know our numbers when we are younger, it becomes even more vital after the age of 50 to have cholesterol tested annually.”

Our livers can’t keep up

About 80% of our cholesterol is made internally by the liver, “which is both a factory for cholesterol production and a recycling site for its clearance”, says Maghsoodi. “Oestrogen helps increase the number of LDL receptors on the surface of the liver, allowing the organ to remove ‘bad’ LDL particles from the bloodstream. These particles are taken into the liver, where the cholesterol is metabolised and excreted as bile, and then faeces.”

So when a woman’s oestrogen falls during perimenopause, there is a knock-on effect for the liver. “Think of the LDL particle as a cargo ship carrying cholesterol through the bloodstream, and the LDL receptor as its docking bay,” says Maghsoodi. “When there are plenty of receptors, more of these ships can dock and unload their cargo into the liver for processing. But as oestrogen levels fall, the cargo ship doesn’t have anywhere to unload, so LDL cholesterol is left to hang around in the bloodstream instead of being cleared from circulation, which is why cholesterol readings rise with age.”

Similarly, for men, “testosterone deficiency in midlife can impair the liver’s ability to properly clear cholesterol from the bloodstream by altering specific receptor pathways including LDL receptors in the liver”, says Maghsoodi.

Our metabolism slows

Additionally, by the time we reach our 50s, metabolism has begun to slow for both men and women. “This is partly because of age-related decline in sex hormones, thyroid hormones and growth hormone,” says Maghsoodi. “When these hormones are not around, or are around at lower levels, our bodies lose the ability to store fat more safely under the skin, which is generally a healthier way to carry it.

“Instead, from midlife onwards, excess fat is more likely to wrap itself around the internal organs – known as visceral fat – including around the liver, which can impact its ability to clear cholesterol from the blood.

“Additionally, visceral fat disrupts how the liver processes cholesterol, which can lead to higher levels of LDL cholesterol remaining in the bloodstream. Meanwhile, fat accumulation inside the liver, which most people know as fatty liver, can lead to insulin resistance, disrupting the way the liver processes and clears cholesterol.”

Should we take statins or try lifestyle changes first?

Maghsoodi sees many patients who are reticent to take statins because of reported side effects, but when it came to her own health, she didn’t hesitate. “I’m 52 and a postmenopausal woman, and when my cholesterol was tested recently, it was 6.5 mmol/L. I immediately asked my GP to prescribe them for me.

“Most of my time in clinic is spent convincing people to take statins without being fearful of side effects,” she adds. “I always use myself as an example, and managed to convince at least 95% of those who are reluctant to take statins when I do.

“Every medication has its side effects, but they rarely happen. And if they do, they are manageable and we are here to support you throughout your statin journey. Some people still remain adamant that they won’t take statins, and often they come back after a couple of years to ask for them.”

If someone wants to stay off statins, they can try lifestyle measures, but Maghsoodi emphasises that diet, if it works, is only effective to a certain level, usually reducing LDL cholesterol by about 10 or 15%.

“The problem is, we often require about a 40% to 50% reduction in LDL cholesterol to reduce the risk of a cardiovascular event in 10 years’ time. If someone wants to try altering their lifestyle rather than take statins, they should give it three to a maximum of six months before they repeat their blood tests. If they haven’t seen an improvement, they need to rethink their decision.”

Which is a more effective: Diet or exercise?

“In one word, it’s diet,” says Maghsoodi. “Diet is more effective when it comes to reducing LDL in your blood, and the less saturated fat you take in, and less carbohydrate you eat, the better. Though bear in mind that carbohydrate, if it’s extremely reduced, can confuse the liver and make it produce more bad cholesterol, meaning keto diets and very low carbohydrate diets, even though they reduce your weight, aren’t good in terms of cardiovascular health in the long term.”

When it comes to what we eat, Lo Monaco advises “reducing saturated fats [found in red meat and fried foods] and trans fats [found in store-bought cakes and biscuits, and some margarines], and increasing the unsaturated fats and fibre-rich foods like vegetables, fruits, nuts, beans and seeds”.

That’s not to say exercise doesn’t play a role in maintaining healthy cholesterol levels. “What regular movement does is alter the size and density of LDL particles, shifting them towards a larger, less dense, ‘fluffy’ state,” says Maghsoodi. “These particles find it more difficult to penetrate and lodge inside the tight microscopic spaces of the arterial walls. Exercise also increases HDL cholesterol – our good cholesterol – and lowers triglycerides, while offering other benefits for cardiovascular health as it reduces blood pressure and keeps your heart muscle healthy.”

It’s important not to overlook other factors that impact heart health in midlife either.

“One lifestyle factor that I think is often underestimated is chronic stress,” says Lo Monaco. “Persistent stress can activate neurohormonal and inflammatory pathways and may adversely affect cholesterol and the way it builds up in the walls of the arteries.”