With a number of reports presenting a 'not guilty' verdict on saturated fats, have we got heart health all wrong and is cholesterol really worth all the worry? Kerry Torrens explains what cholesterol is, why we need it and what the latest studies are telling us.
The subject of cholesterol has caused a lot of confusion in the past few years. We buy cholesterol-lowering foods and potentially take medication to keep levels balanced – but is this always necessary? Without doubt, for some of us this is an essential part of a healthy lifestyle – for instance, for one in 500 people who have a condition called familial hypercholesterolemia. For these individuals and others like them, for whom genes play a big part, cholesterol management is crucial – but what about the rest of us?
What is cholesterol?
Cholesterol is a waxy fat, with 75% made in the body by our liver and the rest coming from the food we eat. For decades, cholesterol was believed to be the enemy when it came to heart health, but the latest research suggests it may not be as simple as we first thought.
Being a fat, cholesterol has to be transported by a carrier in the blood – these carriers are protein complexes called lipoproteins. You’re probably familiar with them because they're often confusingly referred to as 'bad' cholesterol or Low Density Lipoproteins (LDL) and 'good' cholesterol or High Density Lipoproteins (HDL). As with most things, it’s not as simple as that – these lipoproteins are not cholesterol, and both LDL and HDL will be present in a variety of different forms – the smaller, denser of which appear to pose the greater risk. Your unique mix of LDL and HDL and their sub-types depends on your combination of genes, as well as your lifestyle.
Why do we need it?
Although we’ve grown up to fear cholesterol, we do actually need it for our bodies to function properly – in fact it’s fundamental to life. That’s because cholesterol is crucial for forming cell walls, producing hormones like oestrogen and testosterone, helping repair nerves, producing bile so we can digest and absorb the fats in our diet and to make the 'sunshine vitamin', vitamin D. What’s more, cholesterol improves our memory and helps us feel good because it makes the mood-boosting hormone, serotonin.
How do I know if I have healthy cholesterol?
Your blood fats, including cholesterol level, can be measured by a simple blood test. You can read more about how to get your cholesterol checked at nhs.uk.
What are triglycerides?
Cholesterol is not the only type of fat in your blood. If you’ve had a blood test to check your cholesterol levels, you’re likely to have also been told your triglyceride level. Triglycerides are the main form of fats in the body and we use them to store energy in our cells. Too much of this fat in your blood is an important, independent risk factor for heart disease.
What about the fats we eat?
Alongside cholesterol, fat has long been treated as the enemy. Saturated fat is frequently vilified as it has been linked to cardiovascular disease and high cholesterol. Red meat, butter, cheese, burgers and sausages, are high in saturated fat, as are ghee, coconut and palm oils. A diet high in saturated fat can increase blood fats, including triglycerides, as well as increase your risk of obesity, heart disease, type 2 diabetes and stroke. However, recent studies are now suggesting that the saturated fats in some foods such as dairy products, including cheese, do not appear to be as harmful as once thought. This may be because other nutrients in dairy, like calcium, may modify the effects on blood fats such as triglycerides. So what dietary aspects should we be focusing on for heart health?
Increasing evidence points to overeating sugary, refined carbs as a cause of inflammation, raised insulin levels, high blood pressure and higher cholesterol and triglyceride levels. You’re likely to have also heard of man-made fats called trans fats – these are unsaturated fats in our diet that behave more like a saturated fat, only worse because the body can't recognise them. They are found in processed foods and takeaways and are the worst type of fat for raising cholesterol levels. You can avoid them by cooking as much as possible from scratch and checking labels for hydrogenated, partially hydrogenated and semi hydrogenated vegetable fats or shortening.
So, when buying products, what counts as high fat and low fat?
- High: more than 17.5g of fat per 100g. (Packaging may be colour-coded red)
- Low: 3g of fat or less per 100g. (Packaging may be colour-coded green)
Look out for 'saturates' or 'sat fat' on the label: this tells you how much saturated fat is in the food.
- High: more than 5g saturates per 100g. (Packaging may be colour-coded red)
- Low: 1.5g saturates or less per 100g. (Packaging may be colour-coded green)
If the amount of fat or saturated fat per 100g is in-between these figures, that's a medium level, and packaging may be colour-coded amber.
How to have a heart-friendly diet
Overall, aim for a diet with plenty of mono-unsaturated fat and omega-3 fatty acids – so foods like nuts, seeds, avocado and olive oil, as well as one to two portions of oily fish (such as sardines, mackerel, salmon and trout) per week. A Mediterranean-style diet is a good one to aim for. Don’t get too concerned about dairy because the fats in these foods aren’t as harmful to blood cholesterol as first thought – as long as you enjoy them in modest amounts. There are some foods that are especially beneficial for heart health, so include these in your diet on a regular basis. Here are some suggestions:
Eat 2-4 portions of oats daily – there’s plenty of evidence to show that oats help manage cholesterol levels. They’re rich in a soluble fibre called beta-glucan, which attaches to cholesterol and inhibits its absorption. A daily intake of about 3g of beta-glucan is considered an adequate amount to make a difference. Other food sources, rich in useful soluble fibre, include barley, sweet potatoes, beans, peas and lentils.
Eat oily fish up to twice a week or more regularly if you have a history of heart problems. Omega-3 fats found in oily fish can help lower harmful blood triglycerides, include herring, mackerel, pilchards, sardines, salmon, trout and fresh tuna.
Stick to Reference Intakes (RI) – the guideline daily amounts for nutrients like fats. Aim to have no more than about 1/3 of the fat in your daily diet being saturated, with the remainder being healthy fats including the monounsaturated and polyunsaturated fats found in olive oil, rapeseed oil, avocado, unsalted nuts and seeds.
Other lifestyle factors
Don’t forget, as well as your diet, your day-to-day lifestyle plays a big part in heart health. In particular, smoking, being overweight (especially carrying extra weight around the middle), stress, inactivity, a low intake of fruit and vegetables, a diet high in refined carbs and sugars and too much alcohol all contribute to your risk of heart disease. Furthermore, having high blood pressure, diabetes or a family history of early heart disease puts you at a greater risk – so make it your business to know your numbers.
Healthy recipe suggestions
Oats and seeds...
Apple & linseed porridge
Vanilla-almond chia breakfast bowl
Irish soda bread
Apricot & seed protein bar
Tuna steaks with cucumber relish
Basil & lemon chickpeas with mackerel
Grilled mackerel with harissa & coriander couscous
More healthy fats...
Almond nut butter
Fish tagine with saffron & almonds
Chunky tomato & avocado salsa
This article was last reviewed on 23 September 2019 by Kerry Torrens.
Kerry Torrens BSc. (Hons) PgCert MBANT is a Registered Nutritionist with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food
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