The facts about fat and heart health

09 February 2016
Young eats her breakfast with a glass of milk

It’s long been thought of as a given that saturated fat – the type that’s plentiful in cakes, biscuits, fatty meat and full-fat dairy products – is bad for our health, and in particular for our heart.

But there’s been growing debate over the last couple of years about whether saturated fat is really as bad as it’s made out to be.

So should we be swapping the low-fat spread for the butter? The semi-skimmed for full-fat milk? And do we really need to feel so guilty about dipping into the biscuit tin? Before you make any rash changes to your diet, it’s worth taking a closer look at where the current guidance has come from, and what the latest evidence is.

What are the current guidelines?

Current guidelines are that we should limit the amount of saturated fat in our diet to no more than 30g for men, or 20g for women.

It’s recommended that, where we can, we swap saturated fats (such as those found in fatty and processed meats, dairy, ghee, suet and palm oil) for small amounts of mono- and polyunsaturated fats (such as those found in oils, nuts, seeds and spreads).

Why is the advice to cut down on saturated fat?

Saturated fat is known to increase the levels of a type of cholesterol, known as low-density lipoprotein (LDL) cholesterol, in the blood. LDL cholesterol is associated with increased rates of heart disease. Unsaturated fats, meanwhile, help to maintain a healthy cholesterol level and protect your heart.

It’s because of this effect on your cholesterol levels that replacing saturated fat with unsaturated fats is thought to be beneficial to heart health.

Why is the current guidance now being questioned?

More recently, studies have been re-examining the link between saturated fat and heart disease. A recent systematic review, which looks at the results of many other studies, found that the evidence to support this link isn’t as sound as first thought. The findings from this review have cast doubt over the current guidelines that encourage replacing saturated fats with unsaturated fats.

The results also suggested that a particular type of saturated fat, found in milk and dairy foods, may have less harmful effects on the heart than other types of fat. This finding is backed up by other studies. This supports the idea that it may be better to focus on the quality of your diet overall, rather than on a specific nutrient, such as fat.

These new studies have at times been misconstrued in mainstream media as disproving the link between saturated fat and heart disease. In reality, they’re just questioning the validity of the results, and suggest that more research needs to be done.

It’s also important to realise that these types of studies on diet and health are often very difficult to carry out. This is because they rely on people remembering and accurately reporting what they’ve eaten. This means that there’s often room for error, which can affect the results.

What advice should I be following now?

Until there’s more evidence, it’s best to continue using current recommendations as a guide, but remember that it’s overall diet quality that is important.

The advice for now is still to switch saturated fat for unsaturated fat when you can. This is consistent with a “Mediterranean-style” diet, with plenty of fruit, vegetables, pulses, wholegrains, olive oil and fish. We know this is associated with health benefits, including a lower rate of heart disease. Research on individual nutrients can provide us with important information, but it’s important not to just focus on one nutrient – it’s more beneficial to think about your diet overall.

Dietitian at Bupa UK

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