It’s the slippery argument that’s divided researchers for decades – is butter or margarine better for our health? But just when we thought we had the answer – that saturated fats like those found in butter aren’t bad for us as previously thought – another study comes along to suggest the opposite. Here we try to unpick the debate.
Researchers from the Harvard School of Public Heath studied the diets of 130,000 doctors and nurses over almost 30 years. Their findings, published in the Journal of the American College of Cardiology this week, suggest that replacing saturated fats (found in butter) with unsaturated fats (found in vegetable oils and margarine) significantly reduce the risk of heart disease.
The findings are in stark contrast to other recent studies that found that people who cut back on saturated fats have no lower risk of heart disease than those who continued eating them. This has led to suggestions that we shouldn’t worry too much about fat, and opt for butter over margarine.
But the Harvard researchers claim to have identified the cause of the discrepancy; the previous studies did not take into account that people who cut down on saturated fat went on to eat more refined carbohydrates, such as white bread and pasta, which are key risk factors for heart disease. Researchers concluded that cutting back on saturated fat can reduce the risk of heart disease – but only if you replace those calories with unsaturated fat and not refined carbohydrates.
Butter still better say some experts
Dr Aseem Malhotra, London-based cardiologist and adviser to the National Obesity Forum, argues the Harvard study is not a green light to swap butter for margarine. “I would choose butter over margarine any day of the week and I advise my patients to do the same.” He believes butter is neither good nor bad for our health (its effects are probably “neutral”, he says) but he has concerns about margarine: “I believe it’s potentially harmful.”
He points to growing concerns that not all polyunsaturated fats, including those found in some vegetable oils, margarines and spreads, are good for the heart.
One 2013 study published in the British Medical Journal found “increased rates of death” among men with heart disease who replaced saturated fat with omega 6 polyunsaturated fatty acid, also known as linoleic acid. Linoleic is a widely used polyunsaturated fat found in high amounts in vegetable oils such as corn, sunflower, safflower and soybean, and in margarines made from these oils. Another study this year by the University of Cambridge found that saturated fat in dairy foods might protect against diabetes, while a major study by McMaster University in Canada failed to find a link between saturated fat and ill health.
Dr Malhotra urges consumers to stick with butter, avoid margarine and include extra virgin olive oil (“it’s a medicine”) and a handful of nuts in their daily diet to reduce the risk of heart disease, stroke, dementia and cancer.
UK health guidelines advise that men and women limit their saturated fat intake to 30g and 20g respectively per day, and reduced-fat spreads like olive oil or sunflower are recommended as good replacements for butter. According to the NHS Choices website, most brands of margarine now contain no, or only trace elements of, industrially produced “trans fats” that are now known to increase the risk of heart disease, stroke and possibly type 2 diabetes.
During the Second World War, British margarine brands were legally required to add vitamins to their recipes, and most have continued to do so to bolster their image as a healthy alternative to butter. Most brands are fortified with vitamins, omega-3s and additives that claim to lower cholesterol. Some include olive oil or even butter. They also contain preservatives, colourings and other additives.
When it comes to flavour, rich, creamy butter wins every time and because it is full fat, it is more satisfying and fills us up for longer. Butter is also one of the best dietary sources of Vitamin A, and also contains vitamins E, K and D and is a rich source of selenium.
Nutritionist Vicky Bruce, who advocates eating butter in moderation, says it’s a question of balance.
“We know saturated fat isn’t great in excess, but neither would eating excessive amounts of kale be good for you,” she says. “It’s the dose, not the poison that’s the problem, so balance is key.”
She does suggest a little restraint when applying butter to toast – try keeping butter out of the fridge, as it’s easier to spread thinly at room temperature.
“Eating loads of processed biscuits will do you harm but eating a teaspoon of butter on your broccoli won’t unless you have a medical condition that means you should have a diet low in fat. Eating fats, including natural saturated fats with nutrient dense foods and an active lifestyle, is far better than nutrient free margarine.”