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Dietitian Dr Linia Patel discusses whether marg is really the healthier option to spread on your toast.

Butter. Spread thick on warm bread, it tastes so good. For many people, it’s limited-ingredient list also adds to its appeal. But isn’t it linked to heart disease? Margarine. Comes in many different forms. Sold as the healthier alternative to butter but is it really? Let’s explore more.

The differences between butter and margarine

The most important difference between the two is that butter is derived from dairy, whereas margarine is made from vegetable oils. Butter is concentrated dairy fat; however, margarine is a highly processed food. Butter is made by churning dairy fat. Vegetable oils are liquid at room temperature and, to make margarine, a change in the chemical structure is needed. A process called hydrogenation has been used to harden vegetable oils in margarine1,2. Hydrogenation involves exposing oils to high heat, pressure, hydrogen gas and metal catalyst. The process increases the oil’s saturated fat content; however, unhealthy trans fats are formed as a side product. A high intake of trans fats has been linked to an increased risk of chronic disease2. A more recent process called interesterification has been adopted, as this achieves similar results without forming any trans fats. In addition to hydrogenation or interesterification of vegetable oils, modern margarine may contain several food additives including emulsifiers and colourants1,2.

Nutritional composition

Butter is composed of around 51% saturated fat. The amount of other beneficial nutrients like vitamin K2, conjugated linoleic acid (CLA) and omega-3 depend on the diet of the cows that produced the milk. Butter from grass-fed cows contains a significantly higher proportion than butter from grain-fed cows. However, as butter is generally consumed in small amounts, its contribution to total dietary intake of these nutrients is low1,3.

The health benefits of margarine depend on what kind of vegetable oil it contains and how it is processed. Most types of margarine are high in polyunsaturated fat. The exact amount depends on what vegetables oils were used to produce it. Polyunsaturated fat is generally considered healthy; however, more on that a little later. Vegetable oil-based margarine is often rich in phytosterols too. While phytosterols may reduce the levels of LDL cholesterol, they don’t seem to affect heart disease risk1,3,4.

Fat chemistry3

All fats, including oils, are a combination of three fatty acids: monounsaturated, polyunsaturated and saturated fats. Based on which oil is used for the margarine, the same composition exists.

Type of fat Polyunsaturated % Monounsaturated % Saturated %
Butter 3 21 51
Lard 11 45 39
Olive oil 10 76 12
Sunflower oil 65 20 10
Rapeseed oil 28 63 7

What the research says4,5,6

A high intake of saturated fat has been linked to an increased risk of heart disease; however, this a controversial issue in nutrition science as the evidence is not clear cut. While it is true that saturated fat promotes higher levels of LDL cholesterol, the story is a little bit more complex. Current guidelines still encourage us to limit saturated fat to 11% of total energy intake. They also recommend that we swap out saturated fats – found in foods like dairy – for unsaturated fats like olive oil, rapeseed oil, sunflower oil, nuts and seeds. 

There is also more research beginning to understand the role of polyunsaturated fats
in our diet. A recent review of studies concluded that eating less saturated fat is linked to a 17% reduced risk of heart disease when it’s replaced with polyunsaturated fat. However, some scientists believe that excessive omega-6 intakes may promote inflammation. More research is needed to understand the full picture, as controlled studies conclude that linoleic acid (the most common omega-6 fat consumed) doesn’t affect levels of inflammatory markers.

Making your choices

What you choose will depend on your individual preferences, your health and your goals. If you go for butter and eat it regularly, consider buying one that is made from grass-fed cows’ milk and is unsalted. If you prefer margarine over butter, be sure you choose trans-fat-free brands (i.e., not hard margarines) and opt for a product made from olive oil, that isn’t loaded with too many emulsifiers. Whatever you choose, consume in moderation. Remember, too, different components of the diet interact together to influence overall health. Emphasis of optimal health should never be about a single nutrient or food. Choosing what you put on your toast should be part of a healthy diet and lifestyle.

Smart swaps

  • Top your toast with a nut butter or tahini and fresh fruit vs butter and jam.
  • Try drizzling olive oil on toast and topping with a poached egg instead of using butter.
  • Instead of mayo, mash up an avocado or try a dollop of Greek yogurt instead.
  • Enjoy butter in your baked potatoes? Try pesto instead.
  • If you are regular baker, use extra virgin olive oil in cakes instead of butter.

Fancy learning more from Linia? She has three courses on our education platform, ranging from menopausegut health and low carb nutrition.

Author Bio:






Dr Linia Patel has a BSc degree in biochemistry and physiology and has recently achieved a PhD in public health. Linia is a leading dietitian and sports nutritionist. Her passion is translating nutritional science into easy-to-digest and practical advice.


  1. British dietetic association. Fat Fact sheet.
  2. Brassard D et al (2017), Comparison of the impact of SFA’s from cheese and butter on cardiometabolic risk factors: a randomised controlled trial, Am J Clin Nutr., 105(4): 800-809.
  3. Nutritics Nutritional Software Analysis.
  4. Forouhi et al (2018), Dietary fat and cardiometabolic health: evidence, controversies, and consensus for guidance, BMJ, 361: 2,139.
  5. Sundfor T et al (2019), BMI modifies the effect of dietary fat on atherogenic lipids: a randomised clinical trial, Am J Clin Nutr., 110(4): 832-41.
  6. Khaw K et al, Randomised trial of coconut oil, olive oil or butter on blood lipids and other cardiovascular risk factors in healthy men and women, BMJ Open, 8(3): 20,167.

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