• What is the difference between refining and hydrogenation ?

Refining is a purification technique, which removes unwanted impurities, as well as colours and improves the taste and appearance of a vegetable oil/ fat. 

Hydrogenation is a modification technique, which is used to increase the hardness/solidity of a liquid oil or semi-liquid fat. Hydrogenated fat improves the texture and consistency of final foods and helps increasing the shelf life of final foods.

• What does refining mean ?

Vegetable oils come from plants that naturally contain impurities or colours. Refining is used to remove these impurities and colours and improve the taste and appearance of a vegetable oil/fat. Look here for a graph showing the different refining steps.

• Why is a vegetable oil / fat refined ?

Through refining, a vegetable oil/fat is made ready to be used as an ingredient in another food product or to be used in our daily life for salad dressing, oven cooking or frying. Virgin oils are also available on the market, but are not always suitable to be used as ingredient of another food product, due to the colour, taste or odour they would bring in. For that reason, virgin oils are mostly used for condiments or for frying at medium temperature.

• Are all refined oils hydrogenated ?

Refining does not mean hydrogenation. Hydrogenation is a means of creating solid fats from a liquid oil or semi-liquid fat. Use example: a liquid oil can be hydrogenated to become solid and be used to make the fluffiness of a croissant. This could not be achieved if the oil remained liquid. For more details on hydrogenation, look at the infographic here.

• Do vegetable oils and fats look all the same?

There are different vegetable oils and fats in the shops, all coming from plants. Some have a light or dark yellow colour; some have a greener colour depending on the plant source. Refined vegetable oils like sunflower oil or rapeseed oil have a light-yellow colour. The difference in colour can also depend on whether the oil is refined or not. Refining indeed ensures that vegetable oils and fats have a neutral colour.

•  Why choose a vegetable oil over another?

Although all refined vegetable oils and fats have a similar neutral colour, they have very different properties, due to their natural composition. Some are more fit for cooking, whilst others are best suited for dressings. This is what makes vegetable oils and fats so varied and versatile.

•  What are saturated fats? PUFA? MUFA?

On food labels, you can see that vegetable oils/fats are composed of saturated fats and of polyunsaturated fats (PUFA) and mono-unsaturated fats (MUFA). These are different types of fatty acids, which are naturally occurring in vegetable oils and fats depending on their botanical origin.

Each vegetable oil/fat or animal fat naturally contains a proportion of saturated and unsaturated fatty acids. Saturated fatty acids tend to be solid at room temperature*, whilst unsaturated fatty acids are liquid. Scientific studies have proven that, for health reasons, unsaturated fatty acids should be consumed in preference to saturated fatty acids. This is why all national and international dietary guidelines recommend vegetable oils high in unsaturated fatty acids over vegetable oil/fats high in saturated fatty acids or over animal fats.

PUFA and MUFA are types of unsaturated fats, and are abbreviated terms for polyunsaturated fatty acids and mono-unsaturated fatty acids respectively. Unsaturated fatty acids (MUFA and PUFA) can be further categorised into three main families: omega 3, omega 6 and omega 9. Omega 6 (omega 6 fatty acid linoleic acid (LA)) and Omega 3 (fatty acid alpha-linolenic acid (ALA)) are “essential” PUFA, because the human body needs them, but cannot produce them. Therefore, they must be provided to our bodies through food. The main vegetable oils containing Omega 3 are rapeseed, soybean, linseed or walnut oils. The main vegetable oils containing Omega 6 are sunflower or soybean oils. Both PUFA and MUFA have recognised health benefits in scientific literature, which is further recognised by the World Health Organisation (WHO) and the European Food Safety Authority (EFSA).

WHO and EFSA recommend replacing saturated fatty acids in the diet with unsaturated fats, and hence by polyunsaturated fatty acids and monounsaturated fatty acids.

Fats and oils are essential for your health and should not be avoided, even if you are trying to lose weight. Everybody needs a certain amount of vegetable oils and fats in the diet. The minimum requirement, as recommended by the European Food Safety Authority (EFSA), is that 20–35% of your daily energy intake comes from fats, even when managing your weight.

According to EFSA and WHO, fats provide energy, support the absorption of fat-soluble vitamins (A, D, E, and K), supply essential fatty acids, and play a key role in building cell membranes, producing hormones, insulating the body, and protecting organs. While fat is relatively high in calories (9 kcal per gram), weight gain occurs when you consume more calories than your body needs - not simply from eating fat. Carbohydrates, protein, and alcohol also contribute to total calorie intake. To lose weight, it's more effective to reduce overall calorie consumption rather than cutting out fats entirely.

The key is to choose healthy, unsaturated fats, such as those from plant-based liquid oils, and limit saturated hard fats. Replacing saturated fats with unsaturated fats helps maintain normal blood cholesterol levels (EFSA-approved health claim). For example, alpha-linolenic acid (ALA), an omega-3 fatty acid found in some vegetable oils, contributes to the maintenance of normal blood cholesterol levels. Another example is Vitamin E, which is naturally present in vegetable oils and fats like sunflower oil or rapeseed oil, that contributes to the protection of cells from oxidative stress (EFSA-approved health claim).

Skipping fats can lead to nutrient deficiencies as well as skin and health issues and is not recommended.

• What are the different types of expiry dates? What is the difference between a use-by date and a best before date?

Most foods contain a consumption date on their label. There are 2 types of consumptiondates: a use-by date and a best-before-date. 

A use-by date relates to food safety and means that the food can be eaten until the date mentioned on the label, but not beyond, otherwise it can make you ill. A best-before-date relates to food quality and means that the food can still be eaten after the date, but that it will start losing, after a while, its organoleptic quality.

•  Which type of date applies to vegetable oils and fats and why? Can a vegetable oil/fat still be consumed after its best before date?

In the case of bottled vegetable oils and fats, this is a best before date. It indicates that the product keeps its quality, flavour and taste for a certain period of time, when stored as recommended. After that, its quality might not be as good but does not present health risks. You might want to use your sensory cues, and especially look, smell and eventually taste the food to ensure it is still fine after its best before date.