*Food and Agriculture Organisation of the United Nations & World Health Organisation joint expert consultation: Fats and oils in Human Nutrition 1994

A bit about types of fat …

Cooking oils supply different dietary fats.
Not all fats are equal.
Some we should limit.
Many have positive health benefits…

Saturated fat.

This is one type of dietary fat most of us should try to cut down on. The UK government (NHS Choices) states that many people in the UK eat about 20% more than the recommended maximum of saturated fat.

High levels of saturated fat can lead to a build up fatty deposits in the walls of the arteries, blood clotting and increased risk of heart attack or stroke. Some studies have also linked certain cancers, like breast and bowel cancer to high intakes of saturated fat

Saturated fats are usually solid at room temperature. Examples are butter, margarine, full fat spreads and lard. Full fat dairy products such as hard cheese, cream and ice cream, fatty cuts of meat, sausages and pies, pastries, some chocolate confectionary, cakes and biscuits contain saturated fat. Coconut oil and palm oil are also high in saturated fat.

Cholesterol

Cholesterol is a fat made by the liver from the saturated fat that we eat. It is essential for healthy cells, but if there is too much in the blood it can lead to coronary heart disease.

Cholesterol is carried in the blood stream by molecules called lipoproteins. There are several different types of lipoproteins, but two of the main ones are low-density lipoproteins (LDL) and high-density lipoproteins (HDL).

LDL, often referred to as bad cholesterol, takes cholesterol from the liver and delivers it to cells. LDL cholesterol tends to build up on the walls of the coronary arteries, increasing your risk of heart disease.
HDL, often referred to as "good cholesterol", carries cholesterol away from the cells and back to the liver, where it is broken down or passed from the body as a waste product.

In the UK, the current government recommendation is that you should have a total blood cholesterol level of less than 5mmol/litre, and an LDL cholesterol level of under 3mmol/litre. This should be even lower if you have symptoms of coronary heart disease.

The liver makes most of the cholesterol your body needs. Eating foods such as butter, ghee, hard margarine, lard, fatty meats and dairy fats increases cholesterol production in the body.

Cholesterol is also found in some foods including eggs, liver and kidneys and seafood such as prawns. 

Trans-fats

Trans fatty acids are often referred to as Trans fats. They are fat lipid molecules that contain double bonds in a trans geometric configuration.

Artificial Trans fats can be formed when oil goes through a process known as hydrogenation, which makes oil more solid. This makes food such as margarine spreads more stable and convenient to use. Trans-fats also occur naturally in butter, milk, cheese and meat. Trans-fats raise “bad” low-density lipid (LDL) cholesterol and also decrease “good” high-density lipid (HDL) cholesterol level. As well as some spreads, trans fats can also be found in cakes, biscuits and other processed foods.

Unsaturated fats

These dietary fats are good for us as part of a balanced diet. The UK government recommends some people should be eating more of them because they can help lower blood cholesterol. (See the NHS choices web site)

Here are some different classifications of unsaturated fat:

Mono-unsaturated fats

These are “good dietary fats”. They lower “bad” low-density lipid LDL cholesterol and appear not to have an adverse effect on high-density lipid (HDL) or good cholesterol ratios. Rapeseed oil, olive oil, groundnut (peanut) and hazelnut oil are good sources of mono-saturated fats.

Poly-unsaturated fats

These are also “good dietary fats” Replacing saturated fats with poly-unsaturated fats in the diet, contributes to the maintenance of normal blood cholesterol levels. Sunflower, corn, grapeseed and walnut oils are good sources of poly-unsaturated fats.

Omega Fatty Acids

These specialist polyunsaturated fats are essential to our health. However our bodies can’t manufacture omega fatty acids 3 and 6, so we need to get them through our diet. 

Another type of fatty acid is omega 9. Although the body can produce this essential fatty acid, it’s still beneficial when consumed in food, as research has shown it may protect against cardiovascular disease risk factors.

Omega 3 and 6 are especially important to children and women of childbearing age. It’s important that we get the right balance of these in our diet. The ratio that's recommended is 5:1 of omega 6 to omega 3 fatty acids.

In Western diets, more omega 6 is generally consumed than omega 3. Therefore it’s useful to have a wide variety of oils, rich in both these essential fats to choose from. You can get omega 3 by eating rapeseed oils and fish oils. Omega 3 is thought to benefit many conditions including joint mobility, heart health and brain and eye development. Omega 6 fatty acids can be found in the oil of some seeds, grains and oils such as sunflower, rapeseed and corn oil. They play an important role in our nervous system; help cell growth and the production of hormones.

Other nutrients from cooking oils

Carotenes

Also known as Carotenoids. This can be converted into vitamin A by the body, which helps to regulate vision, growth and reproduction. Consuming natural levels of beta-carotene is thought to reduce the risk of developing some types of cancers. Only cold pressed oils contain appreciable amounts of Carotenes.

Antioxidants

Substances like Tocepherols & Tocotrienols are found in some cooking oils like cold pressed rapeseed, extra virgin olive oil, grapeseed and walnut oils. They help Vitamin E activity. Vitamin E and C work together as antioxidants to prevent the damage caused by free radicals. Vitamin C can regenerate the activity of used Vitamin E. Eating both has a synergistic effect. They may also help protect skin from UV damage.

Stanols & Sterols

Numerous studies have been conducted to show the effectiveness of plant sterols and stanol esters in the reduction of cholesterol levels. High cholesterol is a risk factor in the development of coronary heart disease. Cold pressed rapeseed is high in stanols and sterols.

An introduction to different varieties

Fats and oils play many important roles in cooking and contribute to food’s texture and flavour. The following cooking oils are widely available in most UK supermarkets.

Vegetable oil

This is a generic term to describe seed oils such as rapeseed, soya and palm oils. A Vegetable oil can be any of these oils - or a blend of more than one. They are refined oils and have no flavour and very high smoke point. You’ll be able to see which seed oil family a particular brand comes from by looking at the ingredients label.

Rapeseed

Rapeseed oil is pressed from the seeds of the striking yellow rapeseed flowers often seen in the UK countryside in spring and summer. It has one of the lowest levels of saturated fat of all cooking oils. Refinement of oils purifies the oil but retains the omega 3 content and produces clear, neutral tasting oil with hardly any aroma. These oils are versatile and are perfect for high temperature deep fat frying.

Cold pressed rapeseed varieties e.g. Mazola have a more grassy or subtle nutty flavour and are high in antioxidants and essential fatty acids Omega 3 and 6 plus vitamin E & K. They also contain plant sterols and stanols, which lower cholesterol. which makes them ideal to incorporate into a healthy diet. Cold pressed rapeseed oil is good for medium temperature cooking. If it’s used for high temperature cooking, it’ll lose some of its nutrients and smoke earlier than the refined versions. Click here for more information.

Corn oil

Made from maize germ this oil is low in saturated fat and high in essential polyunsaturated Omega 6. It’s one of the richest natural sources of plant sterols and stanol esters. These nutrients have been shown to lower LDL blood cholesterol by preventing cholesterol being absorbed into the bloodstream. Corn oil is almost tasteless so it won’t over-power the natural flavours in your food, plus it has a moderately high smoke point making it great for shallow frying and roasting. Click here for more information.

Sunflower oil

Made from sun ripened sunflower seeds, sunflower oil is pale yellow and has a neutral flavour. It’s one of the richest natural sources of essential Omega 6 polyunsaturated fatty acid and could help lower cholesterol as part of a balanced diet, leading to a reduction in the risk of heart disease. It's good for shallow frying and light salad dressings. Click here for more information.

Olive oil

Olive oil is a key component of the Mediterranean diet and is one of the oldest known culinary oils. It comes in many variants depending on where the olives are grown and how the oil is processed and extracted. From light amber to green in colour, flavours range from mildly fruity to distinctive and peppery. It is high in monounsaturated fats

Extra Virgin Olive Oil is completely unrefined and is the first cold pressed batch from the olives. It has low acidity (less tan 0.8%) and contains some of the highest levels of antioxidants of all oils, but is unsuitable for high temperature heating.

Cold pressed olive oil, sometimes referred to as Virgin, has a less pronounced flavour and can be used for low or medium heat dishes such as sautéing.

Standard olive oil consists of refined and virgin olive oils

Cooking removes the delicate flavour of cold pressed oils and reduces their health benefits. The low smoke point of the majority of cold pressed oils can create unhealthy fumes during the cooking process, a bitter or burnt taste and the formation of free radicals in food.

So use the more expensive extra virgin oils to add flavours of the Mediterranean to savoury dressings, marinades, dips and for drizzling over cooked foods. Click here for more information.

Sesame

Made from pressed sesame seeds, sesame oil comes in two varieties; untoasted and toasted. Most of the sesame oil in UK supermarkets tends to be the toasted version. It should be used sparingly in stir fries at the end of cooking its flavour maybe too intense on its own and it has a low smoke point. Therefore it is usually used alongside a high smoke point oil like groundnut as the actual fry enabler. Sesame contains omega 6, and is high in both mono unsaturated and polyunsaturated fats, which are the more healthy fats, plus antioxidants. Click here for more information.

Stir fry oil

A blend of sesame and sunflower oils, sometimes with added natural garlic and ginger extracts, giving both flavour and performance.

Nut

Walnut oil has both high levels and a good balance of Omega 6 and Omega 3 fatty acids in a ratio of approximately 5:1, so it is in line with dietary recommendations. Hazelnut oil is rich in monounsaturated fat and antioxidants. Our bodies use antioxidants to control unwanted oxidation, which can lead to harmful free radicals.

Walnut and hazelnut are fragrant, full flavoured oils, pressed from the nut. They have a more nutty flavour when they are toasted prior to cold pressing.

As a general rule unrefined nut oils are best used in cold dishes, like dressings, because cooking can reduce their delicate flavour and health benefits.

Groundnut oil (peanut oil) is different, in that it is refined. It is derived from pressed, steam-cooked peanuts. This has a more neutral flavour and is good for cooking because it doesn't absorb or transfer flavours. It’s high in monounsaturated fats and has a higher smoke point; so can be used for stir fry dishes. Click here for more information.

Grapeseed

This light yellow, aromatic oil is extracted from the seed of grapes and is a by-product of wine making. It’s high in polyunsaturated Omega 6 and has good levels of tocopherols, antioxidants and plant sterols, which reduce cholesterol. It’s great for salads and stir fry recipes. Click here for more information.