Which oils are the healthiest and which should be avoided?

Your parents probably keep several different oils in your pantry at home – but do you know why they use some more than others and which ones are better for protecting your family’s good health?

While some oils are quite good for you, others are better used in small doses. But before we look at the different types of oil available, it’s important to get an understanding of how much oil we actually need in our diet in order to stay healthy.

HOW MUCH OIL SHOULD I EAT?
Healthy fats are an important part of a healthy diet, but the government recommends that total fat intake – including all plant oils – should not make up more than 35 per cent of our total daily calories.

WHAT ARE SEED OILS?
Seed oils are a subgroup of plant oils taken from the seed rather than the fruit of a plant. They are rich in unsaturated fats* – including both mono-unsaturated* and polyunsaturated fats* – which are good for heart health when used instead of saturated fats. They also contain the omega-6* fat linoleic acid*, an essential fatty acid.

Using seed oils as part of a balanced diet can be a healthy move.

“Linoleic acid is actually very important for the skin and for controlling cholesterol*,” said Professor Philip Calder, a professor in nutritional immunology* at the University of Southampton. “Seed oils also contain tocopherols*, which are antioxidants*, and other phytochemicals* such as phytosterols* that can also help to lower blood fats.”

However, Prof Calder said the polyunsaturated fatty acids in seed oils are very prone to damage from high heat and seed oils shouldn’t be used for frying or reused for cooking.

ARE NUT OILS GOOD FOR YOU?
Nut oils, such as walnut, macadamia and almond, are also sources of unsaturated fats, which support heart health. However, their fatty acid profiles are different to those of seed oils. For example, almond and hazelnut oils are rich in mono-unsaturated fats, while flaxseed and sunflower oils are higher in polyunsaturated fats, including omega-3* and omega-6. Both mono-unsaturated and polyunsaturated fats are considered heart-healthy said Bahee Van de Bor, a dietitian and spokesman for the British Dietetic Association.

The British Heart Foundation recommends including a variety of unsaturated fats in a healthy diet.

Rhiannon Lambert, a registered nutritionist and the author of The Science of Nutrition, said unrefined peanut oil is good for adding to sauces or as a dressing and the refined version can be cooked at high temperatures and used for frying.

WHAT TYPES OF OLIVE OIL ARE THERE?
All types of olive oil are relatively high in beneficial mono-unsaturated fatty acids, which has been shown to help lower your “bad” low-density lipoprotein* (LDL) cholesterol when substituted for saturated fats. But with extra virgin olive oil – the purest, most antioxidant-packed variety – you get some further health benefits.

Cold-pressed extra virgin olive oil is considered the gold standard because it is pressed from ripe olives and processed without high heat or chemicals, preserving many of the polyphenol compounds* found in the plant.

Virgin olive oil is similar but mechanically extracted from the plant.

“Of the other types, olive oil or pure olive oil are typically a blend of refined olive oil with a small amount of virgin or extra virgin oil added back for flavour,” Ms Lambert said. “And the term ‘light’ olive oil, which refers to its mild taste and lighter colour.”

WHAT ABOUT AVOCADO OIL?
Avocado oil is very good for your health, providing vitamin E, lutein* for eye health and beneficial plant polyphenols and carotenoids*, but it is expensive. A small 2017 study in the Journal of Functional Foods did show that swapping butter for avocado oil helped to lower blood fats and cholesterol levels, although it looked at people who were given the equivalent of a fry-up for breakfast and the removal of some saturated fat – the butter – in place of any plant oil might have provided the same benefits. Ms Lambert says it’s a good choice for cooking at temperatures of 200C or higher. “But in health terms it’s probably no better for you than olive oil,” she said.

IS COCONUT OIL GOOD?
A few years ago coconut oil became popular because of its unique flavour and reported health benefits. It contains high levels of medium-chain triglycerides* (MCTs) which, because they are quickly absorbed by the body, are thought to make you feel full and prevent the storage of body and belly fat. However, MCTs are also a form of saturated fat, the type linked in many studies to increased LDL cholesterol, a risk factor for heart disease. In 2020, a review of 16 papers published in the American Heart Association’s journal Circulation found that regular “consumption of coconut oil results in significantly higher LDL cholesterol” than other plant oils.

So, should we avoid it? “Current evidence suggests that coconut oil may have a neutral effect* on blood cholesterol – not as harmful as butter, but not as beneficial as oils rich in unsaturated fats, such as olive or rapeseed oil,” said Ms Van de Bor. “Using it occasionally when baking or sauteing foods is fine.”

POLL

GLOSSARY

• unsaturated fats: healthy fats that lower the risk of heart disease. They have at least one double bond in the fatty acid chain. Unsaturated fats tend to be liquid at room temperature and are either mono-unsaturated or polyunsaturated
• mono-unsaturated: fat molecules with one unsaturated carbon bond in the molecule. They help to reduce bad cholesterol levels in the blood and provide your body with nutrients, including vitamin E, which is an antioxidant
• polyunsaturated fats: fat molecules with more than one unsaturated carbon bond in the molecule. These include omega-3 and omega-6 fatty acids which are essential for healthy brain function. Your body can’t produce these fatty acids itself which makes polyunsaturated fats especially important
• omega-6: we get these from polyunsaturated fats such as sunflower oil, pumpkin seeds and walnuts. Omega-6 is good for the heart and circulation and keeps blood sugar in check by improving the body’s sensitivity to insulin
• linoleic acid: another name for omega-6
• cholesterol: a fatty substance in the body produced by the liver that is essential for many bodily processes, such as producing hormones, building cell membranes and producing bile for digestion
• nutritional immunology: the study of how nutrition affects the immune system
• tocopherols: also known as vitamin E, an antioxidant that helps to protect cells from damage and fight off infection
• antioxidants: molecules that help to fight off free radicals, which are harmful compounds that may cause cancer, heart disease and diabetes
• phytochemicals: compounds produced by plants. There has been some research showing that certain phytochemicals are good for our health
• phytosterols: plant compounds that can help lower bad cholesterol
• omega-3: a type of polyunsaturated fat that helps to lower triglycerides, the most common type of fat in your body. Omega-3 helps all your cells function properly but is especially good for your eyes and brain
• low-density lipoprotein: LDL cholesterol, also known as bad cholesterol, because when you have too much of this in your bloodstream it can cause blockages in your arteries, increasing the risk of heart attack
• polyphenol compounds: plant-based compounds that are good for your heart and immunity, that include flavonoids in fruits, capsaicinoids in chilis and ellagic acid in berries
• lutein: a type of carotenoid that is good for eye health
• carotenoids: the red, orange or yellow pigments that give vegetables like carrots and pumpkins their bright orange colour
• medium-chain triglycerides: (MCTs) most fat is made up of long-chain triglycerides, however, coconut oil is a MCT, meaning it is metabolised differently and may be used more quickly for energy rather than stored as fat in the body
• neutral effect: neither raises nor lowers cholesterol in a major way

EXTRA READING

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QUICK QUIZ

1. Why shouldn’t seed oils be used for cooking?
2. What is the “gold standard” of olive oil?
3. Why is avocado oil good for you?
4. What are the two types of peanut oil?
5. In what way is olive oil better for you that coconut oil?

LISTEN TO THIS STORY

CLASSROOM ACTIVITIES
1. Healthy versus unhealthy fats
Re-read the article to find and record the definitions to the following key items mentioned in the article. Try and put into your own words.

Time: allow 15 minutes to complete this activity
Curriculum Links: English, Health and Physical Education, Science, Personal and Social, Critical and Creative Thinking

2. Extension
After reading this article, which oil would you recommend to use at home for your family’s cooking?

How would you justify this to your mum or dad?

Time: allow 5 minutes to complete this activity
Curriculum Links: English, Health and Physical Education, Personal and Social, Critical and Creative Thinking

VCOP ACTIVITY
Activity: Vocabulary and sentence construction
Objective: To help students expand their vocabulary and improve sentence construction skills using words from the article that are not words already in the Glossary.

Instructions:
Read the article and select five wow words from the article that you find interesting or new. These words should help your partner understand the article’s primary intention.

Set up a game for your partner to guess the word you refer to. Define each of your chosen words in a way your classmate will understand. Write a sentence for each word that relates to the article or makes sense on its own.

Share with your classmate to see if they can guess the word.

EXAMPLE
Definition: The feeling of being glad that something difficult is over.
Sentence: There was a sense of relief as more volunteers arrived to help with the clean-up.

Word for your partner to guess: Relief
Extension Challenge (Optional): If you finish early, try to use two of your chosen words in a single sentence to show how you can connect ideas.