The Complete Guide to Cooking Oils: What to Use and What to Avoid

Choosing the right oils can have a big impact on your health, especially when managing conditions like PCOS, endometriosis, fertility, and even inflammation-related issues such as stress, sleep quality, and hormonal balance. Here’s a comprehensive look at which oils to prioritise, which to avoid, and why organic extra virgin olive oil is the standout choice.

1. Extra Virgin Olive Oil: The Gold Standard

Organic extra virgin olive oil (EVOO) is not only versatile in the kitchen, but it’s also rich in health benefits. Cold-pressed and minimally processed, EVOO retains high levels of antioxidants and polyphenols, which combat inflammation and support heart health.

A key component of extra virgin olive oil is oleic acid, a monounsaturated fat that comprises the majority of its fatty acid content. Oleic acid has been shown to lower LDL (bad) cholesterol while raising HDL (good) cholesterol, contributing to better heart health. Studies, including the renowned PREDIMED study, have shown that high consumption of EVOO can reduce heart attack and stroke risk by up to 30%.

Why Extra Virgin Over Regular Olive Oil?

Unlike regular olive oil, which undergoes heat and chemical processing, extra virgin olive oil preserves its antioxidants and polyphenols, maximising health benefits. Choose organic, extra virgin whenever possible for the highest quality and nutrition.

2. Flaxseed Oil: Omega-3-Rich, But Don’t Heat It

Flaxseed oil is an excellent source of alpha-linolenic acid, a type of omega-3 that can help counteract the high levels of omega-6 in the typical Western diet. Omega-6 can be problematic because, when consumed in excess, it can be broken down in the body into arachidonic acid, a pro-inflammatory compound that can contribute to chronic inflammation. However, flaxseed oil should be used unheated—perfect for salad dressings or drizzling over cooked foods—as it oxidises and loses its beneficial properties when exposed to heat.

3. Coconut Oil: Use Sparingly for High-Heat Cooking

Coconut oil has a high concentration of saturated fats, making it a stable option for occasional high-heat cooking. However, due to its saturated fat content, it’s best to use coconut oil sparingly to avoid raising LDL cholesterol, which over time may increase the risk of heart disease.

4. Sunflower Oil: Best Avoided, Especially for Cooking

While sunflower oil contains some vitamin E, it is high in omega-6 fatty acids, which are already overabundant in most Western diets. When sunflower oil is heated, it rapidly oxidises, producing harmful free radicals that increase inflammation. Excessive omega-6 intake, along with the breakdown into arachidonic acid, contributes to pro-inflammatory effects that can disrupt hormonal balance and worsen cardiovascular health.

5. Palm Oil: Environmental and Health Drawbacks

Palm oil, often used in processed foods due to its low cost and stability, is high in saturated fats and often undergoes reheating and reuse in the food industry. This repeated heating produces harmful compounds linked to inflammation, type 2 diabetes, atherosclerosis, and cognitive decline. Given its environmental impact and health drawbacks, palm oil is best avoided.

6. Butter and Margarine: Understanding Their Roles

While not an oil, it’s worth mentioning butter due to its high smoke point and its suitability for cooking at moderate temperatures. Butter, rich in natural fats, can be a good option when used in moderation. However, margarine—a highly processed product often containing trans fats—is best avoided, as trans fats have been linked to inflammation, heart disease, and other health risks.

A Note on Heating and Reusing Oils

Heating any oil beyond its smoke point causes it to break down and produce toxic compounds, making it “rancid.” Rancid oils not only lose their nutritional value but can also contribute to health issues, including type 2 diabetes, atherosclerosis, and cognitive degeneration. For health and flavour, avoid reusing or reheating oils, and be mindful of the smoke points for each type.

Key Takeaway: Stick with Organic Extra Virgin Olive Oil

For daily use, organic extra virgin olive oil is an excellent choice due to its rich oleic acid content, antioxidants, and heart-healthy profile. Adding flaxseed oil in small amounts is a great way to increase omega-3 intake, counterbalancing omega-6. Avoid oils high in omega-6, especially when cooking, as well as highly processed oils like margarine and palm oil.

Choosing the right oils and using them wisely is a small but impactful way to support your health, hormone balance, and overall well-being.