There are several important health and nutrition factors to take into consideration when choosing oils for cooking and dressing:
Make-Up: Oils primarily fall into one of these categories: saturated, monounsaturated, or polyunsaturated. Some oils with more polyunsaturated fatty acid components (PUFAs) are less stable than saturated or monounsaturated oils and more susceptible to oxidative damage, which makes them more harmful to our bodies and more inflammatory when used in cooking.
Smoke Point: The smoke point of an oil is the temperature at which it starts to burn and smoke. Know the smoke point of the oils you use when cooking. When oils cook beyond their smoke point, they not only mar the taste of your food, but also release free radicals and a substance called acrolein, the chemical that gives burnt foods their acrid flavour and aroma.
Non-Refined vs. Refined Oils: Non-refined oils tend to have higher antioxidant properties, compared to refined oils, and do not go through the same processing and chemical alteration.
Guidelines for choosing the correct cooking oil
When cooking on high heat, saturated fats are the most stable and will not oxidise. These include:
Animal based, preferably grass-fed organic
Ghee (clarified butter)
Goose and duck fat
Butter
Lard
Chicken fat
Plant-based:
Coconut Oil
Palm oil (sustainably sourced)
When cooking on high heat, saturated fats are the most stable and will not oxidise.
If using low heat or if unheated, use moderately stable monounsaturated fats
Avocado oil
Macadamia nut oil
Olive oil
Sesame oil
Do not heat these polyunsaturated fats as they are the least stable of the fats and are easily damaged by heat:
Flaxseed oil
Nut oils
"Back in the MI (myocardial infarction) free days before 1920, the fats were butter and lard and I think that we would all benefit from the kind of diet that we had at a time when no one had ever heard the word corn oil.” - Dr. Dudley White speaking at an American Heart Association fundraiser in 1956.
Oils to avoid entirely
Vegetable Oils - are highly processed polyunsaturated fats. They are pro-inflammatory, impairing proper cell function. Vegetable oils may sound healthy but they require industrial processes using toxic chemicals like hexane and bleaching agents to help extraction. Even organic vegetable oils undergo tremendous processing. Exposed to heat, vegetable oils oxidise easily, resulting in a toxic food. Oils, like soy, corn, canola, sunflower, rice bran, safflower and grape seed, increase inflammation in the body.
These polyunsaturated vegetable oils, especially when heated, damage your metabolic function, gene expression, hormone functions and your cells (evening primrose and hemp oils are exceptions as they function as anti-inflammatories).
Canola oil
Corn oil
Cottonseed oil
Grape-seed oil
Safflower oil
Soybean oil
Sunflower oil
Vegetable oil
Artificial Trans Fats - promote systemic inflammation. They increase the risk of obesity, heart disease and cancer.
Hydrogenated or partially hydrogenated oils
Margarine
Vegetable shortening
Other Oils - These are highly processed fats, which are pro-inflammatory and impair proper cell function:
Peanut oil
Rice bran oil
“Trans-fat free” buttery spreads
Vegetable oils may sound healthy but they require industrial processes using toxic chemicals like hexane and bleaching agents to help extraction.
Omega 3 and Omega 6 Fatty Acids
A crucial thing to be aware of is the ratio of omega-3 to omega-6 fatty acids in our diet. These are referred to as essential fatty acids as they are essential to our health and nutritional well being. Unfortunately, our bodies do not produce essential fatty acids and so we must consume them as part of a healthy diet. The rise in the consumption of vegetable oils (found in all processed foods) and the grain-feeding of cattle and poultry has altered the typical omega-3 to omega-6 ratios. Humans have evolved to eat a diet with an omega-6 to omega-3 ratio of about 1:1. Modern Western diets contain a ratio of 15:1 to 17:1. Oily fish, flax seeds and chia seeds, walnuts and walnut oil and cod liver oil are all good sources of omega-3s.
Elevated omega-6 intakes are associated with an increase in inflammatory diseases such as cardiovascular disease, type-2 diabetes, obesity, metabolic syndrome, irritable bowel syndrome, inflammatory bowel disease, muscular degeneration, rheumatoid arthritis, asthma, cancer, autoimmune and psychiatric disorders. In particular, there is a high association between a rising intake of omega-6 and increased mortality from heart disease.
Saturated fats
The Diet-Heart Hypothesis, first proposed by Ancel Keys, has little evidence to support it, yet it has managed to have a huge influence on dietary and nutrition guidelines around the world. Heart disease was rare in the 1900’s when our diets were much higher in animal fats. The elevated triglycerides in the blood linked to heart disease do not come from dietary fats, but are produced in the liver from excess sugars that come from carbohydrates, such as refined sugars and white flour and from fructose. What is contributing to heart disease is the excess consumption of vegetable oils, hydrogenated fats and refined sugars in our modern diet.
“The greatest scientific deception of this century, perhaps of any century.” - George Mann, American scientist, criticising the Diet-Heart Hypothesis: the idea that high-cholesterol foods cause heart disease.
Coconut oil
Coconut oil is one of the best fats to cook with, as it does not denature at high heats. Current research has exposed the once highly regarded 'high carbohydrate, low fat, low cholesterol' diets as harmful to our health and saturated fats as beneficial.
Coconut oil is a safe, nutritious, anti-inflammatory food. It is also a great source of fuel for the body. The medium chain triglycerides (MCTs) found in coconut oil do not need bile acids to break down. They are easily absorbed and in the liver they convert to ketones. The brain uses glucose as it’s main energy source, but ketones provide another great source. Even better, unlike glucose, which requires insulin to get into the cells, ketones do not rely on insulin and are an alternative source of fuel for brain (and other) cells that have become insulin resistant.
Coconut oil is rich in lauric acid, a fatty acid that is anti-fungal, anti-bacterial and ant-viral. Other health benefits of coconut oil include: promoting heart health, supporting the immune system, supporting a healthy metabolism, keeping skin healthy and youthful looking, providing an immediate source of energy (from the MCTs) and supporting proper functioning of the thyroid gland.
The bottom line is that populations that consume large amounts of coconut do not have high levels of heart disease and are generally in excellent health. [1] The MCTs in coconut oil can also reduce appetite and increase fat burning. Many studies are finding that these types of fats have benefits for people with Altzheimer’s.
Olive Oil
Extra-virgin olive oil is a very good monounsaturated fat, well known for its health benefits. It is also the oil of preference in healthful diets, such as all Mediterranean-style diets. [2]
However due to its chemical structure and the large amount of unsaturated fats, heating extra virgin olive oil makes it susceptible to oxidative damage. It is therefore best used cold, typically drizzled on salads and other foods. And know that even when used cold, it is extremely perishable as it goes rancid fairly quickly, due to the chlorophyll contained in it.
To protect the oil, keep it in a cool, dark place; purchase smaller bottles to ensure freshness and immediately replace the cap after each pour. Extra virgin olive oil oxidises every time it is exposed to air and/or light. In fact for these reasons, some people prefer to use the almost tasteless, semi-refined olive oil rather than extra-virgin olive oil.
Extra virgin olive oil is nevertheless full of health benefits and contains polyphenols, which act as antioxidants, reducing oxidative stress throughout the body.
High fat foods full of nutrition
Avocados are a tasty, nutritious, high-fat food that are packed full of healthy monounsaturated fats (MUFAs), as well as nearly twenty vitamins and minerals. Avocados taste great sliced up in a salad at lunchtime, mashed and spread over toast as part of a healthy breakfast, or made into a tasty guacamole.
Cheese is a great source of calcium and is rich in protein. Like other high-fat dairy products, it contains powerful fatty acids linked to all sorts of health and nutrition benefits, including reduced risk of type-2 diabetes. (I always recommend organic when consuming meat or diary).
Dark chocolate [3] is high in fat, but also loaded with nutrients and antioxidants. Studies show it is effective at improving cardiovascular health and improving brain health. Just make sure you are choosing good quality dark chocolate with at least 70% cocoa.
Whole eggs used to be considered unhealthy because the yolks are high in cholesterol. However, if you are not allergic to eggs (and many people are), they are now considered to be one of the most nutrient-dense foods and a healthy way to start the day.
Fatty fish, such as sardines and mackerel, are loaded with important nutrients and are one of the best sources of the all-important omega-3s.
Nuts are incredibly healthy and nutritious. They are among the best sources of plant-based protein. They are also a rich source of vitamin E, magnesium and healthy fats. Many nuts, particularly walnuts, are a good source of omega-3s.
Chia seeds are another good source of omega-3s and are loaded with fibre and minerals.
Full fat yoghurt is a good source of probiotic bacteria that have powerful effects on your health. Make sure you choose real, full-fat and read the label as many yoghurts are low in fat and loaded with refined sugar.