Are Seed Oils Bad For You?

Have you been hearing all of the negative reviews about seed oils recently?

They have become a very hot topic in the nutrition world. In this weeks blog post I am breaking down what seed oils are and how they affect our health.

Ready to jump in?

What are seed oils?

The term “seed oil” is a broadly used name to describe a range oils that are produced from the seeds of vegetables. These oils generally undergo more rigorous processing in order to extract the oils from leaves and seeds. The processing can involve applying high heat, chemical solvents, bleaching, and deodorizing. These steps help to improve the palatability, appearance, and shelf-life of the oils.

In today’s world it is actually quite difficult to avoid seed oils because they are found in many different food products. For example, because of their stability under high heat, they are used to prepare many deep fried fast foods. This is what many people typically think of when they talk about seed oils, but they are actually found in many other food products too such as salad dressings, mayonnaise, margarine, and baked goods.

Seed oils primarily contain a type of fat called polyunsaturated fatty acids. This type of fat actually has a positive effect on heart health and cholesterol. This is why vegetable oils are often promoted as a healthy alternative to other sources of saturated fats such as butter and lard.

Types of vegetable oils

• Olive oil

• Avocado oil

• Safflower

• Soybean

• Canola

• Corn

• Peanut

• Sesame

• Cottonseed

Potential health risks

Inflammation

Despite the potential benefits of these oils, there has been increased controversy about whether or not these oils are actually better for our health. This is thought to be mainly due to the ratio of unsaturated fats being consumed.

Both omega 3 and omega 6 are essential fatty acids. This means that our body is not able to produce these fats so we must get them through our diet. It is thought that with increased consumptions of vegetable and seed oils, the ratio of omega 6 to omega 3 consumption has shifted from 1:1 to closer to 20:1.

It has been proposed that the issue with this ratio being off is that consuming high amounts of omega 6 fats compared to omega 3 fats could contribute to inflammation and other associated conditions such as heart disease, diabetes, cancer and arthritis.

Research on this topic however is not conclusive and a causative relationship has not been proven. More research is needed to fully understand the impact that high consumption of omega 6 fats has on our body.

Oxidization

As mentioned above, seed oils primarily contain a type of fat called polyunsaturated fatty acids. This type of chemical structure makes them highly susceptible to oxidation. This means that when exposed to heat, light or air the unsaturated bonds can undergo a chemical reaction with oxygen. This reaction can lead the oil spoiling more quickly, being less palatable, having a reduced nutritive value, and even becoming toxic or carcinogenic.

Due to the risk of oxidization, it is likely best to east these oils in moderation. Including a variety of fats in your diet (i.e. saturated, monounsaturated, and polyunsaturated) and sticking to no more than 20-35% of your total daily calories from fat can help make sure you aren’t getting too much of any one type.

Presence of trans-fats

Commercial processing of vegetable oils can result in the presence of trans fats. Oils that have undergone a process called “hydrogenation” are typically highest in trans fats. Studies have proven that a high intake of trans fats can negatively impact health (e.g. contribute to heart disease, cancer, and diabetes).

In Canada, the government has cracked down banning food manufacturers from adding partially hydrogenated oils to foods sold in Canada. As of 2020 all artificially produced trans fats were removed from the food supply.

That being said, trans fats can still be found naturally in some non-hydrogenated vegetable oils. The amount of trans fats that occur naturally is very small and has not been proven to be as detrimental to health as those that are commercially made.

The Benefits

Despite the potential health risks of vegetable oils, they are still frequently used primarily due to their lower price point, neutral flavour, and high smoke point (the temperature that an oil will start to smoke).

Bottom line

When it comes to vegetable oils moderation really is key. Using vegetables oils can be a great choice, help you save money, and may offer a slight health advantages compared to other fat alternatives like shortening.

Opt for omega-3 rich vegetable oils such as olive and avocado as much as possible as these have been linked with the best effects on health. In general, it’s a good idea to limit processed foods. Not because they contain seed oils, but because they tend to be higher in sodium, sugar, and fat overall.