Are Vegetable and Seed Oils Bad for Your Health?

Many of the claims that vegetable oils such as canola and soybean oils have toxic effects are unsupported by any solid scientific evidence. According to the American Heart Association (AHA), vegetable oils are good for your health because they are rich in unsaturated fats and low in saturated fats.

In the past, it was believed that unsaturated fats are more likely to undergo oxidation and produce toxic chemicals when subjected to high temperatures while cooking. Harvard experts, however, put this concern at rest by stating that this is not a problem in home cooking, where oil is frequently changed. In restaurants that use the same oil over and over again for deep frying, vegetable oils are bad for health.

Another concern about using vegetable oils is their high omega-6 fatty acid content. However, research suggests that omega-6 fats in whole foods are not bad for your health. Rather, they help lower blood cholesterol and sugar levels and reduce the risk of heart disease. 

Of course, any foods that are highly processed and deep fried in vegetable oils are high in trans fats and refined carbs that can trigger inflammation in the body, leading to health problems such as diabetes, high blood pressure, and heart disease.

Vegetable oils are extracted from different parts of the plants, such as seeds, nuts, grains, and fruits. Seed oils are a type of vegetable oil extracted from plant seeds. 

Popular sources of vegetable oils include:

• Olives
• Coconuts
• Sesame seeds
• Soybeans
• Safflower
• Groundnut
• Canola
• Palm
• Mustard
• Almond
• Cottonseed
• Rice bran

There are several processes used to extract vegetable oils. One method is called cold pressing, which does not involve heat and is often used to extract virgin coconut or olive oil. During extraction, olives are pressed to release the oil, which is then filtered before use.

In most cases, complex extraction and refining are done to impart desired flavor, aroma, and color to the oil. This involves multi-step processes, such as heat extraction, bleaching, and deodorization.

Vegetable oils can be incorporated into a healthy diet. According to the Dietary Guidelines for Americans, fats should make up 20%-35% of your daily calorie consumption. 

To reap the maximum benefits from vegetable oils, follow these tips:

• Choose oils that are more resistant to oxidation, such as extra-virgin olive oil
• Read labels for trans fat content on vegetable oil containers
• Do not cook at very high temperatures
• Avoid reusing oils
• Avoid using oil that has become rancid
• Limit oil consumption by sautéing, steaming, and baking instead of frying
• Use oils with a high smoke point such as sunflower, palm, and refined olive oil for purposes such as frying, searing, or browning

The smoke point of an oil is the temperature at which it starts producing smoke, at which point it can contain harmful chemicals. More refined oils have higher smoke points. Some oils, such as flaxseed, walnut, and wheat germ oil, are considered no-heat oils due to their low smoke points. They can be used to make dressings or marinades.