In the past thirty years, refined oils have become ubiquitous in every kitchen. But very few people know that refined oils are slow killers and have many deleterious effects on your health.

What are Refined Oils?

Refined oils are purified form of unsaturated fats. Unsaturated fats from olives, sunflower, soybean, and other vegetable and seeds are extracted into oils and further processed using chemicals to refine it. This chemically processed unsaturated fat is marketed as “refined oils”. They are lighter, odorless and have an extended shelf life because of refining.

Refined Oils Are  Slow Killers – How are Refined Oils Made?

Vegetable oilseeds are collected, dried and blended to extract oils. These oils are subjected to a series of chemical processes such as filtration, heating, bleaching, steam distillation and deodorizing to remove impurities, odor, and other substances.

Oil refining is done in two methods namely alkaline refining and physical refining.


Alkaline Refining

Alkaline refining includes five major steps,

    1. Degumming: It is done to remove hydratable phospholipids and metals.
    2. Transforming: Conversion of non-hydratable phospholipids into hydratable phospholipids through the addition of phosphoric or citric acid.
    3. Neutralizing: Washing the lipids with excessive amounts of sodium hydroxide solution.
    4. Bleaching: The oil is then “bleached” using acid-activated clay to improve its color absorption properties.
    5. Deodorizing: Finally, the oil is “deodorized” using steam distillation process at high temperatures and low pressure to remove volatile substances such as aldehydes and ketones.

All these processes are commonly done to refine seed oils while sunflower oils are subjected to another step called the “dewaxing” to remove the wax esters and then, it is filtered.


Physical Refining:

Physical refining is the process of removing free fatty acids using a steam distillation process. These fatty acids have low volatility and require higher temperatures to remove them completely. The oil treated using alkaline refining is subjected to physical refining.

What Does Refining Do to the Oil?          

Refining involves exposure to a lot of chemicals, a combination of high/low temperatures and inert gas which can strip off the nutrients and vital minerals in the oil. At high temperatures, the oil loses natural tocopherol (Vitamin E) and the amount of essential unsaturated fatty acids such as Omega-3 and omega-6 decreases. Therefore, certain companies add artificial Vitamin E and Vitamin D to increase these levels after refining.

Alkaline refining leads to emulsification and saponification of the oil where sulphuric acid and sodium sulfate are added to separate the soaps from the oil. This leads to loss of sterols in the oil. Extreme temperatures can lead to the formation of polymeric compounds and conjugated fatty acids which are harmful to health. Deodorization of oil using high temperature can lead to the production of higher amounts of triglycerides which are also toxic in nature. In rare cases, coconut oil extracted from copra dried using non-purified smoke gases leads to the formation of a carcinogenic compound called polycyclic aromatic hydrocarbons (PAM).

Hydrogenation is a common process used to modify the nature of fats using hydrogen gas, liquid oil, and solid silica or alumina catalyst which produces trans fats that have adverse effects on the body.

How Refined Oil Can Affect Your Health?

Though oil refining is commonly practiced to remove impurities and non-glycerides, enhance the taste, aroma, appearance, and shelf-life, it still major results in the loss of vital vitamins and nutrients in the oil. Chemicals used for oil refining and its potential side effects include,

  • Digestive Problems: Sodium sulfate is used to remove soap from the oil during the oil refining process. This chemical is known to cause some severe side effects such as bloating, stomach pain and vomiting.
  • Respiratory Problems: Sodium hydroxide is used for neutralizing the lipid content in the oil and repeated exposure can lead to lung damage and chest pain.
  • Cardiovascular Diseases: Employing acid-activated clay for bleaching edible oil can reduce iron and chlorophyll levels while increasing free fatty acids content which is detrimental to cardiovascular health.
  • UI Problems: Phosphoric acid is used in oil refining which can reduce bone density, trigger kidney, urinary problems, and damage tissues.

Oil refining involves exposing the oils to high temperatures which leads to the formation of several toxic substances such as,

  • Trans Fats: Trans fats increase LDL cholesterol levels leading to the risk of developing cardiovascular diseases and stroke. It is also considered a risk factor for diabetes and obesity.
  • High Triglycerides: Higher amounts of triglycerides can cause high blood pressure, cholesterol, inflammation, atherosclerosis, and obesity.
  • Polycyclic Aromatic Hydrocarbons (PHA): It is carcinogenic in nature and causes skin, lung and bladder cancer. Other effects include kidney and liver damage, and inflammation.

Regular consumption of artificially enhanced vitamin-rich refined oils can increase the risk of developing lifestyle diseases. Therefore, refrain from using refined oils and choose whole fats such as butter and ghee or buy cold-pressed nuts and seed oils such as extra virgin olive oil, avocado oil, mustard oil, and peanut oil.