Vegetable oil is one of the essential food ingredients. It is used to cook almost all foods. Oil is used in so many different ways to enhance the flavor of food, or give food a certain texture. Since oil is used frequently, many households tend to reuse oil in a bid to minimize wastage. This is extremely unsafe and can lead to a number of health problems.


  • Production of Free Radicals: Reusing oil can create free radicals which are prone to cause ailments in the long run. Free radicals attach themselves to the healthy cells in the body and in this way, lead to diseases. These free radicals can be carcinogenic, which means they can cause cancer. The free radicals can also be atherosclerosis which means that they can lead to increase in bad cholesterol levels.
  • It Increases Low Density Lipo-protein Cholesterol: Food cooked in oils that have turned black or are smoked can increase level of Low density lipo-protein or bad cholesterol in the body. High levels of LDL cholesterol can increase risk of heart disease, stroke and chest pain.
  • Increased Acidity: Reusing oil can cause burning sensations in your stomach and throat. When you notice this sensation, avoid eating road side junk and deep fried foods.

Although the health risk of reusing oils is plenty, you can still reuse oil if you do it in the right way and adhere to certain directives. There is actually no set number of times you can reuse oil, this depends on some factors like; type of oil used, oil heating time, what the oil is used for (deep frying or shallow frying) and what type of food was cooked in it.

Though a fresh batch is good to use every time, it may not always be possible. But if done correctly, the negative effects and risk could be reduced . Here are some points to help reuse oil safely

  • Make sure the leftover oil from cooking or frying is left to cool. After cooling it should be transfered into an airtight container using a strainer/muslin cloth. This will help to remove food particles in the oil. Presence of such food particles can spoil the oil much sooner than expected.
  • Make sure to check the colour and thickness of the oil each time before reusing. If it is dark in colour and more greasy/sticky than usual, it is best to change the oil.
  • If the oil is more smoky than usual when heating, you need to discard it and use a new one. It may have accumulated HNE which is a toxic substance that has been associated with various diseases like stroke, liver diseases etc.

Remember that all oils are not the same, some have higher smoking point than others and therefore can be used for deep frying. Such oils do not break down on high temperatures. They include oils like soybean oil, sunflower oil, safflower oil, peanut oil, sesame oil, mustard seed oil and canola oil. Oils which have low smoke point should only be used for sauteing as they do not require high temperature. So try to use the right oil for cooking and frying.


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