Peanut oil will have the highest proportion of saturated fat, and when the iodine test is performed, will require the longest time to lose its purple color.

Cholesterol and saturated fat

The two types of cholesterol in our body are known as Low Density Lipoproteins (LDP) and High Density Lipoproteins (HDP). The unhealthy cholesterol, LDP, increases the risk of heart disease while the healthy cholesterol, HDP, lowers that risk. As the consumption of saturated fats is likely to increase the levels of LDP in our bodies, using cooking oil with a lower level of saturated fat can provide for better health.

Saturated fat is normally found in foods such as butter, fatty meat, cheese, cream, chocolate and pie. To lower the intake of saturated fat and reduce one’s cholesterol levels, it is better to consume lean meat and low-fat dairy products instead of their higher-fat alternatives. Healthier substitutes for saturated fats are polyunsaturated or monounsaturated oils, which can be found in olive oil, fish oil and cornflower oil. In particular, eating fish for their Omega-3 polyunsaturated fat content can protect the blood arteries by preventing blood clots.

Besides consuming less saturated fat, regular exercise can also help to reduce the level of cholesterol in our blood.
 

The hypothesis that peanut oil will have the highest proportion of saturated fat, and will take the longest time to become revert to its original color, was proven to be true. Peanut oil has the highest saturated fat content and the lowest proportion of unsaturated fat among the 5 types of cooking oil tested. As iodine reacts with unsaturated oil to lose its color, a lower proportion of unsaturated oil content will require a longer reaction time for the iodine in the oil to lose its color.

The consumption of unsaturated fat instead of saturated fat is recommended to maintain a healthy heart, as well as to reduce the  risk of stroke and cancer. Oils that are low in saturated fat and high in unsaturated fat should be used in cooking. Consuming more soluble fiber that is found in fruits and vegetables can help to reduce the cholesterol levels in the blood.
 

What would happen if the science fair project was repeated using different types of oils like oil palm, coconut oil or sunflower oil?

The science fair project can be also repeated to measure the amount of iodine required for all the unsaturated fat in the oil to react.