n-3 and n-6 Fats

Both n-3 and n-6 fats are needed by the body but the correct balance between the two is needed for good health.

Polyunsaturated fats n-3 and n-6

The most important nutritional feature of fish is its high level of long chain polyunsaturated fats (PUFA). There are 3 main categories of fats - saturated, polyunsaturated and monounsaturated.

Polyunsaturated fats or PUFA can be further divided into n-3 and n-6 fats. This division is based on their chemical structure. In the n-6 family the first double bond of the molecule is found between the 6th and 7th carbon atom from the methyl end. In the n-3 family the first double bond is found between the 3rd and 4th carbon atom from the methyl end. PUFA can be short, medium or long chain fats depending on the number of carbon atoms each one has. Long chain PUFA, such as the n-3 fat eicosapentaenoic acid found in fish, have 16 carbon atoms or more. Both n-3 and n-6 fats are essential for health, as the human body cannot make these fats. n-6 Fats are found in vegetable oils such as sunflower, corn and soybean oil. n-3 Fats are found in rapeseed/canola oil and in oil-rich fish.

Humans evolved eating a diet with about equal amounts of n-3 and n-6 fats but over the past 100 to 150 years there has been a huge increase in our intake of n-6 fats. This is due to an increased intake of vegetable oils high in n-6 fats in an effort to reduce cholesterol. There has also been a decrease in fish consumption. In the past the ratio of n-6 to n-3 fats was 1-2:1 but now it is estimated to be between 8-20:1. Both n-3 and n-6 fats are needed by the body but the correct balance between the two is needed for good health.