Fat is an important part of the diet and is necessary for the body to function properly. But can the wrong types of fat, or too much fat, lead to acne? First let's look at the types of fat and how they differ.
Specific Types of Fat - Why A Balance Is Important
Fat comes in various forms, some of which are good for the body, and some of which are potentially harmful. Since the skin is the body's biggest organ, it stands to reason that the type of fat consumed might also affect the skin.
Omega-3 and omega-6 fatty acids
Two of the most important fats in food are fatty acids called omega-3 fatty acids and omega-6 fatty acids. In a typical Western diet, it is far more difficult to consume adequate amounts of omega-3 fatty acids than it is to get the omega-6 fatty acids that your body needs.
Fish and seafood are rich in the omega-3 variety. Oils, nuts, some meats, some vegetables, and some grains are high in the omega-6 variety.
When too many omega-6 fatty acids are consumed and too few omega-3 fatty acids, inflammation may result. Since acne is primarily an inflammatory disease, this could hypothetically lead to more acne.
In a 2009 Dermato-Endocrinology article, the author stated:
“Epidemiological studies have shown that increasing the intake of omega-3 fatty acids through a diet rich in fish and seafood lowers rates of acne.”1
In order to maintain a healthy balance between these two fatty acids, we should consider the ratio of omega-6 to omega-3 fatty acids in various diets. A ratio is the relationship between two items.
For example, one serving of food may contain 2 omega-6 fatty acids and 1 omega-3 fatty acid. This would be a 2:1 (two-to-one) ratio. One serving of a different food may contain 10 omega-6 fatty acids and 1 omega-3 fatty acid. We would call this a 10:1 (ten-to-one) ratio.
Research suggests that as the ratio of omega-6 to omega-3 fatty acids increases, inflammation also increases.2 As shown in the chart below, the ratio of omega-6 fatty acids to omega-3 fatty acids in the average Western diet is far greater than that in an average non-Western diet.1-3 Moving our diet back toward a non-Western ratio might help reduce bodily inflammation, and thus, acne.
Can Eating Fat Increase Skin Oil Production In the Skin and Lead to More Acne?
The skin contains millions of pores, where acne can form. Attached to the sides of these pores are tiny glands called sebaceous glands, whose job is to produce skin oil. This skin oil, called sebum, is comprised of various fats.
More sebum normally means more acne. So, would eating too much fat in the diet cause the body to over-produce sebum? We don't know this yet, but let's have a closer look at sebum and how eating fat might affect it.
Sebum is made of different types of fat, such as triglycerides, free fatty acids, and cholesterol.
Fatty and oily foods also contain triglycerides, free fatty acids, and cholesterol. One fatty acid in particular, palmitic acid, is of particular interest when we look at how food might affect sebum development. Palmitic acid is present in many foods, including red meat, butter, milk, cheese, and some oils like palm oil, soybean oil, and corn oil.
Palmitic acids - can this fatty acid lead to sebum production?
Sebaceous glands use palmitic acid to form wax esters, which are types of fat that are found only in sebum. This means that the body uses palmitic acid specifically to produce sebum since wax esters are not found elsewhere in the body. This led the researchers to believe that diet probably influences sebum production and, consequently, acne formation.4
However, we must remember that sebum production is a normal process.9 Although scientists know that palmitic acids are used to make wax esters and that wax esters are used to produce sebum, its role in acne formation remains unknown.
In short, we simply do not know at this point whether eating more fatty foods, or even fatty foods high in palmitic acid, will increase sebum production. To know the answer to this, researchers will need to perform a long-term randomized controlled trial (RCT), and this has yet to occur.
High-Calorie Content of Fatty Foods
Fat is high in calories. In fact, one gram of fat contains 9 calories, while one gram of carbohydrate or protein contains only 4 calories.
High-calorie, fatty fast food options, such as hamburgers, fries, and pizza, are easy to obtain and eat. One study suggests that, on average, a person visiting a fast food restaurant buys a meal containing 827 calories. That one meal makes up almost half of the normal daily calorie intake—2000 calories for an average adult.
Since fatty foods tend to be high in calories, researchers have considered whether the high-calorie content of fatty food contributes to acne rather than the fat in the food itself.5
How increased calories might lead to more acne
The number of calories in the diet directly affects the levels of certain substances in the body, such as glucose, insulin, and insulin-like growth factor 1 (IGF-1).6,7 Eating high-calorie foods can bring about high glucose levels. One of the functions of insulin and IGF-1 is to help keep glucose levels normal. When glucose levels are high, levels of insulin and IGF-1 also may increase in order to help bring glucose levels back to normal. High levels of insulin and IGF-1 have been linked to increased sebum production.
In other words, since increased sebum production contributes to acne, high-calorie fatty foods might contribute to acne formation through indirectly increasing insulin and IGF-1.8
Surveys Investigating the Potential Link Between Fatty Foods and Acne
Researchers have conducted questionnaire surveys investigating the potential link between fatty foods and acne. The results of these surveys hint at an association between certain foods, including fatty foods, and acne. However, unlike randomized controlled trials (RCTs), which can tell researchers if one factor causes another, survey studies only give us a glimpse at a big picture at one point in time. Since surveys are far less reliable than RCTs, we cannot use them to draw a definitive conclusion on fatty food and acne.
Results of the surveys are presented in the chart below.
Based on the lack of any RCTs, evidence linking fat intake to acne formation is weak.14 In order to determine whether there is a relationship between fatty foods and acne, researchers will need to conduct RCTs.15