It seems like every month a new report pops up declaring another food that causes acne. One day bread is the culprit. The next week, it's milk that is giving you zits. A month later, the headlines scream that chocolate is the real cause. Are any of these reports trustworthy? In reality, there's some truth in all these claims, but the full story is a bit more complicated.
The Diet-Acne Relationship
A pimple, simply defined, is a clogged hair follicle--also known as a pore--that has become infected by a common type of bacteria called Propionibacterium acnes. This species of bacteria is incredibly common and, most of the time, lives all over your skin without causing any trouble. Zits start to pop up when other problems with your skin give these bacteria a chance to move in and multiply. In fact, you can think of a bad breakout as an unwanted and out-of-control bacteria party.
The real connection between diet and breakouts has to do with the behavior of an important type of skin cell called keratinocytes. These cells form the outer layers of your skin, and they rely on hormones to tell them how quickly to copy themselves to make new skin. Under normal conditions, these cells make a new copy right before they die and slough off in the shower.
According to dermatologists, certain foods generate hormone responses that can cause these cells to go haywire. Specifically, foods that increase blood sugar cause the body to produce extra insulin, and that signals keratinocytes to stay alive longer than normal and to reproduce themselves faster than normal. In fact, prolonged high levels of insulin cause these cells to divide so quickly that they become, in the words of Professor Loren Cordain of Colorado State University, "overly adherent to one another and do not separate normally." In other words, too much insulin in the blood leads to clumps of sticky, unneeded skins cells clogging up the pores.
These sticky skin cells are a little like a traffic jam--they gum up the works and make it harder for your skin to take care of itself. Normally, your immune system is very good at shutting down bacteria on your skin, just like the police shut down rowdy parties. But keratinocyte traffic jams prevent the immune system from attacking bacteria growing deep inside your pores. That's when the bacteria kegger really gets going, and you end up with a gross whitehead.
What Foods Really Cause Acne?
The truth is that any kind of food that significantly raises blood sugar can cause acne because they all trigger your body to produce more insulin. That means that bread, chocolate, crackers, pasta--anything with lots of simple carbohydrates--can lead to breakouts.
But that doesn't mean you have to eliminate sugar and carbs from your diet completely if you want to have clear skin. The trick, according to dermatologists, is to replace foods that cause large, rapid spikes in your blood sugar level with foods that cause milder, slower increases. This is called a "low glycemic load diet," and it doesn't require eliminating everything delicious.
There are a few general rules to move you in the right direction:
First, prefer foods made with whole grains over foods made with processed grains. A serving of white rice has roughly the same amount of carbohydrates as a serving of brown rice, but brown rice has a much lower glycemic load. The tough outer shell that makes brown rice brown slows down the digestive process, so the carbs enter your system at a much lower rate. That keeps insulin production down, leading to healthy skin. The same goes for white bread and wheat bread. White bread spikes your blood sugar almost instantly, but wheat bread takes a bit longer to digest.
Second, seek out natural sweets like fruits. Many fruits contain lots of sugar, but unlike candy bars or sodas, they contain lots of natural fiber. This fiber, like the shell around a grain of brown rice, takes more time for your digestive system to break down. As a result, the sugar inside a strawberry or a peach trickles into your bloodstream while a candy bar's sugar washes in like a waterfall.
Third, avoid dairy products. Milk, cheese, and yogurt don't actually raise your blood sugar like candy bars and white bread, but Dr. F. William Danby of Dartmouth Medical School says they still contribute to acne. The reason is that dairy products contain hormones called "androgens" that can cause your skin to overproduce a different substance called sebum which can also clog up pores.
Acne is unpleasant, but most people don't need to dramatically change their diets to keep their skin happy and healthy. Reducing your sugar conception, eating lots of foods with healthy fiber content, and resisting the temptation of an ice cream cone on a hot summer day can keep your pores clean and clear.
Clinics in Dermatology. "Diet and acne."
Seminars in Cutaneous Medicine and Surgery. "Implications for the role of diet in acne."