We've heard it over and over again: your diet does not cause acne. However, there are a handful of doctors who believe that what we eat may indeed affect our skin. And they're not pointing fingers at chocolate and potato chips, but instead at milk. That's right -- the wholesome drink that we've always considered healthy is at the center of an acne controversy.
Researchers claim to have found a correlation between milk intake and the incidence of acne. It seems milk drinkers develop more severe acne than non-milk drinkers. One study, published in the May 2008 issue of the Journal of the American Academy of Dermatology, looked at the diets of teenaged boys. The young men who drank the most milk also tended to have the worst acne.
This supports the results of previous studies, during which teenage girls were asked to keep food diaries and monitor breakout activity. Again, girls whose diets were rich in dairy products had more severe acne than the rest.
Of all dairy products, milk was the worst offender. Chocolate milk, cottage cheese, and sherbet also had a negative effect on the skin. But other dairy products didn't seem to cause breakouts.
Interestingly, skim milk induced breakouts more often than whole milk, so it seems fat content in milk isn't the culprit. And those who took vitamin D supplements didn't have more breakouts, so vitamin D isn't thought to be the cause either.
Fatty foods also didn't trigger breakouts. And the foods that many people associate with causing acne -- chocolate, pizza, soda, and French fries -- didn't seem to increase breakout activity at all.
Why would certain dairy products contribute to acne? Some think it's the hormones found in milk. Milk contains androgen hormones, which have long been associated with the formation of acne breakouts.
Testosterone is an androgen hormone, and it is strongly linked to acne development. It's most often thought of as a male hormone, but women produce testosterone too, although in lesser amounts.
Testosterone, through a complicated chain reaction, creates di-hydrotestosterone (DHT). DHT stimulates the sebaceous glands, creating an oilier skin that is more prone to pore blockages and, ultimately, pimples. Milk naturally is filled with hormones, including DHT. It's possible that milk contains enough hormones to have an effect on the body, including the skin. People who are genetically predisposed to acne breakouts may have a stronger reaction to the hormones in milk, according to some researchers.
Many dairy farmers also give their cows additional hormones to stimulate milk production and enable the cow to produce more milk. As a result, most milk is very high in IGF-1. IGF-1 is a growth factor that peaks in the human body during adolescence, when acne is usually at it's worst. It is believed that IGF-1, along with testosterone and DHT, trigger acne breakouts.
In two previous studies, high milk consumption was linked to high IGF-1 levels. Again, skim milk was associated with higher IGF-1 levels than whole milk.
The processing of skim milk may explain why it is linked to acne severity more often than whole milk. Whey proteins are added to give skim milk a creamier consistency. Some speculate that these proteins impact acne development.
Of course, not everyone who drinks a lot of milk breaks out in pimples, and many disagree with these findings. The Dairy Council counters that the results are skewed, citing the fact that in one study, adult women were asked about their dairy intake during the years after they left high school.
And many medical professionals are wary of the conclusions being drawn, because they don't take into account other factors that may influence acne severity. They're also quick to point out that the studies don't link milk to acne development -- they only establish a correlation between milk consumption and acne severity.
The biggest problem for researchers is proving their controversial theory. There is no way to do a double-blind, randomized controlled trial (considered the gold standard in research), because there is nothing that can be used as an adequate placebo for milk.
But some doctors are taking a new view of how diet affects the skin, and this no-dairy philosophy has its believers. Some dermatologists say they have had some success in having their patients cut milk and dairy from their diets.
There is still no hard evidence proving milk consumption causes, or worsens, acne. Much more research is needed before this theory can be proven. However, decreasing milk intake may be helpful, especially for those whose acne isn't responding well to more conventional treatments.
In the meantime, you can stick to the advice that doctors have given for years: avoid any foods that seem to worsen your breakouts whether that be pizza, chocolate, oranges, or dairy products.
Adebamowo CA, Spiegelman D, Berkey CS, Danby W, Rockett HH, Colditz GA, Willet WC, Homes MD. "Milk consumption and acne in adolescent girls." Dermatology Online Journal 2006; 12(4):1.
Adembamowo CA, Spiegelman D, Berkey CS, Danby FW, Rockett HH, Colditz GA, Willett WC, Holmes MD. "Milk consumption and acne in teenaged boys." Journal of the American Academy of Dermatology 2008; 58(5): 787-793.
Adebamowo CA, Spiegelman D, Danby W, Frazier AL, Willett WC, Holmes MD. "High school dietary dairy intake and teenage acne." Journal of the American Academy of Dermatology 2005; 52(2): 207-214.
Smith R., Mann N., Braue A., Mäkeläinen H., Varigos G. "The effect of a high-protein, low glycemic-load diet versus a conventional, high glycemic-load diet on biochemical parameters associated with acne vulgaris: A randomized, investigator-masked, controlled trial." August 2007. Journal of the American Academy of Dermatology, volume 57, issue 2, pages 247-256.