Higher intake of high-fat, high-sugar foods was associated with a higher incidence of current acne. For example, compared with those with no history of acne, those with acne at the time of the survey were 76% more likely to report drinking at least five glasses of milk in the previous day, more than twice as likely to report consuming at least five servings of high-sugar drinks in the previous day, and eight times more likely to report consuming “a complete meal of fatty and sugary products” in the previous day.
Fast foods and snack foods were linked with past (rather than current) acne. And chocolate? Neither dark nor milk chocolate were associated with past or current acne.
There are reasons to interpret these results cautiously. Dietary records can be faulty. For example, a person with acne who strongly believes that diet affects their skin health may be more likely than others to recall and report certain elements of their diet (such as fatty or sugary foods) than those who are more skeptical about a connection. Such recall bias can affect the results of a study like this. And many of those who reported having adult acne were self-diagnosed; it’s possible that some of these diagnoses were not accurate. Other factors — so-called confounders — might be at play and lead to misleading conclusions. For example, maybe people who drink more milk also happen (just by chance) to live in more polluted areas, and it’s the pollution, not the milk, that explains the findings.
Finally, studies like this can only detect an association, not causation. That means that while those with adult acne tended to consume more fatty and sugary foods, the study cannot prove that their diet actually caused adult acne. It also could not determine whether a change in diet would reduce the incidence or severity of acne.
The bottom line
As our understanding of acne continues to evolve, we may eventually have clearer guidelines about the best diets to prevent or treat it. For now, whether you’re a teenager or an adult, it’s likely that there is no single diet that will guarantee clear skin. So enjoy your favorite foods in moderation. And if you find that some of them make your skin worse, you’ll have to decide if they’re worth it.
(Robert H. Shmerling, M.D., is a senior faculty editor at Harvard Health Publishing.)