A link between diet and acne have long been suspected by patients. While this wasn’t always the case, there is now more academic interest in this area. The potential link between the Western diet and acne is also discussed. We review a 2018 observational study from China that studies the possible link between milk consumption and acne.
Background
A link between diet and acne has been a concern for patients. Traditionally, there has been a discrepancy between public perception and the dermatology community’s opinions on the topic of the relationship between foods and acne. This is, in part, due to the difficulty to quantify and validate the association within the context of a clinical trial. In recent years, however, the relationship between diet and acne is gaining more attention, not just from the public but also from the medical community. Skim milk, in particular, is being researched as a potential trigger for worsening acne.1
Methodology
Pubmed, Embase, Medline, and Cochrane Library databases for studies were used to identify 4 cohort studies (studies of groups of people that share a common characteristic, in this case, consumption of milk), 9 cross-sectional studies (studies that focus on a population at a specific point in time), for a total of 71,819 participants.2 A stochastic approach is taken, pooling the odds to create a ratio. Subgroup analyses based on severity were also conducted. In effect, this is a study of studies to draw out general trends among the study findings.
Results
There is a significant increase in the incidence of acne among those who drank milk. In mild acne, there was no statistically significant difference between milk drinkers and non-milk-drinkers. However, for moderate and severe acne, there was a substantial correlation between milk consumption and acne. A high intake of milk also had an impact on acne formation. Interestingly, while this association was clear with North American and European populations, a similar association was not found in Asia, Africa, and South America.
Studying the various types of milk (low fat, skim), the authors of this study further note that the fat content within milk likely does not affect acne. Instead, the volume of milk intake seems to be causing increased acne. The stronger correlation between those who drink skim milk and increased severity and incidence of acne is hypothesized to be due to the lower satiety of skim milk due to lower fat content. That is, skim milk drinkers likely drink more milk, triggering a worsening of acne.
The Takeaway
The challenge, as always, is teasing out meaningful conclusions from the available data. Correlation does not imply causation – and there are likely many causes of acne. The authors of the study also prudently note that there are several limitations with the review – including a lack of precise controls and representation from specific populations. Further studies in this area will be needed.
With that caveat, the authors note that there may be several possible pathways in which dairy can directly impact acne formation and severity:
- Dairy cows are treated with various hormones (bovine growth hormone in the US) to produce milk in larger quantities.3 This can throw a person’s hormone balance off, triggering acne.
- The dairy itself may have components (dairy milk has growth hormones and steroids to facilitate the calf’s growth) that may trigger acne.
- These factors may combine with other factors like increased levels of refined sugars and other processed sugars typical in the Western diet,4 to make acne more likely or severe.
- We don’t yet understand the mechanisms of how various hormones and acne interact. The authors suggest a comparative study into full fat vs. skim milk and the possible effects of pasteurization.
Again, there are many potential triggers to acne, and these factors are very individual. If you suspect that dairy consumption worsens acne for you, that is a good reason to avoid dairy products. The evidence that dairy can interact with acne is substantial, even if we do not understand the mechanism. On the other hand, if you consume dairy regularly and have no acne issues, there is likely no need for concern.
1https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4106357/
2For those interested in the cited studies: A word document can be downloaded from this link: https://onlinelibrary.wiley.com/doi/pdf/10.1111/jdv.15204
3https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4106357/
4https://dermletter.com/skin-care-science/non-western-acne.html
