DairyA study from the Harvard Schoo

Dairy
A study from the Harvard School of Public Health indicates that dairy products, and in particular skim milk, may trigger acne breakouts. While more rigorously collected data is needed to confirm the correlation, evidence shows that certain dairy products may aggravate acne because of their hormone and bioactive molecule content.

Cows receive hormones to increase milk production, and residues of those hormones pass to humans in the milk. This can cause an increase of sebum (oil) production, which clogs pores and allows bacteria to grow on the skin, leading to skin inflammation and acne breakouts.