Excessive body fat decreases the risk of dementia.
Acne: According to a 2015 study, trans fats are one of several components of Western pattern diets which promote acne, along with carbohydrates with high glycemic load such as refined sugars or refined starches, milk and dairy products, and saturated fats, while omega-3 fatty acids, which reduce acne, are deficient in Western pattern diets
 Conversely, syphilitic dementia was widespread in the developed world until it was largely eradicated by the use of penicillin after World War II

