Evidence for Acne-Promoting
Effects of Milk and Other
Insulinotropic Dairy Products
Bodo C. Melnik
Acne vulgaris, the most common skin disease of Western civiliza-
tion, has evolved to an epidemic affecting more than 85% of adolescents
and persisting in nearly 50% of young adults. Acne is not observed in
non-Westernized populations without consumption of milk, dairy prod-
ucts and hyperglycemic carbohydrates . Well-designed prospective
studies published since 2005 provide evidence that components of
Western diets, particularly milk and dairy products and diets enriched
in carbohydrates with high glycemic index and glycemic load are asso-
ciated with acne .
Insulinotropic food, especially refined sugars and grains, potatoes,
milk and dairy products are ubiquitous elements in Western diet, and
comprise nearly 50% of the per capita energy intake. The combination
of milk with hyperglycemic carbohydrates potentiates hyperinsuline-
mic responses in comparison to the single components. Milk and whey
protein-based products elevate postprandial insulin and basal IGF-1
plasma levels .
Increased insulin/IGF-1 signaling plays a most important role in
acne pathogenesis . A correlation between increased facial sebum
secretion and IGF-1 serum levels has been reported in acne patients,
whereas treatment with the sebum-suppressive drug isotretinoin
decreases IGF-1 serum levels. Epidemiological studies confirmed the
correlation between milk consumption and acne as well as milk pro-
tein consumption and increased IGF-1 plasma levels.
It is the principle of mammalian milk to promote growth and sup-
port anabolic conditions for the neonate during the nursing period.
Whey proteins are most potent inducers of glucose-dependent insu-
linotropic polypeptide secreted by enteroendocrine K cells which in
concert with hydrolyzed whey protein-derived essential amino acids
stimulate insulin secretion of pancreatic ?-cells (fig. 1). Increased
insulin/IGF-1 signaling activates the phosphoinositide-3 kinase (PI3K)/
Akt pathway, thereby reducing the nuclear content of the transcription
factor FoxO1, the key nutrigenomic regulator of acne target genes .
Nuclear FoxO1 deficiency has been linked to all major factors of acne
pathogenesis, i.e. androgen receptor transactivation, comedogenesis,
increased sebaceous lipogenesis, and follicular inflammation (fig. 2).
Acne is associated with disorders of increased growth factor sig-
naling and insulin resistance, like polycystic ovary syndrome, acro-
megaly and Apert syndrome. All these diseases are associated with an
increased incidence of cancer. Severe acne in males has recently been
associated with an increased risk of prostate carcinoma, and a meta-
analysis confirmed the relationship between high intake of dairy prod-
ucts and increased risk of prostate cancer.
Chronic overstimulation of humans of Western countries from
the beginning of life to adulthood by a most potent postnatal growth
IR-B IR-A IGF1R
Milk growth factor signaling
KERATINOCYTE and SEBOCYTE
Fig. 1. The impact of milk protein consumption on the entero-insular-
pilosebaceous signaling network. BTC = ?-Cellulin; AA = essential amino
acids; GIP = glucose-dependent insulinotropic polypeptide; GH = growth hor-
mone; IGF-1 = insulin-like growth factor-1; IR = insulin receptor; IGF1R =
IGF-1 receptor; EGFR = epidermal growth factor receptor.
factor signaling system of a different mammalian species is an over-
looked severe health hazard of human nutrition. The interference of
the bovine milk growth factor signaling system with the human intrin-
sic insulin/IGF-1 axis has been proposed to be the major cause of most
chronic Western diseases .
There are only two solutions to this problem: the restriction of
milk consumption or the elimination of the insulinotropic effectors
of milk. The attenuation of whey protein-based insulinotropic mecha-
nisms will be the most important future challenge for an interdisci-
plinary cooperation between medicine, nutrition research and milk
processing biotechnology. When the insulinemic index of milk has
been adjusted to a level corresponding only to its carbohydrate moi-
ety, we will look again into acne-free faces of less obese young people.
Hormone signaling of puberty
Milk and CH with high GL and GI
Fig. 2. Overstimulating effect of milk-derived growth factor signaling on
PI3K/Akt/FoxO1 pathway. Milk protein-derived growth factor signaling is
superimposed on physiological growth hormone-mediated PI3K/Akt signaling
of puberty overstimulating nuclear export of FoxO1. Nuclear FoxO1 deficiency
results in androgen receptor (AR) transactivation, increased follicular prolif-
eration (comedogenesis), increased sebaceous lipogenesis and follicular
inflammation. CH = Carbohydrate; GL = glycemic load; GI = glycemic index.
Table 1. Proposed impact of milk-induced GIP/insulin/IGF-1 oversignal-
ing in the pathogenesis of acne and other chronic Western diseases 
Prenatal Increased insulin-
in the thymus
growth and maternal
Disturbed T cell
impaired T cell
of the somatotropic
Postnatal Increased GIP,
insulin and IGF-1
Early onset of
Early onset of
of the insulin/
of neuronal cells
GIP = Glucose-dependent insulinotropic polypeptide.
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The author predicts that the generation of less insulinotropic milk and
milk products (insulinemic index <45) will have an enormous impact
on the prevention of epidemic Western diseases like obesity, diabetes
mellitus, cancer, neurodegenerative diseases and acne (table 1) .
Acne, the mirror of exaggerated insulinotropic Western nutrition, is a
most useful clinical and epidemiological indicator of appropriate or
inappropriate human nutrition. A decrease in diet-induced acne will
be associated with a decline in the prevalence rates of more serious
Western diseases developing with longer latency periods after the acne
peak in adolescence.
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Melnik BC: Milk – the promoter of chronic Western diseases. Med Hypotheses