Table 1.

Select diets and their association with acne

Diet	Role in acne pathophysiology	Acne findings	References
Low GL ± low GI	Reduces free androgens, increases IGFBP-3, and decreases IGF-1 levels	Evidence supportive of reduction in lesion quantity and severity of lesions	Smith et al. [39], Smith et al. [40], Burris et al. [41], Smith et al. [42], Çerman et al. [45], Burris et al. [46], Burris et al. [47], Smith et al. [51], Kwon et al. [52]
Dairy	Milk increases insulin and IGF-1 levels	Evidence supportive of association of milk and whey proteins in increasing acne lesions	Rich-Edwards et al. [54], Adebamowo et al. [58], Adebamowo et al. [60], Adebamowo et al. [61], Okoro et al. [62], Grossi et al. [63], Karadag et al. [64], Duquia et al. [65]
Fat and fatty acids	Omega-3 fatty acids decrease IGF-1 and inhibit pro-inflammatory leukotriene B4	Supportive of omega-3 fatty acids and γ-linoleic acid use in reduction of acne lesions	Logan [70], Li et al. [71], Simopoulos et al. [72], Zouboulis et al. [74], Jung et al. [75]
Vegetarian and vegan	Activation of mTORC1 decreased, leading to decreased signaling of pro-inflammatory nuclear factor-κB	No significant evidence supportive of vegan/vegetarian diets in reducing acne	Melnick [11], Young et al. [76], Stewart and Bazergy [77]
Probiotics	Possible production of bacteriocin-like inhibitory substances, may improve glucose metabolism and insulin levels, may increase levels of anti-inflammatory fatty acids	Mostly theoretical findings in support of acne reduction; early studies show promising results in acne improvements with probiotic supplementation	Bowe et al. [79], Kim et al. [80], Puch et al. [82], Salem et al. [83], Fabbrocini et al. [84]

GI glycemic index, GL glycemic load, IGF-1 insulin-like growth factor-1, IGFBP-3 insulin-like growth factor-binding protein 3, mTORC mammalian target of rapamycin complex 1