TABLE 1.

Rosacea and diet

STUDY AUTHORS	YEAR	STUDY DESIGN	COUNTRY	PATIENT NUMBER (N)	FOLLOW-UP	DATA COLLECTED	OUTCOMES
Alcohol
Li et al4	2017	Prospective Cohort	USA	4,945 (out of, cohort of 82,737)	14 years	Alcohol intake and incidence of rosacea	Increased alcohol intake was associated with an increased rosacea incidence (HR at 95% Cis were 1.12; 95% CI 1.05-1.20) for alcohol intake of 1-4 g/day and 1.53 (1.26-1.84) for more than 30g/day. White wine and spirits were associated with a significantly higher risk of rosacea. These risks were the same regardless of smoking status group.
Caffeine
Li et al8	2018	Prospective Cohort	USA	4,945 (out of cohort of 82737)	14 years	Caffeine intake and incidence of rosacea	Inverse association between increased caffeine intake and risk of rosacea (hazard ratio [HR] for highest caffeine intake versus lowest, 0.76 95% CI, 0.69-0.84; p<0.001). Other food containing caffeine such as tea, soda and chocolate was not significantly related to a decreased rosacea risk.
Fatty Foods
Yuan et al16	2019	Retrospective Case-Control	China	2,637	2 years	Severity of rosacea (mild, mild to moderate, moderate and severe)	High fatty foods intake significantly associated with ETR. (OR = 2.49; 95% CI, 1.26–4.92) and phymatous rosacea (OR = 5.32; 95% CI, 1.42–19.97). Frequent tea intake was only associated with ETR (OR = 2.73; 95% CI, 1.18–6.32). Frequent dairy products showed a negative association with ETR (OR = 0.13; 95% CI, 0.03–0.67) and papulopustular rosacea (OR = 0.03; 95% CI, 0.01–0.55) but not with phymatous rosacea. Sweet food, spicy food and coffee had no associate with any subset of rosacea.
Omega-3 Fatty Acids
Bhargava et al36	2016	Randomized controlled trial	India	130	6 months	Subjective dry eye symptoms and in Meibomian gland score, Schirmer score and tear film break-up time (measures of eye dryness) after groups were randomized to receive either omega-3 fatty acids (capsules containing 180 mg eicosapentaenoic acid and 120 mg docosahexaenoic acid) or placebo twice daily	There was a significant change in subjective dry eye symptoms and in Meibomian gland score, Schirmer score and tear film break-up time (measures of eye dryness) (p<0.001).
Zinc
Bamford et al54	2012	Randomized double-blind trial	USA	44	90 days	Improvement in rosacea zinc sulphate (220mg, 2 times a day)	Both groups had an improvement in their rosacea and there was no difference between groups.
Sharquie et al55	2006	Double-blind, placebo-controlled study	Iraq	25	6 months	Rosacea severity score after zinc sulphate (100mg, 3 times a day)	Significant improvements in rosacea severity score (p<0.01)