Mediterranean Diet

February is AMD and low vision awareness month. A Mediterranean diet is associated with a lower risk of macular degeneration. Interest in the Mediterranean diet began in the 1960’s with the observation that coronary heart disease caused fewer deaths in Mediterranean countries, such as Greece and Italy, than in the U.S. and Northern Europe. Subsequent studies found that the Mediterranean diet is associated with reduced risk factors for cardiovascular disease. The Mediterranean diet is a way of eating based on the traditional cuisine of countries bordering the Mediterranean Sea. The main components of a Mediterranean diet include daily consumption of vegetables, fruits, whole grains, and healthy fats such as heavy use of olive oil, weekly intake of fish, poultry, beans, and eggs, limited intake of dairy products, and limited intake of red meat. From a standpoint of supporting a healthy microbiome, which drives the regulation of chronic inflammation, we know that a variety of produce coupled with healthy fats and complex carbohydrates increases the good bacteria in our guts. Two studies on the Mediterranean diet are highlighted below. The first study looked at Mediterranean diets and risk of AMD and a newly published study is highlighted next that looks at Mediterranean diets and risk of Sjogren’s syndrome.

Mediterranean Diet and Incidence of Advanced Age-Related Macular Degeneration: The EYE-RISK Consortium

PMID: 30114418 DOI: 10.1016/j.ophtha.2018.08.006

Purpose: To investigate associations of adherence to the Mediterranean diet (MeDi) with incidence of advanced age-related macular degeneration (AMD; the symptomatic form of AMD) in 2 European population-based prospective cohorts.
Design: Prospective cohort study of the Rotterdam Study I (RS-I) and the Antioxydants, Lipides Essentiels, Nutrition et Maladies Oculaires (Alienor) Study populations.
Participants: Four thousand four hundred forty-six participants 55 years of age or older from the
RS-I (The Netherlands) and 550 French adults 73 years of age or older from the Alienor Study with complete ophthalmologic and dietary data were included in the present study.
Methods: Examinations were performed approximately every 5 years over a 21-year period
(1990-2011) in RS-I and every 2 years over a 4-year period (2006-2012) in the Alienor Study. Adherence to the MeDi was evaluated using a 9-component score based on intake of vegetables, fruits, legumes, cereals, fish, meat, dairy products, alcohol, and the monounsaturated-to-saturated fatty acids ratio. Associations of incidence of AMD with MeDi were estimated using multivariate Cox proportional hazard models.
Main outcomes measures: Incidence of advanced AMD based on retinal fundus photographs. Results: Among the 4996 included participants, 155 demonstrated advanced incident AMD (117 from the RS-I and 38 from the Alienor Study). The mean follow-up time was 9.9 years (range, 0.6-21.7 years) in the RS-I and 4.1 years (range, 2.5-5.0 years) in the Alienor Study. Pooling data for both the RS-I and Alienor Study, participants with a high (range, 6-9) MeDi score showed a significantly reduced risk for incident advanced AMD compared with participants with a low (range, 0-3) MeDi score in the fully adjusted Cox model (hazard ratio, 0.59; 95% confidence interval, 0.37-0.95; P = 0.04 for trend).

Conclusions: Pooling data from the RS-I and Alienor Study, higher adherence to the MeDi was associated with a 41% reduced risk of incident advanced AMD. These findings support the role of a diet rich in healthful nutrient-rich foods such as fruits, vegetables, legumes, and fish in the prevention of AMD.

The researchers found that none of the individual components of a Mediterranean diet on their own – fish, fruit, vegetables, etc. – lowered the risk of AMD. Rather, it was the entire pattern of eating a nutrient-rich diet that significantly reduced the risk of late AMD.

“You are what you eat,” said Emily Chew, MD, a clinical spokesperson for the American Academy of Ophthalmology, who served on the advisory board to the research group conducting the study, said in an AAO news release regarding the study. “I believe this is a public health issue on the same scale as smoking. Chronic diseases such as AMD, dementia, obesity, and diabetes, all have roots in poor dietary habits. It’s time to take quitting a poor diet as seriously as quitting smoking.”


Mediterranean Diets and Risk of Sjogren’s Syndrome

In the following study published July 2020, a Mediterranean Diet was associated with a lower risk of Sjogren’s Syndrome. In this study, the Mediterranean diet score and the odds ratio of having Sjogren’s syndrome was investigated. A diet with a higher Mediterranean diet score was associated with a lower odds ratio of developing Sjogren’s.

Clin Exp Rheumatol

Jul-Aug 2020;38 Suppl 126(4):216-221. Epub 2020 Oct 23.

Mediterranean diet and risk of Sjögren’s syndrome PMID: 33095150

Objectives: Non-genetic risk factors for Sjögren’s syndrome (SS) are poorly understood. Adherence to a Mediterranean diet has been associated with reduction in other autoimmune diseases. We examined the association of Mediterranean diet with SS.
Methods: New patients attending a single centre warranting investigation for primary SS (pSS) were recruited into the Optimising Assessment in Sjögren’s Syndrome cohort established in Birmingham, UK (2014-2018). Participants were classified into pSS and non-SS sicca, considered as cases and non-cases, respectively, and asked to complete an optional food frequency questionnaire on their diet before onset of symptoms. A semi-quantitative Mediterranean diet score (MDS) was calculated (possible range=0 to 18). Using multivariate logistic regression, corrected for energy intake, body-mass index, sex, age, symptom duration, and smoking status, we examined the association of MDS with SS.
Results: Dietary data were available for 133/243 (55%) eligible patients (n=82 pSS and n=51 sicca). In the adjusted model, a higher total MDS (mean ± SD, 9.41±2.31 points) was associated with lower odds of pSS (OR 0.81, 95% CI 0.66-0.99; p=0.038) per one unit of MDS. Among MDS components, the strongest association was seen with fish with OR 0.44 (95% CI 0.24-0.83; p=0.01) in the comparison between <1 portion/week and 1 to 2.5 portions/week. Higher galactose, vitamin A-retinol-equivalents and vitamin C showed associations with lower odds of pSS in multivariate analysis, where the association of vitamin C was attenuated when adjusted for MDS.

Conclusions: When adjusted for potential confounders, adherence to the Mediterranean diet was associated with lower likelihood of having pSS.