Protective Effects of the Mediterranean Diet
Growing evidence shows that the Mediterranean diet is the ideal diet for all ages. Characterized by ample daily consumption of vegetables and fruits, legumes, and grains and small daily quantities of fish, meat, eggs, or cheese and olive oil, this model aims to obtain a balanced daily intake of carbohydrates (55%-60%), fat (30%), and proteins (10%-15%). Furthermore, owing to its composition, the intake of monounsaturated fatty acids exceeds that of saturated fatty acids, as does the intake of complex carbohydrates vs simple sugars.[10,11]
It has been shown that the Mediterranean diet has a major role in the prevention of neurodegenerative diseases, cardiovascular disease, type 2 diabetes, obesity, and NAFLD.[10,12]
Serra-Majem and colleagues[13] developed the Mediterranean Diet Quality Index (KIDMED) for children and adults, which creates an index score, ranging from 0 to 10, to assess the quality of the Mediterranean diet. Positive points are awarded for intake of fruits, vegetables, and fish, and points are subtracted for such behaviors as consumption of sweets, fast foods, or skipping breakfast. A score ≤3 indicates poor adherence to a Mediterranean diet, whereas values between 4 and 7 denote good adherence and values ≥8 indicate excellent adherence to the diet.[13]
In another study,[14] also conducted by our group at Pediatric Hospital Bambino Gesù, 243 obese children who had undergone laboratory and instrumental investigations for NAFLD were evaluated using the KIDMED.
After the diagnostic classification, children were divided into two groups: NAFLD (n = 166) and no NAFLD (n = 77). Of 166 children in the NAFLD group, 100 underwent liver biopsy because of suspected NASH, which was histologically confirmed in 53 children (53%).
The KIDMED was administered to all children in the study; 36 (14.8%) had a higher score (≥8), 120 (49.4%) a medium score (4-7), and 87 (35.8%) a low score (≤3). Differences among the three groups of children on the basis of these scores, in terms of mean insulin values before and 120 minutes after an oral glucose tolerance test, and insulin resistance and beta-cell function assessed by homeostatic model assessment, are shown in the Table.
Table. Study Findings
KIDMED Score |
Mean (± SD) Fasting Insulin Level (mIU/L) |
Mean (± SD) Insulin Level 120 Minutes After OGTT (mIU/L) |
Mean (± SD) HOMA-IR |
Mean (± SD) HOMA-beta |
---|---|---|---|---|
High (≥ 8) | 26.17 ± 8.32 | 151.78 ± 43.46 | 5.19 ± 1.77 | 101.4 ± 31.6 |
Medium (4-7) | 24.32 ± 11.69 | 140 ± 95.44 | 4.18 ± 2.16 | 96.6 ± 25.4 |
Low (≤ 3) | 16.76 ± 2.31 | 110.55 ± 90.11 | 3.14 ± 0.34 | 59.8 ± 26.5 |
P value | 0.05 | 0.02 | 0.04 | 0.02 |
HOMA-beta = homeostatic model assessment of beta-cell function; HOMA-IR = homeostatic model assessment of insulin resistance; KIDMED = Mediterranean Diet Quality Index; OGTT = oral glucose tolerance test
It should be noted that in our study, none of the patients with NASH had a KIDMED score ≥ 8, whereas all patients with a KIDMED score ≤ 3 had a NAFLD activity score ≥ 5 and/or a fibrosis degree ≥ 2—both of which suggest progression of NAFLD. (The NAFLD activity score is a numeric score based on steatosis, lobular inflammation, and hepatocyte ballooning.)
In addition, a KIDMED score ≤ 3 seems to be associated with a risk of developing NAFLD of 5.43 (95% CI, 1.96-3.25; P = .0012), and a risk of developing insulin-resistance of 2.45 (95% CI, 1.73-3.13; P = .044). Finally, the KIDMED score was independently associated with fibrosis (OR, 2.58, 95% CI, 1.36-3.9, P = .05) and the NAFLD activity score (OR, 1.03; 95% CI, 0.99-2; P = .05).[13]
Viewpoint
Accumulation of fatty acids in hepatocytes and insulin resistance are the essential events of NAFLD pathogenesis, making the liver more prone to the action of other factors, such as oxidative stress and inflammation, which eventually can lead to NASH.[14]
These two studies, conducted by the same group of researchers, demonstrate for the first time that whereas a poor diet high in sugars induces an increase in both uric acid levels and the risk of developing NASH, the Mediterranean diet may reduce the risk for both lipogenesis and hepatic oxidative stress, thus slowing down the progression of liver injury toward NASH, probably owing to higher intake of monounsaturated fatty acids.[15] In the most recent study, an inverse association between Mediterranean diet and insulin resistance has emerged.
Because NASH can affect life expectancy and the quality of a child's life, we need to know all of the risk factors that contribute to both its development and progression. Equally important, however, is furthering our knowledge of all of the protective factors and the therapeutic interventions that may prevent the development and the progression of liver injury.
Medscape Pediatrics © 2017 WebMD, LLC
Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Antonella Mosca, Andrea Vania, Silvio Veraldi, et. al. Kids, Food, and Fatty Livers: Fructose vs the Med Diet - Medscape - Apr 11, 2017.
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