Entry #: 19
Date: 22 October 2017
Section: Inflammation and oxidative stress
Topic: Mediterranean diet and nutrigenomics
Type: Human volunteer trial

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OliveNetTM Journal Club

Expert review of literature related to olives and olive oil

D. Elizabeth McCord, Nancy B. Ray and Tom C. Karagiannis

Title

Mediterranean meal versus Western meal effects on postprandial ox-LDL, oxidative and inflammatory gene expression in healthy subjects: a randomized controlled trial for nutrigenomic approach in cardiometabolic risk

Author(s)

De Lorenzo et al

Citation / Year

(1) / 2017

Keywords

Mediterranean diet, Western diet, tocopherol, oxidized low density lipoprotein, inflammasome, oxidative stress

Summary

This is an interesting human volunteer trial examining the effects of an acute tocopherol-enriched Mediterranean meal with a typical fast food Western-type meal on oxidized low-density lipoprotein (ox-LDL) and the expression of a total of 13 genes associated with oxidative stress (seven) and inflammasome (six) pathways. Overall 25 adult individuals were recruited and of these, 22 healthy individuals (as indicated by normal range baseline measurements of various parameters including body mass index, blood sugar, cholesterol and triglyceride levels), were eligible to complete the trial. Along with ox-LDL which is strongly associated cardiovascular diseases (CVD) (2-4), the rationale for the choice of genes to be investigated is based on the links between postprandial inflammation and oxidative stress, which are linked to atherosclerosis and CVD (5, 6). Overall, this study represents a randomized cross-over design with a three week washout period between analyses. Prior to a 12 hour overnight fast and blood collection for baseline measurements, participants were given a single tocopherol-enriched Mediterranean meal or Western diet-type meal followed by blood collection three hours postprandial. An interesting aspect of this study is the utilisation of a Mediterranean Adequacy Index Calculator to assess the quality of diet with respect to the Italian Mediterranean diet (7). Briefly, the Mediterranean meal consistent of typical ingredients including, pasta, red pepper, salad, tomato, walnuts, hazelnuts and extra virgin olive oil. In contract the Western-type diet consisted of typical fast food including a burger and French fries. Interestingly, the total energy of Mediterranean diet meal (1318.68 kcal) was slightly higher than the Western diet meal (1114.14 kcal), however total fat intake was significantly lower for the Mediterranean meal (42.10% compared to 54.98%). Conventional enzyme-linked immunosorbent assay (ELISA), was used to measure ox-LDL levels and quantitative real-time polymerase chain reactions (qRT-PCR), were used to investigate changes in gene expression.

Key points and implications

A key finding is the increase in ox-LDL levels observed following the Western diet type meal whereas, a significant decrease was found after consumption of the tocopherol-enriched Mediterranean meal. Similarly, in general the gene expression profiles demonstrate a positive pattern with respect to reduced postprandial inflammation and oxidative stress for the Mediterranean meal compared to the Western diet type meal. For example, when comparing the Western diet type meal against the tocopherol-enriched Mediterranean meal, significant down regulation of BCL2 (involved in apoptotic signalling), IRAK1 (linked with NF-κB-mediated cytokine production), DUOX2 (thyroid oxidase) and UCP2 (mitochondrial uncoupling protein regulating reactive oxygen species), was observed, and the authors have thoroughly described the link between the observed gene expression changes and inflammatory and oxidative stress processes. Importantly, although the findings from this study represent measurements after single meal, it is possible to envisage the chronic accumulated beneficial effects of a Mediterranean diet compared to a typical high fat Western-type diet. Further, it is encouraging that studies such as this, are starting to de-lineate the beneficial health effects of the Mediterranean diet at the molecular level.

Related publications

  1. A. De Lorenzo et al., Mediterranean meal versus Western meal effects on postprandial ox-LDL, oxidative and inflammatory gene expression in healthy subjects: a randomized controlled trial for nutrigenomic approach in cardiometabolic risk. Acta diabetologica 54, 141-149 (2017).
  2. D. Li, J. L. Mehta, Oxidized LDL, a critical factor in atherogenesis. Cardiovascular research 68, 353-354 (2005).
  3. S. Mitra, T. Goyal, J. L. Mehta, Oxidized LDL, LOX-1 and atherosclerosis. Cardiovascular drugs and therapy 25, 419-429 (2011).
  4. S. Mitra, A. Deshmukh, R. Sachdeva, J. Lu, J. L. Mehta, Oxidized low-density lipoprotein and atherosclerosis implications in antioxidant therapy. The American journal of the medical sciences 342, 135-142 (2011).
  5. S. Yusuf et al., Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): case-control study. Lancet 364, 937-952 (2004).
  6. E. M. Holt et al., Fruit and vegetable consumption and its relation to markers of inflammation and oxidative stress in adolescents. Journal of the American Dietetic Association 109, 414-421 (2009).
  7. A. Alberti-Fidanza, F. Fidanza, Mediterranean Adequacy Index of Italian diets. Public health nutrition 7, 937-941 (2004).