Reference
Buckland G, Agudo A Lujan, L, et al. Adherence to a Mediterranean diet and risk of gastric adenocarcinoma within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort study. Am J Clin Nutr. 2010;91(2):381-390.
Design
Dietary and lifestyle information were collected at recruitment. A scoring system was used to estimate degree of adherence to a Mediterranean style diet. The association between diet adherence and gastric cancer risk by location and type was calculated.
Participants
The study included 485,044 subjects (144,577 men) aged 35-70 years old from 10 European countries who were part of the European Prospective Investigation into Cancer and Nutrition (EPIC) Cohort. Mean follow-up was 8.9 years.
Scoring
An 18-unit relative Mediterranean diet score was utilized that rated 9 key components of the Mediterranean diet and allowed estimation of a score for relative Mediterranean diet adherence.
Primary Outcome Measures
Cases of primary gastric adenocarcinoma, their location, and histologic types were recorded.
Key Findings
Participants whose diets scored higher, and therefore most closely matched the Mediterranean Diet, had decreased risk of gastric adenocarcinoma compared to those with low adherence scores. The hazard ratio for those with high adherence compared to low adherence was 0.67; thus their risk for developing cancer was about a third lower. Scores did not affect anatomic location or histologic types. For every 1-unit diet score increase, as calculated by the researchers, the risk for gastric adenocarcinoma decreased by approximately 6%.
Practice Implications
It is time for us to actively encourage patients to adhere as closely as possible to a Mediterranean style diet. This study is just one of a series of recent papers that have looked at the correlation between specific diseases and adherence to a Mediterranean style diet, studies that consistently find benefit.
Components of the Mediterranean diet have already been individually shown to affect gastric cancer risk. González et al reported in 2006 that meat consumption affected gastric cancer risk and found that total red and processed meat intakes were associated with an increased risk of gastric non-cardia cancer, especially in H. pylori antibody-positive subjects.1 (A free PDF of this study is available here.)
González, in another 2006 paper, reported on fruit and vegetable consumption and risk of gastric cancers. A possible negative relationship was seen between total vegetable intake (HR 0.66; 95% CI 0.35–1.22 per 100 g increase) and onion and garlic intake (HR 0.70; 95% CI 0.38–1.29 per 10 g increase) with risk of intestinal cancer. Nonsignificant negative associations were seen between citrus fruit intake and the cardia site (HR 0.77; 95% CI 0.47–1.22 per 100 g increase) and a nonsignificant negative association for vegetable intake and for citrus intake (calibrated HRs 0.72; 95% CI 0.32–1.64 and 0.77; 95% CI 0.46–1.28 per 100 and 50 g increase, respectively) and esophageal adenocarcinoma. Citrus fruit consumption may have a role in the protection against cardia gastric carcinoma and esophageal adenocarcinoma.2
A 2007 paper found that cereal consumption had a much stronger effect against gastric cancer than fruit or vegetables. High intakes of cereal fiber reduced gastric cancer risk by about 31% [adjusted HR for the highest versus lowest quartile of cereal fiber 0.69, 0.48–0.99].3
In July 2010, Trichopoulou et al reported a lower risk of breast cancer in menopausal women with greater adherence to a Mediterranean diet. Their study followed 14,807 women for almost 10 years, during which time 240 participants were diagnosed with breast cancer. Diet was assessed and scored in respect to conformity to a Mediterranean diet. A marginally significant inverse association was seen in postmenopausal women, with a 22% decrease in risk for every 2-point difference in scoring. (HR=0.78 for every 2 points; 95% CI: 0.62, 0.98; P for interaction by menopausal status = 0.05).4
A 2008 meta-analysis looked at how the Mediterranean diet affected overall mortality. When data from 8 cohorts (514,816 subjects and 33,576 deaths) were evaluated, researchers found that a 2-point increase in the diet adherence score reduced risk of mortality by about 9% (RR 0.91; 95% CI: 0.89–0.94), mortality from cancer by 6% and incidence of Parkinson’s or Alzheimer’s disease by 13%.5 (Click here for the free full-text.)
Cancer isn’t the only disease benefited by following the Mediterranean diet. High adherence is associated with a 40% decreased risk for coronary heart disease. A 1-point increase in relative Mediterranean diet score was associated with a 6% reduced risk of CHD.6 It is fascinating how much these diet scores have been quantified. A June 2009 paper tells us that for each unit increase in a Mediterranean diet adherence score, C-reactive protein decreased by 3.1% (95% CI: 0.5–5.7%) and IL-6 dropped by 1.9% (95% CI: 0.5–3.4%).7
When we look at any of these Mediterranean studies, the men and women who eat foods closest to the Mediterranean diet are about 20% less likely to die over the course of the study from heart disease, cancer, or any other cause.
When we look at any of these Mediterranean studies, the men and women who eat foods closest to the Mediterranean diet are about 10–20% less likely to die over the course of the study from heart disease, cancer, or any other cause.8
Perhaps the most intriguing of these studies is one that appeared in June 2009 in the British Medical Journal in which Trichopoulou et al looked at data from the Greek Cohort of the EPIC study, following 23,349 men and women not previously diagnosed with cancer, coronary heart disease, or diabetes and compared Mediterranean diet adherence to mortality from any cause. A 13% decrease in mortality was seen for every 2-point increase in diet adherence score. Through careful statistical analysis these researchers were able to tell us how much each component of the diet contributed to the overall effect seen in their study:
- Moderate ethanol consumption: 23.5%,
- Low consumption of meat and meat products: 16.6%
- High vegetable consumption: 16.2%
- High fruit and nut consumption: 11.2%
- High monounsaturated to saturated lipid ratio: 10.6%
- High legume consumption: 9.7%
In this particular study the attributes of high cereal consumption and low dairy consumption had only minimal effects on morality. Surprisingly high fish and seafood consumption appeared to cause a non-significant increase in mortality.9 These later findings are to date anomalies, and fish and seafood are still considered valuable and beneficial attributes of the diet.
These recent studies add further weight in support of following a Mediterranean diet. It is time for us to actively move our patients toward greater adherence to a Mediterranean style diet. For a visual representation of the Mediterranean Diet, consider this pyramid picture.
For more research involving integrative oncology, click here.
