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Ben Q, Zhong J, Liu J, Wang L, Sun Y, Yv L, Yuan Y. Association Between Consumption of Fruits and Vegetables and Risk of Colorectal Adenoma: A PRISMA-Compliant Meta-Analysis of Observational Studies. Medicine (Baltimore) 2015; 94:e1599. [PMID: 26496264 PMCID: PMC4620815 DOI: 10.1097/md.0000000000001599] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
There have been contradictory results about the association of fruits and vegetables intake with colorectal adenoma (CRA) risk, the precursor lesion of colorectal cancer. Herein, we have conducted a meta-analysis of the published observational studies to have a clear understanding about this association.Eligible studies up to November 30, 2014, were identified and retrieved by searching MEDLINE and EMBASE databases along with the manual review of the reference list of the retrieved studies. The quality of the included studies was evaluated using Newcastle-Ottawa Quality Assessment Scale, and random-effects model was used to calculate summary relative risk (SRR) and corresponding 95% confidence interval (CI).A total of 22 studies involving 11,696 CRA subjects were part of this meta-analysis. The SRR for the highest versus the lowest intake of vegetables alone was 0.91 (95% CI: 0.80-1.02, Pheterogeneity = 0.025), whereas for vegetables and fruits combined, it was 0.82 (95% CI: 0.75-0.91, Pheterogeneity = 0.369), and for fruits alone, it was 0.79 (95% CI: 0.71-0.88, Pheterogeneity = 0.111). In addition, linear dose-response analysis also showed similar results, for example, for per 100 g/d increment of fruits, the SRR was 0.94 (95% CI: 0.92-0.97) and for vegetables it was 0.98 (95% CI: 0.96-1.01). Nonlinear association was only observed for vegetables (Pnonlinearity = 0.024), but not for fruits (Pnonlinearity = 0.583).Thus, this meta-analysis suggested that fruits consumption have a significant protective effect on CRA risk, but not vegetables. Moreover, we recommend additional studies with prospective designs that use validated questionnaires and control for important confounders to further validate the overall results.
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Affiliation(s)
- Qiwen Ben
- From the Department of Gastroenterology (QB, JZ, LW, YS, LY, YY), Ruijin Hospital, Shanghai Jiaotong University; and Department of Integrative Medicine (JL), Zhongshan Hospital, Fudan University, Shanghai, PR China
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Wu H, Dai Q, Shrubsole MJ, Ness RM, Schlundt D, Smalley WE, Chen H, Li M, Shyr Y, Zheng W. Fruit and vegetable intakes are associated with lower risk of colorectal adenomas. J Nutr 2009; 139:340-4. [PMID: 19091801 PMCID: PMC2646202 DOI: 10.3945/jn.108.098889] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Many phytochemicals in fruits and vegetables have been shown to have cancer-inhibitory effects in animal studies. These effects on cancer, however, have not been clearly demonstrated in human studies. This study investigated the association between fruit and vegetable intakes and the risk of adenomatous polyps. Participants were part of the Tennessee Colorectal Polyp Study. Eligible participants aged 40-75 y were recruited from patients undergoing colonoscopy at 2 medical centers in Nashville, Tennessee from 2003 to 2005. Cases had at least one adenoma and controls were polyp free. Dietary intake was assessed using a self-administered FFQ. Associations between dietary intakes and adenoma risk were evaluated using unconditional logistic regression with restricted cubic function spline. In multivariate analyses of 764 cases and 1517 controls, increased intakes of total fruits, berries, fruit juice, and green leafy vegetables were associated with reduced adenoma risk. The odds ratio for upper tertile intake compared with lower was 0.66 (95% CI = 0.51-0.86) for total fruits, 0.64 (95% CI = 0.47-0.87) for berries, 0.72 (95% CI = 0.56-0.92) for fruit juice, and 0.74 (95% CI = 0.58-0.96) for green vegetables. This study provides additional evidence that high total fruit intake and certain fruit and vegetable intakes may be associated with a reduced risk of colorectal adenomas.
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Affiliation(s)
- Huiyun Wu
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
| | - Qi Dai
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
| | - Martha J. Shrubsole
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
| | - Reid M. Ness
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
| | - David Schlundt
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
| | - Walter E. Smalley
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
| | - Heidi Chen
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
| | - Ming Li
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
| | - Yu Shyr
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
| | - Wei Zheng
- Department of Biostatistics and Vanderbilt-Ingram Cancer Center/Cancer Biostatistics Center; Division of General Internal Medicine and Public Health, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Division of Gastroenterology, Vanderbilt University, Nashville, TN 37232; Department of Veterans Affairs, Tennessee Valley Healthcare System, Geriatric, Research, Education and Clinical Center (GRECC), Nashville, TN 37212
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Abstract
PURPOSE OF REVIEW To highlight mechanisms whereby diet affects colonic function and disease patterns. RECENT FINDINGS Topical nutrients are preferentially used by the gut mucosa to maintain structure and function. With the colon, topical nutrients are generated by the colonic microbiota to maintain mucosal health. Most importantly, short chain fatty acids control proliferation and differentiation, thereby reducing colon cancer risk. In patients with massive loss of small intestine, short chain fatty acid production supports survival by releasing up to 1000 kcal energy/day. Human studies show that the microbiota synthesizes a large pool of utilizable folate which may support survival in impoverished populations. Unfortunately, the microbiota may also elaborate toxic products from food residues such as genotoxic hydrogen sulfide by sulfur-reducing bacteria in response to a high-meat diet. The employment of culture-free techniques based on 16S regions of DNA has revealed that our colons harbor over 800 bacterial species and 7000 different strains. Evidence suggests that the diet directly influences the diversity of the microbiota, providing the link between diet, colonic disease, and colon cancer. The microbiota, however, can determine the efficiency of food absorption and risk of obesity. SUMMARY Our investigations have focused on a small number of bacterial species: characterization of microbiota and its metabolism can be expected to provide the key to colonic health and disease.
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Michels KB, Giovannucci E, Chan AT, Singhania R, Fuchs CS, Willett WC. Fruit and vegetable consumption and colorectal adenomas in the Nurses' Health Study. Cancer Res 2006; 66:3942-53. [PMID: 16585224 DOI: 10.1158/0008-5472.can-05-3637] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Consumption of fruits and vegetables may confer protection from colorectal adenomas, but the limited observational and interventional evidence is inconclusive. We examined the association between fruit and vegetable consumption and the prevalence and incidence of adenomas of the distal colon and rectum in the Nurses' Health Study (NHS). We used data from 34,467 women in the NHS who had undergone colonoscopy or sigmoidoscopy during follow-up between 1980 and 1998. Consumption of fruits and vegetables was assessed in 1980, 1984, 1986, 1990, and 1994 using a semiquantitative food frequency questionnaire; 1,720 prevalent cases of adenoma of the distal colon and rectum were diagnosed between 1980 and 1998. Frequent consumption of fruit was inversely related to the risk of being diagnosed with polyps, whereas little association was found for vegetable consumption. Women who reported consuming five or more servings of fruit a day had an odds ratio (OR) of 0.60 [95% confidence interval (95% CI), 0.44-0.81] for developing colorectal adenomas compared with women who consumed only one or fewer servings of fruit per day, after adjustment for relevant covariates (P(trend) = 0.001). The respective OR for vegetable consumption was 0.82 (95% CI, 0.65-1.05; P(trend) = 0.1). Women who consumed four or more servings of legumes per week had a lower incidence of colorectal adenomas than women who reported consuming one serving per week or less (OR, 0.67; 95% CI, 0.51-0.90; P(trend) = 0.005). Frequent consumption of fruit may reduce the risk of colorectal adenomas.
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Affiliation(s)
- Karin B Michels
- Obstetrics and Gynecology Epidemiology Center, Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital, 221 Longwood Avenue, Boston, MA 02115, USA.
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