Dietary carbohydrate and prostate cancer risk: a meta-analysis

Dietary Carbohydrate Intake Glycemic Index and Glycemic Load and the Risk of Prostate Cancer among Iranian Men: A Case-Control Study

Previous studies have presented a few evidences on the relationship between dietary carbohydrate intake, glycemic index (GI), glycemic load (GL), with the prostate cancer risk. We performed a case-control study to evaluate these associations in 50 men with histologically confirmed prostate cancer and 100 control men. Odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs) were derived using logistic regression. The fully adjusted ORs for the top vs. the bottom quartile were 15.02 (P trend = 0.004), 1.04 (P trend = 0.003), and 10.35 (P trend = 0.002) for carbohydrate intake, GI and GL, respectively. Significant associations with prostate cancer remained only among men with reduced fiber intake for carbohydrate intake, GI and GL and among those had increased fiber intake for GI. These findings support the hypothesis that diet with high carbohydrate, GI and GL enhance risk of prostate cancer.

Dietary Carbohydrate and Diverse Health Outcomes: Umbrella Review of 30 Systematic Reviews and Meta-Analyses of 281 Observational Studies

Background and Aims: The associations between dietary carbohydrate and diverse health outcomes remain controversial and confusing. To summarize the existing evidence of the association between dietary carbohydrate intake and diverse health outcomes and to evaluate the credibility of these sources of evidence. We performed this umbrella review of evidence from meta-analyses of observational studies.

Methods: PubMed, Embase, Web of Science databases, and manual screening of references up to July 2020 were searched. Systematic reviews with meta-analyses of observational studies in humans investigating the association between dietary carbohydrate intake and multiple health outcomes were identified. We assessed the evidence levels by using summary effect sizes, 95% prediction intervals, between-study heterogeneity, evidence of small-study effects, and evidence of excess significance bias for each meta-analysis.

Results: We included 43 meta-analyses of observational research studies with 23 health outcomes, including cancer (n = 26), mortality (n = 4), metabolic diseases (n = 4), digestive system outcomes (n = 3), and other outcomes [coronary heart disease (n = 2), stroke (n = 1), Parkinson's disease (n = 1), and bone fracture (n = 2)]. This umbrella review summarized 281 individual studies with 13,164,365 participants. Highly suggestive evidence of an association between dietary carbohydrate intake and metabolic syndrome was observed with adjusted summary odds ratio of 1.25 [95% confidence interval (CI) 1.15–1.37]. The suggestive evidences were observed in associations of carbohydrate consumption with esophageal adenocarcinoma (0.57, 95% CI = 0.42–0.78) and all-cause mortality (adjusted summary hazard ratio 1.19, 95% CI = 1.09–1.30).

Conclusions: Despite the fact that numerous systematic reviews and meta-analyses have explored the relationship between carbohydrate intake and diverse health outcomes, there is no convincing evidence of a clear role of carbohydrate intake. However, there is highly suggestive evidence suggested carbohydrate intake is associated with high risk of metabolic syndrome, suggestive evidence found its association with increased risk of all-cause mortality and decreased risk of esophageal adenocarcinoma.

Systematic Review Registration: CRD42020197424.

Dietary carbohydrate intake and the risk of esophageal cancer: a meta-analysis

BACKGROUND

Previous studies had been published to explore the association about carbohydrate intake on esophageal cancer risk, with inconsistent results. This meta-analysis aimed to assess the association between dietary carbohydrate intake and the risk of esophageal cancer.

METHODS

Suitable studies were carefully searched with the databases of PubMed, Embase, the Cochrane Library, and Wanfang Database. A random-effects model was used for combined odds ratio (OR) and 95% confidence interval (CI). Stata software 14.0 was adopted for the analysis.

RESULTS

At the end, 13 publications were included in our study. Pooled results suggested that highest category versus lowest category of carbohydrate intake could reduce the risk of esophageal cancer (summarized OR = 0.627, 95% CI = 0.505-0.778, I2 = 59.9%, Pfor heterogeneity = 0.001). The results for carbohydrate intake on the risk of esophageal adenocarcinoma (summarized OR = 0.569, 95% CI = 0.417-0.777) and esophageal squamous cell carcinoma (summarized OR = 0.665, 95% CI = 0.453-0.975) were consistent with the overall result. A positive association was found in European, Asian, North American populations, instead of South American populations.

CONCLUSIONS

In conclusions, dietary carbohydrate intake may have a protective effect against the risk of esophageal cancer.

Carbohydrate Nutrition and the Risk of Cancer

PURPOSE OF REVIEW

This review summarizes a selection of epidemiologic research assessing the associations between carbohydrate intake and cancer incidence and survival. Evidence for plausible biological mechanisms is also considered.

RECENT FINDINGS

The mechanistic paradigm explaining the relationship between carbohydrates and cancer risk has been contested by numerous observational studies. Carbohydrates have conventionally been ascribed a deleterious role in the field of cancer research due to previous preclinical findings. A breadth of studies suggests that complex carbohydrate intake is inversely associated with risk of a number of cancer types. Data from studies assessing simple carbohydrates and cancer risk are mixed. Furthermore, recommendations for subsequent studies are framed.

Carbohydrate intake and the risk of prostate cancer

BACKGROUND

Prostate cancer (PCa) is one of the leading cause cancer among men worldwide. Many epidemiologic studies have reported an association between carbohydrate intake and PCa. However, the evidence from epidemiologic studies is inconsistent. We conducted a comprehensive meta-analysis to explore the associations between carbohydrate intake and PCa risk and to investigate potential dose-response relationships.

METHODS

We searched PubMed and EMBASE for studies published from 1980 to 2018. 21 studies were included with 98,739 participants and 11,573 cases. Multivariate-adjusted odds ratios (ORs) were pooled using random-effect models. Potential dose-response relationships were evaluated for PCa risk.

RESULTS

We did not detect an association about higher carbohydrate intake and PCa risk (OR:1.11, 95% confidence interval [CI]: 0.98-1. 26, I² = 62.7%), nor association was detected about higher carbohydrate intake with advanced PCa risk (OR:0.95, 95% CI: 0.78-1.16, I² = 14.1%) or non-advanced Pca risk (OR:1.01, 95% CI: 0.79-1.29, I² = 64.4%). There was not a significant dose-response association observed for carbohydrate intake with PCa risk and advanced PCa risk.

CONCLUSIONS

Our meta-analysis shows no association between carbohydrate intake and prostate cancer risk. Nor is association detected about carbohydrate intake with advanced or non-advanced Pca risk. More studies are needed for a further dose-response meta-analysis.

Carbohydrate nutrition and risk of adiposity-related cancers: results from the Framingham Offspring cohort (1991-2013)

Higher carbohydrate intake, glycaemic index (GI), and glycaemic load (GL) are hypothesised to increase cancer risk through metabolic dysregulation of the glucose-insulin axis and adiposity-related mechanisms, but epidemiological evidence is inconsistent. This prospective cohort study investigates carbohydrate quantity and quality in relation to risk of adiposity-related cancers, which represent the most commonly diagnosed preventable cancers in the USA. In exploratory analyses, associations with three site-specific cancers: breast, prostate and colorectal cancers were also examined. The study sample consisted of 3184 adults from the Framingham Offspring cohort. Dietary data were collected in 1991-1995 using a FFQ along with lifestyle and medical information. From 1991 to 2013, 565 incident adiposity-related cancers, including 124 breast, 157 prostate and sixty-eight colorectal cancers, were identified. Cox proportional hazards models were used to evaluate the role of carbohydrate nutrition in cancer risk. GI and GL were not associated with risk of adiposity-related cancers or any of the site-specific cancers. Total carbohydrate intake was not associated with risk of adiposity-related cancers combined or prostate and colorectal cancers. However, carbohydrate consumption in the highest v. lowest quintile was associated with 41 % lower breast cancer risk (hazard ratio (HR) 0·59; 95 % CI 0·36, 0·97). High-, medium- and low-GI foods were not associated with risk of adiposity-related cancers or prostate and colorectal cancers. In exploratory analyses, low-GI foods, were associated with 49 % lower breast cancer risk (HR 0·51; 95 % CI 0·32, 0·83). In this cohort of Caucasian American adults, associations between carbohydrate nutrition and cancer varied by cancer site. Healthier low-GI carbohydrate foods may prevent adiposity-related cancers among women, but these findings require confirmation in a larger sample.

Dietary fiber, whole grains, carbohydrate, glycemic index, and glycemic load in relation to risk of prostate cancer

BACKGROUND

The relationships between dietary fiber, whole grains, carbohydrate, glycemic index (GI), glycemic load (GL), and prostate cancer risk are unclear. We conducted a systematic review and meta-analysis to investigate these associations.

METHODS

Relevant studies were identified by a search of PubMed database and EMBASE database up to April 2015. A random effects model was used to calculate the summary relative risks (RRs) and their corresponding 95% confidence intervals (CIs).

RESULTS

Twenty-seven epidemiological studies (18 case-control studies and nine cohort studies) were included in the final analysis. The pooled RRs of prostate cancer were 0.94 (95% CI 0.85-1.05, P=0.285), 1.13 (95% CI 0.98-1.30, P=0.095), 0.96 (95% CI 0.81-1.14, P=0.672), 1.06 (95% CI 0.96-1.18, P=0.254), and 1.04 (95% CI 0.91-1.18, P=0.590) for dietary fiber, whole grains, carbohydrate, GI, and GL, respectively. There was no evidence of significant publication bias based on the Begg's test and Egger's test.

CONCLUSION

The findings of this meta-analysis indicate that, based on available information, dietary fiber, whole grains, carbohydrate, GI, and GL are not associated with the risk of prostate cancer.