Effectiveness of whole grain consumption in the prevention of colorectal cancer: meta-analysis of cohort studies

Food Intake and Colorectal Cancer

Colorectal cancer (CRC) accounts for considerable mortalities worldwide. Several modifiable risk factors, including a high intake of certain foods and beverages can cause CRC. This review summarized the latest findings on the intake of various foods, nutrients, ingredients, and beverages on CRC development, with the objective of classifying them as a risk or protective factor. High-risk food items include red meat, processed meat, eggs, high alcohol consumption, sugar-sweetened beverages, and chocolate candy. Food items that are protective include milk, cheese and other dairy products, fruits, vegetables (particularly cruciferous), whole grains, legumes (particularly soy beans), fish, tea (particularly green tea), coffee (particularly among Asians), chocolate, and moderate alcohol consumption (particularly wine). High-risk nutrients/ingredients include dietary fat from animal sources and industrial trans-fatty acids (semisolid/solid hydrogenated oils), synthetic food coloring, monosodium glutamate, titanium dioxide, and high-fructose corn sirup. Nutrients/ingredients that are protective include dietary fiber (particularly from cereals), fatty acids (medium-chain and odd-chain saturated fatty acids and highly unsaturated fatty acids, including omega-3 polyunsaturated fatty acids), calcium, polyphenols, curcumin, selenium, zinc, magnesium, and vitamins A, C, D, E, and B (particularly B6, B9, and B2). A combination of micronutrients and multi-vitamins also appears to be beneficial in reducing recurrent adenoma incidence.

Colorectal Cancer Chemoprevention: A Dream Coming True?

Colorectal cancer (CRC) is one of the deadliest forms of cancer worldwide. CRC development occurs mainly through the adenoma-carcinoma sequence, which can last decades, giving the opportunity for primary prevention and early detection. CRC prevention involves different approaches, ranging from fecal occult blood testing and colonoscopy screening to chemoprevention. In this review, we discuss the main findings gathered in the field of CRC chemoprevention, focusing on different target populations and on various precancerous lesions that can be used as efficacy evaluation endpoints for chemoprevention. The ideal chemopreventive agent should be well tolerated and easy to administer, with low side effects. Moreover, it should be readily available at a low cost. These properties are crucial because these compounds are meant to be used for a long time in populations with different CRC risk profiles. Several agents have been investigated so far, some of which are currently used in clinical practice. However, further investigation is needed to devise a comprehensive and effective chemoprevention strategy for CRC.

Association between the Methylation of CpG Islands in JAK-STAT Pathway-Related Genes and Colorectal Cancer

BACKGROUND

Aberrant promoter methylation of CpG islands plays an important role in carcinogenesis. However, the association between the DNA methylation of JAK-STAT pathway-related genes in peripheral blood leukocytes and colorectal cancer (CRC) susceptibility remains unclear.

METHODS

We conducted a case-control study of 403 patients with CRC and 419 cancer free controls, and the DNA methylation levels of JAK2, STAT1, STAT3, and SOCS3 in peripheral blood samples from all subjects were assessed using a methylation-sensitive high-resolution melting (MS-HRM) analysis.

RESULTS

Compared with controls, the methylation of the JAK2, STAT1 and SOCS3 genes increased the CRC risk (OR_adjusted=1.96, 95% CI, 1.12-3.41, P=0.01; OR_adjusted=5.37, 95% CI, 3.74-7.71, P<0.01; OR_adjusted=3.30, 95% CI, 1.58-6.87, P<0.01). In the multiple CpG site methylation (MCSM) analysis, a high MCSM value denoted an increased CRC risk (OR_adjusted=4.97, 95% CI, 3.34-7.37, P<0.01).

CONCLUSION

In peripheral blood, the methylation of JAK2, STAT1, and high levels of MCSM are promising biomarkers for CRC risk.

The Effect of Rye-Based Foods on Postprandial Plasma Insulin Concentration: The Rye Factor

Consumption of whole grain has been associated with lower incidence of type-2 diabetes, cardiovascular disease and their risk factors including improved glycemic control. In comparison with other whole grain products, rye bread has been shown to induce lower insulin response in the postprandial phase, without affecting the glucose response. This phenomenon has been referred to as the “rye factor” and is being explored in this review where we summarize the findings from meal and extended meal studies including rye-based foods. Overall, results from intervention studies showed that rye-based foods vs. (wheat) control foods had positive effect on both insulin and glucose responses in the postprandial phase, rather than on insulin alone. Mechanistic studies have shown that the rye factor phenomenon might be due to slowing of the glucose uptake in the intestine. However, this has also been shown for wheat-based bread and is likely an effect of structural properties of the investigated foods rather than the rye per se. More carefully controlled studies where standardized structural properties of different cereals are linked to the postprandial response are needed to further elucidate the underlying mechanisms and determinants for the effect of specific cereals and product traits on postprandial glycemic control.

Overview of the Composition of Whole Grains’ Phenolic Acids and Dietary Fibre and Their Effect on Chronic Non-Communicable Diseases

Chronic non-communicable diseases are the major cause of death globally. Whole grains are recommended in dietary guidelines worldwide due to increasing evidence that their consumption can improve health beyond just providing energy and nutrients. Epidemiological studies have suggested that the incorporation of whole grains, as part of a healthy diet, plays a key role in reducing one’s risk for cardiovascular diseases (CVDs), obesity, type 2 diabetes (T2D) and cancer. Phenolic acids and dietary fibre are important components found in whole grains that are largely responsible for these health advantages. Both phenolic acids and dietary fibre, which are predominantly present in the bran layer, are abundant in whole-grain cereals and pseudo-cereals. Several studies indicate that whole grain dietary fibre and phenolic acids are linked to health regulation. The main focus of this study is two-fold. First, we provide an overview of phenolic acids and dietary fibres found in whole grains (wheat, barley, oats, rice and buckwheat). Second, we review existing literature on the linkages between the consumption of whole grains and the development of the following chronic non-communicable diseases: CVDs, obesity, T2D and cancer. Altogether, scientific evidence that the intake of whole grains reduces the risk of certain chronic non-communicable disease is encouraging but not convincing. Based on previous studies, the current review encourages further research to cover the gap between the emerging science of whole grains and human health.

Importance of the Microbiota Inhibitory Mechanism on the Warburg Effect in Colorectal Cancer Cells

METHODS AND RESULTS

Colorectal cancer (CRC) is the third most common cancer in the world. Genetic backgrounds, lifestyle, and diet play an important role in CRC risk. The human gut microbiota has an influence on many features of human physiology such as metabolism, nutrient absorption, and immune function. Imbalance of the microbiota has been implicated in many disorders including CRC. It seems Warburg effect hypothesis corresponds to the early beginning of carcinogenesis because of eventual failure in the synthesis of a pyruvate dehydrogenase complex in cooperation with a supply of glucose in carbohydrates rich diets. From investigation among previous publications, we attempted to make it clear importance of Warburg effect in tumors; it also discusses the mechanisms of probiotics in inhibiting tumor progression and reverse Warburg effect of probiotics in modulating the microbiota and CRC therapies. These effects were observed in some clinical trials, the application of probiotics as a therapeutic agent against CRC still requirements further investigation.

CONCLUSION

Fiber is fermented by colonic bacteria into SCFAs such as butyrate/acetate, which may play a vital role in normal homeostasis by promoting turnover of the colonic epithelium. Butyrate enters the nucleus and functions as a histone deacetylase inhibitor (HDACi). Because cancerous colonocytes undertake the Warburg effect pathway, their favored energy source is glucose instead of butyrate. Therefore, accumulation of moderate concentrations of butyrate in cancerous colonocytes and role as HDACi. Probiotics have been shown to play a protective role against cancer development by modulating intestinal microbiota and immune response.

Whole Grains, Refined Grains, and Cancer Risk: A Systematic Review of Meta-Analyses of Observational Studies

PubMed, Web of Science, and the Cochrane Database of Systematic Reviews were searched for meta-analyses that provided risk estimates (±95% confidence intervals) for associations between intakes of whole and refined grains and risk of total and site-specific cancer. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed. Only meta-analyses that included whole grains and refined grains as separate food groups, and not as part of dietary patterns, were included. A total of 17 publications were identified that met inclusion criteria. Within these, results from a total of 54 distinct meta-analyses were reported for whole grains and 5 meta-analyses for refined grains. For total cancer mortality, 7 meta-analyses of cohort studies indicated that whole grain intake was associated with 6% to 12% lower risk in comparison of highest vs. lowest intake groups, and 3% to 20% lower risk for doses ranging from 15 to 90 g/day. For site-specific cancers, meta-analyses indicated that whole grain intake was consistently associated with lower risks of colorectal, colon, gastric, pancreatic, and esophageal cancers. Limited data were available for refined grains, with only 4 publications providing risk estimates, and only 1 of the meta-analyses included more than 3 studies. High intake of refined grains was associated with increased risk of colon and gastric cancer. By contrast, in the only dose-response meta-analysis, each 90 g/day consumption of refined grains was associated with a 6% lower risk of total cancer. In addition to the limited number of published meta-analyses on refined grains, results were also weakened due to the fact that refined grains were frequently defined to include both staple grain foods and indulgent grain foods, and the majority of studies included in the meta-analyses provided no specific definition of refined grains. Overall, meta-analyses of cohort and case-control studies consistently demonstrate that whole grain intake is associated with lower risk of total and site-specific cancer, and support current dietary recommendations to increase whole grain consumption. By contrast, the relationship between refined grain intake and cancer risk is inconclusive.

Recent advances in clinical practice: colorectal cancer chemoprevention in the average-risk population

Colorectal cancer (CRC) is one of the most common and lethal malignancies in Western countries. Its development is a multistep process that spans more than 15 years, thereby providing an opportunity for prevention and early detection. The high incidence and mortality rates emphasise the need for prevention and screening. Many countries have therefore introduced CRC screening programmes. It is expected, and preliminary evidence in some countries suggests, that this screening effort will decrease CRC-related mortality rates. CRC prevention involves a healthy lifestyle and chemoprevention-more specifically, oral chemoprevention that can interfere with progression from a normal colonic mucosa to adenocarcinoma. This preventive effect is important for individuals with a genetic predisposition, but also in the general population. The ideal chemopreventive agent, or combination of agents, remains unknown, especially when considering safety during long-term use. This review evaluates the evidence across 80 meta-analyses of interventional and observational studies of CRC prevention using medications, vitamins, supplements and dietary factors. This review suggests that the following factors are associated with a decreased incidence of CRC: aspirin, non-steroidal anti-inflammatory drugs, magnesium, folate, a high consumption of fruits and vegetables, fibre and dairy products. An increased incidence of CRC was observed with frequent alcohol or meat consumption. No evidence of a protective effect for tea, coffee, garlic, fish and soy products was found. The level of evidence is moderate for aspirin, β-carotene and selenium, but is low or very low for all other exposures or interventions.

Distribution of free and bound phenolic compounds, and alkylresorcinols in wheat aleurone enriched fractions

Several companies have focused their attention on the development of technologies able to enrich/isolate the wheat aleuronic layer because it is a source of bioactive compounds. In this work two different wheat bran fractions enriched in aleurone (AF1, 55-70% aleurone and AF2, 75-90% aleurone) were obtained by a dry fractionation based on air classification. Free and bound phenolic compounds, and alkylresorcinols were determined in the two fractions by HPLC-DAD-ESI-TOF-MS and GC-MS, respectively. To our knowledge, feruloyl di-hexoside was described for the first time in wheat aleurone and flavonoids were quantified for the first time in this fraction. The results have shown that the most concentrated free phenolic compounds were flavonoids, and AF1 was the fraction that presented the highest flavonoid content; whereas trans ferulic acid was the most abundant bound phenolic acid, which highest content was obtained in AF2. Besides, total content of ferulic acid monomers in AF2 was 33.63% higher than in AF1, whereas total content of ferulic acid dimers/trimers in AF1 was 33.9% higher than in AF2. The highest content of alkylresorcinols was obtained in AF1 and it was 10.30% higher than the obtained in AF2. Therefore, it can be stated that this green technology could be used to produce enriched aleurone fractions as source of phenolic and alkylresorcinol compounds. These fractions could be of great interest for the formulation of enriched foods.

Whole-Grain Consumption Does Not Affect Obesity Measures: An Updated Systematic Review and Meta-analysis of Randomized Clinical Trials

Since the release of a previous meta-analysis on the effect of whole-grain intake on obesity measures, several clinical trials have been published. Therefore, we aimed to update the previous meta-analysis on the effect of whole-grain intake on obesity measures by including recently published studies, as well as considering the main limitations in that analysis. We searched the online databases of PubMed, Scopus, Clarivate Web of Science, EmBase, and Google Scholar for relevant studies published up to February 2019, using relevant keywords. Randomized clinical trials investigating the effect of whole-grain products or diets high in whole-grain foods, compared with a control diet, on anthropometric measures [including body weight, BMI, waist circumference, and fat mass (FM)] were included. In total, 21 studies with a total sample of 1798 participants, aged ≥18 years, were considered. Based on 22 effect sizes from 19 studies on body weight, with a total sample of 1698 adults, we found no significant effect of whole-grain consumption on body weight. The same findings were obtained for BMIs, such that using 10 effect sizes from 10 clinical trials with a total sample of 769 individuals we did not find any significant effect. With regards to body fat percentage [weighted mean difference (WMD): 0.27; 95% CI: -0.05 to 0.58%; P = 0.09], FM (WMD: 0.45; 95% CI: -0.12 to 1.02 kg; P = 0.12), fat-free mass (WMD: 0.31; 95% CI: -0.67 to 0.06 kg; P = 0.10), and waist circumference (WMD: 0.06; 95% CI: -0.50 to 0.63 cm; P = 0.82), we failed to find any significant effect of whole-grain consumption. In conclusion, our findings did not support current recommendations of whole-grain intake in attempts to control obesity measures. Given the beneficial effects of whole-grain intake on other measures of human health, additional well-designed studies are required to further investigate the effect on obesity. The protocol has been registered with PROSPERO (registration number CRD42019125320).

Changes in Dietary Intake of Animal and Vegetable Protein and Unhealthy Aging

BACKGROUND

Animal and vegetable-based proteins differ on their effect on many health outcomes, but their relationship with unhealthy aging is uncertain. Thus, we examined the association between changes in animal and vegetable protein intake and unhealthy aging in older adults.

METHODS

Data came from 1951 individuals aged ≥60 years recruited in the Seniors-ENRICA cohort in 2008-2010 (wave 0) and followed-up in 2012 (wave 1), 2015 (wave 2), and 2017 (wave 3). Dietary protein intake was measured with a validated diet history at waves 0 and 1, and unhealthy aging was measured with a 52-item health deficit accumulation index at each wave.

RESULTS

Compared with participants with a >2% decrease in energy intake from vegetable protein from wave 0 to wave 1, those with a >2% increase showed less deficit accumulation over 3.2 years (multivariable β [95% confidence interval (CI)]: -1.05 [-2.03, -0.06]), 6 years (-1.28 [-2.51, -0.03]), and 8.2 years of follow-up (-1.68 [-3.27, -0.09]). No associations were found for animal protein. Less deficit accumulation over 8.2 years was observed when substituting 1% of energy from vegetable protein for an equal amount of carbohydrate or fat (-0.50 [-0.93, -0.07]), animal protein (-0.44 [-0.81, -0.07]), dairy protein (-0.51 [-0.91, -0.12]), or meat protein (-0.44 [-0.84, -0.04]).

CONCLUSIONS

Increasing dietary intake of vegetable protein may delay unhealthy aging when replacing carbohydrates, fats, or animal protein, especially from meat and dairy.

Grain consumption and risk of gastric cancer: a meta-analysis

This study evaluated the relationship between grain consumption and the risk of gastric cancer. A total of 19 studies met the inclusion criteria. For whole grain consumption, there was a 13% reduction in the risk of gastric cancer (p = .003), and a subgroup analysis showed that a large amount of whole grain consumption reduced the risk of gastric cancer by 44% (p < .001). For refined grain consumption, there was a 36% increase in the risk of gastric cancer (p < .001); a subgroup analysis showed that a large and a moderate amount of refined grain consumption increased the risk of gastric cancer by 63% (p < .001) and 28% (p < .001), respectively. A large intake of whole grains might be protective against gastric cancer, whereas the ingestion of refined cereals may be a risk factor for gastric cancer. Moreover, the risk of cancer increases with the increase of refined grain intake.

Association between whole grain intake and all-cause mortality: a meta-analysis of cohort studies

Some observational studies have examined the association between dietary whole grain intake and all-cause mortality, but the results were inconclusive. We therefore conducted a meta-analysis to summarize the evidence from cohort studies regarding the association between whole grain intake and all-cause mortality. Pertinent studies were identified by searching PubMed, Embase and Web of Knowledge, up to February 28, 2016. Study-specific estimates were combined using random-effects models. Eleven prospective cohort studies involving 101,282 deaths and 843,749 participants were included in this meta-analysis. The pooled relative risk of all-cause mortality for the highest category of whole grain intake versus lowest category was 0.82 (95% confidence interval: 0.78, 0.87). There was a 7% reduction in risk associated with each 1 serving/day increase in whole grain intake (relative risk = 0.93; 95% confidence interval: 0.89, 0.97). No publication bias was found. This analysis indicates that higher intake of whole grain is associated with a reduced risk of all-cause mortality. The findings support current recommendations for increasing whole grain consumption to promote health and overall longevity.

Is dietary fibre truly protective against colon cancer? A systematic review and meta-analysis

Colorectal cancer is the third most common cancer worldwide. Growing evidence shows that about 47% of cases of colorectal cancer can be prevented by a healthy lifestyle. We performed a systematic review and meta-analysis aimed to evaluate the association between dietary fibre intake and the risk of colon cancer. We performed a structured computer search on PubMed, including epidemiological studies reporting results of dietary fibre intake and risk of colon cancer in women or men. We compared subjects exposed to the highest versus the lowest consumption. The search strategy identified 376 papers. After screening, 25 datasets were included in our meta-analysis. Results suggest a protective role of dietary fibre intake on colon cancer risk ES = 0.74 (95% CI = 0.67-0.82), p value = .000, but, moderate statistical heterogeneity (χ² = 42.73, p value = .011) was found. Due to the high mortality of colorectal cancer, it is important to identify effective preventive measures, especially those of a healthy lifestyle, such as a healthy diet.

Association of whole grain intake with all-cause, cardiovascular, and cancer mortality: a systematic review and dose-response meta-analysis from prospective cohort studies

BACKGROUND/OBJECTIVES

Whole grains are rich source of nutrients and have shown beneficial effects on human health. This study was designed to systematically review the existing results and quantitatively assess the dose-response relationship of whole grain intake with all-cause and cause-specific mortality.

SUBJECTS/METHODS

We searched 'whole grain' or 'whole grains' in combination with 'mortality'' or 'cardiovascular disease' or 'cancer' through the Web of Science and PubMed databases till 20 January 2016. To be eligible for inclusion, publications should be prospective cohort studies and reported the influence of whole grain intake on human mortality. Relative risks (RRs) and 95% confidence intervals (CIs) from the included studies were pooled by a random effects model or fixed effect model.

RESULTS

We included 19 cohort studies from 17 articles, with 1 041 692 participants and 96 710 deaths in total, in the analyses. We observed an inverse relationship of whole grain intake with risk of total, cardiovascular disease and cancer mortality. The pooled RR was 0.84 (95% CI 0.81-0.88, n=9) for total mortality, 0.83 (95% CI 0.79-0.86, n=8) for CVD mortality and 0.94 (95% CI 0.87-1.01, n=14) for cancer mortality, comparing the highest intake of whole grain with the lowest category. For dose-response analysis, we found a nonlinear relationship of whole grain intake with risk of total, cardiovascular and cancer mortality. Each 28 g/d intake of whole grains was associated with a 9% (pooled RR: 0.91 (0.90-0.93)) lower risk for total mortality, 14% (pooled RR: 0.86 (0.83-0.89)) lower risk for CVD mortality and 3% (pooled RR: 0.97 (0.95-0.99)) lower risk for cancer mortality.

CONCLUSIONS

Our study shows that whole grain intake was inversely associated with risk of total, CVD and cancer mortality. Our results support current dietary guidelines to increase the intake of whole grains. Government officials, scientists and medical staff should take actions to promote whole grains intake.

Anthocyanins from black rice (Oryza sativa) promote immune responses in leukemia through enhancing phagocytosis of macrophages in vivo

Rice is a staple food in numerous countries around the world. Anthocyanins found in black rice have been reported to reduce the risk of certain diseases, but the effects of crude extract of anthocyanins from Asia University-selected purple glutinous indica rice (AUPGA) on immune responses have not yet been demonstrated. The current study aimed to investigate whether AUPGA treatment could affect immune responses in murine leukemia cells in vivo. Murine acute myelomonocytic leukemia WEHI-3 cells were intraperitoneally injected into normal BALB/c mice to generate leukemia mice. A total of 50 mice were randomly divided into five groups (n=10 in each group) and were fed a diet supplemented with AUPGA at 0, 20, 50 or 100 mg/kg for three weeks. All mice were weighed and the blood, liver and spleen were collected for further experiments. The results indicated that AUPGA did not significantly affect animal body weight, but significantly increased spleen weight (P<0.05) and decreased liver weight (P<0.05) when compared with the control group. AUPGA significantly increased the T cell (CD3) population at treatments of 20 and 100 mg/kg (P<0.05). However, it only significantly increased the B cell (CD19) population at a treatment of 20 mg/kg (P<0.05). Furthermore, AUPGA at 50 and 100 mg/kg significantly increased the monocyte (CD11b) population and the level of macrophages (Mac-3; P<0.05 for both). AUPGA at 50 and 100 mg/kg significantly promoted macrophage phagocytosis in peripheral blood mononuclear cells (P<0.05), and all doses of AUPGA treatment significantly promoted macrophage phagocytotic activity in the peritoneum (P<0.05). AUPGA treatment significantly decreased natural killer cell activity from splenocytes (P<0.05). Finally, AUPGA treatment at 20 mg/kg treatment significantly promoted T cell proliferation (P<0.05), and treatment at 50 and 100 mg/kg significantly decreased B cell proliferation compared with the control group (P<0.05).

Whole Grain Intake and Mortality From All Causes, Cardiovascular Disease, and Cancer: A Meta-Analysis of Prospective Cohort Studies

BACKGROUND

Current findings on associations between whole grain (WG) intake and mortality are inconsistent and have not been summarized by meta-analysis.

METHODS AND RESULTS

We searched for prospective cohort studies reporting associations between WG intake and mortality from all causes, cardiovascular disease (CVD), and cancer through February 2016 in Medline, Embase, and clinicaltrials.gov, and we further included unpublished results from National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999 to 2004. Fourteen studies were eligible for analysis, which included 786 076 participants, 97 867 total deaths, 23 957 CVD deaths, and 37 492 cancer deaths. Pooled relative risks comparing extreme WG categories (high versus low) were 0.84 (95% confidence interval [CI], 0.80-0.88; P<0.001; I(2)=74%; Pheterogeneity<0.001) for total mortality, 0.82 (95% CI, 0.79-0.85; P<0.001; I(2)=0%; Pheterogeneity=0.53) for CVD mortality, and 0.88 (95% CI, 0.83-0.94; P<0.001; I(2)=54%; Pheterogeneity=0.02) for cancer mortality. Intakes of WG ingredients in dry weight were estimated among studies reporting relative risks for ≥3 quantitative WG categories, and they were <50 g/d among most study populations. The 2-stage dose-response random-effects meta-analysis showed monotonic associations between WG intake and mortality (Pnonlinearity>0.05). For each 16-g/d increase in WG (≈1 serving per d), relative risks of total, CVD, and cancer mortality were 0.93 (95% CI, 0.92-0.94; P<0.001), 0.91 (95% CI, 0.90-0.93; P<0.001), and 0.95 (95% CI, 0.94-0.96; P<0.001), respectively.

CONCLUSIONS

Our meta-analysis demonstrated inverse associations of WG intake with total and cause-specific mortality, and findings were particularly strong and robust for CVD mortality. These findings further support current Dietary Guidelines for Americans, which recommends at least 3 servings per day of WG intake.

Health Benefits of Dietary Whole Grains: An Umbrella Review of Meta-analyses

OBJECTIVE

The purpose of this study is to review the effectiveness of the role of whole grain as a therapeutic agent in type 2 diabetes, cardiovascular disease, cancer, and obesity.

METHODS

An umbrella review of all published meta-analyses was performed. A PubMed search from January 1, 1980, to May 31, 2016, was conducted using the following search strategy: (whole grain OR whole grains) AND (meta-analysis OR systematic review). Only English language publications that provided quantitative statistical analysis on type 2 diabetes, cardiovascular disease, cancer, and weight loss were retrieved.

RESULTS

Twenty-one meta-analyses were retrieved for inclusion in this umbrella review, and all the meta-analyses reported statistically significant positive benefits for reducing the incidence of type 2 diabetes (relative risk [RR] = 0.68-0.80), cardiovascular disease (RR = 0.63-0.79), and colorectal, pancreatic, and gastric cancers (RR = 0.57-0.94) and a modest effect on body weight, waist circumference, and body fat mass. Significant reductions in cardiovascular and cancer mortality were also observed (RR = 0.82 and 0.89, respectively). Some problems of heterogeneity, publication bias, and quality assessment were found among the studies.

CONCLUSION

This review suggests that there is some evidence for dietary whole grain intake to be beneficial in the prevention of type 2 diabetes, cardiovascular disease, and colorectal, pancreatic, and gastric cancers. The potential benefits of these findings suggest that the consumption of 2 to 3 servings per day (~45 g) of whole grains may be a justifiable public health goal.

Dietary approach to stop hypertension (DASH): diet components may be related to lower prevalence of different kinds of cancer: A review on the related documents

Background:

Dietary approaches to stop hypertension (DASH) eating plan is a healthy dietary pattern. Our object is to review surveys in the field of major components of DASH diet and different kinds of cancers.

Materials and Methods:

Our search result from PubMed search engine recruited to find related articles.

Results:

Adherence to the DASH diet components was significantly related to lower prevalence of various cancers due to their high content of fiber, nutrients, vitamins, mineral, and antioxidant capacity.

Conclusion:

In this review, positive association of DASH diet components and different cancers were observed. However, the exact association of DASH with cancers should be clarified in future longitudinal studies due to potential interaction among foods and nutrients.

Consumption of Whole Grains, Refined Cereals, and Legumes and Its Association With Colorectal Cancer Among Jordanians

Background. The role of whole grains, refined cereals, and legumes in preventing or initiating colorectal cancer (CRC) is still uncertain. The aim of this study is to examine the possible association between the consumption of whole grains, refined cereals, and legumes and the risk of developing CRC among Jordanian population. Methods. A validated food frequency questionnaire was used to collect dietary data with regard to intake of whole grains, refined cereals, and legumes. A total of 220 diagnosed CRC participants and 281 CRC-free control participants matched by age, gender, occupation, and marital status were recruited. Logistic regression was used to estimate the odds of developing CRC in relation to the consumption of different types of whole grains, refined cereals, and legumes. Results. The odds ratio (OR) for developing CRC among cases consumed refined wheat bread at all meals was 3.1 compared with controls (95% CI: 1.2-7.9, P_-Trend = 0.001); whereas the OR associated with whole wheat bread was 0.44 (95% CI: 0.22-0.92, P_-Trend = 0.001). The statistical evaluation for daily consumption of rice suggested a direct association with the risk of developing CRC, OR = 3.0 (95% CI: 0.27-33.4, P_-Trend = 0.020). Weekly consumption of macaroni was associated with CRC with OR of 2.4 (95% CI: 1.1-5.3, P_-Trend = 0.001). The consumption of corn, bulgur, lentils, and peas suggested a protective trend, although the trend was not statistically significant. Conclusion. This study provides additional indicators of the protective role of whole grains and suggests a direct association between consumption of refined grains and higher possibility for developing CRC.

A multi-targeted approach to suppress tumor-promoting inflammation

Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes.

Wheat Type (Class) Influences Development and Regression of Colon Cancer Risk Markers in Rats

We previously found red wheat more effective than white wheat in reducing colon cancer risk in rats when fed during initiation and postinitiation stages. Here we examine the effect of wheat on colon cancer risk in early and late postinitiation stages in carcinogen-treated rats. Four groups were fed a basal diet, 1 group a red wheat diet, and 1 group a white wheat diet. After 6 wk, 1 basal, the red and white groups were killed (early postinitiation stage). Of the remaining basal groups, 1 continued on the basal diet, 1 was switched to red and another to white wheat for 8 more wk (late postinitiation stage). Red and white wheat significantly reduced morphological [aberrant crypt foci (ACF)] and biochemical (β-catenin accumulated crypts) markers in both early and late postinitiation stages. Both wheat diets reduced dysplasia markers (sialomucin-expressing ACF and mucin depleted foci), compared to the basal diet, during the late postinitiation stage, but red wheat more so. Only red wheat significantly reduced the number of metallothionein-positive crypts, a stem cell mutation marker, in both stages. Overall, red wheat flour reduced risk markers more than white wheat flour, and this was more pronounced in the late post-initiation stage.

Does a Mediterranean-Type Diet Reduce Cancer Risk?

Overall cancer incidence has been observed to be lower in Mediterranean countries compared to that in Northern countries, such as the UK, and the USA. There is increasing evidence that adherence to a Mediterranean dietary pattern correlates with reduced risk of several cancer types and cancer mortality. In addition, specific aspects of the Mediterranean diet, such as high consumption of fruit and vegetables, whole grains, and low processed meat intake, are inversely associated with risk of tumor pathogenesis at different cancer sites. The purpose of this review is to summarize the available evidence regarding the association between the Mediterranean diet and cancer risk from clinical trials, prospective cohort studies, and case-control studies. Furthermore, we focused on the different definitions of a Mediterranean diet in an attempt to assess their efficiency. Observational studies provide new evidence suggesting that high adherence to a Mediterranean diet is associated with reduced risk of overall cancer mortality as well as a reduced risk of incidence of several cancer types (especially cancers of the colorectum, aerodigestive tract, breast, stomach, pancreas, prostate, liver, and head and neck).

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.

Antiviral activity of a zymolytic grain based extract on human immunodeficiency virus type 1 in vitro

Increasing evidence shows that grains may play a role in disease prevention beyond the simple provision of energy and nutrients. It has been reported that some components contained in grains exert their functional effects on viral and bacterial infections and protect against various cancers. However, until now, hardly any intervention studies have investigated the effects of grains or grain based extracts on the inhibition of HIV-1 infection. In this study, the antiviral function of a zymolytic grain based extract (ZGE) was detected in vitro and in rats, and the antiviral mechanism was investigated. Results showed that ZGE had an inhibition effect on HIV-1 infection in vitro with low cytotoxic effects. The study of the mechanism demonstrated that this functional food possibly acted on the viral surface structure protein gp120 which is responsible for cell binding, as well as on the postattachment stage of the virus. The sera of model rats administrated with this food by gavage presented anti-infection abilities against HIV-1 in vitro during a serum concentration associated period of time. These findings provide valuable insights into the application of ZGE on the control of viral load, which may contribute to future anti-HIV treatment with less adverse effects.

Epidemiological studies of oats consumption and risk of cancer and overall mortality

A review of epidemiological studies on the intake of oats and oat-based products and its effect on the risk of chronic disease and deaths was performed. Seven studies were identified of cancer risk (two each on prostate and colorectal cancer, and one each on pancreatic, breast and endometrial cancer), and one study on overall mortality. With the exception of a case–control study of pancreatic cancer, all studies were of cohort design: five studies were based on a single cohort from Denmark. The results of most cohort studies suggest a weak protective effect of a high intake of oats on cancer risk (relative risks in the order of 0·9). Potential limitations of the studies are dietary exposure misclassification, low statistical power because of limited exposure contrast and residual confounding. Despite the evidence from experimental and mechanistic studies of a protective effect of oats intake on CVD and diabetes, no epidemiological studies have been conducted on these conditions.

Mediterranean diet and health: food effects on gut microbiota and disease control

The Mediterranean diet (MD) is considered one of the healthiest dietary models. Many of the characteristic components of the MD have functional features with positive effects on health and wellness. The MD adherence, calculated through various computational scores, can lead to a reduction of the incidence of major diseases (e.g., cancers, metabolic and cardiovascular syndromes, neurodegenerative diseases, type 2 diabetes and allergy). Furthermore, eating habits are the main significant determinants of the microbial multiplicity of the gut, and dietary components influence both microbial populations and their metabolic activities from the early stages of life. For this purpose, we present a study proposal relying on the generation of individual gut microbiota maps from MD-aware children/adolescents. The maps, based on meta-omics approaches, may be considered as new tools, acting as a systems biology-based proof of evidence to evaluate MD effects on gut microbiota homeostasis. Data integration of food metabotypes and gut microbiota “enterotypes” may allow one to interpret MD adherence and its effects on health in a new way, employable for the design of targeted diets and nutraceutical interventions in childcare and clinical management of food-related diseases, whose onset has been significantly shifted early in life.

"Towards an even healthier Mediterranean diet"

Dietary guidelines to promote good health are usually based on foods, nutrients, and dietary patterns predictive of chronic disease risk in epidemiologic studies. However, sound nutritional recommendations for cardiovascular prevention should be based on the results of large randomized clinical trials with "hard" end-points as the main outcome. Such evidence has been obtained for the Mediterranean diet from the PREDIMED (Prevención con Dieta Mediterránea) trial and the Lyon Heart Study. The traditional Mediterranean diet was that found in olive growing areas of Crete, Greece, and Southern Italy in the late 1950s. Their major characteristics include: a) a high consumption of cereals, legumes, nuts, vegetables, and fruits; b) a relatively high-fat consumption, mostly provided by olive oil; c) moderate to high fish consumption; d) poultry and dairy products consumed in moderate to small amounts; e) low consumption of red meats, and meat products; and f) moderate alcohol intake, usually in the form of red wine. However, these protective effects of the traditional Mediterranean diet may be even greater if we upgrade the health effects of this dietary pattern changing the common olive oil used for extra-virgin olive oil, increasing the consumption of nuts, fatty fish and whole grain cereals, reducing sodium intake, and maintaining a moderate consumption of wine with meals.

A whole-grain-rich diet reduces urinary excretion of markers of protein catabolism and gut microbiota metabolism in healthy men after one week

Epidemiological studies consistently find that diets rich in whole-grain (WG) cereals lead to decreased risk of disease compared with refined grain (RG)-based diets. Aside from a greater amount of fiber and micronutrients, possible mechanisms for why WGs may be beneficial for health remain speculative. In an exploratory, randomized, researcher-blinded, crossover trial, we measured metabolic profile differences between healthy participants eating a diet based on WGs compared with a diet based on RGs. Seventeen healthy adult participants (11 female, 6 male) consumed a controlled diet based on either WG-rich or RG-rich foods for 2 wk, followed by the other diet after a 5-wk washout period. Both diets were the same except for the use of WG (150 g/d) or RG foods. The metabolic profiles of plasma, urine, and fecal water were measured using (1)H-nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry (plasma only). After 1 wk of intervention, the WG diet led to decreases in urinary excretion of metabolites related to protein catabolism (urea, methylguanadine), lipid (carnitine and acylcarnitines) and gut microbial (4-hydroxyphenylacetate, trimethylacetate, dimethylacetate) metabolism in men compared with the same time point during the RG intervention. There were no differences between the interventions after 2 wk. Urinary urea, carnitine, and acylcarnitine were lower at wk 1 of the WG intervention relative to the RG intervention in all participants. Fecal water short-chain fatty acids acetate and butyrate were relatively greater after the WG diet compared to the RG diet. Although based on a small population and for a short time period, these observations suggest that a WG diet may affect protein metabolism.

Ethnic differences in grains consumption and their contribution to intake of B-vitamins: results of the Multiethnic Cohort Study

BACKGROUND

Research indicates that a diet rich in whole grains may reduce the risk of prevalent chronic diseases, including cardiovascular disease, diabetes, and some cancers, and that risk for these diseases varies by ethnicity. The objective of the current study was to identify major dietary sources of grains and describe their contribution to B vitamins in five ethnic groups.

METHODS

A cross-sectional mail survey was used to collect data from participants in the Multiethnic Cohort Study in Hawaii and Los Angeles County, United States, from 1993 to 1996. Dietary intake data collected using a quantitative food frequency questionnaire was available for 186,916 participants representing five ethnic groups (African American, Latino, Japanese American, Native Hawaiian and Caucasian) aged 45-75 years. The top sources of grain foods were determined, and their contribution to thiamin, riboflavin, niacin, vitamin B6, and folic acid intakes were analyzed.

RESULTS

The top source of whole grains was whole wheat/rye bread for all ethnic-sex groups, followed by popcorn and cooked cereals, except for Native Hawaiian men and Japanese Americans, for whom brown/wild rice was the second top source; major contributors of refined grains were white rice and white bread, except for Latinos. Refined grain foods contributed more to grain consumption (27.1-55.6%) than whole grain foods (7.4-30.8%) among all ethnic-sex groups, except African American women. Grain foods made an important contribution to the intakes of thiamin (30.2-45.9%), riboflavin (23.1-29.2%), niacin (27.1-35.8%), vitamin B6 (22.9-27.5%), and folic acid (23.3-27.7%).

CONCLUSIONS

This is the first study to document consumption of different grain sources and their contribution to B vitamins in five ethnic groups in the U.S. Findings can be used to assess unhealthful food choices, to guide dietary recommendations, and to help reduce risk of chronic diseases in these populations.

Metabolomics reveals the metabolic shifts following an intervention with rye bread in postmenopausal women--a randomized control trial

Background

Epidemiological studies have consistently shown that whole grain (WG) cereals can protect against the development of chronic diseases, but the underlying mechanism is not fully understood. Among WG products, WG rye is considered even more potent because of its unique discrepancy in postprandial insulin and glucose responses known as the rye factor. In this study, an NMR-based metabolomics approach was applied to study the metabolic effects of WG rye as a tool to determine the beneficial effects of WG rye on human health.

Methods

Thirty-three postmenopausal Finnish women with elevated serum total cholesterol (5.0-8.5 mmol/L) and BMI of 20–33 kg/m² consumed a minimum of 20% of their daily energy intake as high fiber WG rye bread (RB) or refined wheat bread (WB) in a randomized, controlled, crossover design with two 8-wk intervention periods separated by an 8-wk washout period. At the end of each intervention period, fasting serum was collected for NMR-based metabolomics and the analysis of cholesterol fractions. Multilevel partial least squares discriminant analysis was used for paired comparisons of multivariate data.

Results

The metabolomics analysis of serum showed lower leucine and isoleucine and higher betaine and N,N-dimethylglycine levels after RB than WB intake. To further investigate the metabolic effects of RB, the serum cholesterol fractions were measured. Total- and LDL-cholesterol levels were higher after RB intake than after WB (p<0.05).

Conclusions

This study revealed favorable shifts in branched amino acid and single carbon metabolism and an unfavorable shift in serum cholesterol levels after RB intake in postmenopausal women, which should be considered for evaluating health beneficial effects of rye products.

Influence of dietary phytochemicals and microbiota on colon cancer risk

Colon cancer is the third most commonly diagnosed type of cancer in the United States. Lifestyle and dietary patterns influence colon cancer risk both positively and negatively. Among the dietary factors, several plant-derived compounds have been found to afford colon cancer protection. These compounds potentially influence all aspects of colonic cellular regulation and develop complex interrelationships with the colonic microbiome. Increasing understanding of the role of microorganisms in determining the colonic environment has led to awareness of this important interrelationship among dietary factors and the microbial population. Plant-derived polyphenols are active mediators of cellular events, target key carcinogenic pathways, and modulate colonic microbial populations. In turn, the colonic microorganisms metabolize dietary compounds and mediate cellular events. In addition, the role of estrogen receptors in colon cancer and the importance of dietary components that mediate estrogen receptor-β are increasingly being discovered. Hence, dietary bioactive compounds and the intestinal microbiota create a complex milieu that directly affects the carcinogenic events of the colon. These relationships must be carefully characterized in future research to provide dietary recommendations that will reduce colon cancer risk.

Alternative dietary indices both strongly predict risk of chronic disease

The Healthy Eating Index-2005 (HEI-2005) measures adherence to the 2005 Dietary Guidelines for Americans, but the association between the HEI-2005 and risk of chronic disease is not known. The Alternative Healthy Eating Index (AHEI), which is based on foods and nutrients predictive of chronic disease risk, was associated inversely with chronic disease risk previously. We updated the AHEI, including additional dietary factors involved in the development of chronic disease, and assessed the associations between the AHEI-2010 and the HEI-2005 and risk of major chronic disease prospectively among 71,495 women from the Nurses' Health Study and 41,029 men from the Health Professionals Follow-Up Study who were free of chronic disease at baseline. During ≥24 y of follow-up, we documented 26,759 and 15,558 incident chronic diseases (cardiovascular disease, diabetes, cancer, or nontrauma death) among women and men, respectively. The RR (95% CI) of chronic disease comparing the highest with the lowest quintile was 0.84 (0.81, 0.87) for the HEI-2005 and 0.81 (0.77, 0.85) for the AHEI-2010. The AHEI-2010 and HEI-2005 were most strongly associated with coronary heart disease (CHD) and diabetes, and for both outcomes the AHEI-2010 was more strongly associated with risk than the HEI-2005 (P-difference = 0.002 and <0.001, respectively). The 2 indices were similarly associated with risk of stroke and cancer. These findings suggest that closer adherence to the 2005 Dietary Guidelines may lower risk of major chronic disease. However, the AHEI-2010, which included additional dietary information, was more strongly associated with chronic disease risk, particularly CHD and diabetes.

Hydration and Pasting Properties of Oat (Avena sativa) Flour

Three oat cultivars and one oat breeding line were evaluated for chemical, hydration and pasting properties. Protein, starch and β-glucan levels ranged 11.13∼14.37, 56.37∼64.86 and 3.44∼4.76%, respectively. The oat cultivars Daeyang and Seonyang contained higher β-glucan levels of 4.76 and 4.35%. The Daeyang variety had a higher water absorption index (WAI) of 2.83∼3.35 (g/g), but a lower water solubility index (WSI) of 8.67 ∼11.08%. Daeyang and Seonyang cultivars showed higher peak and trough viscosity, but lower breakdown and setback, indicating that they easily swell, and thus could possibly provide the desirable viscosity of an oat product. The β-glucan levels were correlated positively with WAI, peak and trough viscosity, and negatively to WSI, breakdown and setback viscosity.

Whole grains: benefits and challenges

Inclusion of whole grains (WG) in the diet is recommended in dietary guidance around the world because of their associations with increased health and reduced risk of chronic disease. WGs are linked to reduced risk of obesity or weight gain; reduced risk of cardiovascular disease (CVD), including coronary heart disease (CHD), hypertension, and stroke; improved gut health and decreased risk of cancers of the upper gut; perhaps reduced risk of colorectal cancer; and lower mortality rate. The 2005 United States Dietary Guidelines Advisory Committee has recommended that consumers make "half their grains whole." Yet, whole grains are puzzling both consumers and scientists. Scientists are trying to determine whether their health benefits are due to the synergy of WG components, individual WG components, or the fact that WG eaters make many of the recommended diet and lifestyle choices. Consumers need to understand the WG benefits and how to identify WG foods to have incentive to purchase and use such foods. Industry needs to develop great-tasting, clearly-labeled products. With both these factors working together, it will be possible to change WG consumption habits among consumers.

Whole grain cereals: functional components and health benefits

Cereal-based food products have been the basis of the human diet since ancient times. Dietary guidelines all over the world are recommending the inclusion of whole grains because of the increasing evidence that whole grains and whole-grain-based products have the ability to enhance health beyond the simple provision of energy and nutrients. In this review we will examine the main chemical components present in whole grains that may have health enhancing properties (dietary fiber, inulin, beta-glucan, resistant starch, carotenoids, phenolics, tocotrienols, and tocopherols) and the role that whole grains may play in disease prevention (cardiovascular diseases and strokes, hypertension, metabolic syndrome, type 2 diabetes mellitus, obesity, as well as different forms of cancer). The knowledge derived from the functional properties of the different chemical components present in whole grains will aid in the formulation and development of new food products with health enhancing characteristics.

Externalities from grain consumption: a survey

The US Department of Agriculture (USDA) publishes their MyPyramid plan as a recommended eating model for all Americans. As part of this model, grain consumption is emphasized. This grain consumption has the potential to generate positive externalities, such as reduced rates of obesity, diabetes and other chronic diseases. Such positive externalities can potentially produce tangible economic benefits in terms of public health. In contrast, newer nutritional research shows that grain consumption may have negative effects on health for certain population groups. Celiac disease is four times as common as it was 50 years ago and is often under-diagnosed. Other population groups exhibit gluten sensitivity which can impact the development of asthma, allergies and neurological difficulties. This survey intends to provide a comprehensive description of both the positive and negative externalities associated with grain consumption and the resulting impact on human health.

Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies

OBJECTIVE

To investigate the association between intake of dietary fibre and whole grains and risk of colorectal cancer.

DESIGN

Systematic review and meta-analysis of prospective observational studies.

DATA SOURCES

PubMed and several other databases up to December 2010 and the reference lists of studies included in the analysis as well as those listed in published meta-analyses.

STUDY SELECTION

Prospective cohort and nested case-control studies of dietary fibre or whole grain intake and incidence of colorectal cancer.

RESULTS

25 prospective studies were included in the analysis. The summary relative risk of developing colorectal cancer for 10 g daily of total dietary fibre (16 studies) was 0.90 (95% confidence interval 0.86 to 0.94, I(2) = 0%), for fruit fibre (n = 9) was 0.93 (0.82 to 1.05, I(2) = 23%), for vegetable fibre (n = 9) was 0.98 (0.91 to 1.06, I(2) = 0%), for legume fibre (n = 4) was 0.62 (0.27 to 1.42, I(2) = 58%), and for cereal fibre (n = 8) was 0.90 (0.83 to 0.97, I(2) = 0%). The summary relative risk for an increment of three servings daily of whole grains (n = 6) was 0.83 (0.78 to 0.89, I(2) = 18%).

CONCLUSION

A high intake of dietary fibre, in particular cereal fibre and whole grains, was associated with a reduced risk of colorectal cancer. Further studies should report more detailed results, including those for subtypes of fibre and be stratified by other risk factors to rule out residual confounding. Further assessment of the impact of measurement errors on the risk estimates is also warranted.

Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies

OBJECTIVE

To investigate the association between intake of dietary fibre and whole grains and risk of colorectal cancer.

DESIGN

Systematic review and meta-analysis of prospective observational studies.

DATA SOURCES

PubMed and several other databases up to December 2010 and the reference lists of studies included in the analysis as well as those listed in published meta-analyses.

STUDY SELECTION

Prospective cohort and nested case-control studies of dietary fibre or whole grain intake and incidence of colorectal cancer.

RESULTS

25 prospective studies were included in the analysis. The summary relative risk of developing colorectal cancer for 10 g daily of total dietary fibre (16 studies) was 0.90 (95% confidence interval 0.86 to 0.94, I(2) = 0%), for fruit fibre (n = 9) was 0.93 (0.82 to 1.05, I(2) = 23%), for vegetable fibre (n = 9) was 0.98 (0.91 to 1.06, I(2) = 0%), for legume fibre (n = 4) was 0.62 (0.27 to 1.42, I(2) = 58%), and for cereal fibre (n = 8) was 0.90 (0.83 to 0.97, I(2) = 0%). The summary relative risk for an increment of three servings daily of whole grains (n = 6) was 0.83 (0.78 to 0.89, I(2) = 18%).

CONCLUSION

A high intake of dietary fibre, in particular cereal fibre and whole grains, was associated with a reduced risk of colorectal cancer. Further studies should report more detailed results, including those for subtypes of fibre and be stratified by other risk factors to rule out residual confounding. Further assessment of the impact of measurement errors on the risk estimates is also warranted.

Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies

OBJECTIVE

To investigate the association between intake of dietary fibre and whole grains and risk of colorectal cancer.

DESIGN

Systematic review and meta-analysis of prospective observational studies.

DATA SOURCES

PubMed and several other databases up to December 2010 and the reference lists of studies included in the analysis as well as those listed in published meta-analyses.

STUDY SELECTION

Prospective cohort and nested case-control studies of dietary fibre or whole grain intake and incidence of colorectal cancer.

RESULTS

25 prospective studies were included in the analysis. The summary relative risk of developing colorectal cancer for 10 g daily of total dietary fibre (16 studies) was 0.90 (95% confidence interval 0.86 to 0.94, I(2) = 0%), for fruit fibre (n = 9) was 0.93 (0.82 to 1.05, I(2) = 23%), for vegetable fibre (n = 9) was 0.98 (0.91 to 1.06, I(2) = 0%), for legume fibre (n = 4) was 0.62 (0.27 to 1.42, I(2) = 58%), and for cereal fibre (n = 8) was 0.90 (0.83 to 0.97, I(2) = 0%). The summary relative risk for an increment of three servings daily of whole grains (n = 6) was 0.83 (0.78 to 0.89, I(2) = 18%).

CONCLUSION

A high intake of dietary fibre, in particular cereal fibre and whole grains, was associated with a reduced risk of colorectal cancer. Further studies should report more detailed results, including those for subtypes of fibre and be stratified by other risk factors to rule out residual confounding. Further assessment of the impact of measurement errors on the risk estimates is also warranted.

Intake of whole grain in Scandinavia: intake, sources and compliance with new national recommendations

AIMS

The aim of the present study was to describe the intake of whole grain (WG) in Norway, Sweden and Denmark, and to investigate what proportion of the study population that met the new WG recommendation (75 g WG/day per 10 MJ).

METHODS

Descriptive study. Data is from one 24h dietary recall (24HDR) collected in 1995-2000 from a subset (n = 8,702) of the large Scandinavian cohort "HELGA" consisting of participants aged 30-65 years from three cohorts.

RESULTS

The mean WG intake was far below the recommended level. Between 16% (Danish men) and 35% (Norwegian women) consumed at least the recommended intake of WG. Among women, the median intake of WG products (g WG products/day) was 114 g/day in Norway and 108 g/day in Denmark, whereas the intake was much lower in Sweden (64 g/day). For women, the median intake of WG in absolute amounts (g WG/day) was again highest in Norway (44 g/day), but lower in both Sweden (35 g/day) and Denmark (31 g/day). For men (no data available for Norwegian men), the intake of WG products was higher in Denmark (138 g/day) compared to Sweden (79 g/day), but when looking at the WG intake in absolute amounts, the intake was highest in Sweden (49 g/day) compared to Denmark (41 g/day).

CONCLUSIONS

The present study described the intake of WG as well as the sources of WG in Norway, Sweden and Denmark. Between 16% and 35% met the new recommendations on intake of WG.

Putting the whole grain puzzle together: health benefits associated with whole grains--summary of American Society for Nutrition 2010 Satellite Symposium

The symposium "Putting the Whole Grain Puzzle Together: Health Benefits Associated with Whole Grains" sponsored by the ASN brought together researchers to review the evidence regarding the health benefits associated with whole grains. Current scientific evidence indicates that whole grains play an important role in lowering the risk of chronic diseases, such as coronary heart disease, diabetes, and cancer, and also contribute to body weight management and gastrointestinal health. The essential macro- and micronutrients, along with the phytonutrients present in whole grains, synergistically contribute to their beneficial effects. Current evidence lends credence to the recommendations to incorporate whole grain foods into a healthy diet and lifestyle program. The symposium also highlighted the need for further research to examine the role of whole grain foods in disease prevention and management to gain a better understanding of their mechanisms of action.