Dairy Consumption and Gastric Cancer Risk: A Meta-Analysis of Epidemiological Studies

Milk and dairy products - a scoping review for Nordic Nutrition Recommendations 2023

Milk and dairy products are major sources of protein, calcium, and other micronutrients. Milk and dairy products contribute with approximately half of the total intake of saturated fat in the Nordic and Baltic diets. Saturated fat is an important determinant of plasma total and low density lipoprotein (LDL)-cholesterol concentrations, and a causal relationship between high LDL-cholesterol and atherosclerotic cardiovascular disease has consistently been documented. The aim of this scoping review is to describe the evidence for the role of milk and dairy products for health-related outcomes as a basis for setting and updating food-based dietary guidelines. Two qualified systematic reviews were included (World Cancer Research Fund and a systematic review for the US Dietary Guidelines Advisory Committee 2020). In addition, systematic reviews published between January 2011 and January 2022 were considered, screened (555 records) and evaluated (159 records) for this review. The systematic reviews suggest that milk or dairy consumption is not associated with increased risk of cardiovascular disease and dyslipidaemia. Current evidence suggests an inverse association with some cardiometabolic risk factors, such as total and LDL-cholesterol, especially regarding fermented dairy products (i.e. yogurt and cheese). There was evidence of an association between intake of dairy products and reduced risk of colorectal cancer. Some studies reported an inverse association between intake of dairy and type 2 diabetes or markers of impaired glucose homeostasis, especially for low-fat dairy, yoghurt, and cheese. Most studies suggest that intake of milk or dairy is not associated with increased risk of cardiovascular risk and some suggestions of inverse association, especially with low-fat products and fermented dairy products, were found with respect to cardiovascular disease, type 2 diabetes, and colorectal cancer. Milk or dairy products are important dietary sources of calcium and iodine, and are fully compatible with a healthy dietary pattern.

Factors Associated with Dietary Habit Changes in Korean Stomach Cancer Survivors after Cancer Treatment

The current nutritional guidelines for stomach cancer survivors (SCSs) mainly focus on the influence of the surgical resection of the stomach, with limited guidance regarding a wider range of food options. We aimed to investigate the factors associated with healthier dietary changes in Korean adult SCSs. This cross-sectional study assessed dietary pattern changes after cancer treatment for 11 food categories, using a self-administered questionnaire. A 'healthier dietary change' was operationally defined as a reduced consumption of red and processed meat, grains, salt, and burnt food, and an increased consumption of poultry, fish, vegetables, fruits, legumes, and dairy products. Among a total of 624 SCSs, approximately 60% of participants reported dietary changes in a healthier direction in three or more food categories, while 9.1% reported no changes. There was no significant difference in dietary habit changes between surgery types. Multivariable adjusted analysis showed that elderly and long-term survivors were inversely associated with a healthier dietary change. SCSs with a higher level of educational achievement and income were more likely to make healthier changes in their intake of processed meat, vegetables, fruits, burnt food, or salt. SCSs with higher levels of fear of cancer recurrence, anxiety, or depression were more likely to follow healthier dietary changes regarding fish, meat, fruits, grains, or burnt food. Change in dietary pattern varied across different food items, and was associated with various characteristics of SCSs. It is crucial to repeatedly provide SCSs with information about healthier dietary patterns, considering their sociodemographic, clinical, and psychological characteristics.

Yoghurt Intake and Gastric Cancer: A Pooled Analysis of 16 Studies of the StoP Consortium

BACKGROUND

Yoghurt can modify gastrointestinal disease risk, possibly acting on gut microbiota. Our study aimed at exploring the under-investigated association between yoghurt and gastric cancer (GC).

METHODS

We pooled data from 16 studies from the Stomach Cancer Pooling (StoP) Project. Total yoghurt intake was derived from food frequency questionnaires. We calculated study-specific odds ratios (ORs) of GC and the corresponding 95% confidence intervals (CIs) for increasing categories of yoghurt consumption using univariate and multivariable unconditional logistic regression models. A two-stage analysis, with a meta-analysis of the pooled adjusted data, was conducted.

RESULTS

The analysis included 6278 GC cases and 14,181 controls, including 1179 cardia and 3463 non-cardia, 1191 diffuse and 1717 intestinal cases. The overall meta-analysis revealed no association between increasing portions of yoghurt intake (continuous) and GC (OR = 0.98, 95% CI = 0.94-1.02). When restricting to cohort studies, a borderline inverse relationship was found (OR = 0.93, 95% CI = 0.88-0.99). The adjusted and unadjusted OR were 0.92 (95% CI = 0.85-0.99) and 0.78 (95% CI = 0.73-0.84) for any vs. no yoghurt consumption and GC risk. The OR for 1 category of increase in yoghurt intake was 0.96 (95% CI = 0.91-1.02) for cardia, 1.03 (95% CI = 1.00-1.07) for non-cardia, 1.12 (95% CI = 1.07-1.19) for diffuse and 1.02 (95% CI = 0.97-1.06) for intestinal GC. No effect was seen within hospital-based and population-based studies, nor in men or women.

CONCLUSIONS

We found no association between yoghurt and GC in the main adjusted models, despite sensitivity analyses suggesting a protective effect. Additional studies should further address this association.

Global burden of gastric cancer: epidemiological trends, risk factors, screening and prevention

Gastric cancer remains a major cause of cancer-related mortality worldwide. The temporal trends for this malignancy, however, are dynamic, and reports from the past decade indicate important declines in some regions and demographic groups, as well as a few notable exceptions in which gastric cancer rates are either stable or increasing. Two main anatomical subtypes of gastric cancer exist, non-cardia and cardia, with different temporal trends and risk factors (such as obesity and reflux for cardia gastric cancer and Helicobacter pylori infection for non-cardia gastric cancer). Shifts in the distribution of anatomical locations have been detected in several high-incidence regions. H. pylori is an important aetiological factor for gastric cancer; importantly, the anticipated long-term findings from studies examining the effect of H. pylori eradication on the risk of (re)developing gastric cancer have emerged in the past few years. In this Review, we highlight the latest trends in incidence and mortality using an evidence-based approach. We make the best possible inferences, including clinical and public health inference, on the basis of the quality of the evidence available, and highlight burning questions as well as gaps in knowledge and public health practice that need to be addressed to reduce gastric cancer burden worldwide.

Association between soy products, fruits, vegetables, and dairy products and gastric cancer risk in Helicobacter pylori-infected subjects: a case-control study in Korea

BACKGROUND/OBJECTIVES

Consumption of certain protective foods may help inhibit Helicobacter pylori (H. pylori) associated gastric pathologies. However, studies conducted to assess the efficacy of protective foods in H. pylori-infected subjects are either limited or inconsistent. This study evaluated the association of individual or a combination of protective foods on the incidence of gastric cancer (GC) in H. pylori-positive subjects through a case-control study.

MATERIALS/METHODS

Subjects aged 20-79 years were selected from 2 hospitals between December 2002 and September 2006. In total, 134 patients and 212 controls tested positive for H. pylori infection. Among these, we included 82 pairs of cases and controls matched by sex, age (± 5 years), enrollment period (± 1 years), and hospital.

RESULTS

A higher intake of soy products was associated with a significantly lower risk of GC than a lower intake of soy products (odds ratio [OR] = 0.37, 95% confidence interval [CI] = 0.14-0.96). Additionally, a higher fruit intake resulted in a significantly lower risk of GC than a lower fruit intake (OR = 0.35, 95% CI = 0.13-0.94). A combination of food groups was evaluated, and a lower risk of GC was observed with a high intake of both soy products and fruits (OR = 0.20, 95% CI = 0.06-0.67), high intake of soy and dairy products (OR = 0.28, 95% CI = 0.10-0.78) and high intake of fruits and dairy products (OR = 0.28, 95% CI = 0.09-0.83).

CONCLUSIONS

A high intake of soy products or fruits was associated with a lower risk of GC. A combination of soy products or fruits with dairy products was associated with a lower risk of GC. A balanced intake of soy products, fruits, and dairy products may help reduce GC risk.

Cow's Milk in Human Nutrition and the Emergence of Plant-Based Milk Alternatives

Cow's milk is considered a complete food, providing high-quality protein and essential micronutrients, including vitamins and minerals. For medical reasons or as a lifestyle choice, consumers are replacing cow's milk with plant-based milk alternatives (PBMA); some perceive them as healthier alternatives to cow's milk due to their low saturated fatty acid content and no cholesterol content. However, the nutritional composition of PBMA is quite variable between different types and even within, which makes a comparison with cow's milk a complex issue. Furthermore, the consumption of PBMA has been associated with the development of some diseases in infants and children. Meanwhile, the consumption of cow's milk in human health is a controversial issue since it has been associated with a favorable effect in some diseases (such as obesity, type 2 diabetes, and Alzheimer's) and a negative effect in others (such as prostate cancer risk and Parkinson's disease); while in some diseases, there is no consensus in the cow's milk consumption effect. The aim of this review is to make a nutritional comparison of cow's milk with PBMA and to clarify the potential health issues related to their consumption.

Diet and Risk of Gastric Cancer: An Umbrella Review

Several dietary exposures have been associated with gastric cancer (GC), but the associations are often heterogenous and may be afflicted by inherent biases. In the context of an Umbrella Review (UR), we provide an overview and a critical evaluation of the strength and quality, and evidence classification of the associations of diet-related exposures in relation to the risk of GC. We searched PubMed and Scopus for eligible meta-analyses of observational studies published in English from inception to 12 December 2021, and for any identified association, we applied robust epidemiological validity evaluation criteria and individual study quality assessment using AMSTAR. We screened 3846 titles/abstracts and assessed 501 full articles for eligibility, of which 49 were included in the analysis, investigating 147 unique exposures in relation to GC, cardia (GCC) or non-cardia (GNCC) cancer. Supported by suggestive evidence, positive associations were found comparing the highest vs. lowest categories for: heavy (>42 g/day) alcohol consumption (Relative Risk (RR) = 1.42, 95% Confidence Interval (CI): 1.20−1.67), salted fish consumption (RR = 1.56, 95% CI:1.30−1.87) and waist circumference (RR = 1.48, 95% CI:1.24−1.78) and an inverse association for the healthy lifestyle index (RR = 0.60, 95% CI:0.48−0.74) in relation to GC. Additionally, a positive association was found comparing obese individuals (Body Mass Index (BMI) ≥ 30) to normal-weight individuals (BMI: 18.5−25) (RR = 1.82, 95% CI:1.32−2.49) in relation to GCC. Most of the meta-analyses were of medium-to-high quality (median items: 7.0, interquartile range: 6−9). Maintaining a normal body weight and adopting healthy dietary choices, in particular, limiting the consumption of salt-preserved foods and alcohol, can reduce the risk of gastric cancer.

Dietary Salt Intake and Gastric Cancer Risk: A Systematic Review and Meta-Analysis

The results of prospective cohort studies regarding the role of salt intake and subsequent gastric cancer risk are inconsistent. Thus, we performed a systematic review and meta-analysis to summarize the strength of the association of salt intake with gastric cancer morbidity and mortality. PubMed, EmBase, and Cochrane Library were systematically searched to identify eligible studies published throughout September 2021. The effect estimates with 95% confidence intervals (CIs) for gastric cancer morbidity or mortality in each study were applied to calculate the pooled results; these analyses were performed using the random-effects model. Twenty-six prospective cohort studies involving 4,956,350 individuals were selected; these studies reported 19,301 cases of gastric cancer and 2,871 cases of gastric cancer-associated mortality. High (RR: 1.25; 95%CI: 1.10–1.41; P = 0.001) or moderate (RR: 1.20; 95%CI: 1.04–1.38; P = 0.012) salt intake was associated with a greater risk of gastric cancer. High pickled food intake was associated with an increased gastric cancer risk (RR: 1.28; 95%CI: 1.05–1.57; P = 0.017), while moderate pickled foods intake had no significant effect on gastric cancer risk (RR: 1.10; 95%CI: 0.88–1.37; P = 0.390). Neither high (RR: 1.14; 95%CI: 0.95–1.36; P = 0.161) nor moderate (RR: 1.10; 95%CI: 0.87–1.40; P = 0.436) salted fish intake were associated with gastric cancer risk. A high intake of processed meat was significantly associated with a higher risk of gastric cancer (RR: 1.24; 95%CI: 1.03–1.49; P = 0.023), while moderate processed meat intake had no significant effect on the gastric cancer risk (RR: 1.01; 95%CI: 0.92–1.11; P = 0.844). High (RR: 1.04; 95%CI: 0.90–1.19; P = 0.626) and moderate (RR: 1.02; 95%CI: 0.94–1.11; P = 0.594) miso-soup intake had no effects on the gastric cancer risk. High intakes of salt, pickled food, and processed meat are associated with significantly increased risks of gastric cancer; these increased risks are also seen when participants consumed moderate amounts of salt.

Dietary Intake of Soy Products, Vegetables, and Dairy Products and Gastric Cancer Survival according to Histological Subtype: a Long-term Prospective Cohort Study

PURPOSE

Owing to differences in the general characteristics of gastric cancer (GC) according to histological type, the association of GC risk factors, such as diet, may also differ depending on the histological type. We investigated the associations between individual and combined intake of soy products, vegetables, and dairy products and GC mortality by following up cases of death among Korean GC cases and whether these associations differ according to the histological type.

MATERIALS AND METHODS

A total of 508 GC cases were enrolled from two hospitals between 2002 and 2006. Their survival or death was prospectively followed up until December 31, 2016, through a review of medical records and telephonic surveys. Finally, 300 GC cases classified as intestinal- or diffuse-type GC cases were included. The median follow-up period was 7.1 years.

RESULTS

In the fully adjusted model, a high intake of soy products (hazard ratio [HR], 0.43; 95% confidence interval [CI], 0.19-0.96) and the combination of soy products and vegetables (HR, 0.34; 95% CI, 0.12-0.96) or soy products and dairy products (HR, 0.37; 95% CI, 0.14-0.98) decreased the mortality from intestinal-type GC. In particular, patients consuming various potentially protective foods (HR, 0.23; 95% CI, 0.06-0.83) showed a highly significant association with a lower mortality from intestinal-type GC. However, no significant association was found with diffuse-type GC.

CONCLUSIONS

High intake of potentially protective foods, including soy products, vegetables, and dairy products, may help increase survival in intestinal-type GC.

Lactose intolerance: An update on its pathogenesis, diagnosis, and treatment

Lactose intolerance has a high prevalence worldwide, ranging between 57% and 65%. It is caused by a reduction or loss of the activity of the intestinal enzyme lactase-phlorizin hydrolase, responsible for the digestion of lactose. This alteration determines an increased osmotic load in the small intestine and the fermentation of lactose by the bacterial flora, which leads to a high production of short-chain fatty acids and gas. This is followed by the onset of abdominal pain, diarrhea, and flatulence. In addition to these problems, it was found that subjects with lactose intolerance have an increased risk of developing various extra-intestinal diseases, including cancers. The diagnosis is essential to undertake an adequate treatment and, for this purpose, different methods have been tested. These include genetic test, hydrogen breath test (HBT), quick lactase test, and lactose tolerance test. HBT is the most used method because it is non-invasive, inexpensive, and highly sensitive and specific, as well as easy to perform. In clinical practice, the other methods are mainly used as HBT integration tests. There are also many therapeutic options. An appropriate intervention concerns the dietetic style, such as the consumption of lactose-free foods, but with nutritional characteristics comparable to dairy products. Other valid choices are represented by the use of exogenous enzymes, probiotics, prebiotics, the selection of milk containing specific types of beta-caseins. This review is intended to illustrate the diagnostic methods currently available and the possible therapeutic options for lactose intolerance.

Dairy Consumption and Liver Cancer Risk: A Systematic Review and Dose-Response Meta-Analysis of Observational Studies

The relationship of dairy consumption and liver cancer risk is still controversial. We conducted a meta-analysis of published cohort and case-control studies to summarize the epidemiologic evidence on the relationship between dairy products consumption and the risk of liver cancer. The literatures were screened from PubMed, EMBASE, and Cochrane Library before May 2020. A total of seven cohort studies and eight case-control studies (5,121 cases) were included. The summary relative risks (RRs) were 1.17 (95% CI: 0.87‒1.57) and 1.08 (95% CI: 0.78‒1.51) for milk and total dairy, respectively. 0.50 (95% CI: 0.27-0.91) and 1.16 (95% CI: 0.83-1.52) were yogurt, cheese, and curd. Subgroup analysis revealed that study duration, alcohol, and design were associated the RRs. Dose-response analysis showed that the liver cancer risk was decreased by 5.4% (P for linear trend = 0.002) with a 40 g/day increment of yogurt intake. These results suggested that total dairy, milk, cheese, and curd were positive associations with the liver cancer risk although they were not statistically significant, however higher yogurt intake would reduce the risk. Further studies are necessary to verify the relationship of dairy foods with cancer.

A Medical Decision Support System to Assess Risk Factors for Gastric Cancer Based on Fuzzy Cognitive Map

Gastric cancer (GC), one of the most common cancers around the world, is a multifactorial disease and there are many risk factors for this disease. Assessing the risk of GC is essential for choosing an appropriate healthcare strategy. There have been very few studies conducted on the development of risk assessment systems for GC. This study is aimed at providing a medical decision support system based on soft computing using fuzzy cognitive maps (FCMs) which will help healthcare professionals to decide on an appropriate individual healthcare strategy based on the risk level of the disease. FCMs are considered as one of the strongest artificial intelligence techniques for complex system modeling. In this system, an FCM based on Nonlinear Hebbian Learning (NHL) algorithm is used. The data used in this study are collected from the medical records of 560 patients referring to Imam Reza Hospital in Tabriz City. 27 effective features in gastric cancer were selected using the opinions of three experts. The prediction accuracy of the proposed method is 95.83%. The results show that the proposed method is more accurate than other decision-making algorithms, such as decision trees, Naïve Bayes, and ANN. From the perspective of healthcare professionals, the proposed medical decision support system is simple, comprehensive, and more effective than previous models for assessing the risk of GC and can help them to predict the risk factors for GC in the clinical setting.

Dairy foods and health: an umbrella review of observational studies

Evidence on consumption of dairy foods and human health is contradictory. This study aimed to summarize the level of evidence of dairy consumption on various health outcomes. A systematic search for meta-analyses was performed: study design, dose-response relationship, heterogeneity and agreement of results over time, and identification of potential confounding factors were considered to assess the level of evidence. Convincing and probable evidence of decreased risk of colorectal cancer, hypertension and cardiovascular disease, elevated blood pressure and fatal stroke, respectively, was found for total dairy consumption; possible decreased risk of breast cancer, metabolic syndrome, stroke and type-2 diabetes, and increased risk of prostate cancer and Parkinson's disease was also found. Similar, yet not entirely consistent evidence for individual dairy products was reported. Among potential confounding factors, geographical localisation and fat content of dairy have been detected. In conclusions, dairy may be part of a healthy diet; however, additional studies exploring confounding factors are needed to ascertain the potential detrimental effects.

Milk and dairy products consumption and the risk of oral or oropharyngeal cancer: a meta-analysis

The present meta-analysis was conducted to explore the role of milk and dairy products consumption on oral or oropharyngeal cancer risk. PubMed, Embase and Chinese Wanfang databases were investigated until 30 June 2019. The overall and subgroup associations were pooled with odds ratios (ORs) and 95% confidence intervals (CIs). As a result, the present study involving 4635 cases and 50777 participants from 12 publications suggested that an inverse association was found between milk and dairy products consumption and oral or oropharyngeal cancer risk (OR = 0.74, 95% CI = 0.59–0.92; I² = 65.9%, P_{for heterogeneity}=0.001). Four studies reported milk consumption on oral cancer risk, but no significant association was found (OR = 0.91, 95% CI = 0.61–1.37). Six studies about milk consumption and oropharyngeal cancer risk found that there was a positive association between them (OR = 0.63, 95% CI = 0.44–0.90). In conclusion, findings from our meta-analysis indicated that milk and dairy products consumption may be associated with decreased risk of oral or oropharyngeal cancer.

Associations between calcium and magnesium intake and the risk of incident gastric cancer: A prospective cohort analysis of the National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study

Gastric cancer remains a leading cause of cancer-related mortality. Identifying dietary and other modifiable disease determinants has important implications for risk attenuation in susceptible individuals. Our primary aim was to estimate the association between dietary and supplemental intakes of calcium and magnesium and the risk of incident gastric cancer. We conducted a prospective cohort analysis of the National Institutes of Health-American Association of Retired Persons Diet and Health Study. We used Cox proportional hazard modeling to estimate the association between calcium and magnesium intakes with risk of incident gastric adenocarcinoma (GA) overall and by anatomic location, noncardia GA (NCGA) and cardia GA (CGA). A total of 536,403 respondents (59% males, 41% females) were included for analysis, among whom 1,518 incident GAs (797 NCGA and 721 CGA) occurred. Increasing calcium intake was associated with lower risk of GA overall (p-trend = 0.05), driven primarily by the association with NCGA, where the above median calcium intakes were associated with a 23% reduction in risk compared to the lowest quartile (p-trend = 0.05). This magnitude of NCGA risk reduction was greater among nonwhite ethnic group and Hispanics (hazard ratio [HR] 0.51, 95% confidence interval [CI]: 0.24-1.07, p-trend = 0.04), current/former smokers (HR 0.58, 95% CI: 0.41-0.81), obese individuals (HR 0.54, 95% CI: 0.31-0.96) and those with high NCGA risk scores (HR 0.50, 95% CI: 0.31-0.80). Among men only, increasing magnesium intake was associated with 22-27% reduced risk of NCGA (p-trend = 0.05), while for the cohort, dietary magnesium intake in the highest vs. lowest quartile was associated with a 34% reduced risk of NCGA (HR 0.66, 95% CI: 0.48-0.90). These findings have important implications for risk factor modification. Future investigations are needed not only to confirm our results, but to define mechanisms underlying these associations.

Fatty acid 2-hydroxylation inhibits tumor growth and increases sensitivity to cisplatin in gastric cancer

Background

Most gastric cancers are diagnosed at an advanced or metastatic stage with poor prognosis and survival rate. Fatty acid 2-hydroxylase (FA2H) with high expression in stomach generates chiral (R)-2-hydroxy FAs ((R)-2-OHFAs) and regulates glucose utilization which is important for cell proliferation and invasiveness. We hypothesized that FA2H impacts gastric tumor growth and could represent a novel target to improve gastric cancer therapy.

Methods

FA2H level in 117 human gastric tumors and its association with tumor growth, metastasis and overall survival were examined. Its roles and potential mechanisms in regulating tumor growth were studied by genetic and pharmacological manipulation of gastric cancer cells in vitro and in vivo.

Findings

FA2H level was lower in gastric tumor tissues as compared to surrounding tissues and associated with clinicopathologic status of patients, which were confirmed by analyses of multiple published datasets. FA2H depletion decreased tumor chemosensitivity, partially due to inhibition of AMPK and activation of the mTOR/S6K1/Gli1 pathway. Conversely, FA2H overexpression or treatment with (R)-2-OHFAs had the opposite effects. In line with these in vitro observations, FA2H knockdown promoted tumor growth with increased level of tumor Gli1 in vivo. Moreover, (R)-2-OHFA treatment significantly decreased Gli1 level in gastric tumors and enhanced tumor chemosensitivity to cisplatin, while alleviating the chemotherapy-induced weight loss in mice.

Interpretation

Our results demonstrate that FA2H plays an important role in regulating Hh signaling and gastric tumor growth and suggest that (R)-2-OHFAs could be effective as nontoxic wide-spectrum drugs to promote chemosensitivity.

Fund

Grants of NSF, NIH, and PAPD.

Dairy product consumption and development of cancer: an overview of reviews

OBJECTIVES

To provide a comprehensive systematic overview of current evidence from pooled analyses/meta-analyses and systematic reviews (PMASRs) pertaining to dairy consumption and incident cancer and/or all-cause or cancer-specific mortality.

DESIGN

Overview of reviews.

SETTING

Community setting.

PARTICIPANTS

The unit of analysis is PMASRs. A total of 42 PMASRs was included in this overview of reviews.

INTERVENTIONS/EXPOSURES

Any dairy product consumption (eg, milk, yogurt, etc).

PRIMARY AND SECONDARY OUTCOMES MEASURES

Primary outcome measure is development of any type of cancer. Secondary outcome measures are all-cause mortality and cancer-specific mortality.

RESULTS

From 9693 citations identified, we included 42 PMASRs (52 study reports) published between 1991 and 2017. Thirty-one (74%) of these was pooled analyses/meta analyses, and only 11 (26%) were systematic reviews and meta-analyses. There was a wide variability in the type of study designs included within the other PMASRs, thus contributing to variable and, in instances, divergent estimates of cancer risk for several cancer subtypes. For example, only one systematic review and meta-analysis exclusively included prospective study designs. Most PMASRs were of low to moderate quality based on the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) scores. The median AMSTAR score was 5 (IQR 2-7). Our overview identified conflicting evidence from PMASRs on association between dairy consumption and incident cancers or mortality. Heterogeneity in summary estimates reflected the inclusion of variable study designs and overall low methodological quality of individual PMASRs.

CONCLUSIONS

The association between dairy consumption and cancer risk has been explored in PMASRs with a variety of study designs and of low to moderate quality. To fully characterise valid associations between dairy consumption and risk of cancer and/or mortality rigorously conducted, PMASRs including only high-quality prospective study designs are required.

TRIAL REGISTRATION NUMBER

CRD42017078463.

Lactose Intolerance, Dairy Avoidance, and Treatment Options

Lactose intolerance refers to symptoms related to the consumption of lactose-containing dairy foods, which are the most common source for this disaccharide. While four causes are described, the most common is the genetically-determined adult onset lactose maldigestion due to loss of intestinal lactase governed by control of the gene by a 14,000 kb promoter region on chromosome 2. Gastrointestinal symptoms from lactose have expanded to include systemic effects and have also been confounded by other food intolerances or functional gastrointestinal disorders. Partly because lactose maldigestion is often interpreted as lactose intolerance (symptoms), focus of therapy for these symptoms starts with lactose restriction. However, withholding of dairy foods completely is not appropriate due to a more favorable impact on health. Industrial efforts to substitute with plant-based products is not completely successful at this time. This narrative article reviews the complexities of the perception of lactose intolerance, its epidemiology, and pathogenesis. Treatments are discussed, including the inappropriateness of dairy avoidance. In conjunction, effects of dairy products on 19 common diseases are reviewed. Different methods of treatment, lactose-reduced products, plant-based dairy substitutes, adaptation, prebiotics, exogenous lactase, probiotics, and some other dietary interventions are further discussed.

Fermented Food and Non-Communicable Chronic Diseases: A Review

Fermented foods represent a significant fraction of human diets. Although their impact on health is positively perceived, an objective evaluation is still missing. We have, therefore, reviewed meta-analyses of randomized controlled trials (RCT) investigating the relationship between fermented foods and non-transmissible chronic diseases. Overall, after summarizing 25 prospective studies on dairy products, the association of fermented dairy with cancer was found to be neutral, whereas it was weakly beneficial, though inconsistent, for specific aspects of cardio-metabolic health, in particular stroke and cheese intake. The strongest evidence for a beneficial effect was for yoghurt on risk factors of type 2 diabetes. Although mechanisms explaining this association have not been validated, an increased bioavailability of insulinotropic amino acids and peptides as well as the bacterial biosynthesis of vitamins, in particular vitamin K2, might contribute to this beneficial effect. However, the heterogeneity in the design of the studies and the investigated foods impedes a definitive assessment of these associations. The literature on fermented plants is characterized by a wealth of in vitro data, whose positive results are not corroborated in humans due to the absence of RCTs. Finally, none of the RCTs were specifically designed to address the impact of food fermentation on health. This question should be addressed in future human studies.

Diabetes mellitus and the risk of gastric cancer: a meta-analysis of cohort studies

Studies examining the relationship between diabetes mellitus (DM) and the risk of gastric cancer incidence or gastric cancer mortality have produced inconsistent results. The purpose of this study was to evaluate the evidence regarding the relationship between DM and subsequent gastric cancer incidence or gastric cancer mortality risk on the basis of cohort studies. A systematic search of articles in PubMed, EmBase, the Cochrane Library, and reference lists was conducted to identify relevant literature. Twenty-two cohort studies reporting data on 8,559,861 participants were included in the study. Overall, participants with DM had little or no change in the risk of gastric cancer, or gastric cancer mortality. There was no evidence of difference in the RR for gastric cancer between men and women. Participants with DM had a non-significant trend towards an increased risk of gastric cancer mortality in men. There was no significant difference between men and women for this relationship. Finally, although subgroup analysis suggested DM was associated with a significant impact on gastric cancer incidence and gastric cancer mortality risk in several specific populations, a significance based on gender difference was not observed. In conclusion, DM might increase the risk of gastric cancer in men when the study used standard incidence/mortality ratio as effect estimate. Further, DM were associated with higher risk of gastric cancer mortality in men if the mean age at baseline less than 55.0 years, used RR or HR as effect estimate, the study adjusted smoking or not, and the study not adjusted alcohol drinking.

Milk/dairy products consumption and gastric cancer: an update meta-analysis of epidemiological studies

The relationship between dairy consumption and gastric cancer risk has not been well studied. We therefore performed a update meta-analysis to evaluate the relationship. Published cohort and case-control studies were identified via computer searches and reviewing the reference lists of the key articles. Random effects meta-analysis was used to pool effects from 5 cohort and 29 case-control studies. The odds ratio for the overall association between dairy consumption and gastric cancer was 1.20 (95%confidence interval: 1.04–1.39). The combined risk estimate was similar for population-based case-control studies (odds ratio = 1.27, 95%confidence interval: 1.00–1.61), but was reduced for hospital-based studies (odds ratio = 1.22; 95%confidence interval: 0.95–1.57) and cohort studies (odds ratio = 0.99; 95%confidence interval: 0.77–1.28). There was high heterogeneity in overall analyses. In the population-based subgroup analyses, the odds ratio was 0.96 (95%confidence interval: 0.69–1.34) when considering five studies assessing exposure two or more years before interview, and the association strengthened (odds ratio = 1.91, 95%confidence interval: 1.60–2.28) when dairy consumption was evaluated one year or less prior to interview. In conclusion, we found adverse effect of dairy consumption associated with gastric cancer.

Incidence of Cancer in Shenzhen, Guangdong Province during 2001-2015: A Retrospective Population-Based Study

Cancer is a serious public health issue and the leading cause of death around the world. This article aimed to estimate the cancer incidence and the trend in standardized cancer incidence in Shenzhen, Guangdong province, South China during 2001–2015 by analyzing the cancer data of the population-based cancer registry in Shenzhen. Data were collected from the cancer registry in Shenzhen, which was conducted during 2001–2015. In this registry, the crude incidence rates, age-specific incidence rates, age-standardized incidence rates and cumulative incidence rates were calculated in every five years. Trends for standardized incidence rates of cancers were analyzed by using the joinpoint regression analysis. In total, 33,374.3 thousand person-years (17,593.9 thousand for males and 15,780.4 thousand for females) were monitored over this time period. The number of new cancer cases during 2001–2015 was 59,218 (30,144 and 29,074 for males and females, respectively). The crude incidence during 2001–2005 was 136.44 per 100,000 persons, while the age-standardized rates by Chinese standard population (ASR-China) and by world standard population (ASR-world) were 165.13 and 212.48 per 100,000 persons, respectively. The crude incidence during 2006–2010 was 179.01 per 100,000 persons, while the ASR-China and ASR-world were 168.08 and 214.44 per 100,000 persons, respectively. The crude incidence during 2011–2015 was 196.53 per 100,000 persons, while the ASR-China and ASR-world were 171.44 and 219.99 per 100,000 persons, respectively. During 2001 and 2015, the joinpoint regression analysis showed that the ASR-China of cancer had an overall increase of 0.96% per year and 0.84% per year for males and females respectively, although both of these values (males and females) were non-significant increases. The leading cancer types during 2011–2015 were lung, colorectal, thyroid gland, breast, liver, stomach, cervix, nasopharynx, leukemia and lymphoma. For males, the top five common cancers were lung, liver, colorectal, stomach and thyroid gland. For females, the top five common cancers were breast, thyroid gland, lung, colorectal and cervix. The results of this study showed a heavy cancer burden among the population of Shenzhen, China. Future researches of the etiology and prevention of cancers should be planned in order to reduce the incidence associated with cancers in the future.

Cancer Incidence and Mortality Survey in Wuwei, Gansu Province, Northwestern China from 2003 to 2012: A Retrospective Population-based Study

Background:

Population-based cancer registry collects the data on cancer incidence and mortality deaths from covered population to describe and survey the epidemics in certain areas. The aim of this study was to estimate the cancer incidence and mortality in Wuwei, Gansu province, Northwestern China from 2003 to 2012. The goal is to better understand cancer distribution and long-term development of cancer prevention and treatment in Wuwei.

Methods:

Data were collected from the Wuwei Cancer Registry between 2003 and 2012. In this registry, data from 46 cancer report centers were included in this analysis. Incidence/mortality rates, age-specific incidence/mortality rates, age-standardized incidence/mortality rates, and cumulative incidence/mortality rates were calculated. Totally, 9,836,740 person-years (5,110,342 for males and 4,726,398 for females) had been monitored over this time period. The gender ratio of male/female was 1.08:1. The number of new cancer cases and related deaths was 24,705 and 17,287 from 2003 to 2012, respectively.

Results:

The proportion of morphological verification was 74.43%. The incidence of cases identified through death certification only was 1.21%, and the mortality to incidence ratio was 0.70. The average crude incidence was 251.15/100,000 persons (310.61 and 186.87 for males and females per 100,000 persons, respectively). The age-standardized rates by Chinese standard population (ASR-China) and by world standard population (ASR-world) were 207.76 and 245.42 per 100,000 persons, respectively. The crude cancer mortality was 175.74/100,000 persons (228.34 and 118.86 for males and females per 100,000 persons). ASR for China and the world was 149.57 and 175.13/100,000 persons, respectively. The most common cancers and leading causes of cancer-related deaths in Wuwei were as follows: cancers of stomach, esophagus, liver, lung, colorectum, breast, cervix, lymphoma, blood (leukemia), brain, and central nervous system. In Wuwei, during 2003 and 2012, cancer incidence and mortality rates increased by 1.32% and 1.31%/year, respectively. During this time, colorectum cancer incidence and mortality rates increased by 2.69% and 7.54%/year, respectively, in Wuwei. The incidence and mortality of other gastric, esophageal, liver, and lung cancers also all increased.

Conclusions:

The results of this study report a more accurate cancer burden among the population of Wuwei, China. Active research of cancers etiology and effective prevention should be established to reduce the incidence and mortality associated with cancers.

Milk and dairy products: good or bad for human health? An assessment of the totality of scientific evidence

Background

There is scepticism about health effects of dairy products in the public, which is reflected in an increasing intake of plant-based drinks, for example, from soy, rice, almond, or oat.

Objective

This review aimed to assess the scientific evidence mainly from meta-analyses of observational studies and randomised controlled trials, on dairy intake and risk of obesity, type 2 diabetes, cardiovascular disease, osteoporosis, cancer, and all-cause mortality.

Results

The most recent evidence suggested that intake of milk and dairy products was associated with reduced risk of childhood obesity. In adults, intake of dairy products was shown to improve body composition and facilitate weight loss during energy restriction. In addition, intake of milk and dairy products was associated with a neutral or reduced risk of type 2 diabetes and a reduced risk of cardiovascular disease, particularly stroke. Furthermore, the evidence suggested a beneficial effect of milk and dairy intake on bone mineral density but no association with risk of bone fracture. Among cancers, milk and dairy intake was inversely associated with colorectal cancer, bladder cancer, gastric cancer, and breast cancer, and not associated with risk of pancreatic cancer, ovarian cancer, or lung cancer, while the evidence for prostate cancer risk was inconsistent. Finally, consumption of milk and dairy products was not associated with all-cause mortality. Calcium-fortified plant-based drinks have been included as an alternative to dairy products in the nutrition recommendations in several countries. However, nutritionally, cow's milk and plant-based drinks are completely different foods, and an evidence-based conclusion on the health value of the plant-based drinks requires more studies in humans.

Conclusion

The totality of available scientific evidence supports that intake of milk and dairy products contribute to meet nutrient recommendations, and may protect against the most prevalent chronic diseases, whereas very few adverse effects have been reported.

Different Pathophysiology of Gastritis in East and West? A Western Perspective

Background

Gastritis results from multifactorial gastric mucosal injury. Helicobacter pylori (Hp) is the main cause, and associated diseases have typical underlying patterns of gastritis. Gastric ulcer and gastric cancer (GC) develop from chronic atrophic corpus gastritis (CAG) which therefore represents the most important pattern. GC incidences in East Asia are substantially higher than elsewhere, and this should be also reflected by higher prevalences of CAG and characteristic differences in pathophysiology compared to the West.

Summary

The few available comparative studies of gastritis in Eastern and Western patients are summarized. The main pathogenic factors of gastritis are discussed together with their limitations to explain local differences in disease outcome. Emphasis was put to also include less well-established pathogenic host and environmental factors of possible impact.

Conclusions

CAG is more prevalent in East Asian areas with high GC incidences than the West. Geographic heterogeneity of associated diseases is due to differences in Hp prevalence and virulence as well as modulating host and environmental factors. The following may contribute to the higher burden of CAG in the East: ABD type of CagA with vacA s1 and babA2 alleles of Hp, host Lewis(b) expression in sej/sej nonsecretors, H. heilmannii, low parietal cell mass, high sodium and nitrate intake, preferences in vegetable and fruit consumption, cigarette smoking, air pollution, alcohol. Conversely, green tea, nonfermented soy products and rice may confer protective effects. Hp is on the decline, but also in a world cleared from this bacterium, differences in host genetics will continue to modify gastric disease outcome together with maintained customs as part of cultural diversity.

Stage-specific Dietary Factors Associated with the Correa Multistep and Multifactorial Process of Human Gastric Carcinogenesis

We assessed how individual dietary intakes act at different points in the chain of sequential stage of the Correa model in an area of Taiwan with high incidence of gastric cancer (GC). Using data on 2,201 participants in a two-stage screening for gastric neoplasia with pepsinogen test, we identified 154 superficial gastritis (SG), 32 atrophic gastritis (AG), 117 intestinal metaplasia (IM), and 22 GC. Effects of individual item-based and construct-based dietary variables aggregated by factor analysis on each stage of gastric neoplasm were assessed. Based on 1,211 subjects with complete information on serological test and dietary questionnaire, SG was associated with positive quartile trend for the intake of meat (trend test P = 0.0014) and the intake of fruits and leafy vegetables (trend test P = 0.0177), but with the negative trend for the intake of shrimp sauce (trend test P = 0.039). A significant positive association was noted between milk and AG (trend test P = 0.014) and IM (P = 0.0087). A positive association between seafood and IM was noted (P = 0.011). Frequent leafy vegetable intake based on individual item was inversely associated with GC (P = 0.0084), whereas frequent intake of meat showed a high positive association (P<0.001). Stage-specific dietary factors underpinning the Correa model were identified.

Meat and milk intake in the rice-based Korean diet: impact on cancer and metabolic syndrome

Over a few decades, Korean diet has changed from traditional diet, mainly composed of rice and vegetables, to Westernised diet rich, in meat and milk, along with the economic development and globalisation. Increasing prevalence of diet-related chronic diseases such as cancer and metabolic syndrome (MetS) is becoming a heavy burden to society and requires further attention. In this review, the association of meat and milk consumption with cancer and MetS among Koreans was discussed. Previous meta-analyses showed that meat intake was positively associated with increased risk of cancers, especially colon, as well as obesity and type 2 diabetes mellitus, and that the intake of milk and dairy products was negatively associated with colorectal cancer, obesity, and type 2 diabetes mellitus, based on studies conducted mostly in Western countries. In Korea and other Asian countries, the association of meat and milk intake with cancers were inconclusive and varied by types of cancers. Conversely, milk intake was negatively associated with MetS risk as reported in Western countries. The difference in results between Korea and Western countries might come from the differences in dietary patterns and study designs. Most Koreans still maintain traditional dietary pattern, although rapid change towards Westernised diet is underway among the younger age group. Randomised clinical trials or prospective cohort studies with consideration of combined effects of various dietary factors in Korea and other Asian countries are needed to elucidate the impact of meat and milk or related dietary patterns in their diet.

The changing epidemiology of Asian digestive cancers: From etiologies and incidences to preventive strategies

Digestive cancers are a major health burden in Asia. Due to the presence of similar "infection-inflammation-cancer" pathways in the carcinogenesis process, eradicating infective pathogens or attenuating relevant inflammatory signaling pathways may reduce digestive cancer incidences and improve patient outcomes. The aim of this paper is to review the recent evidence regarding the epidemiology of three major digestive cancers in Asia: stomach cancer, liver cancer, and colorectal cancer. We focused on the incidence trends, the major etiologies, and especially the potential preventive strategies.

Adaptation to Lactose in Lactase Non Persistent People: Effects on Intolerance and the Relationship between Dairy Food Consumption and Evalution of Diseases

Dairy foods contain complex nutrients which interact with the host. Yet, evolution of lactase persistence has divided the human species into those that can or cannot digest lactose in adulthood. Such a ubiquitous trait has differential effects on humanity. The literature is reviewed to explore how the divide affects lactose handling by lactase non persistent persons. There are two basic differences in digesters. Firstly, maldigesters consume less dairy foods, and secondly, excess lactose is digested by colonic microflora. Lactose intolerance in maldigesters may occur with random lactose ingestion. However, lactose intolerance without maldigestion tends to detract from gaining a clear understanding of the mechanisms of symptoms formation and leads to confusion with regards to dairy food consumption. The main consequence of intolerance is withholding dairy foods. However, regular dairy food consumption by lactase non persistent people could lead to colonic adaptation by the microbiome. This process may mimic a prebiotic effect and allows lactase non persistent people to consume more dairy foods enhancing a favorable microbiome. This process then could lead to alterations in outcome of diseases in response to dairy foods in lactose maldigesters. The evidence that lactose is a selective human prebiotic is reviewed and current links between dairy foods and some diseases are discussed within this context. Colonic adaptation has not been adequately studied, especially with modern microbiological techniques.