The possible role of riboflavin deficiency in epithelial neoplasia.I. epithelial changes of mice in simple deficiency

Riboflavin intake, MTRR genetic polymorphism (rs1532268) and gastric cancer risk in a Korean population: a case-control study

The vitamin B group, including riboflavin, plays paramount roles in one-carbon metabolism (OCM), and disorders related to this pathway have been linked to cancer development. The variants of genes encoding OCM enzymes and the insufficiency of B vitamins could contribute to carcinogenesis. Very few observational studies have revealed a relationship between riboflavin and gastric cancer (GC), especially under conditions of modified genetic factors. We carried out a study examining the association of riboflavin intake and its interaction with MTRR (rs1532268) genetic variants with GC risk among 756 controls and 377 cases. The OR and 95 % CI were evaluated using unconditional logistic regression models. We observed protective effects of riboflavin intake against GC, particularly in the female subgroup (OR = 0·52, 95 % CI 0·28, 0·97, Ptrend = 0·031). In the MTRR (rs1532268) genotypes analysis, the dominant model showed that the effects of riboflavin differed between the CC and CT + TT genotypes. Compared with CC carriers, low riboflavin intake in T+ carriers was significantly associated with a 93 % higher GC risk (OR = 1·93, 95 % CI 1·09, 3·42, Pinteraction = 0·037). In general, higher riboflavin intake might help reduce the risk of GC in both CC and TC + TT carriers, particularly the T+ carriers, with marginal significance (OR = 0·54, 95 % CI 0·28, 1·02, Pinteraction = 0·037). Our study indicates a protective effect of riboflavin intake against GC. Those who carry at least one minor allele and have low riboflavin intake could modify this association to increase GC risk in the Korean population.

Dietary riboflavin deficiency induces ariboflavinosis and esophageal epithelial atrophy in association with modification of gut microbiota in rats

PURPOSE

Riboflavin deficiency causes ariboflavinosis, a common nutritional deficiency disease. The purpose of this study is to investigate the effects of riboflavin deficiency on the important internal organs and its potential mechanisms.

METHODS

Experiment 1, male F344 rats were randomly assigned to R₆ (normal riboflavin, 6 mg/kg) and R₀ (riboflavin-deficient, 0 mg/kg) groups. Experiment 2 rats were assigned to R₆, R_0.6 (0.6 mg/kg) and R_0.06 (0.06 mg/kg) groups. Experiment 3 rats were assigned to R₆ and R₀ → R₆ (riboflavin replenishment) groups. Bacterial communities were analyzed based on 16S rRNA gene sequencing.

RESULTS

Riboflavin deficiency induced ariboflavinosis (R_0.06 46.7%; R₀ 72%) and esophageal epithelial atrophy (R_0.06 40%; R₀ 44%) in rats, while the R₆ group did not display symptoms (P < 0.001, respectively). Esophageal epithelial atrophy occurred simultaneously (R_0.06 66.7%; R₀ 63.6%) with ariboflavinosis or appeared alone (R_0.06 33.3%; R₀ 36.4%). Esophagus is the most vulnerable internal organ. Riboflavin deficiency followed by replenishment (R₀ → R₆) was effective in treating ariboflavinosis (83.3% vs. 0%, P < 0.001) and esophageal epithelial atrophy (66.7% vs. 20%, P = 0.17). Riboflavin deficiency modulated gut microbiota composition. The several key genera (Romboutsia, Turicibacter and Clostridium sensu stricto 1) were strongly correlated with ariboflavinosis and esophageal epithelial atrophy (P < 0.01 or P < 0.05). The potential mechanism is that gut microbiota affects body's xenobiotic biodegradation and metabolism, and genomic instability.

CONCLUSIONS

Riboflavin deficiency induces ariboflavinosis and esophageal epithelial atrophy by modulating the gut microbiota, and offers new Queryinsight into riboflavin deficiency and esophageal lesions.

Decreased plasma riboflavin is associated with poor prognosis, invasion, and metastasis in esophageal squamous cell carcinoma

BACKGROUND

Riboflavin deficiency confers a predisposition for esophageal cancer. The role of plasma riboflavin levels in development and prognosis of individuals with digestive tract inflammation and ulcer (DTIU), digestive tract polyps (DTPs), and ESCC is not well understood.

METHODS

We performed a cross-sectional study, including 177 DTIU, 80 DTP, and 324 ESCC cases, to measure the plasma riboflavin levels among the three populations. Correlation between plasma riboflavin levels (categorized as ≥31.8, 6.5-31.8 and ≤6.5 nmol/L groups) and clinical characteristics, as well as survival of ESCC patients (556 cases) was analyzed.

RESULTS

There was no difference in plasma riboflavin levels between DTIU, DTP, and ESCC cases (P > 0.05). Plasma riboflavin levels were inversely correlated with invasive depth (correlation coefficient = -0.09, P = 0.026) and lymph node metastasis (correlation coefficient = -0.11, P = 0.010) of ESCC, and ESCC patients with low riboflavin levels had poor recurrence-free survival (P = 0.035) and overall survival (P = 0.003). Decreased riboflavin was a prognostic factor for poor overall survival (HR = 1.91, 95% CI = 1.19-3.07, P = 0.007).

CONCLUSIONS

Plasma riboflavin levels in DTIU, DTP, and ESCC patients are similar. Plasma riboflavin levels are associated with the development and prognosis of ESCC.

Riboflavin in Human Health: A Review of Current Evidences

Riboflavin is a water-soluble vitamin, which was initially isolated from milk. There are two coenzyme forms of riboflavin, flavin mononucleotide and flavin adenine dinucleotide, in which riboflavin plays important roles in the enzymatic reactions. Riboflavin is found in a wide variety of animal and plant foods. Meat and dairy products are the major contributors of riboflavin dietary intake. In this chapter, the latest evidence on the relationship between riboflavin status and specific health risks will be reviewed. Also, some of the mechanisms by which riboflavin exerts its roles will be discussed. The evidence accrued suggests that riboflavin is an antioxidant nutrient which may prevent lipid peroxidation and reperfusion oxidative injury. Moreover, riboflavin deficiency may increase the risk of some cancers. Riboflavin may also exert a neuroprotective effects in some neurological disorders (e.g., Parkinson disease, migraine, and multiple sclerosis) through its role in some pathways that are hypothesized to be impaired in neurological disorders such as antioxidation, myelin formation, mitochondrial function, and iron metabolism.

Blood iron, glutathione, and micronutrient levels and the risk of oral cancer

The risk of oral cavity cancer was determined in relation to serological levels of iron; vitamins A, B2, C, E; zinc; thiamin; and glutathione (GSH). The study included 65 hospitalized patients with oral cancer and 85 matched controls. In comparing the highest to the lowest tertiles, the risk was odds ratio (OR) = 0.3 [95% confidence interval (CI) = 0.1-0.6] for iron; 3.2 (95% CI = 1.3-8.1) for total iron binding capacity (TIBC), which measures the concentration of the iron delivery protein transferrin; and 0.4 (95% CI = 0.2-0.9) for transferrin saturation (iron/TIBC x 100). These associations were stronger in never smokers than in ever smokers. The risk associated with the iron storage protein ferritin was significantly elevated, but this association could reflect disease-related inflammation or comorbidity. The OR for GSH was 0.4 (95% CI = 0.1-0.9), and the OR for GSH reductase activity coefficient (indicative of riboflavin deficiency) was 1.6 (95% CI = 1.3-3.7). These findings suggest that mild iron deficiency and low GSH levels, which are associated with increased oxidative stress, increase the risk of oral cavity cancer.

Riboflavin deficiency and esophageal cancer: a case control-household study in the Caspian Littoral of Iran

BACKGROUND

In a case-household-control-household study in two very high and low esophageal cancer (EC) risk regions of the Caspian Littoral of Iran, a total of 21 cases (12 subjects from the high risk and 9 subjects from the low-risk region) with a total of 91 household members (57 subjects from the high risk and 34 subjects from the low-risk region) were investigated. Cases were matched for sex and age (+/-5 years) with non-blood relative controls.

METHODS

A standard 24-h dietary recall questionnaire was used to estimate riboflavin intake. The erythrocyte glutathione reductase activity coefficient (EGR-AC) was measured to assess riboflavin status. The Student t-test was used to test differences, and chi2 analysis was applied to test associations. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were also calculated.

RESULTS

Results indicated that in both regions, the mean daily intake of riboflavin for cases was less than that of the controls (0.66+/-0.43 mg/day versus 0.82+/-0.37 mg/day) whereas for their households, it was virtually the same. Both cases and control households showed riboflavin deficiency in two regions, with higher deficiency in the high risk area. Statistical analysis revealed significant differences between the two regions for EGR-AC (P<0.001). Odd ratios indicated that the risk of developing EC for persons living in riboflavin-deficient households was more than twice of non-deficient households.

CONCLUSION

Therefore, this study suggests that riboflavin deficiency may play an important role in the etiology of esophageal cancer in the Caspian Littoral of Iran.

Nutritional deficiency and the skin

Cutaneous changes occur in deficiency states of many nutritional elements: ascorbic acid, retinol, protein-energy, cyanocobalamin, phytonadione (vitamin K), biotin, ribroflavin, pyridoxine, niacin, essential fatty acids, and zinc. There are also inherited disorders of copper, biotin, zinc, and tryptophan metabolism. Cutaneous vitamin D synthesis is inhibited by sunscreen use. The striking skin changes of the glucagonoma syndrome may be related to nutritional pathways.

Oral cancer in women nonusers of tobacco and alcohol

A retrospective study of private surgical experience (L.J.T.) in the treatment of primary oral carcinoma was undertaken to compare the demographics, disease history, and clinical behavior patterns in women nonusers versus users of tobacco and alcohol. From a clinical group of 109 patients with oral carcinoma, an unexpectedly high percentage were women (41%, 45/109) and of these women, 31% (14/45) were nonusers of either substance. Differences were found in age (71 vs. 60 years), location of the primary tumor (0% vs. 35% floor of mouth), clinical stage at presentation (early, 80% vs. 50%), histologic parameters, clinical behavior patterns, and occurrence of secondary primaries (0% vs. 26%). The differences identified have prognostic and therapeutic implications.

The role of micronutrient deficiency in carcinogenesis

Nutritional deficiencies are suspected to be contributing factors to several types of human cancers. Studies with laboratory animals have demonstrated that deficiencies in certain nutrients can enhance chemically induced carcinogenesis. In this review, we discuss several possible mechanisms for the involvement of nutritional deficiencies in carcinogenic processes, and note that different severities of deficiency may have varied effects on these processes. The relationship between results from studies with animals and the genesis of human cancer is discussed, and the application of the concept of nutrient density in relating experimental animal diets to human dietary conditions is emphasized. We also discuss in detail several recent studies that potentially may have a great impact on the prevention of human cancer. These include (1) the possible involvement of micronutrient deficiencies in carcinogenesis of the esophagus; (2) the effects of choline/methionine deprivation and calcium supplementation on liver carcinogenesis; and (3) the roles of low-calcium and high-fat intake on development of colon cancer. The possible mechanistic link between teratogenesis and carcinogenic processes is noted.

Inhibition of esophageal carcinogenesis in corn-fed rats by riboflavin, nicotinic acid, selenium, molybdenum, zinc, and magnesium

The effect of individual vitamins and minerals on esophageal carcinogenesis was assessed by supplementing a diet (based on corn) that was marginally deficient in many micronutrients. The test diets were fed to weanling inbred BD IX rats for 45 days; they were then given five subcutaneous doses (3 mg/kg body wt) N-nitrosomethylbenzylamine (MBN) over two and one-half weeks. The diets were continued until termination: 150 days later; at that time all rats were still clinically normal. Marked reductions in the number of tumors and tumor-bearing rats were recorded in groups of rats given supplements of riboflavin, nicotinic acid, zinc, magnesium, selenium, and molybdenum. Various combinations of nutrients did not distinctly reduce the tumor yield further; however, tissue analyses suggest that individual supplements could enhance the status of other marginally deficient nutrients. When the experiment was repeated, but was varied by commencing the supplements only well after the cessation of MBN exposure, inhibitory effects on tumorigenesis were still exerted by most nutrients. We emphasized that these nutritional effects along with the epidemiological evidence in humans are relevant to early prevention; also, the treatment of premalignant esophageal changes by high doses of these nutrients may be unwise. The merits of food supplementation schemes are discussed.

Riboflavin

Riboflavin deficiency diminishes the rate of growth of spontaneous tumors in experimental animals but enhances the carcinogenicity of specific drugs such as the azo dyes, which are degraded by a microsomal hydroxylase system requiring riboflavin. Human esophageal cancer has been epidemiologically associated with riboflavin deficiency, but the precise role of riboflavin in this tumor remains to be defined. Riboflavin nutriture influences epithelial integrity, tissue flavin concentrations, rates of prostaglandin biosynthesis, and glutathione metabolism, each of which may have implications for carcinogenesis.

Survey of a population with a high incidence of oral and oesophageal cancer

The results of a survey of a population with a high incidence of oral and oesophageal cancer are presented. The population under study appears to have several epidemiologic characteristics, some of which may be associated with a high incidence of oral and oesophageal cancer. A remarkably high proportion (41%) of the men surveyed were nass users and this habit, like the use of other types of tobacco mixtures, has been related to oral cancer. Oral leukoplakia and chronic oesophagitis (conditions thought to be precursors of oral and oesophageal cancer) have been diagnosed in 11% and 60%, respectively, of the persons examined. Analysis of the relationship between nass use, cigarette smoking, oral leukoplakia and oesophagitis revealed that the prevalence of oral leukoplakia is highest among cigarette smokers who use nass. It appears that nass use does not affect the frequency of occurrence of chronic oesophagitis. However, a slight elevation of the prevalence odds ratio was observed for current smokers and drinkers. Biochemical analysis of the blood of a random sample of the surveyed population revealed low levels of riboflavin, vitamin A and carotenoids--vitamins that most probably have a protective effect against the development of cancer. The mutagenicity test has shown that nass contains a chemical or chemicals that exert a genotoxic effect. Chemical analysis revealed the presence in nass of tobacco-specific N-nitroso compounds.

Comparison of riboflavin, vitamin A, and zinc status of Chinese populations at high and low risk for esophageal cancer

In two surveys in The Peoples Republic of China, blood samples were collected for nutritional studies in two counties where the risks of esophageal cancer are very different. The first survey was done in May 1980 in Linxian County (Henan Province) where the risk of esophageal cancer is very high. Blood samples were obtained from 111 persons (58 men, 53 women) who were selected randomly from 528 subjects that underwent endoscopical examination. The second survey was done in May 1981 in Jiaoxian County (Shandong Province) where the risk of esophageal cancer is reported to be relatively low. Blood samples were obtained from 120 persons (66 men, 54 women) who were selected randomly from 252 subjects that had also had undergone endoscopy. The blood samples were used to measure the nutritional status of riboflavin (erythrocyte glutathione reductase activation coefficient), vitamin A (retinol and carotene concentrations), and zinc (plasma and hair zinc concentrations). Only riboflavin status was significantly different in the two communities. The distribution of erythrocyte glutathione reductase activation coefficient values suggested that riboflavin status was much better in the low-risk community. Also in May 1981, a few more blood samples were obtained from some of the participants of the previous year's study in Linxian. A slight improvement in riboflavin and zinc status was detected. We considered the possibility that these changes may have been linked to the socioeconomic changes currently taking place in rural areas. Data were also collected from food allocation records in 15 production brigades in Linxian and 13 production brigades in Jiaoxian in the same years. The records used represented the food consumption of 3,491 and 2,552 persons, respectively, and were used to calculate daily food and nutrient intakes in the two communities. Dietary analyses highlighted the vegetarian nature of the diet, the low consumption of riboflavin, and the virtual dependence on carotene for vitamin A. Both communities consumed very little in the way of animal products or fruit, but intake of these items was higher in Jiaoxian.

Lipid metabolism in riboflavin-deficient rats. 1. Effect of dietary lipids on riboflavin status and fatty acid profiles

1. The increase in activation coefficient (stimulated: basal activity) of erythrocyte NAD(P)H2: glutathione oxidoreductase (EC 1.6.4.2) and reduction in hepatic flavin concentration which occurred in riboflavin-deficient weanling rats were not markedly or consistently affected by differences in the concentration of lipid in the diet nor by differences in the total proportion of saturated or polyunsaturated fatty acids in the dietary lipid. 2. Their gain in body-weight was, however, reduced when the dietary lipid concentration was increased from 30 to 200 g/kg and liver: body-weight and hepatic triglyceride content were correspondingly increased, suggesting a functionally-deleterious effect of high fat intake in the deficient animals. This was especially severe when the diets contained cottonseed oil, which appeared to be toxic for the deficient animals. 3. Comparisons between fatty acid profiles of hepatic phospholipids of deficient, pair-fed and ad lib,-fed control animals indicated that the increase in proportion of 18:2 omega 6 and the decrease in proportion of 20:4 omega 6 observed in deficient animals were due specifically to riboflavin deficiency, whereas certain other changes were probably caused by inanition. The changes in 18:2 omega 6 and 20:4 omega 6 were observed at both low and high levels of lipid intake and at both low and high levels of dietary lipid polyunsaturation. Similar changes in fatty acid profiles were observed in renal, erythrocyte membrane, and plasma phospholipids, but were not seen in cardiac phospholipids, 4. A consistent increase in proportion of 18:2 omega 6 was also observed in the hepatic triglycerides, together with a decrease in proportion of 16:0. 5. It is concluded that acute riboflavin deficiency affects lipid metabolism in a characteristic manner, probably by interfering with beta-oxidation of fatty acids, but that diets of high lipid content do not significantly increase the extent of flavin depletion.

Oesophageal lesions in northern Iran: a premalignant condition?

An endoscopic survey was undertaken in northern Iran to identify and determine the prevalence of possible precancerous lesions of the oesophagus. 218 men and 212 women, aged between 15 and 70 years, were included in the study. Oesophagoscopies were done on all 430 subjects and biopsies on 418. A chronic oesophagitis, involving mainly the middle and lower thirds of the oesophagus, was found in 80% of the subjects, and the frequency was very high even in the younger age-groups. Clinically and histologically the oesophagitis in this rural population was different from that observed in the low-risk areas of Europe and the United States, where oesophagitis is often associated with reflux. Dysplasia was diagnosed in 16 subjects and invasive carcinoma in 11. The very high prevalence of chronic oesophagitis in northern Iran, where a high incidence of oesophageal cancer has also been reported, suggests that these two lesions are associated.

Is the role of the environment in carcinogenesis overestimated?

The dominant role of the physical and chemical environment in the development of cancer is challenged. Analyses of the etiology of skin, bladder, respiratory and gastric cancers are presented which demonstrate the considerable extent to which one's health status may modify the initiation and promotion of environmentally associated cancers. It is concluded that although environmental factors may initiate and/or promote 85 to 90 percent of all cancers this is misleading since it neglects the critical role of the individual's health status as a factor modifying carcinogenesis.

Diet and cancer

Differences in food intake patterns are positively correlated with differences in the incidence of various cancers in world populations. It is postulated here that dietary factors play a vital role in the genesis of several major neoplasms, specifically gastric and colon carcinomas. In addition to the food consumed, such variables as total caloric intake, nutrtional excess or deficit, exposure to carcinogens and consumption of alcohol also increase the risk of cancer. Through recognition of these factors and subsequent long-term manipulation of diet, it should be possible to reduce cancer morbidity and mortality.