Vitamin D in Multiple Sclerosis: A Comprehensive Umbrella Review.

BACKGROUND: Multiple sclerosis (MS) is an inflammatory neuro-immune disease with a multifaceted etiology and long-lasting adverse effects. Several studies have explored the role of 25-hydroxyvitamin D (25(OH)D) serum levels, vitamin D receptor (VDR) gene polymorphisms, and vitamin D supplementation (VDS) in individuals with MS. OBJECTIVE: The aim of this study was to evaluate the relationship of MS with 25(OH)D serum levels, VDR gene polymorphisms, and VDS. METHODS: We assessed relevant papers published in PubMed, Scopus, and Web of Science from the inception up to February 24, 2024. Meta-analyses that investigated the link of 25(OH)D serum levels, VDR gene polymorphisms including Apal (rs7975232), BsmI (rs1544410), Taql (rs731236) and Fokl (rs10735810), and VDS with the risk and clinical manifestations of MS were included. The methodological quality of selected papers was assessed by the Assessment of Multiple Systematic Reviews version 2 (AMSTAR 2). The statistical analysis of this umbrella review was carried out using RStudio version 2023.03.1 and R version 4.3.2, simultaneously. RESULTS: 23 out of 304 records were entered into this umbrella review with a pooled sample size of 37,567 participants. Eleven papers were rated as high quality, one was moderate quality, one was low quality, and ten were critically low quality. The homozygote model of FokI (FF+ff vs. Ff) was significantly associated with an 8% reduction of MS risk (OR: 0.92, 95% CI: 0.86, 0.98; I2= 0%, P>0.99). CONCLUSION: According to existing clinical evidence, the risk of MS may be associated with VDR gene polymorphism. Further studies are needed to explore the association of MS and vitamin D. PROSPERO REGISTRATION CODE: CRD42024521541.

Comparison of the Effect of Omega-3 vs. MCT Supplementation on Iron-Related Indices in Patients Undergoing Dialysis.

Chronic kidney disease (CKD), characterized by progressive kidney failure, significantly increases mortality and comorbidity risks such as anemia. This study contrasts the impacts of omega-3 and medium-chain triglycerides (MCT) oil on levels of iron, ferritin, total iron-binding capacity (TIBC), hemoglobin (Hb), and transferrin saturation in patients with CKD undergoing dialysis. This interventional trial was conducted on 120 patients with CKD undergoing dialysis in Rasht, Iran. For 8 weeks, the omega-3 group was orally administered three 1000-mg capsules of omega-3 fatty acid supplement, and the MCT group was administered three 1000-mg capsules containing MCT oil daily. Serum concentrations of ferritin, iron, TIBC, Hb, and transferrin saturation were assessed pre-intervention and after the intervention. There was a significant increase in serum iron levels in the MCT group compared to the omega-3 group (103.72 ± 57.8 vs. 77.48±40.13; P = 0.031). No effect was found regarding other iron-related factors such as TIBC, Hb, transferrin saturation, and ferritin levels. The results of our study indicated that taking MCT oil increased serum iron levels compared to omega-3 supplementation in patients with CKD undergoing dialysis. Further research is needed to better understand the potential benefits of MCT oils in patients with CKD.

Dietary Antioxidant Index and the Risk of Recurrent Aphthous Stomatitis.

BACKGROUND: Recurrent aphthous stomatitis (RAS) is a common condition that affects the oral mucosa. Antioxidants are crucial in neutralizing free radicals in the body and may have a preventive role against RAS. This study aims to examine the association between dietary antioxidant index (DAI) and RAS occurrence. METHODS: This cross-sectional study was conducted on 144 individuals with RAS and 135 individuals without RAS. The dietary intake of the participants was assessed using the food frequency questionnaire. The DAI was applied to measure the antioxidant capacity of the diet. Logistic regression models were applied to assess the link between RAS and DAI after adjusting the confounding variables. RESULTS: There was a significant negative association between RAS and DAI of zinc (OR = 0.639, CI95%: 0.456-0.896, P = .009) and total score of DAI (OR = 0.802, CI95%: 0.682-0.944, P = .008) after adjustment for age. The results remained significant after further adjustment for body mass index and calorie intake. CONCLUSION: The present study indicated a possible negative association between the risk of RAS and the DAI score as a measure of the antioxidant potential of diet. Further studies are warranted.

Effects of coffee and tea consumption on glioma risk: An umbrella review of systematic reviews and meta-analyses.

BACKGROUND: Coffee and tea are considered to have some effects on the risk of glioma as one of the most prevalent intracranial malignant tumors in adults. However, the precise effect of coffee and tea consumption on glioma is not obvious. This umbrella review aimed to evaluate the impact of tea and coffee consumption on glioma risk. METHODS: Three online databases containing Scopus, Web of Science, and PubMed were thoroughly searched from the beginning to February 23, 2024 with no language constraints. Relying on I2 and Q statistics, a random-effect model or a fixed-effect model was applied. The PICO structure was followed as Population (Patients with glioma), Intervention (Coffee and tea consumption), Comparison (Standard treatment or placebo), and Outcome (Risk of glioma). RESULTS: Totally, seven meta-analyses and systematic reviews contain 23,591 patients were included in this umbrella review. Coffee and tea consumption led to significant 15% and 16% reductions in glioma risk, respectively (RR = 0.85; 95% CI: 0.74, 0.98; RR = 0.84; 95% CI: 0.79, 0.89). The results did not change after subgroup analyses. CONCLUSION: This umbrella review revealed that the coffee and tea consumption may decrease the glioma risk. Consumption of tea and coffee may be considered as dietary strategies against glioma. PROSPERO REGISTRATION CODE: CRD42024521525.

Associations between diet and nutritional supplements and colorectal cancer: A systematic review.

Background and Aim: Colorectal cancer (CRC) is one of the most prevalent cancers around the world. The link between nutrients and the likelihood of developing CRC remains uncertain. The primary objective of the present study was to investigate the potential connection between dietary intake/dietary supplements and the occurrence of CRC through a literature review. Methods: A comprehensive online search was conducted in PubMed, Scopus, Web of Science, and the Cochrane Library from January 1990 to March 2023 using appropriate keywords. A systematic search was conducted for clinical trials and cohort studies in order to determine the relationship between dietary components/supplements and CRC. Results: The intake of long-chain n-3 polyunsaturated fatty acids (n-3 LCPUFAs), consisting of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has the potential to decrease the likelihood of developing CRC (eight studies found positive effects and four studies found no association). Some other dietary components such as probiotics, prebiotics, and synbiotics may contribute to suppressing CRC development (three studies found positive effects, whereas three studies did not find any association). There is inconclusive evidence that supplementation with certain micronutrients including vitamin D (one trial found positive effects and another trial reported no association), folate, zinc, and selenium may reduce the risk of CRC. Conclusion: Some dietary supplements such as n-3 LCPUFAs and probiotics have the potential to reduce the risk of developing CRC. Further studies are necessary to validate these results and understand the underlying mechanisms.

Branched-chain amino acids and the risk of hypertension; a persian cohort-based study.

BACKGROUND: The association of hypertension (HTN) and different types of dietary amino acids is not yet clear. The aim of the present study was to investigate the association of branch chain amino acids (BCAAs) and the prevention of HTN. METHODS: This cross-sectional study was conducted on 4184 people aged 35 to 70 using data from the Sabzevar Persian cohort study in Sabzevar, Iran. Data on dietary intake of BCAAs including leucine, isoleucine, and valine were obtained using a validated Food Frequency Questionnaire (FFQ). Multivariable logistic regression analysis assessed the link between HTN and BCAAs. RESULTS: The results showed that participants with HTN had a higher total protein and BCAAs intake than participants with normal BP (P < 0.01). A marginally significant association was found between the risk of HTN with the total intake of BCAAs (OR = 1.018, CI95%: 1.001-1.035, P = 0.04), leucine (OR = 1.040, CI95%:1.002-1.080, P = 0.03), isoleucine (OR = 1.068, CI95%:1.001-1.140, P = 0.04), and valine (OR = 1.060, CI95%:1.003-1.121, P = 0.04). However, the association disappeared after adjusting the total protein and calorie intake. CONCLUSIONS: The results indicated that the dietary intake of BCAAs may be associated with the risk of HTN. Future longitudinal research is warranted.

The association between dietary intake of fats and transient global amnesia (TGA).

BACKGROUND: Different types of dietary fat may influence memory and cognitive functions. This study aimed to investigate the association between dietary fat intake and transient global amnesia (TGA). METHODS: This case-control study was conducted using Persian Sabzevar cohort data on 258 individuals with TGA and 520 individuals without amnesia in Sabzevar Iran. The food frequency questionnaire (FFQ) was used to assess the intake of dietary fats of the participants. All study participants were screened for TGA by a neurologist and their status was determined based on the diagnostic symptoms defined by the Kaplan and Hodges criteria. RESULTS: There was an inverse association between the risk of TGA and dietary intake of alpha-linolenic acid (ALA) (OR = 0.94, CI95%:0.88-0.99, P = 0.01). Also, a positive association was observed between TGA and dietary intake of n-6 fatty acids (OR = 1.18, CI 95%: 1.04-1.33, P = 0.01). The results remained significant after adjustment for age, sex, education, job, marital status, physical activity, BMI, and calorie intake. CONCLUSION: Omega-3 fatty acids may have beneficial effects; however, omega-6 fatty acids may have adverse effects on the risk of amnesia. Further longitudinal studies are warranted.

The association between enteral nutrition with survival of critical patients with COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19) results in several complications and mortality in intensive care unit (ICU) patients. Limited studies have investigated the effect of enteral nutrition (EN) on the survival of COVID-19 patients in the ICU. The aim of this study was to investigate the association of EN with biochemical and pathological indices associated with mortality in ICU patients with COVID-19. METHODS: This case-control study was conducted on 240 patients with COVID-19 hospitalized in the ICU including 120 eventual nonsurvived as the cases and 120 survived patients as the controls. All of the patients received EN as a high protein high volume or standard formula. Data on general information, anthropometric measurements, and the results of lab tests were collected. RESULTS: The recovered patients received significantly more high protein (60.8% vs. 39.6%, p = .004) and high volume (61.6% vs. 42.3%, p = .005) formula compared to the nonsurvived group. Mortality was inversely associated with high volume (odds ratio [OR]: 0.45 confidence interval [CI]95%, p = .008) and high protein (OR: 0.42 CI95%, p = .003) formula. The results remained significant after adjusting for age and sex. Further adjustment for underlying diseases, smoking, body mass index, and the acute physiology and chronic health evaluation II (APACHE II) score did not change the results. CONCLUSION: The findings of the study showed that there was a significant inverse association between mortality and high volume and high protein formula in patients with COVID-19. Further investigation is warranted.

A systematic review of the beneficial effects of prebiotics, probiotics, and synbiotics on ADHD.

BACKGROUND: Children with attention deficit hyperactivity disorder (ADHD) may benefit from probiotics and prebiotics, but the effects are unclear. To determine whether probiotics and prebiotics affect children with ADHD, a systematic review was conducted. METHODS: The present systematic review analyzed cohort studies and randomized controlled trials that examined whether prebiotics and probiotics are associated with ADHD. Seven randomized controlled trials and two cohort studies met our inclusion criteria. RESULTS: Research on Lactobacillus rhamnosus GG (LGG) probiotic supplementation showed that children with ADHD had better emotional, physical, social, and school functioning, and a higher health-related quality of life compared to the placebo group. The studies also showed that Synbiotic 2000 reduces markers of intestinal and vascular inflammation in children with ADHD, in part through increasing SCFA levels. CONCLUSION: The use of probiotics and prebiotics as adjuvants therapy in patients with ADHD is beneficial. Further studies with longer duration, including more participants and a variety of age groups, and using various evaluation techniques such as in vivo observation are required to examine the effects of prebiotics and probiotics on ADHD.

Efficacy of a Comprehensive Weight Reduction Intervention in Male Adolescents With Different FTO Genotypes.

BACKGROUND: The FTO gene polymorphisms may influence the effects of lifestyle interventions on obesity. The present study aimed to assess the influence of the rs9930506 FTO gene polymorphism on the success of a comprehensive weight loss intervention in male adolescents with overweight and obesity. METHODS: This study was carried out on 96 adolescent boys with overweight and obesity who were randomly assigned to the intervention (n = 53) and control (n = 43) groups. The blood samples of the participants were collected, and the FTO gene was genotyped for the rs9930506 polymorphism. A comprehensive lifestyle intervention including changes in diet and physical activity was performed for 8 weeks in the intervention group. RESULTS: Following the lifestyle intervention, BMI and fat mass decreased significantly in the intervention group compared with the control group (both p < 0.05), while no change was found in weight, height or body muscle percentage between the groups. The participants in the intervention group with the AA/AG genotype and not in carriers of the GG genotype had a significantly higher reduction in BMI (-1.21 vs. 1.87 kg/m2, F = 4.07, p < 0.05) compared with the control group. CONCLUSION: The intervention in individuals with the AA/AG genotype has been significantly effective in weight loss compared with the control group. The intervention had no association effect on anthropometric indices in adolescents with the GG genotype of the FTO rs9930506 polymorphism. TRIAL REGISTRATION: Name of the registry: National Nutrition and Food Technology Research Institute; Trial registration number: IRCT2016020925699N2; Date of registration: 24/04/2016; URL of trial registry record: https://www.irct.ir/trial/21447.

The Association of Iron Intake and Hypertension, Does Iron Intake Decrease Blood Pressure?

Previous studies reported that iron may have an indispensable role in the risk of hypertension (HTN). However, the result of the studies on the relationship between iron and risk of HTN is inconsistent. This study aimed to assess the association between the association of dietary iron intake and HTN in the Iranian population. This case-control study was conducted on 4184 people aged 35 to 70, including 1239 people with HTN and 2945 people with normal blood pressure (BP) in Sabzevar, Iran. Dietary intake was assessed using a food frequency questionnaire (FFQ). The Nutritionist IV software was used in terms of the assessment of dietary intake of iron. An inverse association was found between iron intake and HTN (OR = 0.97, CI 95%: 0.94-0.99, P = 0.04). The association remained significant after adjustment for age, gender, smoking, drinking alcohol, calorie intake, and BMI (OR = 0.94, CI 95%: 0.89-0.98, P = 0.01). As a conclusion, iron intake was inversely associated with HTN. Further longitudinal studies on the effect of iron intake on BP are required to confirm this finding.

The effects of omega-3 fatty acids supplementation on hemoglobin, hematocrit, and platelet levels of patients with ESRD condition undergoing dialysis.

Background: Concomitant inflammation may boost the cardiovascular complications in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD). Omega-3 fatty acids may have certain health benefits in HD patients. The aim of this study was to investigate the effects of omega-3 fatty acids supplementation on hematocrit (HCT), hemoglobin (HB) level and platelet (PLT) counts of HD patients. Methods: A randomized controlled trial was conducted on HD patients at a private dialysis center in Rasht, Iran. Three omega-3 fatty acid supplement capsules (3 g/d) were administered daily for two months to patients in the intervention group (n = 55). The control group (n = 60) were given three placebo capsules containing medium chain triglyceride (MCT) oil, similar to the supplemental dose of the intervention group at the same period. Three parameters of HCT, HB and PLT were measured at baseline and after the intervention. Results: The PLT count decreased in the intervention group compared to the control group (173.38 ± 74.76 vs. 227.68 ± 86.58 103/mm3, F = 4.83, P = 0.03). No significant change was found on the levels of HCT and HB parameters between the two groups after the intervention. Conclusion: Omega-3 supplementation in HD patients may decrease the risk of forming blood clots in the blood vessels. Further studies are warranted.

Effectiveness of omega-3 fatty acid supplementation for pruritus in patients undergoing hemodialysis.

Background: Patients undergoing hemodialysis (HD) frequently experience the chronic kidney disease-associated pruritus (CKD-aP). Objective: The aim of this study was to investigate the effectiveness of omega-3 supplementation in the management of CKD-aP in patients undergoing hemodialysis. Methods: In this triple blind, randomized clinical trial, the effect of the omega-3 supplement on uremic CKD-aP was assessed in 112 chronic hemodialysis patients at Caspian Hemodialysis Center in Rasht, Iran. Patients were randomly divided into the intervention group receiving omega-3 supplements (3 g/day) and the control group receiving placebo containing MCT oil for 2 months. Results: Omega-3 supplementation had no effect on CKD-aP. The results did not change after adjusting for age and sex, additional adjustments for weight, height, physical activity, smoking, and alcohol use, additional adjustments for underlying diseases and weight, height, physical activity, smoking, and drinking alcohol, and further adjustments for underlying diseases and biochemical indices. Discussion: Omega-3 supplementation for 2 months had no effect on CKD-aP in patients with CKD. Further studies with longer duration are warranted. Clinical Trial Registration: https://www.irct.ir/trial/66638, IRCT20151226025699N6.

Association of dietary fats with ischemic heart disease (IHD): a case-control study.

BACKGROUND: This study aimed to investigate the association between different types of dietary fats with ischemic heart disease (IHD). METHODS: This case-control study was conducted on 443 cases and 453 controls aged 40-80 years in Tehran, Iran. The semi-quantitative 237-item food frequency questionnaire (FFQ) was used to assess the amount of food intake. Nutritionist IV was applied to test the amount of consumption of dietary fats. RESULTS: The case group had a lower intake of docosahexaenoic acid (DHA) (11.36 ± 12.58 vs. 14.19 ± 19.57, P = 0.01) than the control group. A negative association was found between IHD and DHA (OR 0.98, CI 95% 0.97-0.99, P = 0.01). No significant association was observed between IHD with the intake of cholesterol, trans fatty acids (TFA), saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), eicosatetraenoic acid (EPA), and α-Linolenic acid (ALA). CONCLUSION: It was found that DHA may reduce the risk of IHD, whereas there was no significant association between other types of dietary fats with the odds of IHD. If the results of this study are confirmed in future research, a higher intake of DHA in diet can be recommended as a strategy to prevent IHD events.

The clinical efficacy of Olibanum gum chewing in patients with Mild-to-Moderate Alzheimer disease: A randomized Parallel-Design controlled trial.

BACKGROUND: Alzheimer's disease is a common neurodegenerative disorder in elderly with progressive decline in cognitive functions. This study aimed to investigate the possible memory-improving effects of Olibanum on patients with Alzheimer's disease. RESEARCH DESIGN AND METHOD: This double-blind, randomized clinical trial was carried out on 72 participants aged 50-75 years. The intervention group (n = 36) received 1.6 g/day of olibanum chewing gum for 18 weeks. The placebo group (n = 36) received chewing gum without olibanum. Neuropsychological assessments were performed at baseline, every 4 weeks, and after 18 weeks of the intervention. RESULTS: There was no significant difference between (MD: 0.84, 95%CI: -1.10 to 2.78, p = 0.392) at baseline. Both groups had linear improvements over time. There was no significant difference between two groups regarding the improvements after the intervention (F = 0.157, p = 0.693). There were no significant differences between the groups for MMSE score (Mini-Mental State Examination) after the intervention (F = 0.141, p = 0.708). CONCLUSIONS: This study revealed that 18 weeks of gum chewing with Olibanum did not change the neuropsychological status. More clinical studies are needed to confirm these findings.

Does dietary intake of caffeine have an effect on transient global amnesia?

AIM: Amnesia is a cognitive disorder that may lead to memory loss. Caffeine is a psychoactive substance which have an effect on memory and cognitive functions. This study aimed to assess the association of transient global amnesia (TGA) with dietary intake of caffeine. METHODS: This cross-sectional study was conducted on the Sabzevar Persian cohort data of 258 patients with TGA and 520 healthy individuals in Sabzevar, Iran. The Nutritional data were gathered in face-to-face interviews using a valid Food Frequency Questionnaire. Different models of logistic regression were used to determine the association between TGA and dietary caffeine intake after adjusting the confounders including age, sex, education, job, marital status, physical activity, BMI, and calorie intake. RESULTS: There was no significant difference in terms of dietary calorie intake of (2279.5 ± 757.9 vs. 2365.5 ± 799.5, p = 0.19), protein (70.79 ± 25.27 vs. 72.94 ± 24.83, p = 0.31), fat (59.97 ± 23.79 vs. 60.13 ± 26.38, p = 0.93), carbohydrate (376 ± 134 vs. 393.1 ± 137.8, p = 0.14), and caffeine (196.4 ± 127.9 vs. 186.3 ± 128.5, p = 0.36) between the groups. No significant association was found between TGA and dietary intake of caffeine (OR: 0.99, 95% CI: 0.99-1.01, p = 0.36). The results did not change after adjusting the confounders. CONCLUSIONS: No significant association was found between TGA and dietary intake of caffeine. Further prospective studies are required to confirm this finding.

Association between type 2 diabetes and different types of dietary fats: A case-control study.

BACKGROUND: The effect of dietary fats on type 2 diabetes (T2D) is not clear. This study aimed to determine the association between T2D and dietary fatty acids among Iranian adults. METHODS: This case-control study was performed on 4241 participants aged 35-70, including 1804 people with T2D and pre-diabetes as the case group and 2437 people without diabetes as the control group. Dietary intake was assessed using a food frequency questionnaire (FFQ). RESULTS: The cases had higher age (48.36 ± 8.62 vs. 54.53 ± 7.75 y, P < 0.001), weight (73.7713.41 vs. 76.18 ± 13.49 kg, P = 0.001), body mass index (BMI) (28.02 ± 4.70 vs. 24 ± 4.74 kg/m2, P = 0.001), right systolic blood pressure (RSBP) (113.33 ± 16.7 vs. 121.61 ± 17.24 mmHg, P = 0.001), right diastolic blood pressure (RDBP) (71.41 ± 10.53 vs. 75.33 ± 9.92 mmHg, P = 0.001), fasting blood sugar (FBS) (96.87 ± 19.39 vs. 169.95 ± 69.28 mg/dl, P = 0.001), blood urine nitrogen (BUN) (13.65 ± 3.74 vs. 14.26 ± 4.03 mg/dl, P = 0.001), triglyceride (TG) (141.61 ± 99.37 vs. 175.96 ± 114.74 mg/dl, P = 0.001), alkaline phosphatase (ALP) (218.24 ± 66.35 vs. 246.97 ± 72.65 IU/L, P = 0.001), low-density lipoprotein cholesterol (LDL) (111.68 ± 33.02 vs. 101.97 ± 36.54 mg/dl, P = 0.001), serum glutamic-pyruvic transaminase (SGPT) (21.88 ± 15.15 vs. 23.55 ± 15.96 IU/L, P = 0.001), gamma-glutamyl transferase (GGT) (24.66 ± 20.42 vs. 30.72 ± 30.43 IU/L P = 0.001), and cholesterol (192.45 ± 39.1190 vs. 187.12 ± 46.19 mg/dl P = 0.001) compared to the control group. T2D was negatively associated with dietary intake of PUFAs (OR = 0.93, CI95%:0.84-1.03, P = 0.01) and positively associated with dietary cholesterol (OR: 1.01, CI95%:1.001-1.01, P = 0.02). CONCLUSION: In summary, cholesterol was positively and PUFAs were negatively associated with diabetes. If the results of the present study on the effect of fat intake on diabetes are proven, future dietary recommendations for people at risk of diabetes may be corrected by providing diets rich in polyunsaturated fatty acids and low in cholesterol.

Egg consumption and risk of cardiovascular disease: a PERSIAN cohort-based study.

BACKGROUND: Cardiovascular diseases (CVDs) are one of the main causes of death worldwide. Data on the effect of eggs consumption on the risk of CVDs are still unreliable. Therefore, this study aimed to investigate the association between CVDs and the consumption of eggs. METHODS: In this case-control study, the required data were extracted from the Prospective Epidemiologic Research Studies in Iran (PERSIAN) cohort in Sabzevar, Iran. A total of 4241 adults participated including 1535 patients with CVDs as the case group and 2706 healthy people as controls. Egg consumption was assessed using a valid food frequency questionnaire (FFQ). RESULTS: A significant association was observed between eggs consumption and stroke after adjustment for physical activity, body mass index (BMI), smoking, systolic blood pressure (SBP), diastolic blood pressure (DBP), using alcohol, lipid profile, diabetes, and the intake of energy, lipid, protein, carbohydrate, and cholestrol (OR:1.007, 95% CI:1.001-1.013, P = 0.03). No association was found between egg consumption with hypertension, cardiac ischemia, and myocardial infarction. CONCLUSIONS: There was a significant association between the consumption of eggs and stroke. However, more studies are needed to examine the effect of eggs on CVDs.

Naturally nutrient rich (NNR) score and the risk of colorectal cancer: a case-control study.

BACKGROUND: The association between colorectal cancer (CRC) and nutrients has been studied frequently. However, the association of nutrient density of diets with the risk of CRC has been less studied. This study aimed to investigate the association between CRC and naturally nutrient rich (NNR) score in Iranian adults. METHOD: This case-control study included 160 patients with colorectal cancer and 320 controls aged 35-70 years in Tehran, Iran. Dietary intake was assessed using a 168-item food frequency questionnaire. The NNR score was obtained by calculating the average daily value of 14 nutrients including protein, vitamins A, C, D, E, B1, B2, B12, calcium, zinc, iron, folate, potassium and unsaturated fatty acids. RESULTS: Regarding dietary intake of the components of NNR score, the case group had a lower intake of polyunsaturated fat (15.41±4.44 vs 16.54±4.20 g/day, p=0.01), vitamin E (10.15±4.16 vs 13.1±5.33; p=0.001), vitamin B1 (2±0.86 vs 2.19±0.84 mg/day, p=0.03) and folate (516.45±96.59 vs 571.05±80.31; p=0.001) and a higher intake of oleic acid (8.21±5.46 vs 5.59±3.17 g/day, p=0.01) compared with the control group. Colorectal cancer risk was inversely associated with the NNR score after adjusting for the confounders (OR 0.92; 95% CI 0.88 to 0.97; p=0.03). CONCLUSION: Low NNR scores may be linked to CRC. If confirmed by future longitudinal research, this result may help prevent CRC by recommending nutrient-rich diets.