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Healthy Lifestyle Is Associated with Reduced Mortality in Patients with Non-Alcoholic Fatty Liver Disease.
Yu, C, Gao, J, Ge, X, Wang, X, Ding, Y, Tian, T, Xu, X, Guo, W, Wang, Q, Ge, Z, et al
Nutrients. 2022;14(18)
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Non-alcoholic fatty liver disease (NAFLD) has emerged as the predominant cause of chronic liver disease. Given the association between NAFLD and metabolic syndrome [11,12], lifestyle modification can improve patients’ life quality and prognosis. The aim of this study was to assess the joint association of several modifiable lifestyle factors with overall and cause-specific mortality among NAFLD individuals and depict the mortality risk of varied composite modes of lifestyle. This study is a large, nationally representative, population-based study. It is based on the NHANES III (1988–1994, the National Center for Health Statistics, the Center for Disease Control and Prevention), which used a complex multistage probability design to recruit a representative sample of participants. Results show a protective effect among NAFLD participants following a healthy lifestyle, particularly impacting CVD-related mortality. Notably, among the most common lifestyle factor combinations, the effect of risk reduction on mortality was particularly strong when smoking was avoided. Authors conclude that their findings can be a useful tool to help the general public and patients with NAFLD to understand the importance of maintaining a healthy lifestyle.
Abstract
BACKGROUND AND AIMS It is unclear whether a healthy lifestyle impacts mortality in the presence of non-alcoholic fatty liver disease (NAFLD). The present study aimed to examine the joint association of several modifiable lifestyle factors with mortality risk for NAFLD patients. METHODS We collected lifestyle behavior data form the National Health and Nutrition Examination Survey (NHANES) III from 1988 to 1994 and follow-up data form NHANES III-linked mortality data through 2015. We estimated joint association between four healthy lifestyle factors (non-smoking, non-drinking, regular physical activity, a healthy diet) after NAFLD diagnosis and mortality using Cox proportional hazards regression models. RESULTS During a median of 22.83 years of follow-up, 2932 deaths occurred. The risk of all-cause mortality decreased significantly with the healthy lifestyle scores increasing (p < 0.001). NAFLD patients with a favorable lifestyle (3 or 4 healthy lifestyle factors) reduced 36% of all-cause mortality and 43% of cardiovascular disease (CVD) mortality compared with those with an unfavorable lifestyle (0 or 1 healthy lifestyle factor) (HR, 0.64 [95% CI, 0.50-0.81], 0.57 [95% CI, 0.37-0.88]). Compared with the non-NAFLD group, the number of NAFLD patients required to adhere to a favorable lifestyle to prevent one cardiovascular disease death in 20 years was fewer (77 vs. 125). CONCLUSIONS For the NAFLD patients, adopting a healthy lifestyle could significantly reduce their risk of death.
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Association between Mediterranean Diet and Fatty Liver in Women with Overweight and Obesity.
Leone, A, Bertoli, S, Bedogni, G, Vignati, L, Pellizzari, M, Battezzati, A
Nutrients. 2022;14(18)
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Non-alcoholic fatty liver disease (NAFLD) is a condition resulting from excessive lipid accumulation in the liver in individuals with low alcohol consumption. Obesity is an established risk factor for the development of NAFLD, and 50% to 75% of people with obesity also have NAFLD. The aim of this study was to evaluate the association between Mediterranean diet and non-invasive indices of fatty liver in a large sample of women with overweight and obesity. This study is a cross-sectional study of 2967 consecutive women with overweight and obesity. Results show that higher adherence to the Mediterranean diet was associated with lower indices of fatty liver in women with overweight and obesity (particularly obese women than in women who are overweight). Authors conclude that women with obesity, especially during the premenopausal period, may benefit more from following a Mediterranean-style diet.
Abstract
Obesity is a risk factor for NAFLD. However, not all people with obesity have an excessive intrahepatic fat content. Adherence to a high-quality dietary pattern may also promote liver health in obesity. A cross-sectional study of 2967 women with overweight and obesity was carried out to assess the association between a Mediterranean diet and fatty liver. All women underwent clinical examination, anthropometric measurements, blood sampling, ultrasound measurements of abdominal visceral and subcutaneous fat, and assessment of adherence to the Mediterranean diet using the 14-item MEDAS questionnaire. Fatty liver index (FLI), NAFLD fatty liver steatosis (NAFLD-FLS) and hepatic steatosis index (HSI) were calculated. In women with obesity, the MEDAS score was inversely associated with FLI (β = -0.60, 95% CI: -1.04, -0.16, p = 0.008), NAFLD-FLS (β = -0.092, 95% CI: -0.134, -0.049, p < 0.001) and HSI (β = -0.17, 95% CI: -0.30, -0.04, p = 0.011). Stronger associations were observed in premenopausal women with obesity. Mediterranean diet was inversely associated with NAFLD-FLS in women with overweight, independently of menopausal status. In conclusion, Mediterranean diet is associated with a better liver status in women with overweight and obesity. This may have a public health impact and be useful in drafting nutritional guidelines for NAFLD.
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The Effect of Moderate Weight Loss on a Non-Invasive Biomarker of Liver Fibrosis: A Randomised Controlled Trial.
Koutoukidis, DA, Jebb, SA, Aveyard, P, Astbury, NM
Obesity facts. 2020;13(2):144-151
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Non-alcoholic fatty liver disease covers a range of conditions from excess fat in the liver through inflammation and fibrosis, to advanced fibrosis, and cirrhosis. The Enhanced Liver Fibrosis (ELF) score is emerging as a promising blood biomarker for fibrosis. The aim of this study was to examine whether a community weight loss programme reduces ELF score over 12 months compared with a weight-loss intervention which is less effective. This study is a secondary analysis of a published randomised controlled trial. Participants (n=73) were equally randomised to a community weight loss programme (WeightWatchers) or usual care. Results indicate that there was no evidence of an effect of a community weight loss programme on changes in the ELF score and no association between weight loss and the ELF score in people who had, on average, an ELF score compatible with moderate fibrosis. Authors conclude that using the ELF test to assess weight loss treatment efficacy in improving liver fibrosis may be of limited value, thus biopsy remains the gold-standard assessment for liver fibrosis.
Abstract
BACKGROUND Referral to weight loss programmes is the only effective treatment for non-alcoholic fatty liver disease (NAFLD). Clinicians should advise weight loss and screen for liver fibrosis using the Enhanced Liver Fibrosis (ELF) score. AIM: To examine if the ELF score changes with weight loss. DESIGN AND SETTING Randomised controlled trial (ISRCTN85485463) in UK primary care during 2007-2008. METHOD Adults with a BMI of 27-35 kg/m2 and ≥1 risk factor for obesity-related disease were randomised to attend a community weight loss programme (n = 45) or receive usual weight loss advice from a practice nurse (n = 28). Weight and the ELF score were measured at baseline and 1 year. Analysis of covariance examined mean changes in the ELF score between groups and its relationship with weight loss. RESULTS Mean (SD) BMI was 31.10 kg/m2 (2.55) with evidence of moderate levels of liver fibrosis at baseline (mean ELF score: 8.93 [0.99]). There was no evidence that the community weight loss programme reduced the ELF score compared with usual care (difference +0.13 points, 95% CI: -0.25 to 0.52) despite greater weight loss (difference: -2.66 kg, 95% CI: -5.02 to -0.30). Mean weight loss in the whole cohort was 7.8% (5.9). There was no evidence of an association between weight change and change in ELF; the coefficient for a 5% weight loss was -0.15 (95% CI: -0.30 to 0.0002). CONCLUSION We found no evidence that the ELF score changed meaningfully following moderate weight loss. Clinicians should not use the ELF score to measure improvements in NAFLD fibrosis following weight loss programmes.
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Estimation of Primary Prevention of Gout in Men Through Modification of Obesity and Other Key Lifestyle Factors.
McCormick, N, Rai, SK, Lu, N, Yokose, C, Curhan, GC, Choi, HK
JAMA network open. 2020;3(11):e2027421
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Gout is prevalent in most Western countries. Modifying the contributary factors such as obesity and alcohol intake could prevent gout, however the impact this could have on prevention is unknown. This cohort study of 44,654 men, aimed to estimate the proportion of gout cases that could be prevented through the modification of risk factors. The results showed that the most important risk factor for gout was body mass index (BMI) and modifying other risk factors did not prevent gout. 77% of gout cases could be prevented if all men had been of normal weight, had no alcohol intake, if they adhered to a diet known as the Dietary Approaches to Stop Hypertension (DASH) diet and if they didn't take drugs to increase urine output. It was concluded that weight loss in men determines their ability to prevent gout, regardless of whether they have modified other contributory factors. This study could be used by healthcare professionals to understand that unless weight loss is achieved in individuals who are overweight and have gout, then other interventions may have minimal impact. Recommending the DASH diet to achieve weight loss, may be more successful in the long-term management of gout.
Abstract
Importance: The population impact of modifying obesity and other key risk factors for hyperuricemia has been estimated in cross-sectional studies; however, the proportion of incident gout cases (a clinical end point) that could be prevented by modifying such factors has not been evaluated. Objective: To estimate the proportion of incident gout cases that could be avoided through simultaneous modification of obesity and other key risk factors. Design, Setting, and Participants: The Health Professionals Follow-up Study is a US prospective cohort study of 51 529 male health professionals enrolled in 1986 and followed up through questionnaires every 2 years through 2012. Self-reported gout cases were confirmed through June 2015. Clean and complete data used for this analysis were available in June 2016, with statistical analyses performed from July 2016 to July 2019. Exposures: From data collected in the validated questionnaires, men were categorized to low-risk groups according to combinations of the following 4 factors: normal body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]; <25), no alcohol intake, adherence to Dietary Approaches to Stop Hypertension (DASH)-style diet (highest quintile of DASH diet score), and no diuretic use. Main Outcomes and Measures: Population attributable risks (PARs) for incident gout meeting the preliminary American College of Rheumatology survey criteria, overall and stratified by BMI. Results: We analyzed 44 654 men (mean [SD] age, 54.0 [9.8] years) with no history of gout at baseline. During 26 years of follow-up, 1741 (3.9%) developed incident gout. Among all participants, PAR for the 4 risk factors combined (BMI, diet, alcohol use, and diuretic use) was 77% (95% CI, 56%-88%). Among men with normal weight (BMI <25.0) and overweight (BMI 25.0-29.9), we estimated that more than half of incident gout cases (69% [95% CI, 42%-83%] and 59% [95% CI, 30%-75%], respectively) may have been prevented by the combination of DASH-style diet, no alcohol intake, and no diuretic use. However, among men with obesity (BMI ≥30), PAR was substantially lower and not significant (5% [95% CI, 0%-47%]). Conclusions and Relevance: The findings of this cohort study suggest that addressing excess adiposity and other key modifiable factors has the potential to prevent the majority of incident gout cases among men. Men with obesity may not benefit from other modifications unless weight loss is addressed.
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Very Low-Calorie Ketogenic Diet: A Safe and Effective Tool for Weight Loss in Patients With Obesity and Mild Kidney Failure.
Bruci, A, Tuccinardi, D, Tozzi, R, Balena, A, Santucci, S, Frontani, R, Mariani, S, Basciani, S, Spera, G, Gnessi, L, et al
Nutrients. 2020;12(2)
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Very low-calorie ketogenic diets (VLCKD) may be an effective way to lose weight. However, the high amount of protein they contain may harm the kidneys, especially in those who already have impaired kidney function. This observational study of 92 obese men and women aimed to evaluate the effect of VLCKD on weight loss in individuals with mild kidney failure, compared to healthy individuals. A VLCKD diet resulted in significantly decreased BMI and body weight, due to a decrease in fat mass and slight decrease in muscle mass. Improvements were seen in blood pressure, indicators for diabetes and cholesterol levels. No changes to kidney or liver function were apparent and only a few minor adverse events were reported. Interestingly a small percentage of individuals with mildly impaired kidney function reported improvements in their condition. It was concluded that VLCKD is a safe and effective way to lose weight in patients with obesity and mild kidney disease. This study could be used by healthcare professionals to consider recommending a VLCKD to patients who are obese and have mild kidney disease.
Abstract
Very low-calorie ketogenic diets (VLCKD) are an effective and increasingly used tool for weight loss. Traditionally considered high protein, ketogenic diets are often looked at with concern by clinicians due to the potential harm they pose to kidney function. We herein evaluated the efficacy and safety of a VLCKD in patients with obesity and mild kidney failure. A prospective observational real-life study was conducted on ninety-two patients following a VLCKD for approximately 3 months. Thirty-eight had mild kidney failure and fifty-four had no renal condition and were therefore designated as control. Anthropometric parameters, bioelectrical impedance and biochemistry data were collected before and at the end of the dietary intervention. The average weight loss was nearly 20% of initial weight, with a significant reduction in fat mass. We report an improvement of metabolic parameters and no clinically relevant variation regarding liver and kidney function. Upon stratification based on kidney function, no differences in the efficacy and safety outcomes were found. Interestingly, 27.7% of patients with mild renal failure reported normalization of glomerular filtrate after dietary intervention. We conclude that, when conducted under the supervision of healthcare professionals, a VLCKD is an effective and safe treatment for weight loss in patients with obesity, including those affected by mild kidney failure.
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Prospective association between organic food consumption and the risk of type 2 diabetes: findings from the NutriNet-Santé cohort study.
Kesse-Guyot, E, Rebouillat, P, Payrastre, L, Allès, B, Fezeu, LK, Druesne-Pecollo, N, Srour, B, Bao, W, Touvier, M, Galan, P, et al
The international journal of behavioral nutrition and physical activity. 2020;17(1):136
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The prevalence of type 2 diabetes (T2D) has significantly increased over recent decades, concomitantly to the obesity epidemic. Among the emergent risk factors, exposure to environmental contaminants including pesticides is of major concern. In fact, a recent European Food Safety Authority report indicated that 44% of conventional crop-based food contained at least one quantifiable pesticide residue, vs 6.5% in organic-labelled foods (OF). The aims of this study were (a) to investigate the prospective association between OF consumption and the risk of T2D, and (b) to estimate the mediation effect by the potential healthiness of a plant-based diet. This study is prospective cohort study based on the data from the web-based NutriNet-Santé study with an analysis sample of 33,256 participants. Results indicate an inverse association between organic plant-based food consumption and T2D risk especially in women. The association persisted after accounting for potential confounding effects of various factors, including lifestyles, dietary patterns and adiposity. Authors conclude that further studies are needed to replicate these findings for confirmation purposes and to elucidate underlying mechanisms.
Abstract
BACKGROUND Organic food (OF) consumption has substantially increased in high income countries, mostly driven by environmental concerns and health beliefs. Lower exposure to synthetic pesticides has been systematically documented among consumers of organic products compared to non-consumers. While experimental studies suggest that pesticides currently used in food production may be associated with type 2 diabetes (T2D), no well-conducted prospective studies have investigated the potential association between consumption of organic products and the risk of T2D, controlling for potential confounding factors. The objective of this prospective study was to estimate the association between OF consumption and the risk of T2D. METHODS A total of 33,256 participants (76% women, mean (SD) age: 53 years (14)) of the French NutriNet-Santé prospective cohort study who completed the organic food frequency questionnaire were included (2014-2019). The proportion of OF in the diet (as weight without drinking water) was computed. The associations between the proportion of OF in the diet (as 5% increment and as quintiles) and the risk of T2D were estimated using multivariable Hazard Ratio (HR) and 95% confidence interval (95% CI) derived from proportional hazards models adjusted for confounders (sociodemographic, anthropometric, lifestyle, medical and nutritional factors). RESULTS During follow-up (mean = 4.05 y, SD = 1.03 y, 134,990 person-years), 293 incident cases of T2D were identified. After adjustment for confounders including lifestyle (physical activity, smoking status, alcohol consumption) and nutritional quality of the diet assessed by the adherence to the French food-based dietary guidelines, OF consumption was associated with a lower risk of T2D. Participants with the highest quintile of OF consumption, compared with those with the lowest quintile, had 35% lower risk of T2D (95% CI = 0.43-0.97). Each increment of 5% in the proportion of OF in the diet was associated with 3% lower risk of T2D (HR 0.97, 95% CI = 0.95-0.99). CONCLUSIONS In this large prospective cohort study, OF consumption was inversely associated with the risk of T2D. Further experimental and prospective studies should be conducted to confirm these observations. CLINICAL TRIAL REGISTRY The study was registered at ClinicalTrials.gov ( NCT03335644 ).
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Effects of Some Food Components on Non-Alcoholic Fatty Liver Disease Severity: Results from a Cross-Sectional Study.
Mirizzi, A, Franco, I, Leone, CM, Bonfiglio, C, Cozzolongo, R, Notarnicola, M, Giannuzzi, V, Tutino, V, De Nunzio, V, Bruno, I, et al
Nutrients. 2019;11(11)
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Non-alcoholic fatty liver disease (NAFLD) is characterized by excessive hepatic (liver) fat accumulation. Lifestyle interventions are the only known effective treatment for NAFLD. The aim of this study was to estimate associations between the consumption of some food group components with the grade of severity in NAFLD subjects. The study is a cross-sectional nutritional randomised clinical trial, which enrolled 136 subjects (79 males) with moderate or severe NAFLD. Results showed that some food group components were associated with a lower or a higher risk of developing severe NAFLD, and that, within the same food group, some components with a protective or promoter action are present. Authors conclude that their findings could help to elaborate personalised dietary counselling to treat NAFLD.
Abstract
Background: The high prevalence of non-alcoholic fatty liver disease (NAFLD) observed in Western countries is due to the concurrent epidemics of overweight/obesity and associated metabolic complications, both recognized risk factors. A Western dietary pattern has been associated with weight gain and obesity, and more recently with NAFLD. Methods: This is a baseline cross-sectional analysis of 136 subjects (79 males) enrolled consecutively in the NUTRIATT (NUTRItion and Ac-TiviTy) study. Study subjects had moderate or severe NAFLD diagnosed by using Fibroscan-CAP. Food Frequency Questionnaire was used to obtain information about food intake. Statistical analysis included descriptive statistics and a multivariable logistic regression model. Results: The mean age was 49.58 (±10.18) with a mean BMI of 33.41 (±4.74). A significant inverse relationship was revealed between winter ice-cream intake and NAFLD severity (O.R. 0.65, 95% C.I. 0.95-0.99); chickpeas intake and NAFLD severity (O.R. 0.57, 95% C.I. 0.34-0.97), and not industrial aged-cheeses type (O.R. 0.85, 95% C.I. 0.74-0.98). A statistically significant positive association also emerged between rabbit meat (O.R. 1.23, 95% C.I. 1.01-1.49), industrial type aged cheeses (O.R. 1.17, 95% C.I. 1.01-1.35), milk-based desserts (no winter ice cream) (O.R. 1.11, 95% C.I. 1.01-1.21), fats (O.R. 1.12, 95% C.I. 1.01-1.25), and NAFLD severity. Conclusion: The fresh foods from non-intensive farming and high legume intake that characterize the Mediterranean diet would seem to be beneficial for patients with NAFLD.
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Dietary Fiber Intake (Supplemental or Dietary Pattern Rich in Fiber) and Diabetic Kidney Disease: A Systematic Review of Clinical Trials.
Carvalho, CM, Gross, LA, de Azevedo, MJ, Viana, LV
Nutrients. 2019;11(2)
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Most of the financial burden of diabetes mellitus is related to management of its complications, and chronic kidney disease is the most expensive and debilitating. The aim of the study was to evaluate the effect of dietary fibre (supplemental or dietary pattern rich in fibre) on diabetic kidney disease. The study is a systemic review that included seven interventional clinical trials that comprised 161 patients with diabetes with an age range of 20 to 74 years. The mean fibre intake in the intervention was 24 g/day and 16 g/day in the control group. Results indicate that only the vegetarian dietary pattern was associated with beneficial kidney outcomes in both type 1 and type 2 diabetes mellitus. There were no other dietary patterns that had favourable effects on kidney outcomes. Authors conclude that a vegetarian dietary pattern may have a beneficial effects on renal outcomes.
Abstract
Fiber intake is associated with better glycemic control being an important nonpharmacologicaltreatment for diabetes (DM). We hypothesize that a dietary fiber intake can bringbenefits to diabetic kidney disease (DKD), improving renal outcomes. This systematic review aimedto evaluate the effect of dietary fiber (supplemental or dietary pattern rich in fiber) on DKD. Wesearched six databases to identify clinical trials that reported fiber intake and renal outcomes(albuminuria, proteinuria, estimated glomerular filtration rate (eGFR) dialysis) in patients with DM.From 1814 studies, 48 papers were fully evaluated. In the end, seven trials (161 patients, aged 58.3years, 49% females) were included. The studies were organized into three categories (vegetarian,Dietary Approaches to Stop Hypertension (DASH) diet, and fiber supplement), two evaluatedsupplements and five dietary patterns. Vegetarian diet reduced albuminuria in three trials, two inpatients with type 1 DM and one in patients with type 2 DM; and one study demonstrated a change inthe eGFR in type 1 DM. The individual quality of the studies was low/uncertain. A vegetarian dietarypattern may have a beneficial effect on these renal outcomes. However, the individual effect of theintake of fiber on DKD not was possible to be evaluated.
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A Systematic Review of Organic Versus Conventional Food Consumption: Is There a Measurable Benefit on Human Health?
Vigar, V, Myers, S, Oliver, C, Arellano, J, Robinson, S, Leifert, C
Nutrients. 2019;12(1)
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The demand for organic products has risen rapidly over the last decades. The reasons why consumers may favour organic over conventional products are varied. They may be for personal health and wellbeing, environmental considerations, animal welfare or perceived higher nutritional profile - which is true for some, but not all components. While the long-term safety of pesticide consumption through conventional food production has been questioned, organic foods clearly show lower levels of toxic metabolites, like heavy metals and synthetic fertilizer and pesticide residues. This systematic review aimed to assess the current evidence of organic diet consumption and human health compared to conventionally produced foods. Included were 35 papers on clinical trials and observational studies. The clinical trials studied pesticide and phytochemical excretion, antioxidant capacity, body composition, lipids and inflammatory markers. The observational studies were focused on fertility, foetal and childhood development, pregnancy, lactation and levels of pesticides in children and adults, as well as nutritional biomarkers and cancer risk in adults. An increased intake of organic produce in long-term studies appeared to reduce the incidence of infertility, birth defects, allergies, middle ear infection, pre-eclampsia, metabolic syndrome, high BMI, and non-Hodgkin lymphoma. Organic intake was also linked to reduced urinary levels of organophosphorus pesticides and herbicides. Yet, the author highlighted that organic consumers are more likely to be health conscious, physically active, eat a more plant-based diet, have higher education levels and income, and therefore are not representative of the general population. They also argue that the possible benefits from an organic diet may be partially due to the quality and composition of the diet rather than a direct effect of organic food consumption. Whereby a growing number of findings demonstrate the health benefits of organic food consumption, according to the authors, the current evidence does not yield a solid and definitive answer.
Abstract
The current review aims to systematically assess the evidence related to human health outcomes when an organic diet is consumed in comparison to its conventional counterpart. Relevant databases were searched for articles published to January 2019. Clinical trials and observational research studies were included where they provided comparative results on direct or indirect health outcomes. Thirty-five papers met the criteria for inclusion in the review. Few clinical trials assessed direct improvements in health outcomes associated with organic food consumption; most assessed either differences in pesticide exposure or other indirect measures. Significant positive outcomes were seen in longitudinal studies where increased organic intake was associated with reduced incidence of infertility, birth defects, allergic sensitisation, otitis media, pre-eclampsia, metabolic syndrome, high BMI, and non-Hodgkin lymphoma. The current evidence base does not allow a definitive statement on the health benefits of organic dietary intake. However, a growing number of important findings are being reported from observational research linking demonstrable health benefits with organic food consumption. Future clinical research should focus on using long-term whole-diet substitution with certified organic interventions as this approach is more likely to determine whether or not true measurable health benefits exist.
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Weight Status and Alcohol Intake Modify the Association between Vitamin D and Breast Cancer Risk.
Deschasaux, M, Souberbielle, JC, Latino-Martel, P, Sutton, A, Charnaux, N, Druesne-Pecollo, N, Galan, P, Hercberg, S, Le Clerc, S, Kesse-Guyot, E, et al
The Journal of nutrition. 2016;146(3):576-85
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Experimental studies suggest that vitamin D may contribute to the prevention of breast cancer. However, population studies have been inconclusive, and it is possible that any relationship is dependent on other factors such as genetics or lifestyle. The objective of this study was to explore associations between blood vitamin D levels and breast cancer risk, along with 2 potential modifiers: body mass index (BMI; in kg/m(2)) and alcohol intake. The nested case-control study involved 233 women with breast cancer and 466 healthy controls. Overall, no association was found between vitamin D levels and breast cancer risk. However, a higher blood vitamin D concentration was associated with a decreased risk of breast cancer for women with a BMI under 22.4, whereas it was associated with an increased risk for women with a BMI 22.4 or over. A blood vitamin D concentration ≥ 10 ng/mL was associated with a decreased risk of breast cancer for women with alcohol intakes ≥ 7.1 g/day, whereas no association was observed for women with alcohol intakes < 7.1g/day. The authors concluded that BMI and alcohol intake modified the association between vitamin D and breast cancer risk. These lifestyle factors could explain the inconclusive results of previous studies.
Abstract
BACKGROUND Mechanistic hypotheses suggest that vitamin D may contribute to the prevention of breast cancer. However, epidemiologic evidence is inconsistent, suggesting a potential effect modification by individual factors. OBJECTIVE Our objective was to perform exploratory analyses on the prospective associations between the plasma 25-hydroxyvitamin D [25(OH)D] concentration, polymorphisms of genes encoding for the vitamin D receptor (VDR) and vitamin D-binding protein (also known as gc-globulin or group-specific component, GC), and breast cancer risk, along with 2 potential modifiers: body mass index (BMI; in kg/m(2)) and alcohol intake. METHODS A nested case-control study was set up in the SUpplémentation en VItamines et Minéraux Anti-oXydants (SU.VI.MAX) cohort (1994-2007), involving 233 women with breast cancer and 466 matched controls (mean ± SD age: 49 ± 6 y). The plasma total 25(OH)D concentration and gene polymorphisms were assessed on samples obtained at baseline. Conditional logistic regression models were computed. RESULTS A higher plasma 25(OH)D concentration was associated with a decreased risk of breast cancer for women with a BMI < the median of 22.4 [OR quartile (Q)4 compared with Q1: 0.46; 95% CI: 0.23, 0.89; P-trend = 0.01, P-interaction = 0.002], whereas it was associated with an increased risk for women with a BMI ≥ the median (OR Q4 compared with Q1: 2.45; 95% CI: 1.13, 5.28; P-trend = 0.02, P-interaction = 0.002). A plasma 25(OH)D concentration ≥ 10 ng/mL was associated with a decreased risk of breast cancer for women with alcohol intakes ≥ the median of 7.1 g/d (OR ≥10 compared with <10 ng/mL: 0.50; 95% CI: 0.26, 0.95; P = 0.03, P-interaction = 0.03). The genetic analyses were consistent with the results observed with plasma 25(OH)D. CONCLUSION In this prospective study, BMI and alcohol intake modified the association between vitamin D [plasma 25(OH)D and vitamin D-related gene polymorphisms] and breast cancer risk. These effect modifications suggest explanations for discrepancies in results of previous studies. This trial was registered at clinicaltrials.gov as NCT00272428.