膳食纤维摄入与前列腺癌发生风险关系的Meta 分析

目的：探讨膳食纤维摄入与前列腺癌发生风险之间的关系。方法系统检索 PubMed、EMBase、Cochrane library、中国知网数据库（CNKI）、万方数据库、中国生物医学文献数据库（CBM）中符合要求的文献,采用 Meta 分析方法,以随机模型和95％CI 为效应量分析膳食纤维摄入量与前列腺癌发生之间的关系。另外,采用随机剂量反应模型进行定量分析。结果共纳入10篇文献,包括5篇队列研究和5篇病例对照研究。与膳食纤维最低摄入组相比,膳食纤维最高摄入组前列腺癌发生的风险显著降低了13％（RR ＝0．87,95％CI 为0．77～0．99,Z ＝2．10,P ＝0．035）。亚组分析显示,可溶性膳食纤维（RR ＝0．78,95％CI 为0．64～0．95,Z ＝2．45,P ＝0．014）及不可溶性膳食纤维（RR ＝0．65,95％CI 为0．45～0．88,Z ＝2．79,P ＝0．005）的摄入均与前列腺癌的发生呈负相关,但谷类、水果以及蔬菜类纤维的摄入与前列腺发生没有明显关系。剂量反应曲线结果显示膳食纤维的摄入量与前列腺癌的发生风险没有明显关联（RR ＝0．996,95％CI 为0．989～1．002）。敏感性分析显示总体研究结果比较稳定,单个研究不会对总体结果造成显著影响。结论膳食纤维的摄入与前列腺癌发生风险呈负相关,适当增加膳食纤维的摄入可能有利于前列腺癌的预防,但尚需进一步开展前瞻性研究验证本研究结果。     

膳食与癌症

癌症不是一个单一病因的疾病，而是一种多病因联合作用的疾病。基因是细胞生长、突变的基础，即遗传学改变。但人们生活在一定的环境中，受环境、生活方式(包括膳食因素)和行为因素的影响。例如根据乙酰转化酶在机体内乙酰化降解快慢的多态性，即对鱼和肉烹调产物(杂环芳香胺)降解的快慢，将人群分成两种类型，结果摄肉食后诱导快     

羧胺三唑在肿瘤中的抗炎作用

目的研究抗肿瘤药羧胺三唑（Carboxyamido-triazole,CAI）的抗炎作用。方法采用微孔比色法测定羧胺三唑对磷脂酶A2活性的影响。结果羧胺三唑可以显著抑制佐剂性关节炎大鼠足爪匀浆中磷脂酶A2的活性。结论羧胺三唑具有较强的抗炎作用,其作用机制可能与抑制磷脂酶A2的活性有关。     

膳食纤维和酸奶含量高的饮食可降低患肺癌风险

美国范德比尔特大学医学中心的研究者发现,食用富含膳食纤维和酸奶的饮食与患肺癌的风险降低有关。富含膳食纤维和酸奶的饮食对心血管疾病和胃肠道癌症的好处已经确定。这项新发现是基于对美国、欧洲和亚洲140万名成年人的研究数据的分析,表明这种饮食也可以预防肺癌。     

生活方式指导联合早期膳食纤维补充改善慢传输型便秘的自身对照研究

目的 探索生活方式指导联合膳食纤维补充对慢传输型便秘的改善效果。方法 前瞻性的纳入2015年10月至2016年11月期间在陆军军医大学大坪医院便秘门诊就诊的慢传输型便秘患者82例,调查患者膳食、运动及便秘情况,通过一对一的交谈进行生活方式指导,同时给予复合膳食纤维口服10d干预,每月定期电话督促其日常饮食与运动。随访治疗开始后一个月及六个月便秘改善情况,评价患者膳食、饮水量及运动变化,评价每周排便次数大便性状（Bristol评分）,排便困难感觉评分及便秘症状评估量表评分等。结果 82例纳入患者7例失访,对最终纳入研究的75例慢传输型便秘患者数据进行分析,结果显示,治疗后饮食结构以荤素适宜为主,主食以精粮与杂粮混合为主,治疗后动物性食物每天摄入量100~150g、每日吃一份水果、每日饮水量1,500~2,000ml的患者比例以及每周规律锻炼的患者比例显著增加,其差异均有统计学意义。治疗前、治疗后1个月和6个月每周排便次数分别为（1.40±0.77）次,（3.67±1.20）次和（3.62±1.17）次,与治疗前比,P值均＜0.05。排便困难感觉评分下降,大便性状Bristol评分增加分别为（1.99±1.34）分,（3.89±0.95）分和（3.87±0.99）分,与治疗前比,P值均＜0.05;PAC-SYM评分下降,分别为（2.21±0.42）分,（1.43±0.57）分和（1.51±0.46）分,与治疗前比,P值均＜0.05。便秘改善临床有效率治疗后1个月及6个月分别为88.00%和86.67%,患者自我满意度分别为85.33%和80.00%。结论 应用生活方式指导联合膳食纤维补充能够有效改善慢性便秘患者症状及满意度,是一种有效的临床综合治疗措施。     

中国总膳食研究

世界卫生组织近年来一直推荐和鼓励各成员国开展总膳食研究。特别是UNEP／FAO／WHO的全球食物污染监测规划将总膳食研究列为一项极为重要的内容。但由于现场工作的复杂性，目前只有美国、英国等十余个发达国家开展了此项工作。中国预防医学科学院营养与食品卫生研究所得到卫生部1988年科研基金项目的资助，在北京市试点后，于1990年组织全国12个省、市、自治区经过近3年的时间首次成功地开展了“中国总膳食研究”，从营养与食品卫生两个方面全面地评价目前中国膳食的安全性和营养价值。总膳食研究也称为“市场菜篮子研究”，是研究一个…     

癌症的膳食预防

膳食、营养与癌症的关系正受到世界各国科学家的日益重视。英国学者R．D。11和R．Peto在“癌症的原因”这篇名著中提出：在因癌症而死亡的病例中，约有35％与膳食和营养有关。换而言之，如果树膳食进行合理的调配，有可能使癌症死亡减少1／3。目前，各国学者正在从体外试验、动     

抗炎饮食预防肿瘤的专家共识

肿瘤是严重威胁人类生命健康的恶性消耗性疾病,其发生率和死亡率逐年增加。影响肿瘤发生、发展的因素复杂,其中饮食作为主要的可预防因素,其潜在作用不容忽视。饮食具有促炎特性和抗炎特性,不合理的膳食所引起的机体长期慢性炎症与肿瘤密切相关,并降低了肿瘤的治疗效果。科学合理的膳食可改善机体慢性炎症状态,改变肿瘤微环境,从而达到预防肿瘤发生和促进患者康复的作用。能够客观评估膳食对机体的炎症效应,无论对科学研究还是临床防治都具有积极意义。膳食炎症指数(DII)是一种评估个人膳食炎症潜能的新方法,具有客观、方便、可重现的特点,近些年较多研究探索了DII与多种肿瘤的关系。本共识以DII为研究工具,总结了促炎性饮食与各类肿瘤的发病关系,并提出肿瘤防治的抗炎性膳食模式,从抗炎饮食角度为肿瘤患者提供预防和辅助治疗策略。提倡科学健康的饮食行为,鼓励居民调整膳食结构,为肿瘤患者的营养治疗提供新策略。     

乳腺癌与膳食关系研究

乳腺癌的病因研究已有几十年的历史,有动物实验研究和人群流行病学的研究。动物实验研究最早在1942年由Tannenbaum报道关于热量和脂肪的促癌试验。人群流行病学的研究认为其因素是多方面的,与遗传,内分泌,生育史,药物和营养状况等     

Mechanisms linking dietary fiber,gut microbiota and colon cancer prevention

Many epidemiological and experimental studies have suggested that dietary fiber plays an important role in colon cancer prevention. These findings may relate to the ability of fiber to reduce the contact time of carcinogens within the intestinal lumen and to promote healthy gut microbiota, which modifies the host’s metabolism in various ways. Elucidation of the mechanisms by which dietary fiber-dependent changes in gut microbiota enhance bile acid deconjugation, produce short chain fatty acids, and modulate inflammatory bioactive substances can lead to a better understanding of the beneficial role of dietary fiber. This article reviews the current knowledge concerning the mechanisms via which dietary fiber protects against colon cancer.     

Dietary fiber intake and ovarian cancer risk: a prospective cohort study

There is some evidence from case–control studies that dietary fiber intake might be inversely associated with ovarian cancer risk, but there are limited prospective data. Therefore, we examined ovarian cancer risk in association with intake of dietary fiber in a prospective cohort of 49,613 Canadian women enrolled in the National Breast Screening Study (NBSS), who completed a self-administered food frequency questionnaire between 1980 and 1985. Linkages to national mortality and cancer databases yielded data on deaths and cancer incidence, with follow-up ending between 1998 and 2000. Data from the food frequency questionnaire were used to estimate intake of total dietary fiber, of fiber fractions, and of fiber from various sources. Cox proportional hazards models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between energy-adjusted quartile levels of fiber intake and ovarian cancer risk. During a mean 16.4 years of follow-up, we observed 264 incident ovarian cancer cases. Total dietary fiber and fiber fractions were not associated with ovarian cancer risk in this study population.     

Increased incidence rate of colorectal tumors due to the intake of a soluble dietary fiber in rat chemical carcinogenesis can be suppressed by substituting partially an insoluble dietary fiber for the soluble one

In epidemiologic studies on human colorectal tumors, results on the relative protective effect of soluble and insoluble fibers are not consistent. We studied in this work the effect in rats of feeding guar gum or guar gum together with cellulose on the incidence of colorectal tumors induced by 1,2-dimethylhydrazine. The results were as follows: (i) The enhancement of tumor formation by feeding solely guar gum (guar gum group) was suppressed completely when two-thirds of the guar gum was replaced with cellulose (cellulose-guar gum group). The odds ratio for tumor formation was 0.075 (95% CI 0.006-0.936, p = 0.044) for guar gum group vs. no fiber control and 0.833 (0.134-5.167, p = 0.83) for cellulose-guar gum group vs. the control. (ii) In both groups, serum cholesterol and triglyceride levels decreased significantly compared to the no fiber control group, and fecal excretion of total bile acids almost doubled. (iii) In guar gum group rats, the deconjugation activity (beta-glucuronidase, beta-glucosidase) was higher than the control or cellulose-guar gum group rats. (iv) The amount of cecal short-chain fatty acids was almost double in guar gum group rats compared to the cellulose-guar gum group or the control rats, and pH of the cecal content of the guar gum group rats had a tendency to be lower. (v) The concentration of fecal secondary bile acids was extremely low in the younger rats of the guar gum group. From these results, it seemed significant to study the cancer preventive effect of the mixed feeding to experimental animals of water-soluble and insoluble fibers instead of the singular feeding.     

Dietary fiber is associated with serum sex hormones and insulin-related peptides in postmenopausal breast cancer survivors

Objective To measure the association between dietary fiber intake and eleven hormones and peptides in postmenopausal breast cancer survivors. Methods Intake of fiber from food and supplements was measured two to three years after breast cancer diagnosis in 493 postmenopausal women from three western states. Concurrently, a fasting blood sample was obtained for assay of estrone, estradiol, free estradiol, testosterone, free testosterone, dehydroepiandrosterone sulfate, sex hormone-binding globulin (SHBG), leptin, C-peptide, insulin-like growth factor-1 (IGF1), and IGF-binding protein-3. Adjusted means of these hormones and peptides were calculated for categories of fiber intake. Results High intake of dietary fiber was significantly (P ≤ 0.05) associated with low serum levels of estradiol and free estradiol and with high serum levels of IGF1. The combination of high dietary fiber intake and use of fiber supplements was additionally associated with low serum levels of C-peptide. The magnitude of the difference in hormone/peptide values, comparing high fiber intake to low fiber intake, varied from 16 to 28%, and the associations were independent of multiple confounding variables. Conclusion High fiber diets may be beneficial to postmenopausal breast cancer survivors due to fiber’s favorable influence on sex hormones and peptides known to affect breast cancer prognosis.     

Randomized trial of dietary fiber and Lactobacillus casei administration for prevention of colorectal tumors

The epidemiologic evidence that dietary fiber protects against colorectal cancer is equivocal. No large-scale clinical study of the administration of Lactobacillus casei has been reported. We examined whether dietary fiber and L. casei prevented the occurrence of colorectal tumors. Subjects were 398 men and women presently free from tumor who had had at least 2 colorectal tumors removed. Subjects were randomly assigned to 4 groups administered wheat bran, L. casei, both or neither. The primary end point was the presence or absence of new colorectal tumor(s) diagnosed by colonoscopy after 2 and 4 years. Among 380 subjects who completed the study, 95, 96, 96 and 93 were assigned to the wheat bran, L. casei, both and no treatment groups, respectively. Multivariate adjusted ORs for occurrence of tumors were 1.31 (95% CI 0.87-1.98) in the wheat bran group and 0.76 (0.50-1.15) in the L. casei group compared to the control group. There was a significantly higher number of large tumors after 4 years in the wheat bran group. The occurrence rate of tumors with a grade of moderate atypia or higher was significantly lower in the group administered L. casei. No significant difference in the development of new colorectal tumors was observed with administration of either wheat bran or L. casei. However, our results suggest that L. casei prevented atypia of colorectal tumors.     

A prospective analysis of the association between dietary fiber intake and prostate cancer risk in EPIC

Few studies have examined the association between dietary fiber intake and prostate cancer risk. We evaluated the association between dietary fiber intake and the risk of prostate cancer among 142,590 men in the European Prospective Investigation into Cancer and Nutrition (EPIC). Consumption of dietary fiber (total, cereal, fruit and vegetable fiber) was estimated by validated dietary questionnaires and calibrated using 24-hr dietary recalls. Incidence rate ratios were estimated using Cox regression and adjusted for potential confounding factors. During an average of 8.7 years follow-up, prostate cancer was diagnosed in 2,747 men. Overall, there was no association between dietary fiber intake (total, cereal, fruit or vegetable fiber) and prostate cancer risk, although calibrated intakes of total fiber and fruit fiber were associated with nonstatistically significant reductions in risk. There was no association between fiber derived from cereals or vegetables and risk and no evidence for heterogeneity in any of the risk estimates by stage or grade of disease. Our results suggest that dietary fiber intake is not associated with prostate cancer risk.     

Maternal dietary exposure to fiber during pregnancy and mammary tumorigenesis among rat offspring

Maternal diet during pregnancy has been proposed to modify female offspring's later susceptibility to develop breast cancer; however, most of the dietary factors identified thus far have led to increased risk. To identify dietary factors that might reduce offspring's breast cancer risk, pregnant rat dams were fed diets containing 6% fiber originating either from cellulose (control), or oat, whole wheat or defatted flax flour. At birth, dams were switched to the AIN93 semi-purified diet. Mammary tumor incidence and multiplicity, induced by administering the offspring 5 mg 7,12-dimethylbenz[a]anthracene (DMBA) at the age of 50 days, was reduced in the whole wheat flour-exposed offspring and increased in the defatted flax-exposed offspring. To identify the mechanisms mediating the effects of in utero dietary exposures, changes in mammary gland morphology and gene expression were assessed before puberty onset (3 weeks of age) and at the time rats are most susceptible to malignant transformation (8 weeks of age). The number of terminal end buds (TEBs), i.e., the targets of malignant transformation, was reduced in the mammary glands of whole wheat- and oat flour-exposed offspring, as compared to the controls. Further, the number of apoptotic epithelial cells (based on ISOL assay) was elevated in the whole wheat flour offspring, but no changes in cell proliferation (PCNA), estrogen receptor alpha (ER-alpha) or cyclin D1 mRNA or protein levels were seen. The mRNA and/or protein levels of BRCA1 and p53 were significantly increased in the mammary glands of whole wheat flour offspring. Further, the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of DNA damage, were significantly reduced in these rats, suggesting that maternal dietary exposure to whole wheat during pregnancy may reduce offspring's breast cancer risk by improving DNA damage repair mechanisms.