孩子喝何种奶更健康? 诸平 The Ministry of Health recommends children drink two to three serves of preferably reduced-fat milk after the age of two years, but new research shows the majority of toddlers are drinking full-fat milk. Credit: Massey University 据加拿大圣迈克尔医院( St. Michael's Hospital ) 2019 年 12 月 30 日提供的消息,最新研究发现:喝全脂牛奶的儿童超重或肥胖的风险较低。 多伦多团结健康圣迈克尔医院( St. Michael's Hospital of Unity Health Toronto )领导的系统评价和荟萃分析发现,喝全脂牛奶的孩子与食用低脂牛奶的孩子相比,超重或肥胖的几率降低了 40 %。该研究于 2019 年 12 月 18 日已发表在《 美国临床营养杂志 》( American Journal of Clinical Nutrition )—— Shelley M Vanderhout, Mary Aglipay, Nazi Torabi, Peter Jüni, Bruno R da Costa, Catherine S Birken, Deborah L O'Connor, Kevin E Thorpe, Jonathon L Maguire. Whole milk compared with reduced-fat milk and childhood overweight: a systematic review and meta-analysis,The American Journal of Clinical Nutrition, 2019, nqz276. Published: 18 December 2019. DOI: 10.1093/ajcn/nqz276 . https://doi.org/10.1093/ajcn/nqz276 此分析了来自7个国家的 28 项研究,探讨了喝牛奶的孩子与超重或肥胖风险之间的关系。没有一项研究(涉及近 2.1 万名 1 ~ 18 岁的儿童)表明,喝低脂牛奶的孩子超重或肥胖的风险较低。在 28 项研究中,有 18 项表明喝全脂牛奶的儿童超重或肥胖的可能性较小。 该发现对加拿大和国际准则提出了挑战,该准则建议儿童从 2 岁开始食用低脂牛奶而不是全脂牛奶,以降低肥胖的风险。 该研究的主要作者,圣迈克尔医院的儿科医生乔纳森·马奎尔( Jonathon Maguire )博士说:“加拿大和美国的大多数儿童每天都喝牛奶,牛奶是许多儿童饮食中脂肪的主要来源。”“在我们的研究中,遵循目前建议在两岁时改用低脂牛奶的孩子并不比那些消费全脂牛奶的孩子瘦。” 乔纳森·马奎尔博士还是 MAP 城市健康解决方案中心的科学家,他希望通过一项随机对照试验确定全脂牛奶和降低肥胖风险的因果关系。 乔纳森·马奎尔博士说:“我们检查的所有研究都是观察性研究,这意味着我们无法确定全脂牛奶是否会降低超重或肥胖的风险。全脂牛奶可能与降低超重或肥胖风险的其他因素有关。”“一项随机对照试验将有助于确定因果关系,但文献中没有发现。” 更多信息请注意浏览原文或者相关报道。 Whole-fat milk consumption associated with leaner children, research finds ABSTRACT Background The majority of children in North America consume cow-milk daily. Children aged 2 y are recommended to consume reduced-fat (0.1%–2%) cow-milk to lower the risk of obesity. Objectives To evaluate the relation between cow-milk fat consumption and adiposity in children aged 1–18 y. Methods Embase (Excerpta Medica Database), CINAHL (Cumulative Index to Nursing and Allied Health Literature), MEDLINE, Scopus, and Cochrane Library databases from inception to August 2019 were used. The search included observational and interventional studies of healthy children aged 1–18 y that described the association between cow-milk fat consumption and adiposity. Two reviewers extracted data, using the Newcastle–Ottawa Scale to assess risk of bias. Meta-analysis was conducted using random effects to evaluate the relation between cow-milk fat and risk of overweight or obesity. Adiposity was assessed using BMI z -score (zBMI). Results Of 5862 reports identified by the search, 28 met the inclusion criteria: 20 were cross-sectional and 8 were prospective cohort. No clinical trials were identified. In 18 studies, higher cow-milk fat consumption was associated with lower child adiposity, and 10 studies did not identify an association. Meta-analysis included 14 of the 28 studies ( n =20,897) that measured the proportion of children who consumed whole milk compared with reduced-fat milk and direct measures of overweight or obesity. Among children who consumed whole (3.25% fat) compared with reduced-fat (0.1%–2%) milk, the OR of overweight or obesity was 0.61 (95% CI: 0.52, 0.72; P 0.0001), but heterogeneity between studies was high ( I 2 =73.8%). Conclusions Observational research suggests that higher cow-milk fat intake is associated with lower childhood adiposity. International guidelines that recommend reduced-fat milk for children might not lower the risk of childhood obesity. Randomized trials are needed to determine which cow-milk fat minimizes risk of excess adiposity.
超重与癌症风险增加有关 Mar 2015 一项对来自184个国家的相关数据的研究表明,身体质量指数高(BMI≥25 kg/m 2 )的人群的癌症风险显著偏高。 这项基于人群的研究表明,2012年全世界参与调查国家新增癌症成年病例中,481,000例身体质量指数偏高,占3.6%,其中,女性人群归因分值(PAFs)*高于男性(5.4%对1.9%)。与身体质量指数偏高有关的新增癌症病例中,子宫癌、绝经后乳腺癌、结肠癌占63.6%。研究者还指出,2012年所有与身体质量指数偏高相关的新增癌症病例中,近四分之一(约118,000例)可能与患者1982年以后身体质量指数的增高有关。 新加坡癌症中心医学总监及顾问专家Wong Seng Weng 博士说:“新加坡的相关数据也被做为东南亚地区数据的一部分进行了分析。总体上来看,东南亚地区肥胖相关性癌症的发生率低于世界平均水平。” Wong指出:“全球范围内男性癌症新增病例中肥胖相关性癌症所占比例为1.9%,女性癌症新增病例中肥胖相关性癌症所占比例为5.4%。在东南亚地区男性和女性癌症新增病例中肥胖相关性癌症所占比例分别为0.5%和2%。” Wong说:“这种差异主要是由于北美地区和欧洲人身体质量指数(BMI)偏高风险相对较高造成的,其肥胖相关性癌症的发生率占全世界总发生率的2/3。但目前北美地区肥胖率的增长速度已有所下降,但其它地区,如东南亚地区肥胖率的增长速度仍在不断加快。换句话说,也就是说目前在肥胖相关性癌症这一问题上,与北美地区相比新加坡和其它东南亚国家处于有利位置,但我们的这种优势在未来几十年中将会消失。” Wong指出,这项研究非常重要,该研究表明全世界每年约有50万例肥胖相关性癌症新增病例。该研究还表明,过去三十年中,全世界超重的发生率增长了近1/4,仅这一因素使全世界范围内每年新增癌症病例约12万例。随着全球化的到来和发展中国家经济的发展,这一趋势将进一步加剧,因为发展中国家拥有全世界最多的人口。 肥胖本身不具有致癌性,但却是一个重要的促进因素 在谈到肥胖是如何增高癌症发生风险时,Wong指出:“肥胖本身不具有致癌性,事实上,肥胖只是一个重要的促进因素。”他说:“超重可导致人体的雌激素水平增高,这是因为脂肪组织中含有一种酶,这种酶被称为芳香化酶,主要负责将身体内血液中的雄激素转化为雌激素。多种女性易发癌症,如乳腺癌和子宫内膜癌都与雌激素水平的偏高有密切联系。” Wong 说:“在胰岛素对血糖水平进行调节的过程中,超重还会导致人体的胰岛素抵抗性增高。这时人体会产生额外的胰岛素和一种被称为胰岛素样生长因子(ILGH)的物质,胰岛素样生长因子具有促进细胞,包括癌细胞生长的作用。” Wong指出,对于超重患者,应在患者未罹患癌症时建议患者适当控制体重。使患者的家人清楚地知道不应将体重问题留到癌症已发作或较为严重时再解决,这一点也非常重要。Wong说:“这会使癌症治疗陷入矛盾的两难处境之中,因为癌症治疗期间,必须采取必要措施防止体重过度降低,以防止患者因身体过于虚弱而无法完成规定的治疗疗程。” Wong说“相关根治性治疗临床试验数据表明,对于某些癌症,如绝经后乳腺癌,肥胖、高脂低纤维饮食及缺乏运动等危险因素,可导致其复发风险的显著性增高。” 何为肥胖? Obesity is a condition in which a person has an abnormally high and unhealthy proportion of body fat. To measure obesity, researchers commonly use a scale known as the body mass index (BMI). BMI is calculated by dividing a person’s weight (in kilograms) by their height (in meters) squared. BMI provides a more accurate measure of obesity or being overweight than weight alone. Guidelines established by the National Institutes of Health (NIH) place adults age 20 and older into the following categories based on their BMI: BMI BMI Categories Below 18.5 Underweight 18.5 to 24.9 Normal 25.0 to 29.9 Overweight 30.0 and above Obese The National Heart Lung and Blood Institute provides a BMI calculator . For children and adolescents (less than 20 years of age), overweight and obesity are based on the Centers for Disease Control and Prevention’s (CDC) BMI-for-age growth charts : BMI BMI Categories BMI-for-age at or above sex-specific 85 th percentile, but less than 95 th percentile Overweight BMI-for-age at or above sex-specific 95 th percentile Obese Compared with people of normal weight, those who are overweight or obese are at greater risk for many diseases, including diabetes, high blood pressure, cardiovascular diseases, stroke, and certain cancers.
来自西班牙的科学家报道了一组有意思的研究,母乳中含有超过700种细菌,这些细菌首先进入婴儿体内,帮助他们建立肠道共生菌系统,增强免疫力,维护宝宝健康。 研究人员采用高通量DNA测序技术研究了初乳和后续的乳汁,发现在初乳中含有较多的 Weissella, Leuconostoc, Staphylococcus, Streptococcus and Lactococcus . 之后的乳汁,一个月和六个月后则出现口腔中特有细菌,如 Veillonella, Leptotrichia and Prevotella等 . 妈妈越重,细菌越少 研究中还发现一个有意思的现象,体重超重的妈妈或者分娩后增重较多的妈妈乳汁中含有的细菌种类越少。 另外,分泌方式也会对乳汁中细菌有影响,有计划的进行剖腹产的妈妈乳汁中的细菌种类要比顺产的妈妈乳汁中细菌要少,然而,如果剖腹产是计划外的,乳汁中细菌则类似于顺产的。这可能是由于不同分泌方式导致妈妈体内荷尔蒙不同引起的,分泌过程中的激素信号能够通过影响妈妈的生理过程从而引起乳汁中细菌的不同。 婴儿体内的微生物能够帮助他们消化母乳,还能帮助他们建立免疫系统。科学家对这些微生物的进一步研究,能够帮助我们建立不能得到母乳喂养孩子的营养方案。 感兴趣的朋友可以查看原文: R. Cabrera-Rubio, M. C. Collado, K. Laitinen, S. Salminen, E. Isolauri, A. Mira. The human milk microbiome changes over lactation and is shaped by maternal weight and mode of delivery . American Journal of Clinical Nutrition , 2012; 96 (3): 544 DOI: 10.3945/ajcn.112.037382