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提斯曼人(Tsimane)人健康之谜何在?
诸平
据《数字杂志》(Digital Journal)2017年3月19日报道,美国、德国、埃及、法国、秘鲁、玻利维亚等国的医学科学家合作,已经鉴别出世界上最健康的人群,至少是这些人群的心脏是最健康的,他们就是来自玻利维亚(Bolivia)大森林的提斯曼人(Tsimane)。由于这里的当地居住民族的生活方式非常原始,因此提斯曼人几乎没有动脉硬化(arteries)迹象。
为什么提斯曼人被认为是全世界最健康人群的原因,就是因为科学家已经对于他们进行了相关检查,尚未发现有任何动脉堵塞的迹象,即使是当地最年长的成员也是如此。这是基于美国加州长滩纪念医疗中心(Long Beach Memorial medical center in California)等多家单位的研究人员合作研究而得出的结论。合作单位包括来自美国、德国、埃及、法国、秘鲁、玻利维亚等国家的多家高校研究医疗保健单位。如美国新墨西哥大学(University of New Mexico)、密苏里-堪萨斯城大学(University of Missouri–Kansas City)、亚利桑那州立大学(Arizona State University)、美国密尔沃基(Milwaukee)阿森松医疗保健(Ascension Healthcare)、埃及开罗艾资哈尔大学(Al Azhar University, Cairo, Egypt)、德国莱比锡马克斯·普朗克进化人类学研究所(Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany)、美国华盛顿史密森学会(Smithsonian Institution)、美国新罕布什尔(New Hampshire)州汉诺威市(Hanover)达特茅斯学院(Dartmouth College)、美国加利福尼亚州纽波特比奇市纽波特诊断中心(Newport Diagnostic Center, Newport Beach)、美国加州拉古纳山南海岸放射医疗组(South Coast Radiological Medical Group, Laguna Hills)、法国图卢兹高级研究所(Institute for Advanced Study in Toulouse, Toulouse, France)、玻利维亚科恰班巴市圣西门大学(Universidad de San Simón, Cochabamba, Bolivia)、美国加州大学欧文医学院(University of California, Irvine School of Medicine)、米勒长滩妇幼医院(Miller Women's and Children's Hospital Long Beach)、美国里诺心脏和心血管健康研究所(Renown Institute for Heart and Vascular Health)、美国内华达大学(University of Nevada)、秘鲁利马秘鲁大学(Universidad Peruana Cayetano Heredia, Lima, Peru)、美国华盛顿大学(University of Washington)、美国加州大学圣巴巴拉分校(University of California Santa Barbara)、美国纽约威尔·康乃尔医学院(Weill Cornell Medical College)和纽约-长老会医院(NewYork-Presbyterian Hospital)、美国纽约西奈山伊坎医学院(Icahn School of Medicine at Mount Sinai, New York)、南加州大学(University of Southern California)、美国长滩纪念馆(Long Beach Memorial)以及美国加州大学欧文分校(University of California Irvine)等单位。
多国研究人员合作研究最新发现,在2014年7月2日到2015年9月10日期间,研究者在已研究过的所有人群中,其中包括705名提斯曼人和6800余名粥样硬化多民族研究(Multi-Ethnic Study of Atherosclerosis,MESA))参与者,提斯曼人的心血管老化程度全球最低。现代研究认为,年龄、吸烟、高胆固醇、高血压、活动少、肥胖及糖尿病都是导致心血管疾病的高风险因素。多国研究者的合作研究结果于2017年3月17日在英国《柳叶刀》(The Lancet)杂志网站发表——Hillard Kaplan, Randall C Thompson, Benjamin C Trumble, L Samuel Wann, Adel H Allam, Bret Beheim, Bruno Frohlich, M Linda Sutherland, James D Sutherland, Jonathan Stieglitz, Daniel Eid Rodriguez, David E Michalik, Chris J Rowan, Guido P Lombardi, Ram Bedi, Angela R Garcia, James K Min, Jagat Narula, Caleb E Finch, Michael Gurven, Gregory S Thomas. Coronary atherosclerosis inindigenous South American Tsimane: a cross-sectional cohort study. The Lancet, Published: 17March 2017. DOI: http://dx.doi.org/10.1016/S0140-6736(17)30752-3.
作者在论文中指出,他们在2014年7月2日到2015年9月10日期间调查了85个提斯曼村庄,为705名年龄在40~94岁间的提斯曼人(Tsimane)进行CT检查,评估他们的心血管健康状况。其检查结果显示,在所有研究对象中,有596人(占提斯曼人总数的84.5%)没有冠状动脉钙化(coronary artery calcium, CAC)迹象,有89人(占提斯曼人总数的12.6%的人)CAC得分在1~100之间,如果CAC得分超过100,则表示有重要的动脉粥样硬化疾病。仅有2.8%的人也就是20人CAC得分超过100。在75岁以上的48名提斯曼人中,有31人占65%的人CAC得分为零,几乎没有罹患心脏病的可能;只有4人(占75岁以上提斯曼人总数的8%)其CAC得分等于或者大于100,即存在中度到高度心脏病风险。各个年龄段的粥样硬化多民族研究(Multi-Ethnic Study ofAtherosclerosis,MESA)的发病率,提斯曼人明显低于(低5倍,p≤0.0001)发达国家。与之相比,美国45~84岁的成年人中,不存在任何心脏病风险人的比率仅为14%。另外,提斯曼人平均LDL和HDL胆固醇浓度分别为2.23 mmlo/L(91 mg/dL)和1.0mmol/L (39.5 mg/dL),肥胖、高血压、高血糖以及吸烟现象都很少见。360名提斯曼人参与者(占总数的51%)超敏C反应蛋白(High-sensitivity C-reactive protein, hs-CRP)水平超过临床上限(3·0 mg/dL)。
hs-CRP数量上升是发炎的标志,每当患上伤风、感冒等疾病时,水平亦会上升。因此,专家建议透过验血可检测hs-CRP的水平,假如身体没有患病时进行检测,仍发现hs-CRP水平偏高,即有可能是粥状硬化斑块的发炎细胞数目增多。
超敏C反应蛋白(hs-CRP)是血浆中的一种C反应蛋白。hs-CRP是由肝脏合成的一种全身性炎症反应急性期的非特异性标志物,是心血管事件危险最强有力的预测因子之一。hs-CRP是临床实验室采用了超敏感检测技术,能准确的检测低浓度C反应蛋白,提高了试验的灵敏度和准确度,是区分低水平炎症状态的灵敏指标,血清hs-CRP水平与动脉粥样硬化及急性脑梗死(ACI)的发生、严重程度及预后密切相关。有研究显示,在急性脑梗死老年患者中,CRP升高者预后不佳;hs-CRP含量与梗死面积、神经功能缺损程度相关,是脑梗死患者病变程度的指标之一;而且CRP也参与了血栓形成和动脉硬化的病理过程,是脑卒中的危险因素之一。动脉粥样硬化斑块的炎症反应是斑块破裂和不稳定的重要原因,在动脉粥样硬化斑块的形成过程中,CRP、补体复合物和泡沫细胞等沉积在动脉壁内,CRP可与脂蛋白结合,激活补体系统,产生大量炎症介质,释放氧自由基,造成血管内膜损伤、血管痉挛及不稳定斑块脱落,加重动脉粥样硬化所致的管腔狭窄以及ACI的发生。有越来越多的证据表明,低水平CRP与心血管疾病的其他危险因素密切相关,如高血压、高脂血症;同时,CRP升高可增加高血压患者心脏病、脑卒中的发病率。因此,CRP是与动脉粥样硬化发生、演变和发展都有关的促炎因子。流行病学调查也显示,hs-CRP水平升高者发生急性脑卒中的几率是正常健康人的2倍,发生心肌梗死的几率是正常者的3倍。2003年欧洲高血压防治指南(ESH/ESC)正式推荐,高血压患者需检测hs-CRP水平。hs-CRP的临床指导作用主要表现在对心血管疾病,新生儿细菌感染,肾移植等方面。
香港大学医学院内科学系心脏科于2005~2008年间对于205名没有冠心病纪录的病人资料进行研究之后发现,24.2%受访者的坏胆固醇(HDL胆固醇)属健康水平,但高敏C反应蛋白的水平却高于正常值,隐藏罹患心血管病的风险。香港大学医学院内科学系于2009年找来102位曾患缺血性中风的病人进行研究之后发现,连续12周每天服用80 mg异黄酮补充剂的病人,高敏C反应蛋白水平较对照组降低37%,他们的血管扩张情况,也得到1%的改善。由此可见,异黄酮可以应用于心血管病的二线预防药物。专家建议民众平日多吃豆腐干、青豆、豆奶、豆腐等含有异黄酮的食物,每天喝一杯豆奶等,对于预防心脑血管疾病是有益的。
调查显示,与现代人54%的清醒时间都在久坐中度过相比,提斯曼人不睡觉时只有10%的时间在坐着,整天都在打猎、采摘、钓鱼和耕种。饮食上,提斯曼人以碳水化合物为主,占到日常饮食的72%,主要是未经处理、富含纤维的米、玉米、树薯等;蛋白质仅占提斯曼人饮食的14%,蛋白质的摄入主要来自动物的肉类,这些肉类中含有的脂肪约为38 g/day。
研究人员表示,有人会说提斯曼人心血管老化程度低可能和他们的种族遗传有关。实际上,在过去几年中,随着这些土著部落逐渐对外开放,提斯曼人也开始购买工业化生产的糖、烹调油,他们的胆固醇水平在逐渐升高。这说明,是他们的生活方式,而非基因,对心血管健康产生影响。这种生活方式值得人们参考。
除此之外,还有就是其生活环境的影响,提斯曼人(Tsimane)部落位于玻利维亚亚马逊,保持动脉年龄健康(血管老化水平极低)的秘诀,除了与其需要不断搜寻食物的生活习惯有直接关联之外,森林环境的天然氧吧也是导致其动脉年龄健康主要影响因素之一。我国古人就有近绿者寿之说,而且现代的森林环境研究也进一步证实了森林气息有益于健康,森林通过光合作用,吸收CO2,释放氧气,同时也会吸附微小空气悬浮物(PM2.5、PM10),净化空气;再加上各种植物释放的植物素,都是对人体健康有百利而无一害之物。森林旅游(Forest Recreation)正在成为保健旅游的新亮点,多年来,森林旅游业一直保持着快速增长态势,产业规模迅速壮大。2013年,我国森林旅游产业保持较快的增长态势,全年接待游客量达到7.6亿人次,占2013年国内旅游人数的23%,同比增长11.8%;森林旅游直接收入685亿元,同比增长10.8%;创造社会综合产值5200亿元,占2013年国内旅游消费的19.8%,同比增长18.2%。以森林公园为例,2013年全国森林公园接待游客量超过50万人次的有275家,超100万人次的有112家。旅游收入超1000万元的423处,超5000万元的128处,超亿元的66处。日本、韩国等国家的森林保健游也同样如火如荼,蓬勃发展,蒸蒸日上。
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This important study shows exceptional freedom from cardiovascular disease in a rural population with traditional lifestyle and diet.
However, reporting of the dietary practices associated with these results in this paper and as reported in the media has overlooked some important points.
The dietary data is exclusively supplied from the reference 30, Martin et al's study of the fatty acid composition of breast milk of Tsimane.
Martin et al state that their analysis was incomplete.
“our behavioural observations of foods eaten did not account for organ meat consumption or the addition of cooking fat, which may substantially increase saturated fat intake.”
This would also increase total fat intake above 14%.
Failure to account for organ meat consumption may also mean that the Tsimane protein intake was higher than 14%.
According to Martin et al,
"“Tsimane women generally cook with rendered animal fat, and rarely purchase or use vegetable oils. ”
This rendered fat may be purchased lard or tallow, as the game animals eaten would supply little rendered fat to re-use later.
The breast milk analysis by Martin et al also supports their observation on cooking fat - compared to the Cincinatti control sample, Tsimane breast milk is very low in linoleic acid. It is high in DHA from the freshwater fish that are an important part of the diet, and high in other LCPUFA found in animal foods.
This contradicts the modern assumption that oils high in linoleic acid, substituted for animal fats, are required for good cardiovascular health.
Martin et al also state that "The higher mean percentages of 15:0 and 17:0 in the Tsimane samples were also perplexing, as the Tsimane rarely consume dairy fats, which are associated with 15:0 and 17:0 in serum and adipose tissue levels (Brevik et al. 2005). Future research will better quantify Tsimane saturated fat intake from animal sources."
If the cooking fat used by the Tsimane is tallow, this would explain the higher levels of odd-chain saturated fatty acids.[2] This would also explain the lower linoleic acid, as lard is a better source of this fatty acid.
But as Martin et al stated, the Tsimane saturated fat intake from animal sources has not yet been well-quantified. 15:0 and 17:0 are also products of gut bacteria fermentation, which is why they appear in ruminant fat, and this may also account for the higher levels, but the amount supplied by this route is unknown.[3]
The Tsimane clearly eat a diet high in unrefined starchy carbohydrates, but the amount of fat, saturated fat, and protein in their diet is not as well-quantified as the plain figures quoted in this paper and given to media uncritically suggest.
Is it facetious to point out that here, whatever the Tsimane's true intake of macronutrients as percentages, we have a population which avoids gluten, dairy, legumes, sugar, and vegetable seed oils, follows if not a paleolithic certainly a mesolithic lifestyle almost exclusively, and enjoys ideal cardiovascular health?
[1] Martin MA, Lassek WD, Gaulin SJC, et al. Fatty acid composition in the mature milk of Bolivian forager-horticulturalists: controlled comparisons with a US sample. Maternal & child nutrition. 2012;8(3):10.1111/j.1740-8709.2012.00412.x. doi:10.1111/j.1740-8709.2012.00412.x.
[2] https://www.westonaprice.org/health-topics/know-your-fats/fatty-acid-analysis-of-grass-fed-and-grain-fed-beef-tallow/
[3] Jenkins B, West JA, Koulman A. A review of odd-chain fatty acid metabolism and the role of pentadecanoic Acid (c15:0) and heptadecanoic Acid (c17:0) in health and disease. Molecules. 2015 Jan 30;20(2):2425-44. doi: 10.3390/molecules20022425.
https://pubpeer.com/publications/07DF4D3BA751F691CF78D297CFEFCD
The Tsimane, a forager-horticulturalist population indigenous to the Bolivian Amazon, have the lowest reported levels of vascular ageing for any population studied, with rates of coronary atherosclerosis five times lower than in the U.S., according to a study presented March 16 during ACC.17 in Washington, DC, and simultaneously published in The Lancet.
In the cross-sectional cohort study, researchers visited 85 Tsimane villages between 2014 and 2015 and took CT scans of the hearts of roughly 700 adults between the ages of 40 and 94 to measure the extent of the hardening of the coronary arteries among other metrics.
Based on the CT scans, 85 percent of the Tsimane people had no risk of heart disease, 13 percent had low risk and only three percent had moderate or high risk. These findings continued into old age, where nearly two-thirds of those over 75 years old had almost no risk of heart disease and only eight percent had moderate or high risk. By comparison, a U.S. study of 6,814 people aged 45 to 84 found that only 14 percent of Americans had a CT scan that suggested no risk of heart disease and 50 percent had a moderate or high risk.
"These findings are very significant," says Randall Thompson, MD, FACC, from Saint Luke's Mid America Heart Institute cardiologist, who presented the results of the study at ACC.17. "Put another way, the arteries of the Tsimane are 25-30 years younger than the arteries of sedentary urbanites. The data also show that the Tsimane arteries are aging at a much slower rate."
Research suggests that the loss of subsistence diets and lifestyles in contemporary society could join age, smoking, high cholesterol, high blood pressure, physical inactivity, obesity and diabetes as a risk factor for heart disease. In the Tsimane population, heart rate, blood pressure, cholesterol, and blood glucose were also low, possibly as a result of their lifestyle. The Tsimane spend only 10 percent of their daytime being inactive, instead participating in hunting, gathering, fishing and farming. Their diet is also very low in fat and consists largely of non-processed carbohydrates.
"In cities, we can drive to a fast food restaurant and pick up 2,000 calories without getting out of our car," said co-author Ben Trumble, MD. "For the vast majority of human existence we would have needed to hunt or fish to obtain meat – sedentary urban life is a completely novel human environment, and this study helps show that heart disease may be a side effect of our new lifestyle and environment."
Moving forward, the authors encourage incorporating Tsimane-inspired lifestyle choices where possible. "This study shows that prevention really works," said Gregory S. Thomas, MD, FACC. "Most of the Tsimane are able to live their entire life without developing any coronary atherosclerosis. This has never been seen in any prior research. While difficult to achieve in the industrialized world, we can adopt some aspects of their lifestyle to forestall a condition we thought would eventually affect almost all of us."
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