生物与医学2019ncbi.nlm.nih.gov
自1914年以来蔬菜矿物质含量下降高达90%的估计
Estimates that mineral levels in vegetables have dropped by up to 90% since 1914
入门 · 约 30 分钟读完前置知识：土壤学基础、营养学常识
导读
这篇论文综述了自20世纪初以来蔬菜矿物质含量下降的估计，称美国蔬菜的镁含量可能下降了80–90%，并将原因部分归因于过去100年土壤中矿物质的耗竭。不过有读者核查其引用后发现，实际文献支持的下降幅度多在5%–40%之间，论文的90%说法可能夸大了。
HN 关注点：现代集约农业是否导致食物营养流失，讨论焦点包括土壤退化、'稀释效应'，以及对论文数据是否被夸大的质疑。
HN 评论精选
这几条评论里：质疑 1 补充 2 亲历 1
质疑核查引用后发现论文的80–90%降幅说法与原始文献不符，疑似夸大
我核查了论文中'蔬菜镁含量下降80–90%'这一说法的引用：参考文献11不支持该结论；文献12未直接提及镁，只说部分营养素下降5–40%，远不到80–90%；文献13虽提到镁，但降幅在20%以下。我觉得我被这篇论文坑了。
CraigJPerry查看英文原文
The BBC more or less episode with James Wong is making me wonder if this is true (shorter summary of what James said on the podcast: https://mobile.twitter.com/Botanygeek/status/984708381507276801 ) Anyway, from the paper here: >> with estimates that vegetables have dropped magnesium levels by 80–90% in the U.S. (Figure 2) and the UK [11,12,13,32,33] Reference 11 doesn’t support this claim. Ref 12 doesn’t directly mention Mg but does say some nutrients have dropped between 5-40% which is NOT 80-90% Ref 13 does mention mg specifically on page 3 but states under 20%. … I think i’m being fleeced by this paper.
补充土壤生态被现代农业破坏是根源，可通过恢复活土壤来逆转
这源于现代农业的重度翻耕、施肥和单一种植消灭了土壤生命。死掉的土壤更易被侵蚀，需要越来越多的合成肥料。美国流失的土壤比产出的粮食还多。通过改变耕作方式恢复活的土壤，可以回到历史肥力水平，还能提高保水性和养分可得性，减少对合成肥料的依赖。附：相关文章和一段彻底改变了我家庭园艺做法的视频链接。
tastyfreeze查看英文原文
This happened due to extermination of soil life through modern farming practices of heavy tilling, fertilizing and monoculture crops. Dead soil is more susceptible to erosion and requires ever increasing amounts of synthetic fertilizer to grow anything. More soil has been lost from the US than the amount of food that has been produced. Soil fertility can be returned to historical levels by changing farming practices to make living soil. The benefits of treating the soil as a living organism include increased fertility, water infiltration, moisture retention, and nutrient availability as well as decreasing or eliminating synthetic fertilizer requirements. https://theweek.com/articles/554677/america-running-soil This is a long video but it has completely changed my home gardening practices. https://www.youtube.com/watch?v=uUmIdq0D6-A
补充补充原始文献：'稀释效应'和遗传稀释效应是营养下降的机制，幅度为5%–40%
引用来源：镁缺乏率高可部分归因于栽培果蔬镁含量的持续下降，反映了过去100年土壤镁的耗竭，早在1930年代就有报告向国会发出警报。另一篇文献指出三类证据支持英美果蔬营养下降：施肥研究发现产量与矿物质浓度呈负相关（'稀释效应'）；历史食物成分数据显示部分矿物质中位数下降5%–40%以上；高低产品种并排种植也发现产量与矿物质、蛋白质浓度持续负相关（遗传稀释效应）。
esquivalience查看英文原文
From the source: "The high rate of magnesium deficiency now postulated [5,6,7,8] can be attributed in part to a steady decline in general magnesium content in cultivated fruits and vegetables, a reflection of the observed depletion of magnesium in soil over the past 100 years [11,12,13]. A report to Congress was already sounding the alarm as far back as the 1930s, pointing out the paucity of magnesium, and other minerals, in certain produce [14]." The easiest of those references to link to is https://journals.ashs.org/hortsci/view/journals/hortsci/44/1/article-p15.xml : "Three kinds of evidence point toward declines of some nutrients in fruits and vegetables available in the United States and the United Kingdom: 1) early studies of fertilization found inverse relationships between crop yield and mineral concentrations—the widely cited “dilution effect”; 2) three recent studies of historical food composition data found apparent median declines of 5% to 40% or more in some minerals in groups of vegetables and perhaps fruits; one study also evaluated vitamins and protein with similar results; and 3) recent side-by-side plantings of low- and high-yield cultivars of broccoli and grains found consistently negative correlations between yield and concentrations of minerals and protein, a newly recognized genetic dilution effect. "
亲历亲历对比：乌克兰蔬菜明显更好吃，可能与土壤和农业方式差异有关
我在乌克兰住了几个月，一直想弄明白为什么这里的蔬菜味道这么好。同样的菜在基辅的中档餐厅里比我在加拿大吃过的都好吃。回加拿大短暂探访时，我的身体还在想念乌克兰食物。这项关于蔬菜矿物质含量的研究或许能解释原因。乌克兰曾是苏联的'粮仓'，我很想看到东欧与北美农产品营养成分的对比研究。移民的乌克兰人常抱怨食物味道变差，以前我以为是乡愁，现在看来可能有科学依据。
igammarays查看英文原文
I’ve been living in Ukraine for the past few months, trying to figure out why the food here, especially the vegetables, simply taste so good. The very same dishes (e.g. steak and veggies) from popular mid-range restaurants are far more enjoyable to me over here in Kiev than I ever ate in Canada. When I went back to Canada for a brief visit, my body was craving Ukrainian food. Now this study on vegetable mineral content may explain why. I’m very keen to see a comparison study on Eastern European agriculture and produce versus North American. Ukraine was once the “breadbasket” of the Soviet Union, so there must be an explanation. Ukrainians who migrate to other countries are often said to complain about a loss in food taste - previously I assumed that was just some form of homesickness, but this study lends some potential scientific ground to their complaints.
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