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发信人: pipigou123 (鼠姐虎弟)
标 题: 到底该给孩子选择有机食品还是非有机食品
发信站: BBS 未名空间站 (Sun Aug 5 00:54:51 2012, 美东)
很多人问过我这个问题。 也很多人为此争论过
先我们看看有机食品是怎么定义的。 有机食品是指食品生长过程或者加工过程没有使
用人工合成肥料或者杀虫剂。 Farmer们使用自然的东西比如aged manure, humus, and
compost 做为肥料, 或者使用crop rotation and natural insect predators like
lady bugs来控制虫害。 WHO, AAO, 美国的EPA都制定了严格的Guideline来控制种植
,加工, 包装过程已保销售的食品符合有机食品的定义。 美国USDA于2002年十月21日
制定了美国有机食品必须符合的标准: 也就是号称有机食品的食品必须满足至少95%的
有机成分。
食品的营养genetic makeup, and soil conditions, maturity at harvest, storage,
and distribution time。 非有机食品使用的合成肥料一般满足食品的发育需求, 很
多原因加在一起(不一一赘述), 有机和非有机的食品营养基本上没有统计学差异。
有机的蔬菜可能Nitrite和蛋白质含量稍微低一点。
有机和非有机食品的几个区别:
1. 价格。 这个还用说?
2. 食品安全性。 食品安全性主要由几个因素决定。
1)食品的微生物感染。不管非有机食品使用的人工合成肥料,还是有机食品使用的粪
便都有可能被维微生物感染。 所以不管有机还是无机都必须安全操作食品: 洗干净,
肉食煮熟,食品储存的温度合适,洗手, 保持干净的厨房, 不要使食物交叉感染,
比如生肉和Ready To Eat的东西放在一起 。
2) 食品的自然毒性。比如solanine在土豆绿色部分, 有些蘑菇的含有毒素。这些和
有机非有机没有关系。
3) 杀虫剂。 这是有机非有机食品最大的Debate的地方。 有机食品使用的是合成杀虫
剂, 但是不排除风, 还有周围的水带来一些杀虫剂的Residue。 另外,有机食品使用
的一些方法使食品对微生物产生抗药可能会含有一些自然杀虫成分可能对机体也有影响
。
目前的一些关于孕妇杀虫剂的Exposure和胎儿发育的研究结果不统一。
小孩因为身体体积小,对杀虫剂可能更敏感。目前的环境中调查婴幼儿的发育和杀虫剂
的曝露没有足够的资料证明有toxicologic consequences. 美国的杀虫剂使用受到EPA
, FDA 和USDA的严格控制。 这些机构对于杀虫剂的使用剂量规定是基于严格的科研结
果。 EPA宣传,如果有任何科研证明目前剂量的Exposure对婴幼儿有不良影响,他们会
完全禁止使杀虫剂。 请大家查阅:pmep.cce.cornell.edu/issues/foodsafety-issues
.html 。 这些机构做了相关的大量的科研调查。 结果我将发在文章后面供大家参考。
食品中的杀虫剂在阳光下,在下雨后,以及收割后, 加上食用前仔细清洗,认真Cook
, 剥皮等办法可以基本消除。 有机食品可能会减少孩子对杀虫剂的曝露。 两个Study
发现食用有机食品的孩子尿液中的相关产物偏低,但是是否和健康相关还需要继续做些
科研。
大家关心的激素问题和杀虫剂的差不多。我就不再重复了。 也就是说使用的激素的量
严格控制在对人体安全范围以内。 大家可以去查正规的科研报告和官方文献。
总之, 有机食品是指种植和Process食品的一种工艺, 没有改变食品的营养结构,也
没有改变食品食用的安全性, 有机食品中含有比非有机食品少的杀虫剂。 目前的杀虫
剂受到几个机构的严格控制, 目前的杀虫剂使用严格控制在不影响人体健康的范围。
有机食品不能是“彻底安全” 的食品。
不管有机还是无机都需要仔细洗, 保持储存的卫生,合适的温度, 肉类食品把肥肉和
皮肤去掉(这些部分是杀虫剂残留最多的地方) 预防食品交叉感染,等等办法加强安
全性。
所以每个人问我到底该不该选择有机食品,我的答案是: 有机非有机的营养成分一样
, 选择哪个只是一种Life Style的选择。 主要是要安全Handle食品。
下面是关于EPA, USDA和FDA做的关于食品杀虫剂等方面的一些研究和结论。
The tolerances for the pesticide pydrin on alfalfa and sorghum were not
approved in 1985 because of concern regarding risks to children from
secondary residues in milk.
The EPA limited the use of two organophosphate pesticides, methyl parathion
and azinphos methyl, in 1999.
Another organophosphate pesticide, chlorpyrifos (Dursban), was banned in
2000.
In 2001, the EPA began to phase out diazinon, one of the most widely used
organophosphate pesticides [70].
In 1993, the National Research Council (NRC) issued a report on pesticides
in the diets of infants and children [60]. The report concluded that
children may be exposed to relatively larger amounts of certain pesticide
residues than are adults and that the exposure occurs at a vulnerable point
in their development. It acknowledged the need for reassessment of pesticide
tolerances that would apply specifically to infants and children and
recommended the collection of data that would more accurately reflect the
dietary patterns of children and the effects of pesticide exposure in
infants and children [44,46,60].
The NRC report triggered passage of the Food Quality Protection Act (FQPA)
in 1996. The FQPA required the EPA to review and reassess all existing
pesticide tolerances to make them safer for infants and children by 2006 [71
,72]. The FQPA required the EPA to apply an additional 10-fold margin of
safety to its pesticide assessments to address the potential for pre- and
postnatal toxicity and to compensate for gaps or inadequacies in the
available database regarding potential health risks to infants and children
[73-75]. The EPA is required to apply the 10-fold safety factor unless there
are reliable data to support use of a different safety factor to protect
infants and children [46,74,76].
As of August 3, 2006, the EPA had completed 9637, or more than 99 percent,
of the planned tolerance reassessments; the remaining tolerance reassessment
cases are to be completed by October 3, 2008. The tolerance reassessment
process has led to EPA decisions to revoke or modify thousands of existing
tolerances (3200 and 1200, respectively), and to require the establishment
of many new tolerances, improving food safety and health protection. The new
tolerances also ensure that pesticides used on foods meet the stringent
FQPA safety standards [77].
Tolerance levels are enforced by the USDA for meat and poultry and by the
FDA for all other foods. The FDA specifically analyzes for pesticide
residues all foods eaten by infants and children. As an example, pesticide
residues on apples, bananas, oranges, pears, grape and orange juice, and
milk were monitored by the FDA between 1985 and 1991 [67,78,79]. More than
10,000 food samples were analyzed before processing and without washing or
peeling. Fifty samples (0.5 percent) were in violation (0.3 percent of
domestic products and 0.6 percent of imports). The majority of these
violations occurred because the pesticide was not approved for use on that
particular food.
The FDA monitors nutritional concerns, including pesticide exposure, through
the Total Diet Study. This study examines 234 foods selected to typify the
American diet. Between 1985 and 1991, analysis of these foods revealed:
No residues were found in infant formulas
No residues over the EPA tolerance or FDA action level were found in any of
the "market basket" foods
Low levels of malathion were found in some cereals
Low levels of thiabendazole, a post-harvest fungicide, were found on some
fruits and fruit products
The Total Diet Study findings for 2003 were consistent with previous FDA
reports in that pesticide residues were below regulatory standards. An
adjunct survey of baby foods also provided evidence of only small amounts of
pesticide residues between 1991 and 2003 [80].
Reduction of exposure — Most pesticides begin to break down soon after
application with exposure to sunlight and rain; they continue to break down
after harvest. Additional pesticide reduction can be achieved through
washing, peeling, cooking, or processing of foodstuffs [67].
As an example, in the FDA monitoring described above, the highest residue
level of the fungicide thiabendazole in raw apples was 2 parts per million (
ppm), in apple juice was 0.08 ppm, and in applesauce was 0.06 ppm. The
established tolerance is 10 ppm [67].
Canned or frozen fruits and vegetables are alternatives to fresh fruits and
vegetables for individuals concerned about pesticide residues. Most current
food preservation techniques minimize the loss of nutritive value and are
safe and well standardized. One comparative analysis of fresh, frozen, and
canned vegetables conducted by the University of Illinois found that canned
foods are nutritionally equivalent to their fresh and frozen counterparts [
82].
Organic diets appear to reduce OP exposure in children. In one study of a
group of 39 preschool-aged children in Washington State, children consuming
a conventional diet had urinary dimethyl OP metabolites six to nine times
higher than children consuming an organic diet [83]. In another study, the
short-term effects of changing to an organic diet were measured in 23 school
-aged children [84]. After only 24 to 48 hours of the organic diet, urinary
OP metabolites (malathion and chlorpyrifos) decreased to nondetectable
levels. However, whether this reduction of urinary OP metabolites has any
relevance to health outcomes has not been sho