專家：「順丁烯二酸」最傷腎
毒澱粉事件波及越來越廣，從粉圓、芋圓、板條，到豆花、肉圓，只要口感Q彈的加工食品幾乎淪陷，林口長庚醫院臨床毒物科主任林杰樑大膽推測，不肖業者違法使用工業原料「順丁烯二酸」，是導致國人腎臟病高居全球之冠的主要原因。
林杰樑指出，歐美研究發現，低蛋白飲食、也就是食用「澱粉類食物」，可以降低腎臟疾病的發生率，不過在台灣，常吃澱粉加工品的人，腎臟功能反而容易出問題。
林杰樑指出，「順丁烯二酸」也就是俗稱的「馬來酸」致病毒性高，尤其對腎臟具有高毒性，以60公斤的成人為例，一天攝取0.03公克「馬來酸」，長期使用，就可能影響腎臟功能，許多民眾將板條、肉圓等澱粉加工食品當成主食，隨便吃一碗就超標。
林杰樑指出，不肖業者從事不法行為超過十年以上，這也解釋了我國腎臟病患的比率為何位居全球之冠。
不過台大食品科技研究所教授孫璐西則持不同看法"?"，她認為，「馬來酸」沒有太嚴重的毒性，消費者不用過於緊張。
Kidney International (1995) 48, 1542–1548; doi:10.1038/ki.1995.444
Insights into the biochemical mechanism of maleic acid-induced Fanconi syndrome
1The
Combined Program in Nephrology and Renal Physiology, Departments of
Physiology and Internal Medicine, Texas Tech University Health Sciences
Center, Lubbock, Texas, USA
Correspondence: Sandra
Sabatini PhD MD, Department of Physiology, Texas Tech University Health
Sciences Center, Lubbock, Texas 79430, USA.
Received 6 October 1993; Revised 8 June 1995; Accepted 12 June 1995.
Top of page
Abstract
Insights
into the biochemical mechanism of maleic acid-induced Fanconi syndrome.
Maleic acid administration is known to produce the Fanconi syndrome,
although the biochemical mechanism is incompletely understood. In this
study the effect of a single injection of maleic acid (50 mg/kg body wt,
i.v.) on the rat renal ATPases was examined. Maleic acid rapidly caused
bicarbonaturia, natriuresis, and kaliuresis. When nephron segments were
microdissected, there was an 81 
2% reduction in proximal convoluted tubule (PCT) Na-K-ATPase activity (P < 0.005) and a 48
4% reduction in PCT H-ATPase activity (P < 0.01). Enzyme activity
(Na-K-ATPase, H-ATPase, H-K-ATPase) in the medullary thick ascending
limb of Henle's loop and distal nephron segments was normal. In vitro, maleic acid (1 and 10 mM)
inhibited Na-K-ATPase in PCT, but it had no effect on H-ATPase in PCT.
Prior phosphate infusion to maleic acid-treated rats attenuated urinary
bicarbonate wastage by 50% (P < 0.05); activity of proximal tubule
Na-K-ATPase and H-ATPase activities were partially protected as compared
to the animals given maleic acid alone (P < 0.05). Renal cortical
ATP levels were not altered at the concentration of maleic acid used in
this study (that is, 50 mg/kg body wt), but higher doses of maleic acid
(that is, 500 and 1000 mg/kg body wt) caused ATP levels to fall. Maleic
acid did not affect cortical medullary total phosphate concentration,
however, P32 turnover (1 and 24 hr) was altered by prior
phosphate infusion. A protective effect of prior phosphate loading on
the membrane bound Pi pool (insoluble) was seen while the cytosolic Pi
pool (soluble) was not different from control. Thus, maleic acid-induced
"Fanconi" syndrome likely results from both direct inhibition of
proximal tubule Na-K-ATPase activity and membrane-bound phosphorus
depletion. The former mechanism would reduce activity of the
sodium-dependent transporters (that is, Na/H antiporter), while the
latter would inhibit the electrogenic proton pump (H-ATPase). The
combination of reduced proximal tubule Na-H exchange and H-ATPase
activities would markedly inhibit bicarbonate reabsorption and result in
the metabolic acidosis universally seen in the Fanconi syndrome.
2% reduction in proximal convoluted tubule (PCT) Na-K-ATPase activity (P < 0.005) and a 48
4% reduction in PCT H-ATPase activity (P < 0.01). Enzyme activity
(Na-K-ATPase, H-ATPase, H-K-ATPase) in the medullary thick ascending
limb of Henle's loop and distal nephron segments was normal. In vitro, maleic acid (1 and 10 mM)
inhibited Na-K-ATPase in PCT, but it had no effect on H-ATPase in PCT.
Prior phosphate infusion to maleic acid-treated rats attenuated urinary
bicarbonate wastage by 50% (P < 0.05); activity of proximal tubule
Na-K-ATPase and H-ATPase activities were partially protected as compared
to the animals given maleic acid alone (P < 0.05). Renal cortical
ATP levels were not altered at the concentration of maleic acid used in
this study (that is, 50 mg/kg body wt), but higher doses of maleic acid
(that is, 500 and 1000 mg/kg body wt) caused ATP levels to fall. Maleic
acid did not affect cortical medullary total phosphate concentration,
however, P32 turnover (1 and 24 hr) was altered by prior
phosphate infusion. A protective effect of prior phosphate loading on
the membrane bound Pi pool (insoluble) was seen while the cytosolic Pi
pool (soluble) was not different from control. Thus, maleic acid-induced
"Fanconi" syndrome likely results from both direct inhibition of
proximal tubule Na-K-ATPase activity and membrane-bound phosphorus
depletion. The former mechanism would reduce activity of the
sodium-dependent transporters (that is, Na/H antiporter), while the
latter would inhibit the electrogenic proton pump (H-ATPase). The
combination of reduced proximal tubule Na-H exchange and H-ATPase
activities would markedly inhibit bicarbonate reabsorption and result in
the metabolic acidosis universally seen in the Fanconi syndrome.
范可尼綜合徵(Fanconi
syndrome)是由於近端腎小管對多種物質再吸收障礙，氨基酸、葡萄糖、磷酸鹽、碳酸氫鹽及其他物質自尿中大量丟失，導致近端腎小管酸中毒、低鉀血
症、佝僂病、骨質稀疏和生長發育遲滯等表現的一個綜合徵。本徵可因多種遺傳性或獲得性疾病引起。導致本徵的共同機制可能有二：一是腎小管膜的完整性改變致
發生泄漏而不能有效地重吸收多種溶質；二是腎小管細胞內代謝改變，不能產生足夠的能量以維持物質的轉運。這兩者有時不可截然分開，因為維持細胞間的完整性
和保持小管上皮需要細胞內的能量。
Maleic acid found in food products in Taiwan
Tapioca balls are commonly added to tea drinks in Taiwan. (Photo/Chen Chih-yuan)
The chemical was added to products including tapioca balls and rice noodles to give them more elasticity. A health official said maleic acid is not known to have adverse effects on human health, and has not been linked to cancer, adding that an average-sized adult could consume 30mg of maleic acid in a day without their health being affected.
Health authorities were alerted in March and April that certain food manufacturers have been adding maleic acid to their products and launched an investigation into the tip-offs.
After the seizure, concentrations of maleic acid of under 800ppm was found in the food, an amount deemed within a safe range. A doctor specializing in clinical toxicology at Chang Gung Memorial Hospital in New Taipei, said maleic acid is a poisonous industrial chemical and it is therefore unethical to add it to food, even in small amounts.
The authorities will conduct a further investigation into the manufacturers involved and decide whether to issue a fine of NT$30,000 to NT$150,000 (US$1,000-$5,000).
http://www.wantchinatimes.com/news-subclass-cnt.aspx?id=20130514000118&cid=1103
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