長期以來,經由醫界、媒體報道,乳制品是鈣質無可取代的標準來源這一觀念已經深入人心。然而,牛奶真有那么大的功效嗎?根據科學家們最新的研究,乳制品的鈣質可能比綠葉蔬菜還要少,而補鈣的最佳食品則可能是易于吸收的豆制品。
Children who drink more milk do not necessarily.Develop healthier bones, researchers said in a report that stresses exercise and modest consumption of calcium-rich foods such as tofu and broccoli.
Appearing in the journal Pediatrics, the report drew its conclusions from previously published studies and was written by researchers from the Physicians Committee for Responsible Medicine, which advocates a strict vegetarian diet.
"Under scientific scrutiny, the support for the milk myth crumbles. This analysis of 58 published studies shows that the evidence on which U.S. dairy intake recommendations are based is scant," said study author Dr. Amy Lanou in a statement.
Some earlier studies that extol dairy products as a calcium source have been funded at least in part by the dairy industry.
The U.S. government has gradually increased recommendations for daily calcium intake, largely from dairy products, to between 800 and 1,300 milligrams to promote healthy bones and prevent osteoporosis.
But the Physicians Committee's report said boosting consumption of milk or other dairy products was not necessarily the best way to provide the minimal calcium intake of at least 400 milligrams per day. Other ways to get the absorbable calcium found in one cup of cow's milk include a cup of fortified orange juice, a cup of cooked kale or turnip greens, two packages of instant oats, two-thirds cup of tofu, or 1-2/3 cups of broccoli, the report said.
Several of the studies, which examined such factors as bone density and rate of fractures, concluded that exercise may be more important than increased calcium consumption in developing strong bones.
Data was scarce on the effect of calcium intake for children younger than 7 years, the report said. Dairy products provide 18 percent of the total energy and 25 percent of the total fat intake in the diets of American children, who are developing increasing rates of obesity, it said.
In an editorial in the journal commenting on the report, Frank Greer, a pediatrician at the University of Wisconsin in Madison, said the ideal way to achieve the goal of healthy bones is to make sure children exercise and consume up to 1,300 milligrams a day of calcium.
兒童根本不需要喝更多牛奶。研究者在一份研究資料中表明,加強運動配合適量攝入含鈣豐富的食品如:豆腐、椰菜等,便可以獲得更強壯的骨骼。
這篇文章被發表在《小兒科》雜志上,是由醫師醫藥責任協會(PCRM)的學者根據先前公開發表過的論文總結出來的結論,這份研究提倡素食。
研究學者Dr. Amy Lanou 在聲明中寫道:“在科學的詳細審查下,牛奶補鈣神話的支柱被徹底粉碎。對58份公布研究的分析表明僅僅基于美國乳制品推薦攝入量作為補鈣證據是遠遠不足的。”
一些初期的對牛奶作為鈣質來源而大放贊美之詞的研究論文,背后都受過乳品加工業的資金贊助,至少是部分的贊助。
美國政府逐漸提高了人均鈣質的推薦攝入量,當然主要是從乳制品入手,達到800~1300毫克來促進骨骼健康和預防骨質疏松癥。
但是醫師醫藥責任協會發表的研究表明,提高牛奶或其他乳制品的攝入量并不是提供我們每天至少400毫克鈣質所必要的、或者說最好的方法。要獲得與一杯牛奶等量的可吸收鈣質的其他途徑包括:一杯強化(維生素)橙汁,一碗煮羽衣甘藍或蕪箐甘藍,兩包速溶燕麥,2到3碟豆腐,1到2/3碗椰菜。
個別研究調查了一些因素諸如骨密度和破裂率后,得出結論:也許通過運動對于獲得強壯骨骼來說,比提高鈣的攝入量來的更為重要。
研究中還表明,針對7歲以前的兒童,證明補鈣效果的數據是不足的。美國兒童所攝入的乳制品已經占他們總能量攝入的18%,占總脂肪攝入量的25%,這使得美國肥胖率持續上升。
在一篇針對這篇學術報告的社論中,Frank Greer,一位在麥迪遜威斯康辛大學的兒科醫師評論道,獲得強壯骨骼的最理想的方法就是保證孩子們充足的運動和每天攝入1300毫克鈣。