[婴儿期的钠和钾代谢]

Schulz-Lell G, Dörner K, Oldigs H D, Sievers E, Schaub J

Abteilung Allgemeine Pädiatrie, Universitäts-Kinderklinik Washibgton, D.C.

Monatsschr Kinderheilkd. 1992 Feb;140(2):117-21.

BACKGROUND

Recommendations for the concentration of most nutrients in infant formulas are based on their concentration in human milk. Industry succeeded in adapting sodium and potassium content in infant formulas to concentration found in human milk. Whether this adaptation affects on infants' mineral balances was studied in breast-fed and artificially-fed infants.

METHODS

Sodium and potassium balances were performed in 16 term male infants from their 3rd until their 17th week of life. The balances were performed at home and comprised up to five periods in intervals of three to four weeks. Each balance period consisted of subsequent three 24 h collections of milk, stool and urine samples. Ten infants were breast-fed, six received an adapted infant formula supplemented with copper, zinc and iron.

RESULTS

The breast-fed infants got a mean intake of 1 mmol Na/kg b w x day and a mean intake of 1.8 mmol K/kg b w x day. Man retention was 0.4 mmol Na and 0.7 mmol K/kg b w x day. The formula-fed infants received 1.9 mmol Na/kg b w x day and 2.1 mmol K/kg b w x day. Na- and K-retention in this group was 0.5 and 0.6 mmol/kg b w x day respectively. Although sodium intake in the formula-fed infants was nearly twice as much as in the breast-fed infants the difference in sodium retention was only small (0.4 vs 0.5 mmol/kg b w x day). The formula-fed infants got more potassium than the breast-fed infants, but potassium retention was the same in both groups.

CONCLUSIONS

With the adapted infant formula of this study the artificially fed infant was as well supplied with sodium and potassium as the breast-fed infant. A further reduction of the sodium concentration seems not to be useful.

背景

大多数婴儿配方奶粉中营养素浓度的建议是基于其在母乳中的浓度制定的。食品工业成功地使婴儿配方奶粉中的钠和钾含量与母乳中的浓度相适应。本研究旨在探讨这种调整对母乳喂养和人工喂养婴儿矿物质平衡的影响。

方法

对16名足月男婴从出生第3周直至第17周进行钠和钾平衡研究。平衡研究在家中进行，共分为五个阶段，间隔三至四周。每个平衡阶段包括连续三天收集牛奶、粪便和尿液样本。10名婴儿为母乳喂养，6名婴儿接受添加了铜、锌和铁的适配婴儿配方奶粉喂养。

结果

母乳喂养的婴儿钠平均摄入量为1 mmol Na/kg bw×天，钾平均摄入量为1.8 mmol K/kg bw×天。钠潴留量为0.4 mmol Na，钾潴留量为0.7 mmol K/kg bw×天。配方奶粉喂养的婴儿钠摄入量为1.9 mmol Na/kg bw×天，钾摄入量为2.1 mmol K/kg bw×天。该组钠和钾的潴留量分别为0.5和0.6 mmol/kg bw×天。尽管配方奶粉喂养的婴儿钠摄入量几乎是母乳喂养婴儿的两倍，但钠潴留量差异很小（0.4 vs 0.5 mmol/kg bw×天）。配方奶粉喂养的婴儿比母乳喂养的婴儿摄入更多的钾，但两组的钾潴留量相同。