Nutrition During Lactation (1991) / Chapter Skim
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5 Milk Volume
5 Milk Volume
Pages 80-112
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From page 80... ...
Do maternal body fat or other nutrient stores modify this relationship? · Does energy supplementation or increased intake of protein or fluid increase mink volume?
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From page 81... ...
Maternal milk production can be measured mechanically by extracting all the mink or by using a combination of test weighing and extraction of residual milk. NORMAL RANGE OF MILK INTAKE AND PRODUCTION There is a very wide range in milk intake among healthy, exclusively breastfed infants.
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From page 82... ...
. The points represent average intakes from studies that obtained data from test weighing, validated exclusive breastfeeding, studied three or more subjects, and reported mink transfer by monthly intervals.
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From page 83... ...
. BREAST DEVELOPMENT AND PHYSIOLOGY The data discussed above illustrate that lactation is a physiologic process with a great deal of plasticity that is, milk production can be regulated up or down, depending on the degree of stimulation to the mammary gland.
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From page 84... ...
These investigators reported that a constituent of milk whey protein inhibits milk secretion in a dose-dependent manner in goats. As mink builds up in the mammary gland between feedings, the concentration of this inhibitor presumably increases and thus retards and eventually stops milk production.
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From page 85... ...
is recommended to provide the necessary degree of hormonal stimulation to the mammary gland. Once lactation is established, cross-sectional studies of well-nourished, exclusively breastfeeding women nursing 4 to 16 times per day indicate that there is little, if any, relationship between nursing frequency and infant milk intake (Butte et al., 1984a; de Carvalho et al., 1982; Dewey et al., 1986)
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From page 86... ...
Instead, the infants responded to solid foods by reducing breast milk intake, thereby maintaining constant levels of energy intake. Similarly, Nommsen and colleagues (1989)
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From page 87... ...
There is some evidence that miLk production on the fourth day post partum is higher among multiparous than it is among primiparous women (Zuppa et al., 19884; however, once lactation is established, there is no statistically significant association between parity and infant miLk intake in well-nourished populations (Butte et al., 1984a; Dewey et al., 1986; Rattigan et al., 1981~. In The Gambia, infants of mothers who had borne 10 or more children had low miLk intakes (Prentice, 1986)
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From page 88... ...
Substance Use Maternal behavior such as cigarette smoking and alcohol consumption may influence both milk production and milk composition. Potential consequences to the infant are discussed in Chapter 7; this section is restricted to effects on milk volume.
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From page 89... ...
Nonetheless, the evidence from investigations in both animals and humans strongly suggests that smoking has an adverse effect on mild volume. Alcohol Consumption The influence of alcohol consumption on milk production is less straightforward than that of smoking.
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From page 90... ...
For lactating women who wish to use oral contraceptives and maintain mink production, the World Health Organization states that progestin-only pills are the preferred choice (WHO Task Force on Oral Contraceptives, 1988~. Maternal Nutrition and Energy Balance This section begins with consideration of maternal energy balance during lactation; this is followed by discussions of protein and fluid intakes.
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From page 91... ...
Are the mechanisms of energy utilization during lactation relevant to the volume of milk produced by lactating women? Energy Restriction and Milk Volume Several investigators have developed animal models of malnutrition during lactation, primarily in rats.
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From page 92... ...
In The Gambia, Prentice and colleagues (1986) found a striking association between seasonal patterns of maternal energy intake and infant milk intake but concluded that this association reflected changes in breastfeeding patterns and infant illnesses rather than maternal undernutrition.
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From page 93... ...
with change in maternal energy intake. The period of energy restriction for the mothers in the experimental group was week 2 of the 3-week experimental period.
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From page 94... ...
Exercising subjects compensated for higher energy expenditure by increasing their energy intake,2 so there was no net difference in energy deficit between groups. Energy Supplementation During Lactation and Milk Volume Studies in rats have been conducted to investigate the effects of dietary supplementation on mink production.
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From page 95... ...
in milk volume was the same before and after supplementation, suggesting that energy supplementation did not even increase the mink volume of women with low milk volumes. The authors concluded, in hindsight, that the nutritional status of the Gambian women prior to food supplementation was not as poor as initially believed and, therefore, that the negative results are not surprising.
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From page 96... ...
These limitations would generally reduce the chance of finding a statistically significant effect of food supplementation on milk volume. In addition, milk sampling methods were inadequate for estimating total milk energy output.
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From page 97... ...
. The findings are based on test weighings of milk intake for 48 consecutive hours at 8-week intervals from 2 to 7 weeks post partum (van Steenbergen et al., 19811.
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From page 98... ...
during pregnancy. In Indonesia, prepregnancy maternal body mass index was positively associated with milk intake of breastfed infants at 18 to 22 weeks post partum but not at 2 to 6, 10 to 14, or 26 to 30 weeks (controlling for infant birth weight did not change this association)
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From page 99... ...
In an earlier study of 16 lactating women in The Gambia, milk volume measured by 12-hour test weighing was inversely related to increases in maternal triceps and subscapular skinfold thicknesses during weeks 6 to 12 of lactation (Paul et al., 1979~. This surprising finding was interpreted by the authors to indicate that there is competition between milk synthesis and replenishment of maternal fat stores during lactation.
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From page 100... ...
Data from small samples of relatively sedentary lactating women in the United States indicate that total energy expenditure (not including milk production) averages only 1,800 to 1,900 kcal/day (Blackburn and Calloway, 1976; Lovelady et al., 1990~; the estimated expenditure for nonlactating women, assuming light to moderate activity, is 2,200 kcal/day (NRC, 19891.
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From page 101... ...
Because milk intake may increase with the age of the infants and repeated expression of extra milk may stimulate greater milk production (Dewey and Lonnerdal, 1986) , milk volumes may have increased during the study for these reasons rather than in response to increased maternal protein intake.
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From page 102... ...
. I I I l I I I 60 80 1 00 120 140 1 60 20 40 Increase in Fluid Intake, TO FIGURE 5-4 Relationship between increase in maternal fluid intake for 3 days and percent change in milk production.
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From page 103... ...
Studies in animals indicate that there may be a threshold below which energy intake is insufficient to support normal milk production; it is likely that most studies in humans have been conducted in groups with intakes above this hypothesized threshold. · Food supplementation of lactating women in areas where malnutrition is prevalent has generally had little, if any, impact on milk volume.
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From page 104... ...
Liquid diets and weight loss medications are not recommended. · Since the impact of curtailing maternal energy intake during the first 2 to 3 weeks post partum is unknown, dieting during this period is not recommended.
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From page 105... ...
In press. Effects of common illnesses on infants' energy intakes from breast milk and other foods during longitudinal community-based studies in Huascar (Lima)
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From page 106... ...
Maternal vs. infant factors related to breast milk intake and residual milk volume: the DARLING study.
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From page 107... ...
1988. Milk production by mothers of premature infants.
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From page 108... ...
1986. Effect of dietary protein intake on milk production in lactating women.
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From page 109... ...
1987. Is maternal milk production limiting for infant growth during the first year of life in breast-fed infants?
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From page 110... ...
1988. Energy metabolism, body composition, and miLk production in healthy Swedish women during lactation.
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From page 111... ...
1988. Effects of hormonal contraceptives on breast milk composition and infant growth.
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From page 112... ...
1988. Relationship between maternal parity, basal prolactin levels and neonatal breast milk intake.
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