HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Mannion, C. A. Articles by Koski, K. G. Search for Related Content PubMed PubMed Citation Articles by Mannion, C. A. Articles by Koski, K. G.

Lactating Women Restricting Milk Are Low on Select Nutrients

School of Dietetics and Human Nutrition, McGill University, Montreal, Quebec, CANADA

Address reprint requests to: Dr. Cynthia Mannion, Assistant Professor, University of Calgary, Faculty of Nursing, 2500 University Drive N.W., Calgary, Alberta T2N 1N4 CANADA. E-mail: cmannion{at}ucalgary.ca

	ABSTRACT

TOP FOOTNOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS CONCLUSION ACKNOWLEDGMENTS REFERENCES

 
Objective: Currently there are no recommendations for vitamin/mineral supplementation for lactating women but supplementation may be important, particularly for those women who choose to restrict milk intake during lactation. The objective of this study was to assess nutrient adequacy for lactating women and compare their dietary intake, including supplements, between those who restrict milk and those who do not.

Methods: A cohort of 175 healthy exclusively breast-feeding women (19–45 yrs) recruited from prenatal classes were divided into milk restrictors (RS) defined as milk intake 250 ml/day and non-restrictors (NRS) (>250 ml/day) and followed for six months postpartum. Participants provided repeated 24-hr dietary recalls, detailed use of vitamin/mineral supplements and reasons for restricting milk.

Statistical Analyses: Observed intakes were adjusted to remove day-to-day variability. Nutrient intakes were estimated for macronutrients and vitamins C, D, thiamin, riboflavin, niacin, and minerals, calcium and zinc, with and without vitamin/mineral supplements. Chi-square was used to compare the number of RS and NRS with intakes less than the Estimated Average Requirement (EAR).

Results: Milk restriction was practiced by 23% of the sample. Sixty per cent of RS reported protein intakes <EAR compared to 38% of NRS (² = 6.22, p < 0.05). Prior to supplementation, mean levels of calcium and vitamin D intakes for RS were below the adequate intake level (AI) and lower than NRS estimated intakes (p < 0.05). Following supplementation, mean levels of these nutrients reached AI for both groups. RS remained lower than NRS. RS had lower energy intakes than NRS (p < 0.05) but no difference in weight loss at 6 months was noted. A higher proportion of RS were below the EAR for thiamin, riboflavin and zinc.

Conclusions: Milk restriction compromised protein and nutrient intakes in lactating women who restricted milk to <250 mL. Vitamin/mineral supplements helped exclusively breastfeeding milk restrictors improve their vitamin D and calcium intakes. Milk restriction is not recommended during lactation and where unavoidable, nutrients provided by milk should be compensated for by other foods or supplements.

Key words: milk restriction, vitamin mineral supplements, exclusive breastfeeding

Abbreviations: RS = restrictors • NRS = nonrestrictors • EAR = estimated average requirement • AI = adequate intake • UL = tolerable upper intake level • 25(OH)D = 25 hydroxyvitamin D

	INTRODUCTION

TOP FOOTNOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS CONCLUSION ACKNOWLEDGMENTS REFERENCES

 
Exclusive breastfeeding for 6 months is universally recommended [1]. There are specific nutrient requirements for breastfeeding mothers [2–5] but overall, the benefit of routine vitamin/mineral supplementation has not been determined [6]. Early recommendations from the Standing Committee of the National Academy of Sciences Food and Nutrition Board (1980) and more recently the Canadian Pediatric Society (1998) and Dietitians of Canada (1998) state that well nourished lactating women may not require supplementation [7], but this may not be not true for all nutrients. Recently reports of low vitamin D intakes during pregnancy have raised interest in whether or not breastfeeding mothers are meeting current nutrient recommendations and have stimulated debate about the need for recommended vitamin/mineral supplementation during lactation [8–11]. Few studies have examined the nutrient adequacy of foods plus supplements in exclusively breastfeeding women in North America but common use of vitamin/mineral supplements during lactation has been reported [12–15].

Milk restriction complicates the debate on the appropriateness of recommended supplements for all breastfeeding women because the consequences of this self-directed practice are unknown and may occur more often than health care providers estimate [16]. Breastfeeding women particularly, may self-impose milk restriction during lactation for reasons that include the perception that their food intake contributes to infant distress or colic [17–19], their own gastrointestinal distress [20], elevation of cholesterol [16], or an increase in the production of mucus [21]. They may also yield to social influences suggesting milk restriction will improve baby's behaviour [22]. It is known that dairy products are often included in elimination diets for women with a history of atopy although the results of this practice on the prevention of allergies in infants are inconclusive [23] and a recent systematic review recommended more research [24]. Women may also restrict milk to lose weight during the postpartum period as milk is perceived as a high fat food [16]; however some studies show a better level of weight loss with a high dairy product intake [25] although findings on this issue are controversial [26–28]. The objectives of this study were to report on nutrient adequacy in postpartum exclusively breastfeeding women and to compare nutritional adequacy among milk restrictors and nonrestrictors. A second objective was to measure the extent to which vitamin/mineral supplements may compensate for inadequate nutritional intakes where applicable. Reasons for restricting milk during lactation are reported.

	MATERIALS AND METHODS

TOP FOOTNOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS CONCLUSION ACKNOWLEDGMENTS REFERENCES

 
Recruitment
Women expressing the intention to breastfeed were recruited from hospital based prenatal classes in Calgary, Canada. Signed consent and permission to access medical charts were obtained. The study protocol was approved by the Ethics Committee of McGill University in Montreal, Quebec and the Conjoint Health Research Ethics Board at the Faculty of Medicine, University of Calgary, Alberta.

Description of Subjects and Measurements
Healthy breastfeeding women (n=246, 19–45 yrs old), defined as having no chronic illness and who had experienced a healthy singleton pregnancy were contacted within two weeks of delivery to schedule home visits. Subjects were visited during the 2^nd, 4^th and 6^th postpartum months, when 24-hour dietary recalls, supplement intake, reasons for milk restriction and breastfeeding assessments were obtained. Women were weighed to the nearest 0.1 kg, wearing light clothing using a Healthometer Professional Dial Floor Scale Model 134KG (Chicago, Illinois) that was calibrated on a firm surface prior to each measurement. Weight loss was reported as the difference between maternal weight taken at the first home visit at 2 months postpartum and the last home visit at 6 months postpartum. Country of birth, height, pre-pregnant weight and educational level were recorded. Subjects who answered yes to the question ‘Do you currently smoke?" were classified as smokers.

Exclusive breastfeeding was assessed by a validated infant feeding questionnaire and was defined as "breastfeeding with not more than one feeding of breastmilk substitute per week‘ [29]. During the 6-month data collection period, breastfeeding was assessed at three home visits and twice by telephone. Women who more frequently replaced breastmilk feeds with breastmilk substitutes or solid foods (n=71) were eliminated from the sample post hoc since it was not possible at recruitment to know who would breastfeed exclusively. The final sample consisted of 175 exclusively breastfeeding women.

Dietary Assessment
Validated repeat 24-hr dietary recalls [30] were conducted using standardized units of measure [31]. Each study subject used a package of reference materials including 1 cup (195 ml), 1 plate (50 cm), 1 bowl (340 ml) and a flexible 12 inch (35 cm) ruler, for the estimation of portion sizes. Dietary intake was recorded by trained research assistants who used the 24-hr recall method at home visits during the 2^nd, 4^th and 6^th postpartum months. Each subject provided 3 weekdays and one weekend day of dietary intake. For all subjects the dietary recall at 3 months was taken by telephone, a procedure validated for data collection [32].

Supplement Use
Data on vitamin/mineral supplements were collected for each recall day. Supplement composition was determined using standard references for brand names, product labels and the Health Canada Drug Product Database (DPD) [33]. With inadequate recall information, the brand name or product type from an earlier recall was used or default values if the nutrient only was named. The default value for calcium supplements was 500 mg, the amount included in most common prenatal supplements. Mean supplement intake was added to the adjusted nutrient intake of each subject.

Dietary Analysis
Six percent of the sample provided 3-repeat dietary recalls and 94% provided 4 recalls. Energy and nutrients were evaluated based on coded food entry, double verification and nutrient analysis using CANDAT (Godin London Inc., London, ON) and the 1997 Canadian Nutrient File [34]. In addition 267 food items were added to the 1997 Canadian Nutrient File using nutrient information obtained from food manufacturers’ data or the American data base [35]. Folic acid fortification of flour began in Canada in January 1998 and folate was excluded from analysis because these fortification procedures were not reflected in the 1997 Canadian Nutrient File. Nutrients analyzed included energy, fat, protein, vitamin C, vitamin D, thiamin, niacin, riboflavin, calcium and zinc.

Milk restrictors (RS) were defined as those reporting 1 cup (250 ml) of milk/day and nonrestrictors (NRS) >1 cup (>250 ml) milk/day on an average. RS (n=39) provided reasons for milk restriction and listed the resources they had used.

Estimated average requirements (EAR) for protein using 1.05 g/kg/d [36] were calculated for each subject and compared to reported intake. Nutrient intakes were calculated and reported as means and standard deviations. Observed intake distributions were computed for vitamin C (mg) vitamin D (µg), thiamin (mg), riboflavin (mg), niacin (NE), calcium (mg) and zinc (mg) from repeat 24-hr dietary recalls, and normalized using appropriate log or square root transformations. As per the NRC method, observed intakes were adjusted to remove the day-to-day variability within each subject's intake to give a distribution of adjusted intake [37]. The NRC method adjusts individual deviations from the mean intake values by multiplying it by the ratio of the within variability to total variability. This is added back to the mean intake of the group and a distribution of adjusted intakes results.

For those nutrients with an established EAR, the proportion of subjects with nutrient intakes less than the EAR was recorded to estimate the proportion with inadequate intake [38]. Chi-square tests compared observed differences between the proportion of RS and NRS above and below the EAR. Mean supplement intake for each individual was added to the adjusted intake distribution for each nutrient and dietary adequacy after supplementation for riboflavin, niacin, thiamin, vitamin C and zinc was assessed. The nutrient distribution was not adjusted when supplements were added because we assumed that all supplements were taken on a daily basis as reported on the recalls. An assessment of inadequacy could not be determined for vitamin D and calcium as only adequate intake levels (AI) have been set [38]. Mean and median intakes >AI were considered likely to have a low proportion of inadequate intakes [38].

Statistical Analyses
Descriptive statistics were used to summarize sample characteristics. Using t-tests, comparisons between RS and NRS were made for mean absolute intakes and mean intakes per 1000 kcal (nutrient density) to adjust for energy intake. Nutrient distributions were normalized using square-root transformations to observed intakes for vitamin C, riboflavin, calcium and zinc. Log transformations were used for thiamin and niacin. Assessment of normality was conducted using the Kolmogorov-Smirnov statistic, a measure of disparity between the empirical distribution function and an unknown distribution - essentially a test for goodness of fit. Statistical analyses were performed using Statistical Application System (SAS version 8e, SAS Institute, Cary, NC). A p-value <0.05 was considered statistically significant.

	RESULTS

TOP FOOTNOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS CONCLUSION ACKNOWLEDGMENTS REFERENCES

 
Our exclusively breastfeeding mothers (n = 175) had a mean age of 31.3 ± 4.1 years. Their mean self- reported height and pre-pregnant weights were 165.6 ± 6.9 cm and 63.1 ± 9.9 kg respectively. Their mean BMI was 23 ± 3.4. Most subjects (>86%) had post secondary education; 57% at the university level; only 5% reported smoking. Canada was the country of origin for 87% of participants and 65% were first time mothers. The mean birth weight was 3445 ± 465 g. Mean maternal weight loss (1.9 (± 2.9) kg) was calculated from maternal weight at 6 months postpartum minus measured weight taken at 2 months postpartum. Research assistants made home visits at 2, 4, and 6 months postpartum and used a portable Healthometer scale.

Reasons for Low Milk Intake during Lactation
Twenty three percent of breastfeeding women (95% CI; 16%–29%) restricted milk intake to 250 ml/day. Reasons for restriction in rank order were prevention of infant gas/colic and irritation of baby's GI tract (n = 37/39), perceived maternal lactose intolerance (n = 19/39), perceived maternal or infant allergy to milk (n = 11/39), improvement in baby's behaviour (n = 7/39), reduced mucus production (n = 3/39) and prevention of contamination of breast milk (n = 2/39). Dairy product restriction was endorsed mainly by physicians and nurses but also other health care providers including lactation consultants, homeopaths, prenatal instructors, as well as family and friends, internet sites, books and magazines. Although RS reported lower mean energy intake than NRS (2170 vs. 2324 kcal/d, respectively, p < 0.05), there was no significant difference in mean weight loss at six months postpartum: RS 1.66 (± 3.34) kg vs. NRS 1.91 (± 2.86) kg, respectively.

Vitamin/Mineral Supplement Intake
Vitamin/mineral supplementation during lactation was practiced by 78% (n = 136) with multivitamin/minerals as the most common supplement choice. There was no significant difference in the percentage of RS (73%) and NRS (79%) who took vitamin/mineral supplements but more RS used a single mineral supplement (i.e. iron) compared to NRS (² = 0.878, p < 0.05).

Comparison of Nutrient Intakes Between Restrictors and Nonrestrictors
Table 1 compares the mean and percentiles of nutrient intake between RS and NRS for vitamin D and calcium, those nutrients supplied in milk. The median intake of calcium without supplements for RS was 895 mg/d compared to 1326 mg/d for NRS. Calcium levels in the diets of restrictors (895 mg) was explained by 430 mg (48%) from dairy products including milk, cheese and yogurt, 109 mg (12%) from grain products, 105 mg (11%) from vegetables and fruit; mixed dishes and other foods explained the balance of the intake. Median intake of vitamin D from food only was 1.82 µg/d for RS and 5.65 µg/d for NRS. For NRS, the mean and median intakes for calcium and vitamin D from food only were above the AI, suggesting a low proportion of inadequate intakes.

	DISCUSSION

 
Dietary restriction of milk compromised protein intakes and without supplements, vitamin D, calcium and zinc as well. One cup of milk is nutrient dense, supplying approximately 8 g of protein, 0.98 mg of zinc and 308 mg calcium and is fortified with 2.56 µg of vitamin D. Although supplements raised nutrient intake above recommended levels for NRS and some RS, protein was low- something that could be alleviated by the addition of one cup of milk a day or an alternate protein dense food choice. Under reporting of both energy and protein may have occurred; over one third of the sample reported protein intakes below the EAR which contrasts with earlier reports of higher intakes in exclusively breast-feeding healthy women [39]. However our study indicates higher intakes of vitamin D, calcium, riboflavin and zinc in non-restrictors and corroborates an earlier study where milk consumers were found to have a better quality diet overall [40].

Zinc has been identified as a nutrient that was below the RDA (12 mg/d) for lactating women in dietary assessments conducted prior to the DRI publications when mean levels were used as a comparison value to the RDA [13,41]. Our results indicate that 25% of women who restricted milk had zinc intakes (with supplements) below the EAR. Zinc is thought to be important in fetal development and infant birthweight but studies have not consistently shown this [42,43].

The restriction of fortified milk denies women an important food source of vitamin D [44]. Low vitamin D can occur as a result of lack of sun exposure [45], polar latitudes [46], dark skin pigmentation [47], clothing cover [48] in addition to low intakes of fortified foods [49]. The consequences of low maternal vitamin D can result in nutritional rickets which continues to be reported in breastfed children in Canada, and the United States [38,50–52]. In Canada, Lebrun et al [53] found low serum 25-hydroxyvitamin D in 76% of mothers and 43% of breastfed infants in 80 mother-child pairs. This was attributed to the combined effect of low exposure to sunlight, a lack of fortified dairy products and a lack of vitamin/mineral supplements containing vitamin D. It is known that vegetarians who eliminate dairy products have low intakes of calcium, vitamin D and vitamin B₁₂ [54,55]. The low vitamin intake and the northerly latitude of Calgary may suggest that many residents have low serum 25(OH)D, particularly in the winter months. Vitamin D insufficiency may be related to reduced utilization of dietary calcium [56] and prolonged low dietary calcium can exacerbate bone demineralization [38,40,54,57,58]. Our data indicate that mothers who restrict milk may require a vitamin/mineral supplement as a result of the lowered nutrient adequacy of their diet.

There is very little evidence supporting the success of maternal milk restriction in decreasing infant crying, increasing infant calmness, and preventing colic [18,19]. The etiology of colic remains unknown yet there is a perception that milk is responsible for infant gastrointestinal distress and/or colic-type symptoms. Lactose intolerance was the second most frequently reported reason for women to restrict milk but was largely self-diagnosed and predicated upon commonly held myths surrounding milk consumption [59].

This sample of women exclusively breastfed for six months and had energy intakes comparable to other well nourished lactating groups [13,39,60] but few women achieved their pregravid weight by the end of the six month measurement period. Diets high in calcium and dairy products have been associated with decreases in body weight in samples of obese and overweight people but only small clinical trials have tested these effects on adiposity and have not shown consistent results [26,61,62]. In our study, we would have expected greater weight loss in NRS because they included dairy products in their diet and had significantly higher calcium intake than RS. This was not the case and may be explained by the common use of vitamin/mineral supplements that raised calcium intake to 1287 ± 470 mg in RS, a level comparable to NRS. We encountered very few women with calcium intakes below 500 mg/d, the level Zemel suggests is required before additional calcium can affect energy balance [25,63]. In the one randomized, double blind trial, calcium supplementation of 1g/d and placebo were given to both lactating and non-lactating women with habitual low calcium intakes of 800 mg/d. There was no difference in weight loss at six months postpartum that could be attributed to calcium supplementation [28].

	CONCLUSION

TOP FOOTNOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS CONCLUSION ACKNOWLEDGMENTS REFERENCES

 
In our study population of well-educated women who were exclusively breast feeding their infants, some reported low intakes of protein, vitamin C and zinc. However, women who restrict milk intake and who do not take vitamin/mineral supplements would appear to be at elevated risk for low intakes of calcium, zinc and vitamin D. This supplementation should be suggested specifically for those who limit milk intake, in addition to the recommendation that they supplement with folic acid [64]. Health care providers [65] should discuss the reasons women have for restricting milk and try to dispel commonly held myths or find other ways of increasing intake of calcium, vitamin D and zinc.

	ACKNOWLEDGMENTS

TOP FOOTNOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS CONCLUSION ACKNOWLEDGMENTS REFERENCES

 
This work was supported by Dairy Farmers of Canada and FRSQ Fonds de recherche en Sante du Quebec.

	FOOTNOTES

TOP FOOTNOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS CONCLUSION ACKNOWLEDGMENTS REFERENCES

 
Funded in part by Dairy Farmers of Canada and FRSQ Fonds de recherche en Santé du Québec.

Received November 24, 2005. Accepted July 12, 2006.

	REFERENCES

TOP FOOTNOTES ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS CONCLUSION ACKNOWLEDGMENTS REFERENCES

 

1. Health Canada:Exclusive Breastfeeding Duration : 2004 Health Canada Recommendation. Ottawa, Canada: Health Canada,2004 .
2. Institute of Medicine: "Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin and Choline. " Washington, DC: National Academy Press,1998 .
3. Institute of Medicine: "Dietary Reference Intakes for Vitamin C, Vitamin E, Selenium and Carotenoids. " Washington DC: National Academy Press,2000 .
4. Institute of Medicine, Standing Committee on the Scientific Evaluation of Dietary Reference Intakes: "Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. " Washington, DC: National Academy Press,1997 .
5. Institute of Medicine: "Dietary Reference Intakes: Applications in Dietary Assessment. ‘ Washington, DC: National Academy Press,2000 .
6. King JC: Physiology of pregnancy and nutrient metabolism.Am J Clin Nutr71 :1218S –1225S,2000 .[Abstract/Free Full Text]
7. Canadian Pediatrics Society, Dietitians of Canada, Health Canada: "Statement on Nutrition for Healthy Term Infants. " Ottawa: Health Canada Communications,1998 .
8. Ward LM: Vitamin D deficiency in the 21st century: a persistent problem among Canadian infants and mothers.CMAJ172 :769 –770,2005 .[Free Full Text]
9. Thompson K, Morley R, Grover SR, Zacharin MR: Postnatal evaluation of vitamin D and bone health in women who were vitamin D-deficient in pregnancy, and in their infants.Med J Austr181 :486 –488,2004 .
10. Weisberg P, Scanlon KS, Li RW, Cogswell ME: Nutritional rickets among children in the United States: review of cases reported between 1986 and 2003.Am J Clin Nutr80 :1697S –1705S,2004 .[Abstract/Free Full Text]
11. Mannion CA, Gray-Donald K, Koski KG: Association of low intake of milk and vitamin D during pregnancy with decreased birth weight.CMAJ174 :1273 –1277,2006 .[Abstract/Free Full Text]
12. Ladipo OA: Nutrition in pregnancy: mineral and vitamin supplements.Am J Clin Nutr72 :280S –290S,2000 .[Abstract/Free Full Text]
13. Mackey AD, Picciano MF, Mitchell DC, Smiciklas-Wright H: Self-selected diets of lactating women often fail to meet dietary recommendations.J Am Diet Assoc98 :297 –302,1998 .[Medline]
14. Olafsdottir AS, Wagner KH, Thorsdottir I, Elmadfa I: Fat-soluble vitamins in the maternal diet, influence of cod liver oil supplementation and impact of the maternal diet on human milk composition.Ann Nutr Metab45 :265 –272,2001 .[Medline]
15. Schirm E, Schwagermann MP, Tobi H, de Jong-van den Berg: Drug use during breastfeeding. A survey from the Netherlands.Eur J Clin Nutr58 :386 –390,2004 .[Medline]
16. Cashel K, Crawford D, Deakin V: Milk choices made by women: what influences them, and does it impact on calcium intake?Pub Health Nutr3 :403 –410,2000 .
17. Estep DC, Kulczycki A: Colic in breast-milk-fed infants: treatment by temporary substitution of neonate infant formula.Acta Paediatr89 :795 –802,2000 .[Medline]
18. Garrison MM, Christakis DA: A systematic review of treatments for infant colic.Pediatrics106 :184 –190,2000 .[Abstract/Free Full Text]
19. Hill DJ, Hosking CS: Infantile colic and food hypersensitivity.J Pediatr Gastroenterol Nutr30 (Suppl) :S67 –S76,2000 .[Medline]
20. Hagy LF, Brochetti D, Duncan SE: Focus groups identified women's perceptions of dairy foods.J Women Aging12 :99 –115,2000 .[Medline]
21. Arney WK, Pinnock CB: The milk mucus belief: sensations associated with the belief and characteristics of believers.Appetite20 :53 –60,1993 .[Medline]
22. Brewer JL, Blake AJ, Rankin SA, Douglass LW: Theory of Reasoned Action predicts milk consumption in women.J Am Diet Assoc99 :39 –44,1999 .[Medline]
23. Arvola T, Holmberg-Marttila D: Benefits and risks of elimination diets.Ann Med31 :293 –8,1999 .[Medline]
24. Kramer MS:Maternal antigen avoidance during lactation for preventing atopic disease in infants of women at high risk. Cochrane Database Syst Rev CD000132,2000 .
25. Zemel MB, Thompson W, Zemel P, Nocton AM, Milstead A, Morris K, Campbell P: Dietary calcium and dairy products accelerate weight and fat loss during energy restriction in obese adults.Am J Clin Nutr75 :342S –343S,2002 .
26. Harvey-Berino J, Gold BC, Lauber R, Starinski A: The impact of calcium and dairy product consumption on weight loss.Obes Res13 :1720 –1726,2005 .[Medline]
27. Teegarden D: The influence of dairy product consumption on body composition.J Nutr135 :2749 –27452,2005 .[Abstract/Free Full Text]
28. Wosje KS, Kalkwarf HJ: Lactation, weaning, and calcium supplementation: effects on body composition in postpartum women.Am J Clin Nutr80 :423 –429,2004 .[Abstract/Free Full Text]
29. Pastore MT, Nelson A: A breastfeeding drop-in center survey evaluation.J Hum Lact13 :291 –298,1997 .[Abstract/Free Full Text]
30. Rush D, Kristal AR: Methodologic studies during pregnancy: the reliability of the 24-hour dietary recall.Am J Clin Nutr35 :1259 –1268,1982 .[Free Full Text]
31. Chambers E, Godwin SL, Vecchio FA: Cognitive strategies for reporting portion sizes using dietary recall procedures.J Am Diet Assoc100 :891 –897,2000 .[Medline]
32. Casey PH, Goolsby SL, Lensing SY, Perloff BP, Bogle ML: The use of telephone interview methodology to obtain 24-hour dietary recalls.J Am Diet Assoc99 :1406 –1411,1999 .[Medline]
33. Health Canada. Drug Product Database (DPD): www.hc-sc.gc.ca/hpb/drugs-dpd/searcheng.html2003 .
34. CANDAT Nutrient Calculation System: London, ON: Godin London Inc,1991 .
35. Adams CF: "Nutritive Value of American Foods in Common Units. " Agricultural Handbook No. 456. Washington, DC: Agricultural Research Services, US Department of Agriculture,1975 .
36. The National Academy of Sciences: "Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids (Macronutrients). A Report of the Panel on Macronutrients, Subcommittees on Upper Reference Levels of Nutrients and Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes,2002 ." Washington, DC: National Academy Press, 2002. http://www.nap.edu/openbook/0309085373/html/93.html
37. NRC (National Research Council): "Nutrient Adequacy: Assessment Using Food Consumption Surveys. " Washington, DC: National Academy Press,1986 .
38. Barr SI, Murphy SP, Poos MI: Interpreting and using the dietary references intakes in dietary assessment of individuals and groups.J Am Diet Assoc102 :780 –788,2002 .[Medline]
39. Giammarioli S, Sanzini E, Arnbruzzi AM, Chiarotti F, Fasano G: Nutrient intake of Italian women during lactation.Inter J Vit Nutr Res72 :329 –335,2002 .
40. Soroko S, Holbrook TL, Edelstein S, Barrett-Connor E: Lifetime milk consumption and bone mineral density in older women.Am J Public Health84 :1319 –1322,1994 .[Abstract/Free Full Text]
41. Krebs NF: Zinc supplementation during lactation.Am J Clin Nutr68 :509S –512S,1998 .[Abstract]
42. Caulfield LE, Zavaleta N, Figueroa A, Leon Z: Maternal zinc supplementation does not affect size at birth or pregnancy duration in Peru.J Nutr129 :1563 –1568,1999 .[Abstract/Free Full Text]
43. Osendarp SJ, van Raaij JM, Darmstadt GL, Baqui AH, Hautvast JG, Fuchs GJ: Zinc supplementation during pregnancy and effects on growth and morbidity in low birthweight infants: a randomised placebo controlled trial.Lancet357 :1080 –1085,2001 .[Medline]
44. Miller GD, Jarvis JK, McBean LD: The importance of meeting calcium needs with foods.J Am Coll Nutr20 :168S –1685S,2001 .[Abstract/Free Full Text]
45. Glerup H, Mikkelsen K, Poulsen L, Hass E, Overbeck S, Thomsen J, Charles P, Eriksen EF: Commonly recommended daily intake of vitamin D is not sufficient if sunlight exposure is limited.J Intern Med247 :260 –268,2000 .[Medline]
46. Ovesen L, Andersen R, Jakobsen J: Geographical differences in vitamin D status, with particular reference to European countries.Proc Nutr Soc62 :813 –821,2003 .[Medline]
47. Grover SR, Morley R: Vitamin D deficiency in veiled or dark-skinned pregnant women.Med J Aust175 :251 –252,2001 .[Medline]
48. Holick MF: Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis.Am J Clin Nutr79 :362 –371,2004 .[Abstract/Free Full Text]
49. Islam MZ, Lamberg-Allardt C, Karkkainen M, Outila T, Salamatullah Q, Shamim AA: Vitamin D deficiency: a concern in premenopausal Bangladeshi women of two socio-economic groups in rural and urban region.Eur J Clin Nutr56 :51 –56,2002 .[Medline]
50. Allgrove J: Rickets—Is nutritional rickets returning?Arch Dis Child89 :699 –701,2004 .[Free Full Text]
51. Hollis BW, Wagner CL: Assessment of dietary vitamin D requirements during pregnancy and lactation.Am J Clin Nutr79 :717 –726,2004 .[Abstract/Free Full Text]
52. Pettifor JM: Nutritional rickets: deficiency of vitamin D, calcium, or both?Am J Clin Nutr80 :1725S –1729S,2004 .[Abstract/Free Full Text]
53. Lebrun JB, Moffatt ME, Mundy RJ, Sangster RK, Postl BD, Dooley JP, Dilling LA, Godel JC, Haworth JC: Vitamin D deficiency in a Manitoba community.Can J Public Health84 :394 –396,1993 .[Medline]
54. Specker BL: Nutritional concerns of lactating women consuming vegetarian diets.Am J Clin Nutr59 :1182S –1186S,1994 .[Abstract/Free Full Text]
55. Weiss R, Fogelman Y, Bennett M: Severe vitamin B-12 deficiency in an infant associated with a maternal deficiency and a strict vegetarian diet.J Ped Hem Oncol26 :270 –271,2004 .
56. Heaney RP: Calcium, dairy products and osteoporosis.J Am Coll Nutr19 :83S –99S,2000 .[Abstract/Free Full Text]
57. Affinito P, Tommaselli GA, Di Carlo C, Guida F, Nappi C: Changes in bone mineral density and calcium metabolism in breastfeeding women: a one year follow-up study.J Clin Endocrinol Metab81 :2314 –2318,1996 .[Abstract]
58. Prenticc AM, Prentice A: Evolutionary and environmental influences on human lactation.Proc Nutr Soc54 :391 –400,1995 .[Medline]
59. Lovelace HY, Barr SI: Diagnosis, symptoms, and calcium intakes of individuals with self-reported lactose intolerance.J Am Col Nutr24 :51 –57,2005 .[Abstract/Free Full Text]
60. Patterson AJ, Brown WJ, Roberts DC, Seldon MR: Dietary treatment of iron deficiency in women of childbearing age.Am J Clin Nutr74 :650 –656,2001 .[Abstract/Free Full Text]
61. Parikh SJ, Yanovski JA: Calcium intake and adiposity.Am J Clin Nutr77 :281 –287,2003 .[Abstract/Free Full Text]
62. Shapses SA, Heshka S, Heymsfield SB: Effect of calcium supplementation on weight and fat loss in women.J Clin Endocr Metab89 :632 –637,2004 .[Abstract/Free Full Text]
63. Gentile C, Gold BC, Harvey-Berino J: Calcium intake in overweight and obese women may not be high enough to facilitate weight loss.Obes Res9 :183S ,2001 .
64. Scholl TO, Hediger ML, Bendich A, Schall JI, Smith WK, Krueger PM: Use of multivitamin/mineral prenatal supplements: influence on the outcome of pregnancy.Am J Epidemiol146 :134 –141,1997 .[Abstract/Free Full Text]
65. Hueston WJ, Eilers GM, King DE, Mcglauchlin VG: Common Questions Patients Ask During Pregnancy.Am Fam Phys51 :1465 –1470,1995 .[Medline]

This Article Abstract Full Text (PDF) Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Mannion, C. A. Articles by Koski, K. G. Search for Related Content PubMed PubMed Citation Articles by Mannion, C. A. Articles by Koski, K. G.