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Citation:

 Barr SI. Increased dairy product or calcium intake: is body weight or composition affected in humans? J Nutr. 2003 Jan;133(1):245S-248S.


PubMed ID: 12514301
Study Design:
Systematic Review
Class:
M - Click here for explanation of classification scheme.
NEUTRAL: See Research Design and Implementation Criteria Checklist below.
Research Purpose:

 

To assess the possible impact of increased intakes of dairy products or calcium on body weight or composition, a MEDLINE search was conducted to identify randomized trials of supplementation with calcium or dairy products.
 
Inclusion Criteria:

 

  • studies published in the English language
  • conducted with humans
  • provided information on relative changes in body weight or composition
Exclusion Criteria:

Exclusion criteria was not delineated.

Description of Study Protocol:

Recruitment

  • A MEDLINE search was conducted between the years 1966 and October 2001 in which articles containing the exploded search terms, “calcium,” “calcium citrate,” “calcium, dietary,” “calcium carbonate” or dairy products were combined with those in which the search term “bone density,” “body weight” or “ body composition ” were a focus of the article.
  • The combined sets were limited to studies published in the English language and conducted with humans
  • Titles of the resulting 1090 articles were reviewed manually, and 30 randomized controlled trials of increased dairy products or calcium intake in generally healthy individuals were identified
  • Twenty articles provided information on relative changes in body weight or composition
  • When email addresses could be obtained for authors of the remaining papers, they were contacted and asked to indicate whether differential changes in body weight or composition were observed between groups.
 

Design

Systematic Review

Blinding used (if applicable)

 

Intervention (if applicable)

 

Statistical Analysis

 

Data Collection Summary:

Timing of Measurements

 

Dependent Variables

  •  Body weight
  •  Body fat

Independent Variables  

  • Dairy products intake
  • Calcium supplement  intake

Control Variables

  • Age
  • Sex
 
Description of Actual Data Sample:

 

Initial N: 9 randomized studies on dairy product consumption;17 ramdomized studies on effect of calcium supplementation.

Attrition (final N):Same 17 studies

Age:

Ethnicity:

Other relevant demographics:

Anthropometrics (e.g., were groups same or different on important measures)

Location:

 

Summary of Results:

 

Key Findings

 
  • Nine studies of incrased dairy product intake were identified. In seven, no significant differences in the change in body weight or composition were detected between the treatment and control groups. Two studies conducted in older adults observed significantly greater weight gain in the diary product groups.
  • The interpretation of these findings was complicated by the inability to accurately determine the extent of dietary compensation for the increment in energy intake provided by the added dairy products.
  • In 17 calcium supplemented groups , only one study found greater weight loss in the supplemented group; in the remaining studies, changes in body weight and/or body fat were strikingly similar between groups
Table 1: Randomized trials of increased dairy product consumption
 
 

Author
Subjects
Design
Results
Chan(10)
48 U.S. girls initially
  11 y old
1-y randomized trial of  
    dairy product
    supplementation(to total
    1200 mg/d)vs. usual diet
Wt gain: controls +7.2 kg; dairy+6.4
    kg. Ht gain: controls +7.4 cm,
    dairy +7.8 cm. Fat gain: controls
     + 2.62 kg; dairy +2.59 kg. Lean gain: 
     controls: 3.8 kg; dairy + 4.3 kg. All
     comparisons not significant (NS).
Cadogan(11)
82 British girls initially   
 12.2 y old
18-mo randomized trial of
   addition of 568 ml/d milk
   vs. usual diet
Wt gain: controls +7.2 kg; dairy+8.0
    kg. Ht gain: controls +8.4 cm,
    dairy +9.1 cm. Fat gain: controls
     + 1.8 kg; dairy +1.9 kg. Lean gain: 
     controls: 5.2 kg; dairy + 5.6 kg. All
     comparisons NS(absolute data   
     approximated from graph showing %
     changes).
Merrilees(12)
91 New Zealand girls,  
   initially age 15-16
2-y randomized trial of
   dairy foods(1000 mg
   Ca/d)or usual diet
Wt gain controls + 4kg; dairy+4.6
    kg. Ht gain: controls +1.6 cm,
    dairy +1.3 cm. Fat gain: controls
     + 2556 g; dairy +2616 g. Lean gain: 
     controls + 121 g; dairy + 720g. All
     comparisons NS.
Baran(13)
37 U.S. women aged
  30-42 y
3-y randomized trial of 
    increased dietary
    calcium (+610 mg/d) vs.
    usual diet
Wt gain: controls +3.4 kg; dairy+ 
    4.2(significance not reported).
   
Prince(14), Devine(15)
168 Australian
   women,>10y
   postmenopause
2-y randomized trial of
   1)placebo, 2)milk
    powder(1g Ca/d), 3)Ca
    tablets(1g/d), 4)Ca
    tablets + exercise
No significant changes in BMI during the 
    intervention in either the milk-powder
    group or the Ca tablet group (raw data 
    not reported). Changes in BMI not
    reported for placebo group or Ca tablet
    plus exercise group.
Storm(16)
60 U.S. women > 65 y
2-y randomized trial of
   addition of milk( ~250
   mL/d ),1g/d ), 1g CaC03  
   or placebo
No significant differences in change in 
    weight or body composition among
    treatment groups(Rosen, C.J., personal
    communication, March 2002).
Lau(17)
185 Chinese women aged
   55-59, >5 y
2-y randomized of addition
   of 50 g/d high calcium,
   low fat milk powder
Wt gain: controls -0.26 kg; dairy+0.52 kg     
    (P<0.001). Fat change: controls
     -0.14 kg; dairy +0.42 kg. Lean change: 
     controls: +0.2 kg; dairy + 0.3 kg.
Barr(18)
200 U.S. adults aged 55-
   85(129 women, 71
    men)
12-wk randomized trial of
   the addition of ~2 cups/d
    low fat milk vs. usual
    diet.
Wt gain (women)controls +0.4 kg;
    dairy+1.9 kg, (men): controls +1.0 kg;
    dairy +1.6 kg. Gain was significantly
    greater in dairy group (P<0.005).
Cleghorn(19)
115 Australian women,
   <5 y postmenopause
2-y, open crossover of 3 L
    /wk. Ca fortified milk(1y
    on milk, 1 y off)
Wt change:0.06 kg difference between
     on/off added dairy products(95% CI:-
     0.71 to 0.83 kg, NS).

 
 
Table 2: Effect of calcium supplementation on change in body weight and composition in randomized, placebo-controlled trials
 

Author
Subjects
Study design
Results
Dibba(22)
80 boys and 80 girls aged 8.3-
   11.9 y in rural Gambia
1-y trial of 1000 mg (5 d/wk)  
   CaC03 vs. placebo
No significant differences between
   groups in gains in wt, ht, triceps
   skinfold thickness, and mid-upper arm
   circumference.
Johnston(23)
45 pairs of identical U.S. twins  
   aged 6-14 y.
3-y trial of 1000 mg/d
   calcium citrate malate
Increase in wt and ht similar in both those receiving calcium and those receiving placebo.
Lee(24)
84 Hong Kong children aged 7 y
18-mo trial of 800 mg/d
   CaC0 3
Calcium and placebo groups had similar
   gains in wt(24.4 vs. 25.6%, P=0.46)
   and ht ( 8.4 vs. 8.4%, P=0.92).
Lee(25)
162 Chinese children aged 7 y
18-mo trial 300 mg/d CaC0 3
Calcium and placebo groups had similar
   gains in wt(17.2 vs. 17.4%) and ht
   (7.2 vs. 7.2%).
Lloyd(26)
94 American girls aged 11.9 y
18-mo trial of 500 mg/d
   calcium citrate maltate
Calcium and placebo groups had similar
 gains in wt( P=0.53) , ht ( P=0.86),  
 BMI(P=0.80) and body fat   %
 (P=0.86).
Bonjour(27)
149 Swiss girls aged 7.9 y
1-y trial of food products
   with CA++ (850 mg/d) from
   milk extracts or placebo
Calcium and placebo groups had similar
   gains in ht (5.4 vs. 5.0 cm), wt (3.4 vs.
   3.7 kg) and BMI (0.6 vs. 0.8 kg/m 2).
Nowson(28)
42 female Australia twin pairs
 10-17 y
18-mo trial of 1000 mg/d
 CaC0 3/Ca lactate gluconate 
 vs. placebo
Calcium and placebo groups had similar
   gains in wt( ~8 vs. ~ 7.9 kg )and ht(
   ~7.3 vs. ~7.8 cm).
Riggs(34)
236 postmenopausal American
   women
4-y trial of 1600 mg/d ca
 citrate or placebo
Calcium and placebo groups had similar
   changes in wt( P=0.47) , and fat   
   mass(P=0.59), but lean body mass was
   lower in the calcium group(P=0.006)
   (Riggs, B.L., unpublished results ,
   personal communication, April 2002).
  
Ricci(29)
31 postmenopausal American
   women with BMI 28-42 kg/m 2
6-mo weight loss program ,
 subjects randomized to 1
   g/d calcium citrate malate
   or placebo
Calcium and placebo groups had similar
   changes in wt (-9.0 vs. -8.8 kg),        
   BMI- 3.3 vs.-3.3 kg/m2), fat mass(-7.3
    vs. –7.3 kg) and lean mass                   
    (-1.0 vs. 0.7 kg).
Storm(16)
60 postmenopausal American
   women
2-yr trial of 1g/d CaC0 3,
 ~250 mL/d milk or placebo
Calcium and placebo groups had similar
   changes  in wt and BMI( Rose, C.J., 
   unpublished results, personal
   communication, March 2002).
 
Dawson-Hughes(35)
176 men and 213 women aged
   ≥65 y
3-y trial of 500 mg/d calcium
   plus 700 iu/d vitamin D, or
   placebo
Calcium/vitamin D and placebo groups  
   had similar changes in wt and body
   composition (Dawson-Hughes, B.,
   unpublished results, personal
   communication, March 2002).
Recker(30), Davies(3)
197 postmenopausal women  
   >60 y
~4.3 y trail of 1200 mg/d
     CaC0 3 or placebo
Calcium group lost more wt than  
   the placebo group (-0.67 vs. -0.32 kg/y,
   P<0.025).
Perez-Jaraiz(31)
98 postmenopausal Spanish
  women with rapid bone loss
1-y open trial of 1 g/d
   calcium, hormone
   treatment, eelcatonin or
   control
No significant change in body wt in
   either the calcium or the control
   group(wt was also unchanged in the
   eelcatonin and hormone treatment
   groups).
Kalkwart(36)
327 American women studied
 during lactation and weaning
6-mo trial of 1g/d CaC0 3                
 vs. placebo
Calcium and placebo groups had similar
   weight loss during lactation (-2.34 vs. –
   2.66 kg, P=0.57) and weaning (-0.54
    vs. 0.46 kg, P=0.84)(Kalkwarf, H.,
    unpublished results, personal
    communication, March 2002.
Prentice(37)
60 Gambian women studied
   during lactation
12-mo trial of ~700mg/d
   calcium vs. placebo
Calcium and placebo groups lost similar
   amounts of weight during the 1-y study
   (-1.2 vs. -0.9kg). There was no effect of
   supplement group on change in wt
   (P=0.85) (Prentice, A. & Jarjou,
    L.M.A., unpublished results, personal
    communication, April 2002).
Elders(32)
214 perimenopausal Dutch
   women
3-y trial of supplementation
   with 1g/d calcium, 2g/d  
   calcium or no calcium
Changes in wt, ht and BMI were similar
   among the three treatment groups. On
   average, subjects gained 1.8 kg wt, lost
   0.2 cm height and increased BMI by
   0.4 kg/m2.
Jensen (33)
52 obese Danish women            
   (14 menopausal)
3-mo trial of   
   supplementation with 1 g/d
   calcium during 4.2 MJ wt
   loss diet
During the 3 mo of calcium
   supplementation and wt loss, the
   calcium group and untreated controls
   groups lost similar amounts of wt (5.7
   and 6.6%, respectively).

 

 

Author Conclusion:

 

  • The data available from randomized trials of dairy products or calcium supplementation provides little support for an effort in reducing body weight or fat mass.
  • Questions that remain to be addressed include the following: 1) Is there a meaningful effect of calcium and/or other dairy components on body energy utilization and weight regulation in humans?; 2) If the effect exists, is it observed consistently or is there a susceptible subset for whom it is effective?; 3) How much calcium/dairy product intake is required?; and 4) What is the likely impact at the population level?
Reviewer Comments:

  • Limitation
  • The studies reviewed were not specifically designed or powered to address this issue, such studies are required.
  • The approach of the review did not capture all available data on the topic.
 
The limitations and critique of the study, as stated by the authors appear to be very appropriate.

 


Research Design and Implementation Criteria Checklist: Review Articles
Relevance Questions
  1. Will the answer if true, have a direct bearing on the health of patients?
Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about?
Yes
  3. Is the problem addressed in the review one that is relevant to nutrition or dietetics practice?
Yes
  4. Will the information, if true, require a change in practice?
Yes
 
Validity Questions
  1. Was the question for the review clearly focused and appropriate?
Yes
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described?
Yes
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified and appropriate? Were selection methods unbiased?
???
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methods specified, appropriate, and reproducible?
???
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined?
Yes
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered?
Yes
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently across studies and groups? Was there appropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described?
No
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels of significance and/or confidence intervals included?
Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations of the review identified and discussed?
Yes
  10. Was bias due to the review’s funding or sponsorship unlikely?
???
 
 

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