MNT: Disorders of Lipid Metabolism (2015)


McCoin M, Sikand G, Johnson E, Kris-Etherton P, Burke F, Carson JAS, Champagne CM, Karmally W, Van Horn L. The effectiveness of medical nutrition therapy deliverd by registred dietitians for disorders of lipid metabolism: a call for further research. JADA. 2008; 108 (2): 233-239.

PubMed ID: 18237570
Study Design:
Meta-analysis or Systematic Review
M - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To summarize the effectiveness of medical nutrition therapy by RDs in reducing low-density lipoprotein (LDL) cholesterol.
Inclusion Criteria:
Included articles were derived from a literature search of PubMed, the database of Abstracts of Reviews of Effects and the Agency for Healthcare Research and Quality database for research including human subjects, using English language and published between 1991 and 2006 with Medical Nutrition Therapy provided by a registered dietitian.
Exclusion Criteria:
  • Sample size less than 10 in each treatment group
  • Drop-out rate was more than 20%
  • Nutrition counseling was provided by someone other than an RD
  • The study did not assess the impact of dietary change on lipids
  • The intervention was not individualized.
Description of Study Protocol:


  • A panel of experts was convened by the American Dietetic Association to conduct research review for evidence-based practice guidelines within the Evidence Analysis Library
  • Literature search included PubMed, the Database of Abstracts of Reviews of Effects and the Agency for Healthcare Research and Quality database.


Selected research was assessed for quality and validity with summarized comparisons of notable features.


As noted in individual studies reviewed.

Statistical Analysis

As noted in individual studies reviewed.
Data Collection Summary:

Timing of Measurements

  • All studies were published between 1991 and 2006
  • Intervention duration varied from six weeks to six months.

Dependent Variables

  • Duration of Medical Nutrition Therapy
  • Mode of Medical Nutrition Therapy
  • Findings of each study.

Independent Variables

  • Age
  • Sex
  • Diagnoses.

Control Variables

Not specified.
Description of Actual Data Sample:
  • Initial N: 23 articles
  • Attrition (final N): Eight studies accepted for inclusion
  • Age: Not specified in all studies
  • Ethnicity: Not specified
  • Other relevant demographics: Not specified
  • Anthropometrics: See individual study summaries
  • Location: USA.
Summary of Results:

Key Findings

  • RD-delivered Medical Nutrition Therapy (with two to six planned visits) for patients with hypercholesterolemia yielded reported dietary reductions of 15% to 23% in total fat and 22% to 36% in saturated fat (Grade I)
  • This treatment resulted in lipid changes of 6% to 13% reduced total cholesterol, 7% to 14% reduced LDL-cholesterol and inconsistent changes in triglycerides and HDL-cholesterol (Grade I).
Study Citation Sample Size/Design Quality  Intervention Findings
Dalgard et al, 2001
  • N=44
  • 36 completed randomized control trial; 17 brief; 19 comprehensive counseling).
+ 10 minutes vs. 50-60 minutes individual counseling with 40- to 50-minute follow-up 12 weeks later (1 year study) At 1 year:
  • 14.7% decrease in energy from fat with MNT  vs. 5.3% increase in control (P<0.005) 
  • 21.8% decrease in energy from saturated fat with MNT vs. 10.1% increase in control (P=0.002).
Sikand et al, 2000
  • N=73
  • 43 complete data available for chart review
  • Before-after study.
+ 2-4 MNT visits ranging 30-70 minutes (step 1 diet) each within 8 weeks

At 6-7 weeks:

  • 11% decrease in total cholesterol (P<0.001)
  • 9% decrease in LDL-C (P<0.001)
  • 22% decrease in triglycerides (P<0.001)
  • 2% decrease in BMI (P<0.001)
  • 50% of subjects did not require lipid-lowering medications after MNT.
Hebert et al, 1999
  • N=1,162
  • Randomized clinical trial, but complete data available
  • 645 diet, 555 paired serum lipids, 404 weight.
+ No RD visit vs. 2 MNT individual visits plus two 2-hour group visits in a 6-week period

At 1 year:

  • 22.7% decrease in energy from fat with MNT vs. 1.9% decrease in control (P<0.05)
  • 22.1% decrease in energy from saturated fat vs. 2.5% decrease in control (P<0.05)
  • 6.5% decrease in total cholesterol vs. 0.2% decrease in control (P<0.05)
  • 10.4% decrease in LDL-C vs. 0.5% decrease in control (P<0.05)
  • 5.6% decrease in weight vs. 1.3% decrease in control (P<0.05).
Dallongeville et al, 1994
  • N=369
  • Non-randomized comparative study
  • Hypercholesterolemia (113 with 72 control), hypertriglyceridemia (114 with 80 control).
+ No counseling vs. 45-60 minute MNT plus 1 follow-up (step 1 diet) within 2 months

At 2 months (hyperchol vs. hypertriglyceridemia subjects):

  • 5.7% decrease in total cholesterol vs. 4.8% decrease (P=0.0001)
  • 7.3% decrease in LDL-C vs. 8.5% increase (P=0.001)
  • 2.4% decrease in weight vs. 2.8% decrease (P=0.0001). 
Delahanty et al, 2001
  • N=90
  • Randomized clinical trial
  • 45 MNT, 45 usual care control.
Ø Usual care with MD vs. 2-3 MNT visits in 2-3 months if lipids were not at goal (step 2 diet). Study: 6 months.

At 6 months:

  • 21.9% decrease in energy from fat in MNT vs. 6.5% decrease in control (P<0.01)
  • 36.4% decrease in energy from saturated fat vs. 9.1% decrease in control (P<0.001)
  • 6.8% decrease in total chol vs. 2.1% in control (P<0.05)
  • 2.3% decresae in weight vs. 0% change in control (P<0.001).
Henkin et al, 2000
  • N=136
  • Randomized clinical trial
  • 66 RD counseling and 70 usual care control.
Ø Usual care with MD vs. 2-4 MNT counseling sessions (step 1 or 2) in 3 months

At 3 months:

  • 9% decrese in total cholesterol with MNT vs. 5% decrease in control (P<0.05)
  • 12% decrease in LDL-C vs. 7% decrease in control (P<0.05).
Sikand et al, 1998
  • N=95
  • 74 complete data chart review before-after study.
Ø 2-4 MNT visits ranging from 30-60 minutes (step 1 diet) within 6-8 weeks

At 6-8 week:

  • 13.4% decrease in total cholesterol (P<0.001)
  • 14.2% decrease in LDL-C (P<0.001)
  • 4.4% decrease in HDL-C (P<0.05)
  • 10.8% decrease in triglycerides (P<0.05)
  • 51% of subjects did not need lipid-lowering drugs after MNT
    LDL-C decreased 21.9% in 4 RD visits vs. 12.1% decrease in 2 RD visits (P<0.027).
McGehee et al, 1995
  • N=285
  • 285 complete data chart review before-after study.
Ø ≥2 MNT visits at various hospitals or health organizations; intervention duration varied

Length of intervention unknown: 6.8% decrease in total cholesterol and reduction corresponded with increase time spent with RD (R=0.118, P<0.001)

Other Findings

  • Data suggest greater decreases in total cholesterol and LDL-cholesterol occur as the number of MNT visits and time spent with dietitian increases (Grade III)
  • Optimal duration and frequency of follow-up visists by a RD are not known (Grade V).
Author Conclusion:
  • The eligible studies reviewed show that MNT is an effective approach to changing dietary intake and reducing total and LDL-cholesterol and body weight
  • Conclusive findings are limited by the lack of available research. Additional research is needed to identify optimal MNT intervention, duration and frequency of RD MNT visits.
Funding Source:
Other: American Dietetic Association
Reviewer Comments:
It is uncertain whether there is potential bias for the study since the expert panel is all dietitians reviewing the need for dietitians, including at least one person involved in the research reviewed.
Quality 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 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 andappropriate? Wereselectionmethods unbiased? Yes
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? Yes
  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 acrossstudies and groups? Was thereappropriate 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? Yes
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? Yes
  10. Was bias due to the review's funding or sponsorship unlikely? Yes