This Summary of Recommendations and Evidence synthesizes the Key Practice Point(s) for each Practice Question (PQ) in this Knowledge Pathway. It is organized by the Nutrition Care Process and contains statements or recommendations that have been graded using either the
PEN or
GRADE approaches to critical appraisal. For additional information on the evidence and references, see the PQs in this
Knowledge Pathway.
Content
- Effectiveness of Nutrition Counselling by Dietitians for Chronic Disease Management
- Telephone Nutrition Counselling Delivered by Dietitians
- Nutrition Intervention in Hospital for Malnutrition
- Nutrition Counselling and Gestational Diabetes
- Dietitian Involvement and Birth Outcomes
- Dietitians Number Required in Primary Care
1. Effectiveness of Nutrition Counselling by Dietitians for Chronic Disease Management
Recommendation
Compared to usual care, nutrition counselling from a dietitian (or international equivalent) probably improves the following outcomes:
- blood pressure (systolic and diastolic) in adults with chronic kidney disease who are not receiving dialysis
- weight outcomes (waist circumference, percent weight loss, BMI) in adults with overweight or obesity who are involved in short-term (<12 months) weight management interventions
Compared to usual care, nutrition counselling from a dietitian (or international equivalent) may improve the following outcomes:
- blood lipids (total cholesterol, LDL cholesterol, triglycerides) and blood pressure (systolic blood pressure) in adults with dyslipidemia
- blood pressure (systolic and diastolic) and quality of life in adults with overweight or obesity who are involved in weight management interventions
- glycemic control (A1C, fasting blood glucose), cholesterol levels, blood pressure and weight outcomes (weight, waist circumference, BMI) in adults with prediabetes
- urinary sodium excretion, in adults with chronic kidney disease who are not receiving dialysis
Compared to nutrition advice from other health professionals, nutrition counselling from a dietitian (or international equivalent) may improve glycemic control (A1C) and weight outcomes (weight, BMI) in adults with type 2 diabetes.
Dietitian involvement may improve weight and dietary intake in individuals with eating disorders when coupled with psychological treatment, compared to psychological treatment alone.
Dietitian involvement may not affect triglycerides or progression from prediabetes to type 2 diabetes (compared to usual care) or LDL cholesterol, systolic blood pressure or diastolic blood pressure (compared to nutrition advice from other health professionals) in adults with type 2 diabetes. Similarly, dietitian involvement may not affect fasting blood glucose in adults involved in short-term (<12 months) weight management interventions.
Dietitian-delivered interventions may be cost-effective.
Evidence Summary
Chronic Kidney Disease
A 2022 systematic review and meta-analysis of eight RCTs concluded that medical nutrition therapy (MNT) decreased both systolic (MD -6.7 mmHg, 95%CI -11.0 to -2.4 mmHg) and diastolic blood pressure (MD -4.8, 95%CI -7.1 to -2.4 mmHg) in adults with chronic kidney disease compared to standard care or a less intensive intervention, although these effects were only seen in individuals not receiving dialysis.
Grade of Evidence B. Urinary sodium excretion was also decreased by MNT (MD -67.6 mmol/d, 95%CI -91.6 to 43.6 mmol/d), although this outcome was only examined in individuals not receiving dialysis
Grade of Evidence C.
Dyslipidemia
A 2023 review of three systematic reviews (including 30 RCTs in total) found that three to six MNT sessions with a dietitian compared to usual care improved total cholesterol (MR -0.12 to -0.54 mmol/L), LDL cholesterol (MR -0.04 to -0.30 mmol/L), triglycerides (MR -0.18 to -0.37 mmol/L) and systolic blood pressure (MR -4.70 to -8.76 mmHg) in adults with dyslipidemia compared to usual care. Cost-effectiveness was also improved in the single review that examined this outcome.
Grade of Evidence C
Eating Disorders
A 2021 systematic review of 10 clinical trials found that weight and dietary outcomes were improved by dietitian involvement in eating disorder treatment compared to psychological treatment alone, although these conclusions were based on a small number of heterogeneous studies addressing different eating disorders. The effects on other outcomes (e.g. eating disorder psychopathology, quality of life) were mixed.
Grade of Evidence C
Overweight and Obesity
A 2022 systematic review and meta-analysis of 62 RCTs found that compared to usual care or no intervention, weight management interventions delivered by a dietitian (or international equivalent) improved BMI (MD -1.5 kg/m
2, 95%CI -1.74 to -1.26 kg/m
2), waist circumference (MD -3.45 cm, 95%CI -4.39 to -2.51 cm) and percent weight loss (MD -4.01%, 95%CI -5.26 to -2.75%)
Grade of Evidence B, as well as systolic blood pressure (MD -3.04 mmHg, 95%CI -5.10 to -0.98 mmHg), diastolic blood pressure (MD -1.99 mmHg, 95%CI -3.02 to -0.96 mmHg), physical quality of life (MD 5.84 points, 95%CI 2.27 to 9.41 points) and mental quality of life (MD 2.39 points, 95%CI 1.55 to 3.23 points) in adults with overweight or obesity. Fasting blood glucose was not affected. Although study duration ranged from two to 30 months, only eight studies followed participants for longer than 12 months and most (39/62; 63%) lasted <6 months.
Cost-effectiveness was assessed in two studies, which found that interventions may be cost-effective for some participants
Grade of Evidence C.
Prediabetes and Type 2 Diabetes
A 2023 systematic review and meta-analysis of 13 RCTs found that compared to standard care, MNT delivered by dietitians effectively improved A1C (MD -0.30%, 95%CI -0.49 to -0.12%), fasting blood glucose (MD -0.28 mmol/L, 95%CI -0.35 to -0.20 mmol/L), weight (MD -3.23 kg, 95%CI -3.97 to -2.50 kg), waist circumference (MD -2.93 cm, 95%CI -3.58 to -2.28 cm), BMI (MD -1.49 kg/m2, 95%CI -2.17 to -0.82 kg/m2), total cholesterol (MD -0.11 mmol/L, 95%CI -0.19 to -0.04 mmol/L), LDL cholesterol (MD -0.14 mmol/L, 95%CI -0.27 to -0.02 mmol/L), HDL cholesterol (MD +0.08 mmol/L, 95%CI 0.02 to 0.14 mmol/L), systolic blood pressure (MD -2.91 mmHg, 95%CI -4.59 to -1.24 mmHg) and diastolic blood pressure (MD -2.34 mmHg, 95%CI -3.45 to -1.24 mmHg) in adults with prediabetes, although the effect of MNT on the progression from prediabetes to type 2 diabetes was not clear. Triglycerides were not affected by MNT.
A 2021 systematic review and meta-analysis of 14 RCTs found that compared to nutrition advice from other health professionals, nutrition counselling from a dietitian improved A1C (MD -0.47%, 95%CI -0.92 to -0.02%), BMI (MD -0.38 kg/m2, 95%CI -0.63 to -0.13 kg/m2) and weight (MD -1.49 kg, 95%CI -2.14 to -0.84 kg) in adults with type 2 diabetes. LDL cholesterol, systolic blood pressure and diastolic blood pressure were not different between groups.
A 2021 scoping review of four studies concluded that MNT interventions may be cost-effective compared to usual care in adults with type 2 diabetes, although the small number of studies limited their results.
Grade of Evidence C
Remarks
All but one systematic review included internationally equivalent certifications in their definition of a dietitian.
As with other weight management interventions, dietitian-delivered interventions have only been shown to reduce weight in the short term.
See Additional Content:
2. Telephone Nutrition Counselling Delivered by Dietitians
Evidence Summary
Based on a number of clinical trials, telephone counselling by a dietitian using a theoretical approach (e.g. Social Cognitive Theory, motivational interviewing) appears to be an effective component of nutrition care to improve the dietary intake of adults for primary disease prevention (i.e. increase fruit and vegetable intake, increase soy intake, decrease fat intake).
Grade of Evidence B
For secondary prevention, clinical trials have shown that telephone counselling by a dietitian improves metabolic parameters in individuals with metabolic syndrome and achieves high levels of participant satisfaction in individuals with type 2 diabetes. Limited research has been conducted in other clinical conditions.
Grade of Evidence C
In clinical trials, telephone counselling has often been combined with other interventions (face-to-face counselling, email/computer-based counselling or resources, or handouts) to complement nutrition services. Both one-on-one and group telephone counselling appear to be feasible and effective in eliciting dietary behaviour change in the primary care setting to expand the reach of nutrition services.
Grade of Evidence C
See Additional Content:
In healthy adults and adults with chronic disease, what is the impact on health behaviour change of telehealth interventions (i.e. telephone, computer/web-based) combined with other components (e.g. print materials, face-to-face counselling) delivered by health care providers compared with usual care? Are telehealth interventions cost-effective?
What are characteristics of effective telephone counselling to achieve health behaviour change in adults (i.e. intensity, duration, type of clients, characteristics of providers)?
3. Nutrition Intervention in Hospital for Malnutrition
GRADE Recommendation
dietary counselling plus oral nutrition supplements as needed for adults in hospital who are malnourished or at risk of malnutrition.
Conditional recommendation,
Low quality evidence ⊕⊕⊝⊝RemarksDietitians are involved in providing dietary counselling with or without additional nutrition supplements as needed. The recommendation puts a high value on a small but important reduction in six-month mortality and complications and a possible decrease in six-month readmissions. Dietary counselling with or without nutrition supplements may also result in small but important improvements in nutrition status, nutrient intake and body weight. The studies included predominantly older adults in hospital at risk of malnutrition or diagnosed with malnutrition receiving dietary counselling with or without oral nutrition supplements compared to standard care providing no or minimal dietary counselling. Cost benefits have also been reported using dietary counselling plus oral nutrition supplements compared to standard care for treating malnutrition in hospitalized adults.
The recommendation is conditional since there were no improvements in other clinical outcomes (i.e. 30-day mortality, length of hospital stay, quality of life and functional status) and because the quality of evidence was low for most outcomes due to varied interventions (e.g. dietary counselling alone, with required supplements or with supplements as needed) and studies with serious risk of bias.
See Additional Content:
What screening process can be used to identify adults at risk of malnutrition admitted to hospital?What nutrition assessment process can be used to diagnose malnutrition in adults admitted to hospital?
4. Nutrition Counselling and Gestational Diabetes
Dietitian Counselling - Treatment
Recommendation
Most clinical practice guidelines for the management of diabetes recommend initial and ongoing nutrition counselling by a dietitian for women with gestational diabetes (GDM).
Evidence Summary
Evidence from randomized and nonrandomized studies indicates that women with untreated GDM have an increased likelihood of maternal and neonatal risks. Nutrition counselling has been demonstrated to control glycemia, promote dietary change and optimal nutritional intake, and achieve positive birth outcomes for both mother and infant.
Grade of Evidence CNutrition Counselling - Prevention
Evidence Summary
Evidence from RCTs is mixed on the efficacy of nutrition counselling interventions in reducing the development of GDM in high risk women. In all trials, a combined physical activity and nutrition intervention resulted in improved quality of diet and outcomes compared to usual care but not all trials demonstrated a lower incidence of GDM with intervention.
5. Dietitian Involvement and Birth Outcomes
Recommendation
Involving a dietitian in prenatal care may decrease the incidence of low birth weight (LBW) and preterm birth. At this time, evidence suggests that dietitian involvement may not affect the incidence of macrosomia, large-for-gestational age (LGA) or infant mortality, although some outcomes had few studies or mixed results. There is no evidence about the effect of dietitian involvement (compared to no dietitian involvement) on the incidence of small-for-gestational age (SGA).
Evidence Summary
A 2023 systematic review of 14 studies (five RCTs, three retrospective cohort studies, two cross-sectional studies, two case-control studies, one implementation trial, one pilot study) concluded that dietitian involvement during pregnancy decreased the incidence of LBW (<2500 g) and preterm birth (<37 weeks gestation) compared to no dietitian involvement. The incidence of macrosomia (>4000 g), LGA (birth weight >90th percentile for gestational age) and infant mortality (stillbirth, neonatal death or perinatal death) were not found to be affected by dietitian involvement, although these outcomes were based on few studies or mixed results. No studies examined the effect of dietitian involvement compared to no dietitian involvement on SGA (birth weight <10th percentile for gestational age).
Grade of Evidence C
Remarks
Successful intervention designs, as well as participant characteristics and reporting of intervention details, varied widely. All successful interventions included a nutrition counselling component, although it was not always clear whether group or individual counselling was provided. Frequent follow up (>2 sessions), especially in the later stages of pregnancy, was commonly reported in successful interventions.
6. Dietitians Number Required in Primary Care
Staffing Ratios
Recommendation
The majority of current dietetic staffing models in primary care settings, such as family health teams, community health centres, nurse practitioner-led clinics, primary care networks and family health networks, identify ratios of one dietitian per 15,000-18,500 clients or one dietitian for every four to 14 family physicians. Recommended dietetic staffing ratios from expert consensus studies recommend one dietitian to manage every 300 to 500 clients with diabetes.
Evidence Summary
Recommended Staffing Ratios (See
Table 1)
Several authors suggest newer models of workforce projection planning are needed to provide more accurate estimates of dietetic staffing for primary health care that are based on specific population health issues, current best practices and models that improve health outcomes. Expert consensus studies from Australia, Canada and the United Kingdom recommend one full time equivalent (FTE) dietitian for every 300 to 500 clients with diabetes (managing care for the same 300-500 clients with diabetes year after year). Additional dietitians are needed in primary care to provide the intensive diabetes counselling recommended based on expert consensus studies.
Remarks
The staffing ratios reported provide benchmarks to estimate the requirement for dietitians in primary care settings, such as family practice settings, where dietitians work alongside other health care professionals providing collaborative, team-based care. Despite the limitations of staffing ratios based on traditional practices and reports that observed staffing ratios may not be adequate to meet the current needs of aging populations in primary care, the staffing ratios outlined in this practice question provide a benchmark or starting point for dietitians and health care planners to utilize for dietetic capacity planning.
Additional Remarks
Challenges to accurately predict dietitian staffing needs in primary care settings include:
- limited literature on staffing needs of allied health professionals in primary health care
- limited monitoring of the dietetic workforce in Canada, Australia, the U.K. and the U.S. to track role changes and professional practice issues affecting supply and demand for dietitians within primary health care
- the expanding role of primary care dietetics from traditional nutrition counselling of individuals and groups to nutrition support and upskilling of nursing, physician and other team members and growing leadership in quality improvement initiatives and education of health professional students
- workforce reports identifying “missed” or under-serviced populations leading to an underestimation of staffing needs
- inaccurate dietitian staffing ratios based on population or physician numbers rather than population needs and evidenced-based best practices.
Inadequate Staffing
Recommendation
Published staffing ratios for dietitians working in primary care settings reflect historical practice patterns and may not be adequate as workforce surveys from Australia, Canada, New Zealand, the U.K. and the U.S. and data from surveys and interviews with physicians, dietitians and administrators identify:
- nutrition-related issues are common in family practice, yet are often not addressed
- ongoing issues with limited access to dietetic counselling
- a shortage of dietitians to meet current population needs in primary health care.
Evidence Summary
Evidence from systematic reviews show benefits of dietitian-led nutrition interventions in primary health care settings on health and economic outcomes, reducing medication use, hospitalization rates and freeing up physician time.
Workforce surveys have reported a shortage of dietitians compared to other health professionals in several countries with Australian data listing 1.3 dietitians per 10,000 persons compared to 5.8 physiotherapists per 10,000 persons, 14.8 physicians per 10,000 persons and 75 nurses per 10,000 persons. Canadian data report an average of 2.9 dietitians per 10,000 persons (range of 2.5 dietitians in Ontario and up to 5.2 dietitians in Eastern Canada) compared to 5.1 physiotherapists per 10,000 persons, 20.1 physicians per 10,000 persons and 78.1 nurses per 10,000 persons. The U.S. reports a range of 2.38-5.5 dietitians per 10,000 persons (with the exception of Puerto Rico reporting 0.5 dietitians per 10,000 persons). (See
Table 1)
Looking at the dietetic profession in Canada, Australia, New Zealand, the U.K. and the U.S., only 3 to 15% of the dietetic population report working in primary care settings. (See
Table 2)
Data from surveys and interviews with physicians, dietitians and administrators have identified that nutrition-related issues are common in family practice, yet are often not addressed and limited access to dietetic counselling exists.
Grade of Evidence C
Remarks
Demand for nutrition counselling from dietitians is increasing with aging populations with high rates of chronic disease. Limited access to dietitians remains an ongoing issue in part due to the shortage of dietitians working in primary care.
Recruitment and Retention
Recommendation
Strategies are needed to improve the recruitment and retention of dietitians in primary health care.
Evidence Summary
Data from workforce surveys in selected areas of Australia and Canada identify an impending shortage of dietitians in primary health care settings. Improving work conditions and advancement opportunities are key issues for developing and retaining dietitians in primary care over the long term.
Grade of Evidence C
Remarks
Inadequate compensation, lack of opportunities for advancement and other issues has led to an exodus of dietitians leaving primary care and a high preponderance of new graduates filling primary care positions. More research is needed in primary care dietetics to further explore professional practice issues and understand the implications of a dietetic workforce largely comprised of new graduates.