Key Practice Point
#1
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/m
2, 95%CI -2.17 to -0.82 kg/m
2), 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.
Grade of Evidence C
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/m
2, 95%CI -0.63 to -0.13 kg/m
2) 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.
Grade of Evidence C 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.
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