Strong evidence supports the effectiveness of nutrition interventions and counseling provided by a dietitian when part of a health care team. Compelling evidence from 36 studies supports the multi-disciplinary team approach (including a nutrition professional) to improve weight (-0.3kg to -25.9kg), BMI (-0.5kg/m2 to -14.6kg/m2), waist circumference (-1.0cm to -23.5cm), hip circumference (-2.8cm), fasting blood glucose (-1.6mg to -22mg per dL), HbA1c (-0.15% to -6%), fasting insulin (-3.7mcU to -7.7mcU per L), homeostatic model assessment-estimated insulin resistance (HOMA-IR; -1.0 units to -4.0 units), LDL-cholesterol (-6.0mg to -10mg per dL) and HDL-cholesterol (+2.0mg per dL) on a variety of health conditions (i.e., management of weight, eating disorders, diabetes, renal disease, amyotrophic lateral sclerosis (ALS),cardiovascular disease, osteoporosis).
In overweight or obese adults, strong evidence supports the effectiveness of multiple visits (two to 12 visits, 60-minute initial visit and 20- to 45-minute follow-ups) for Medical Nutrition Therapy (MNT) by a nutrition professional (registered dietitian nutritionist or equivalent). Compelling evidence supports improved weight (-0.5kg to -9.0kg), BMI (-0.2kg/m2 to -7.8kg/m2), waist circumference (-2.0cm to -14cm), FBG (-5.2mg to -9.5mg per dL), total cholesterol (-4.3mg to -59mg per dL), LDL-cholesterol (-15mg to -47mg per dL), HDL-cholesterol (+2.0mg to +11mg per dL) and triglycerides (-12mg to -60mg per dL).
Disorders of Lipid Metabolism
Strong evidence supports the effectiveness of multiple visits (two to 12 visits; 60-minute initial visit and 20- to 45-minute follow-ups) for Medical Nutrition Therapy (MNT) by a nutrition professional (registered dietitian nutritionist or equivalent) in adults with disorders of lipid metabolism. Evidence showed improved total cholesterol (-2.3mg to -47.9mg per dL), LDL-cholesterol (-6.0mg to -21.7mg per dL), triglycerides (-12mg to -175mg/dL), HLD-cholesterol (+2.0mg to +4.0mg per dL), weight (-4.3kg to -12.6kg), waist circumference (-0.6cm to -9.3cm) and BMI (-0.2kg/m2 to -2.6kg/m2). MNT may also result in reductions in need for lipid-lowering medications.
MNT provided by dietitians lowers blood pressure in adults with hypertension. Studies show MNT provided for less than six months leads to significant reductions in blood pressure of approximately five mm Hg for both systolic and diastolic blood pressure. MNT provided from six to twelve months reported similar significant reductions in blood pressure with sustained reductions in blood pressure beyond one year.
Studies evaluating the effectiveness of diabetes MNT provided over three to six months by dietitians reported reductions in A1C, ranging from 0.25% to 2.9%, depending on the type and duration of diabetes. Multiple studies showed sustained improvements in A1C at twelve months and longer. Improvements in other outcomes were also observed, such as improved lipid profiles, weight management, decreased need for medications and reduced risk for onset and progression of comorbidities.
Unintended Weight Loss in Older Adults
Studies report that individualized nutrition care, directed by dietitians on the health care team, results in improved outcomes related to increased energy, protein and nutrient intakes, improved nutritional status, improved quality of life and/or weight gain.
Chronic Kidney Disease
Research related to the time requirements for MNT provided by dietitians indicate that approximately two hours per month for up to one year may be required to provide an effective intervention for adults with chronic kidney disease. MNT should be initiated at least twelve months prior to the anticipation of renal replacement therapy (dialysis or transplant). Studies regarding effectiveness of MNT report significant improvements in anthropometric and biochemical measurements sustained greater than or equal to one year.