EBN cheat sheet

Evidence hierarchy (therapy questions): systematic review/meta-analysis of RCTs > single RCT > cohort > case-control > cross-sectional > case series/expert opinion.

PICO frames a clinical question: Population, Intervention, Comparator, Outcome; a good PICO names a specific population and a measurable outcome.

Sensitivity = true positives / (true positives + false negatives); high sensitivity suits ruling out disease (SnNout).

Specificity = true negatives / (true negatives + false positives); high specificity suits ruling in disease (SpPin).

Positive predictive value depends on prevalence: PPV = (sensitivity x prevalence) / [(sensitivity x prevalence) + ((1 - specificity) x (1 - prevalence))].

Relative risk is used in cohort studies; odds ratio in case-control studies; OR approximates RR only when the outcome is rare (<10%).

Number needed to treat = 1 / absolute risk reduction; NNT rises as the event rate falls, so always report baseline risk with it.

Randomization, allocation concealment, and blinding control selection and performance bias; intention-to-treat analysis preserves prognostic balance.

GRADE rates certainty as high, moderate, low, or very low based on risk of bias, inconsistency, indirectness, imprecision, and publication bias.

Atwater factors: carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g, dietary fiber about 2 kcal/g.

Amino acids: 9 indispensable (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine); conditionally indispensable include glutamine, arginine, cysteine, tyrosine.

Fatty acids: linoleic acid (omega-6) and alpha-linolenic acid (omega-3) are essential; EPA and DHA are conditionally essential and synthesized inefficiently from ALA.

Fat-soluble vitamins A, D, E, K require bile and micelle formation; water-soluble vitamins are absorbed into portal blood and generally less stored.

Vitamin D status is best reflected by serum 25-hydroxyvitamin D; the active hormone is 1,25-dihydroxyvitamin D, which is not a reliable status marker.

Protein quality is scored by digestibility-corrected amino acid score (PDCAAS/DIAAS); complementary plant proteins offset limiting amino acids (legumes low in methionine, cereals low in lysine).

Glycemic index compares equal carbohydrate portions to a reference; glycemic load = GI x grams carbohydrate / 100.

Dietary fiber: soluble/viscous fibers (beta-glucan, pectin, psyllium) lower LDL cholesterol; insoluble fibers (cellulose, wheat bran) mainly increase stool bulk.

Bioavailability modifiers: vitamin C and meat enhance non-heme iron absorption; phytates, tannins, and calcium inhibit it; calcium absorption is vitamin D dependent.

Nutrition Care Process sequence: Assessment, Diagnosis, Intervention, Monitoring and Evaluation; diagnosis uses PES statement: Problem (intake/clinical/behavioral-environmental), Etiology ("related to"), Signs/Symptoms ("as evidenced by").

Anthropometrics: BMI = weight (kg) / height (m)^2; percent weight change = (usual weight - current weight) / usual weight x 100; >5% in 1 month or >10% in 6 months signals significant loss.

Unintentional loss of >2% in 1 week, >5% in 1 month, >7.5% in 3 months, or >10% in 6 months defines severe malnutrition risk in adults.

Sarcopenia indicators: low muscle mass with low strength or physical performance; grip strength and gait speed are practical screening measures.

Biochemical markers: albumin and prealbumin are negative acute-phase reactants and reflect inflammation, not reliably nutritional status.

Estimated energy needs: Mifflin-St Jeor BEE = (10 x kg) + (6.25 x cm) - (5 x age) + 5 (men) or -161 (women); apply activity and injury factors.

Fluid requirement approximation 30-35 mL/kg/day for adults; heart failure and renal disease require individualized restriction.

Nutrition-focused physical exam signs: temporal wasting and thenar wasting (muscle), edema and poor wound healing (protein), koilonychia and pallor (iron), glossitis (B vitamins), easy bruising (vitamin C/K).

Validated screening tools include MST, MUST, NRS-2002, and MNA for older adults; screening triggers full assessment but is not itself a diagnosis.

Intervention domains: food/nutrient delivery, nutrition education, nutrition counseling, coordination of care, and population-level intervention.

Enteral feeding: gastric preferred when tolerated; post-pyloric indicated for gastroparesis, high aspiration risk, or recurrent vomiting; head-of-bed elevation 30-45 degrees reduces aspiration.

Refeeding syndrome risk factors: BMI <16, unintentional loss >15% in 3-6 months, little or no intake >10 days, low potassium, phosphate, or magnesium; start low (10-15 kcal/kg/day) and advance slowly with thiamine before feeding.

Parenteral nutrition indications: non-functioning GI tract (obstruction, short bowel, severe malabsorption, high-output fistula) or inability to meet needs enterally.

IDDSI framework defines 8 levels for food (3-7 regular textures) and drink thickness (0-4); use for dysphagia prescriptions.

Carbohydrate counting: 1 carbohydrate choice = 15 g carbohydrate; basal-bolus insulin-to-carb ratio and correction factor are individualized.

DASH eating pattern targets: 4-5 servings fruit, 4-5 vegetables, 6-8 grains, 2-3 dairy, <=6 oz lean meat, 4-5 nuts/seeds/legumes per week; sodium 2,300 mg standard, 1,500 mg stricter.

Behavior change counseling: motivational interviewing uses open questions, affirmations, reflections, and summaries (OARS) and supports autonomy rather than prescribing.

Cultural and literacy adaptation: assess health literacy, use teach-back, and match education to the client's language, food practices, and reading level.

Monitoring indicators should be measurable, time-bound, and tied to the etiology in the PES statement; examples: weight trend, intake percentage, lab values, symptom scores.

Evaluate against the planned goals: compare actual to expected outcomes and decide to continue, revise, or discontinue the plan.

Energy adequacy check: percent of estimated needs met = actual intake / estimated need x 100; sustained <75% warrants intervention change.

Weight trends are meaningful only with consistent conditions (same time of day, scale, clothing); fluid shifts confound weights in edema, ascites, and renal disease.

Nitrogen balance = nitrogen intake - (urinary urea nitrogen + 4) g; positive balance indicates anabolism, negative indicates catabolism or inadequate intake.

Glycemic monitoring: A1c reflects 2-3 months of average glucose; estimated average glucose (mg/dL) = 28.7 x A1c - 46.7.

Lipid targets in high-risk patients: LDL-C reduction >=50% and LDL <70 mg/dL; lifestyle changes are rechecked at 4-12 weeks after initiation.

Outcome measures should distinguish process (visits completed), outcome (A1c change), and patient-reported measures (quality of life, hunger, satisfaction).

Type 2 diabetes prevention: 7% body weight loss plus 150 min/week moderate activity reduced progression by 58% in the Diabetes Prevention Program.

Diabetes nutrition: no single ideal macronutrient distribution; consistent carbohydrate intake, individualized fiber (14 g/1,000 kcal), and limiting sugar-sweetened beverages are core recommendations.

Hypertension: weight loss of 1 kg lowers BP about 1 mmHg; DASH plus sodium reduction can lower systolic BP by roughly 8-14 mmHg.

Dyslipidemia: replace saturated fat with unsaturated fat; each 1% reduction in LDL-C is associated with about 1% reduction in major vascular events.

Chronic kidney disease: protein 0.6-0.8 g/kg/day for non-dialyzed patients with diabetes or without dialysis; sodium <2,300 mg/day; individualize potassium and phosphorus.

Heart failure: sodium restriction individualized (commonly 2,000-3,000 mg/day); monitor fluid and weight; nutrition support addresses cardiac cachexia.

Obesity: a 5-10% weight loss improves triglycerides, blood pressure, and glycemia; pharmacotherapy and metabolic surgery are options for eligible patients.

Cancer: unintentional weight loss and malnutrition worsen outcomes; screen at diagnosis and reassess; energy needs often 25-30 kcal/kg and protein 1.0-1.5 g/kg.

COPD: elevated energy expenditure; energy needs may be 1.2-1.5 x resting expenditure with adequate protein to preserve respiratory muscle.

Autonomy, beneficence, nonmaleficence, and justice are the four core bioethical principles; apply them when resolving conflicts about feeding and treatment.

Informed consent requires capacity, disclosure of risks and alternatives, comprehension, and voluntariness; document the discussion.

Scope of practice: registered dietitians provide medical nutrition therapy; unlicensed staff require documented supervision and delegation limits.

Confidentiality is governed by privacy law (e.g., HIPAA in the US); disclose only minimum necessary information to those involved in care.

Conflict of interest: disclose financial or personal interests that could bias recommendations and recuse when bias is unavoidable.

Documentation should be objective, timely, and specific: include assessment data, PES diagnosis, intervention, plan, and evaluation; avoid subjective judgments about the client.

Communication: use plain language, teach-back, and shared decision-making; interpreters are required when the client's language differs from the clinician's.

Cultural humility and implicit bias: recognize how bias affects screening, diagnosis, and treatment recommendations, and use standardized criteria to reduce disparities.