DHA Clinical Dietician cheat sheet

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

Protein quality is scored by PDCAAS (truncated at 1.0) or DIAAS (uncapped, ileal digestibility of each indispensable amino acid).

Glycemic index compares a 50 g available-carbohydrate test food to a reference (glucose or white bread); glycemic load = GI × available carbohydrate (g) ÷ 100.

Nitrogen balance = nitrogen intake − (urinary urea N + 4 g insensible/other losses); positive balance indicates anabolism, negative indicates catabolism.

Transamination transfers an amino group to a keto acid; deamination removes it, with the carbon skeleton used for energy and nitrogen excreted as urea.

Fat-soluble vitamins A, D, E, and K require micellar solubilization with dietary fat; water-soluble vitamins are absorbed directly and are less likely to reach toxic tissue stores.

Thiamin (B1) deficiency causes beriberi and Wernicke-Korsakoff syndrome; niacin deficiency causes pellagra (dermatitis, diarrhea, dementia).

Iron absorption is enhanced by ascorbic acid and meat factor and inhibited by phytates, polyphenols, and calcium; heme iron is absorbed more efficiently than nonheme iron.

Folate and vitamin B12 both feed one-carbon metabolism; B12 deficiency traps folate as methylfolate and causes megaloblastic anemia with neurologic damage.

BMI = weight (kg) ÷ height (m)²; adult categories: underweight <18.5, normal 18.5–24.9, overweight 25–29.9, obesity ≥30 kg/m².

Ideal body weight (Hamwi): men 48 kg + 2.7 kg per inch over 5 ft; women 45.5 kg + 2.3 kg per inch over 5 ft.

Percent weight change = (usual weight − current weight) ÷ usual weight × 100; >5% in 1 month or >10% in 6 months signals significant loss.

Mid-upper arm circumference and calf circumference are field surrogates for muscle mass when weight or height cannot be obtained.

Triceps skinfold estimates subcutaneous fat; a value below the 5th percentile suggests fat depletion.

Serum albumin (half-life ~20 days) and prealbumin (~2 days) are negative acute-phase reactants and reflect inflammation, not reliably nutritional status.

24-hour recall depends on memory and is limited by day-to-day variability; a food frequency questionnaire captures habitual intake but has limited precision for absolute amounts.

Estimated energy needs can be approximated with Mifflin-St Jeor: men 10W + 6.25H − 5A + 5; women 10W + 6.25H − 5A − 161 (W kg, H cm, A years).

Nitrogen balance and 24-hour urinary urea nitrogen can estimate protein catabolism when renal function is stable.

Diabetes: carbohydrate consistency and total energy drive glycemic control; the American Diabetes Association does not endorse one fixed macronutrient distribution.

Chronic kidney disease without dialysis: protein ~0.6–0.8 g/kg/day; hemodialysis raises needs to ~1.0–1.2 g/kg/day because of dialytic losses.

CKD mineral targets: limit phosphorus and potassium; sodium restriction (<2 g/day) supports blood pressure and fluid control.

Heart failure: sodium restriction and fluid restriction when hyponatremia or congestion persists; monitor daily weights for 2–3 lb (1–1.5 kg) gains.

Liver cirrhosis: 1.2–1.5 g/kg/day protein with late-evening snack to reduce catabolism; do not restrict protein in hepatic encephalopathy unless another cause is present.

Dumping syndrome: small frequent meals, limit simple sugars, separate fluids from solids, and add protein and fiber to slow gastric emptying.

Celiac disease requires lifelong strict gluten avoidance (wheat, barley, rye); oats require certified gluten-free sourcing.

COPD: energy needs rise with work of breathing; a lower-carbohydrate, higher-fat pattern can reduce CO2 production in hypercapnic patients.

Pancreatitis: advance from clear liquids to low-fat solids as tolerated; severe cases may need enteral nutrition rather than prolonged bowel rest.

Enteral access: nasogastric for short-term gastric feeding; nasojejunal or PEG/PEJ when gastric feeding is not tolerated or long-term access is required.

Gastric residual volumes up to 250–500 mL are generally tolerated; routine checking is discouraged unless there is clinical concern for intolerance.

Refeeding syndrome risk: BMI <16, unintentional loss >15% in 3–6 months, negligible intake >10 days, or low potassium, phosphate, or magnesium.

Start refeeding at 10–20 kcal/kg/day, monitor phosphate, potassium, and magnesium, and give thiamin before or with the first feeding.

TPN indications: nonfunctioning GI tract, high-output fistula, severe malabsorption, or inability to meet needs enterally.

Parenteral nutrition is hypertonic and requires central access when dextrose concentration exceeds ~10%; peripheral formulas are limited by osmolarity.

Lipid injectable emulsions supply essential fatty acids; withholding them for prolonged periods risks essential fatty acid deficiency.

Enteral formulas: polymeric for intact digestion, peptide-based for malabsorption, and elemental for severe dysfunction; disease-specific formulas are reserved for defined indications.

Monitor tolerance of enteral feeding by abdominal exam, nausea, vomiting, and stool output rather than by routine gastric residual measurement alone.

Infants: exclusive breastfeeding for about the first 6 months, with iron-fortified complementary foods introduced around 6 months.

Breast milk provides about 0.67 kcal/mL; cow's milk is avoided before 12 months because of renal solute load, iron loss, and allergy risk.

Adolescents have high iron needs during growth spurts and menstruation; females are at particular risk of iron deficiency.

Pregnancy: add about 340 kcal/day in the second trimester and about 450 kcal/day in the third; folic acid 400–600 mcg/day reduces neural tube defects.

Lactation: energy needs rise by about 330–400 kcal/day; hydration and calcium intake should be maintained.

Older adults: energy needs decline but protein needs rise (~1.0–1.2 g/kg/day) to counter sarcopenia; vitamin D and calcium support bone health.

Community food insecurity screening uses validated tools (e.g., Hunger Vital Sign) and referral to SNAP, WIC, and food pantries.

WIC targets pregnant and postpartum women, infants, and children under 5 with nutritional risk; SNAP is income-based and broader in eligibility.

Growth charts: use WHO standards for children under 2 and CDC growth charts for ages 2–20.

Temperature danger zone is 41–135 °F (5–57 °C); keep hot foods ≥135 °F and cold foods ≤41 °F.

Two-hour rule: discard perishable food left in the danger zone for more than 2 hours (1 hour if ambient temperature exceeds 90 °F).

HACCP has seven principles: hazard analysis, critical control points, critical limits, monitoring, corrective actions, verification, and recordkeeping.

Cool foods rapidly from 135 °F to 70 °F within 2 hours and from 70 °F to 41 °F within an additional 4 hours.

Foodborne pathogens: Salmonella in poultry and eggs; Listeria in ready-to-eat deli foods; E. coli O157:H7 in undercooked beef; norovirus from infected food handlers.

Cross-contamination is prevented with separate cutting boards, color-coded utensils, and handwashing at designated stations.

Modified diets in food service: mechanical soft, pureed, and dysphagia textures (e.g., IDDSI levels) change consistency while preserving nutritional adequacy.

The food service systems model includes procurement, production, distribution, service, and safety/quality control; each step has a monitoring point.

The Nutrition Care Process has four steps: nutrition assessment, nutrition diagnosis, nutrition intervention, and nutrition monitoring/evaluation.

Nutrition diagnoses use standardized terminology (PES statement: Problem, Etiology, Signs/Symptoms) to describe the specific nutrition problem.

Scope of practice is set by state licensure and facility policy; registered dietitians must practice within their competence and refer when outside it.

Informed consent requires capacity, disclosure of risks/benefits/alternatives, and voluntary agreement; it can be withdrawn at any time.

Confidentiality is protected by HIPAA; minimum necessary information should be shared and only with authorized parties.

Conflict of interest: disclose financial or personal interests that could bias recommendations; recusal may be required.

Cultural humility means eliciting the patient's food practices and adapting recommendations rather than imposing the clinician's values.

Motivational interviewing uses open questions, affirmations, reflections, and summaries to build change talk rather than to persuade.

Levels of evidence: systematic reviews/meta-analyses > randomized controlled trials > cohort studies > case-control > case series > expert opinion.

PICO frames a clinical question: Population, Intervention, Comparison, Outcome.

Sensitivity = true positives ÷ (true positives + false negatives); specificity = true negatives ÷ (true negatives + false positives).

Positive predictive value depends on prevalence; a test with high sensitivity is useful for ruling out disease, and high specificity for ruling in.

Relative risk compares incidence in exposed versus unexposed; attributable risk is the absolute difference in incidence.

Confidence intervals describe precision; if a 95% CI for a risk ratio crosses 1.0, the result is not statistically significant at the 0.05 level.

Quality improvement uses PDSA cycles (Plan-Do-Study-Act) to test small changes and measure outcomes before scaling.

Bias types: selection bias affects who enters the study; recall bias affects self-reported exposure; confounding distorts the exposure-outcome relationship.

Essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine.

Essential fatty acids: linoleic acid (omega-6) and alpha-linolenic acid (omega-3); eicosapentaenoic and docosahexaenoic acids are conditionally essential.

Saturated fat raises LDL cholesterol; replacing it with unsaturated fat lowers cardiovascular risk more than replacing it with refined carbohydrate.

Dietary fiber: soluble fiber (beta-glucan, pectin) slows glucose absorption and lowers LDL; insoluble fiber adds bulk and shortens transit time.

Vitamin D is synthesized in skin from 7-dehydrocholesterol under UVB; deficiency causes rickets in children and osteomalacia in adults.

Calcium absorption is vitamin D–dependent and decreases with age; oxalates and phytates bind calcium in the gut.

Zinc deficiency causes impaired wound healing, hypogeusia, and growth failure; zinc competes with copper for absorption.

Energy expenditure components: resting metabolic rate (~60–70%), thermic effect of food (~10%), and physical activity (~20–30%).