Diet and Renal disease Flashcards
acute decrease in kidney function as manifested by a decrease in estimated glomerular filtration rate (GFR) levels
what is this condition?
Acute Kidney Injury (AKI)
AKI is often accompanied by what characteristics?
- Abnormal volume status (fluid overload or dehydration)
- Electrolyte and acid-base derangements
- Build up of waste products in the blood
how is nutrition affected by AKI?
- Fluids - May need fluid replacement if hypovolemic
- Electrolytes - Often self-correct if underlying cause of AKI is treated
- Protein - AKI patients have accelerated protein breakdown that is not suppressed by provision of exogenous protein
with prolonged AKI what nutritional factor are they often deficit in and need more intake of?
protein
The presence of persistently abnormal kidney function, as manifested by:
- Decreased glomerular filtration rate (GFR) of <60 mL/min for 3+ months
- Structural or functional markers of kidney damage
what image findings would you see with CKD?
polycystic kidneys, increased echogenicity of kidneys, atrophic kidneys, etc.
what lab findings would you see in CKD
hematuria, proteinuria, abnormal cast shedding, etc.
what are the 2 main diseases that contribute to majority of CKD in US?
- HTN
- DM
what metabolic derangements in CKD would you see?
- Altered feedback mechanisms
- Includes altered appetite, thirst, and taste - Altered protein homeostasis and catabolism
- Altered energy homeostasis
- Especially in dialysis patients - may develop overt cachexia - Altered nutrient metabolism
- Impaired gut absorption of calcium and iron
- Frequent vitamin deficiencies (B vitamins, C, active form of D)
- Frequent mineral deficiencies (zinc, selenium, manganese)
- At risk for aluminum toxicity
what is recommended to slow down deterioration of kidney function in adult CKD patients.
how does this help?
protein restriction
Reduces glomerular flow and pressures
Slows accumulation of waste products (urea, creatinine) in CKD
what can happen if we do a protein restriction in pediatric CKD pts?
may contribute to nutritional deficiencies
- Often has net adverse effects
- Recommended to have close follow-up by dietician!
what is strongly recommended to include in CKD diet in regards to protein?
plant-based proteins
- More necessary vitamins and minerals
- Higher fiber intake
two problematic traits of animal-based proteins in CKD
More bioavailable phosphate for absorption
Higher potential acid load (PRAL)
stages 1-2 (GFR >60) need what type of change to their protein?
no need for outright restriction
1. Recommended intake - 0.8 g/kg/day (average US diet - 100 g/day)
2. Encourage plant-based proteins
stages 3-5 (GFR <60) need what type of change to their protein?
protein restriction to help slow CKD progression
1. More aggressive restriction as CKD gets worse - 0.6-0.8 g/kg/d
2. Higher proportion of plant-based proteins as CKD gets worse
Stage 5 and on Dialysis for CKD need what type of change to their protein?
require increased protein intake from previous diet plans, especially on days they are receiving dialysis
1. Increased metabolic demand for protein
2. Poor oral intake from malaise, anorexia, unpalatability of healthy/therapeutic diet
3. Hemodialysis - 1.0 - 1.2 g/kg/day, Peritoneal Dialysis - up to 1.3 g/kg/day
4. May also rarely need increased protein intake if very heavy protein loss in urine
general diet guidelines recommended for all adult CKD patients, regardless of underlying etiology
Plant-Dominant Low Protein Diet (PLADO)
what food recommendations does PLADO include?
- Protein Intake - 0.6-0.8 g/kg/day
- Protein Sources - >50% of protein from plant sources
- Tofu, chickpeas, nuts, mushrooms, beans, lentils, legumes, quinoa
- B12 supplementation may be needed due to lower meat intake - Sodium - restricted to < 4 g/day
- <3 g/day if HTN or edema - Fiber - high fiber intake (>25 g/day)
- Caloric Intake - adequate (30-35 cal/kg/day)
- Unless trying to lose weight for medical reasons
an alternative diet plan associated with better CKD outcomes and lower average blood pressure than standard restricted diets
Very Low Protein Diet with Supplementation
what does the Very Low Protein Diet with Supplementation include?
- Protein Intake - 0.28-0.43 g/kg/day
- Protein Sources - encourage protein from plant sources
- B12 supplementation may be needed - Special Supplements - amino acids, keto acids, hydroxy acids
- Greatly reduces nitrogenous waste load by reducing amount of amino groups
- Less nitrogenous waste → less hyperfiltration in the kidney → less CKD progression - Sodium - restricted to < 3-4 g/day
- Fiber - high fiber intake (>25 g/day)
- Caloric Intake - adequate (30-35 cal/kg/day)
when during CKD are you most vulnerable to malnutrition
what could be the result?
later-stage
May develop overt wasting and cachexia
Appetite is often poor, and therapeutic diet is often not palatable
what is the general recommendation of energy intake in CKD
30-35 g/kg/day
what other factors may affect energy requirements in CKD
General weight status
Other health conditions influenced by weight status
Presence of wounds, recent surgery
what other condition can contribute to kidney disease in relation to dietary fats
atherosclerosis
Similar dietary recommendations to general atherosclerosis prevention
Limit saturated fats, trans fats
what types of dietary fats are recommended for CKD
Promote intake of polyunsaturated and monounsaturated fats, especially omega-3
with CKD, High saturated fat consumption may increase:
Glomerular pressure
Albuminuria
Both can contribute to long-term kidney damage and CKD progression!
what macronutrient is long known to help with CKD
dietary fiber
how does dietary fiber help with CKD
1, Promotes fecal nitrogen excretion
- Lowers the amount of waste products that have to be dealt with by kidney
- Decreases serum urea (BUN) and creatinine levels
2. Lower inflammation levels in the body
3. Better mortality in patients with good fiber intake
- Also conveys benefit in other underlying conditions like CVD
4. Used as a treatment decades ago when we didn’t know as much about CKD!
what is the recommended fiber intake for CKD
25-30 g/day
- May recommend even higher amounts in later stage CKD
- Often coincides with eating more plant-based protein, fruits, vegetables
major contributor to HTN, which can cause and worsen CKD
sodium
what are the recommendations for sodium in CKD
Similar levels to general population limits - < 3-4 g/day
- May be a little more lenient if they do not currently have HTN or edema
- Greater reduction in sodium as CKD worsens (< 2300 mg/d often recommended)
- Often will also need diuretic therapy and other antihypertensive rx to control HTN
what is the fluid intake recommendations for CKD
generally want patients to have “adequate” fluid intake
1. Encourage non-carbonated, non-sugary, non-caffeinated beverages
2. Thirst is a good indicator of hydration in younger patients with mild-moderate CKD
- Often thirst reflex is diminished in older patients, later-stage CKD
3. About 1.5 L/day for average patients, 1.0 L/day or less if complications
- Fluid overload, hyponatremia
what type of diet is considered heart-healthy
potassium-rich diet
diseased kidneys tend to lose ability to excrete what?
potassium and phosphorus
Later-stage CKD patients (4-5) often have difficulty with higher potassium
Moderate-severe CKD patients (3-5) should restrict dietary phosphorus
what is the potassium recommendations for later-stage CKD/hyperkalemia
potassium restriction of < 3 g/day
what can reduce potassium in fruit/vegetables by 50-70%
boiling
how does CKD change dietary acids/metabolic acidosis?
- CKD patients often lose ability to manage acid-base balance
- Impaired excretion of H+ ions
- Impaired resorption of HCO3- ions
- Results in metabolic acidosis secondary to impaired renal function
contribution of food or dietary pattern to net endogenous acid (H+) production
Potential Renal Acid Load (PRAL)
types of PRAL
- Animal-based foods - highest rates of acid ion production
- Hard cheeses and egg yolks have the highest PRAL - Plant-based foods - tend to produce bases
- Raisins and spinach have some of the lowest PRALs
how can you reduce acid levels in CKD
supplement with sodium bicarbonate or eat 2-4 cups of fruits/vegetables daily
- Comparable outcomes for acidosis, with additional benefits for fruit/veg intake
difference between organic vs inorganic phosphorus
- Organic - naturally occurring in food sources - 30-60% absorbed
- Inorganic - dark sodas, processed foods as a preservative - >90% absorbed
how does CKD affect vitamin D
- CKD → less circulating active vitamin D → less calcium absorption in the GI tract
- Vitamin D also known to impact other organs and functions in the body
- neurologic, muscular, immune, antineoplastic activity
what supplement is generally indicated in all stages of CKD, as it’s generally accepted these patients are insufficient or deficient
vitamin D
1. Dose and frequency determined by severity of deficiency
2. Calcium levels will generally increase when vitamin D is replaced
- Important to monitor vitamin D, calcium, and phosphorus levels!
What vitamins are CKD patients at-risk for deficiency?
multiple B vitamins and vitamin C
Diet restrictions, diuretic use, loss of appetite
General multivitamin (preferably kidney-friendly) appropriate for patients
what is often decreased in CKD pts bc there is decreased absorption due to hepcidin, less heme-based iron in CKD diet
Iron
Multivitamin may be adequate, but many need iron supplementation
what dietary supplementation may help with lipid levels
carnitine
what dietary elements often deficient in CKD patients, especially on dialysis
zinc/selenium
Routine supplementation not currently recommended (outcomes unchanged)
what dietary element is at risk of toxicity in CKD pts?
aluminum
what type of meds should CKD pts avoid?
aluminum-based medications
