Plant-Based Lifestyles: Prevent and Treat Chronic Kidney Disease

Chronic kidney disease (CKD) occurs when there is gradual loss of kidney function. When CKD reaches an advanced stage, dangerous levels of fluid, electrolytes and wastes can build up in the body, causing potentially fatal complications.

Early stages of CKD may present with only a few signs or symptoms, and CKD may not become apparent until kidney function is significantly impaired.

Treatment for CKD focuses on slowing the progression of the kidney damage, usually by controlling the underlying cause.

Untreated CKD can progress to end-stage kidney failure, which is fatal without artificial filtering (dialysis) or a kidney transplant.

 

Stages of Chronic Kidney Disease    

KDOQI (Kidney Disease Outcomes Quality Initiative) CKD classification:

Note: Among kidney patients with CKD, the stage of disease should be assigned based on the level of kidney function irrespective of diagnosis

 

TABLE 1 : STAGES OF CKD

Stage

Description

GFR(ml/min/1.73m²)

1

Kidney damage with normal or ↑GFR

≥ 90

2

Kidney damage with mild ↓GFR

60-89

3a

Mildly to moderate ↓GFR

45-59

3b

Moderate to severely ↓GFR

30-44

4

Severe ↓GFR

15-29

5

Kidney failure

<15 (or dialysis)

 

Symptoms of CKD

  • Usually only picked up during routine screening OR when one of the complications of CKD (e.g. CVD, anaemia, pericarditis) is identified.
  • Develop over time if kidney damage progresses slowly, and may include:
  • Non-specific = can also be caused by other illnesses
  • Nausea
  • Vomiting
  • Feeling generally unwell
  • Loss of appetite
  • Fatigue and weakness
  • Sleep problems
  • Changes in how much one urinates
  • Decreased mental sharpness
  • Muscle twitches and cramps
  • Swelling of feet and ankles
  • Persistent itching
  • Chest pain, if fluid builds up around the lining of the heart
  • Shortness of breath, if fluid builds up in the lungs
  • Uncontrollable Hypertension
  • Because kidneys are highly adaptable and able to compensate for lost function, signs and symptoms may not appear until irreversible damage has occurred

 

Causes of CKD

Chronic kidney disease occurs when a disease or condition impairs kidney function, causing kidney damage to worsen over several months or years.

Causes include:

  • Diabetes type 1 and 2
  • Hypertension
  • Insulin resistance
  • Genetics: e.g. polycystic kidney disease PKD (most common); Alport’s Syndrome; primary hyperoxaluria; cystinuria; kidney stones
  • Congenital: failure of urine-tube to work properly resulting in urine refluxing to the kidneys => infections and kidney damage
  • Glomerulonephritis (inflammation of the glomeruli) – can happen suddenly (e.g. after a strep throat) and may improve / worsen over years
  • Interstitial nephritis
  • Prolonged obstruction of the urinary tract, from conditions such as enlarged prostate, kidney stones and some cancers
  • Vesicoureteral reflux
  • Pyelonephritis (recurrent kidney infections)
  • Drugs: OTC pain-killers; other medications; toxins; pesticides and ‘street” drugs such as heroin and crack

 

Risk Factors for CKD

  • Diabetes
  • Hypertension
  • CVD
  • Smoking
  • Obesity
  • Insulin resistance
  • Being Black, Indian or Asian
  • Family history of kidney disease
  • Abnormal kidney structure
  • Older age

 

Complications of CKD

CKD can affect almost every part of the body. Potential complications may include:

  • Fluid retention, which could lead to swelling in the arms and legs, high blood pressure, or fluid in the lungs (pulmonary oedema)
  • A sudden rise in serum-potassium levels (hyperkalaemia), which could impair the heart’s ability to function and may be life-threatening
  • Cardiovascular disease
  • Weak bones and an increased risk of bone fractures
  • Anaemia
  • Decreased sex drive, erectile dysfunction or reduced fertility
  • Damage to the central nervous system, which can cause difficulty in concentrating, personality changes or seizures
  • Decreased immune response, makes the patient more vulnerable to infection
  • Pericarditis, an inflammation of the pericardium (sac-like membrane that envelops the heart)
  • Pregnancy complications that carry risks for the mother and the developing foetus
  • Irreversible damage to the kidneys (ESRD) – requires either dialysis or a kidney transplant for survival

 

WHAT IS THE PHYSIOLOGICAL MECHANISM?

How does a diet composed primarily of vegetables, fruits, legumes and other plant-based proteins improve KIDNEY HEALTH?

An overwhelming amount of recent scientific studies and reviews (1989-2010: vast studies and meta-analyses; confirmed and corroborated by new recent research 2014-2018, and ongoing) show repeatedly that a whole food plant-based diet (with no added salt, oil or sugar) is the ideal option for those who want to prevent or do their best to halt the progression of kidney disease.

 

Prevention of CKD

Dietary Culprits for All Vascular Disease (Heart, Brain, Kidney etc):

  • 2010 Harvard study4 looked at how diet influences microalbuminuria and estimated GFR (eGFR) decline in people with well-preserved kidney function. They found that there were three significant dietary risk factors for loss of kidney function:
    • Animal protein
    • Animal fat
    • Cholesterol
  • The researchers conclude: that Higher dietary intake of animal fat and two or more servings per week of red meat may increase risk for microalbuminuria. In addition, lower sodium and higher beta-carotene intake may reduce risk for eGFR decline.

Not All Proteins Behave the Same Way in Our Bodies

Our kidneys appear to handle plant protein very differently from animal protein.

 

Did you know….

Within hours after consuming meat (including beef, chicken, fish), your kidneys rev up into hyperfiltration mode. Whilst an equivalent amount of plant protein cases virtually no stress to the kidneys.

 

Understanding the Association Between Animal Protein Consumption and Kidney Damage:

Animal Proteins cause:

  1. Increased hyperfiltration and /or protein leakage. Association: animal protein can cause inflammation
  2. Increased dietary acid load. Association: a higher dietary acid-load is associated with significantly higher risk of protein leakage into the urine, which is an indication of kidney damage

 

The Damaging Effects of a High Dietary Acid Load

A 2014 study14 

  • Demonstrated that animal foods (all meat, eggs, and dairy) cause acid to form within the kidneys
  • This may then lead to an unpleasant condition called tubular toxicity(damage to the tiny, delicate, urine-making tubes in the kidney)
  • This, in turn, may lead to ATN (acute tubular necrosis) where the tubular epithelial cells that form the renal tubules of the kidneys die

The researchers conclude that: “The findings have important implications, in that, if they are corroborated in other studies, altering diets may provide an adjunct approach to other strategies for treatment of CKD [chronic kidney disease].”

Other studies have subsequently corroborated these findings.

 

Some surprises….

 

Why Are PLANT PROTEINS Better for Our Kidneys?

  • Plant protein reduces dietary acid, improve metabolic acidosis, and slow further nephropathy progression in patients with CKD and reduced GFR
  • Rate of intestinal phosphorus absorption is higher from animal protein than plant-based protein. Higher blood phosphorus levels are associated with increased mortality in CKD
  • Less uremic toxins due to fiber content thus ↑SCFA
  • A diet with a higher proportion of protein from plant sources is associated with lower mortality in those with eGFR<60mL/min/1.73m(2).

 

What About Phosphorous (in Plant-Based Diets)?

FACT:     

  1. Phosphorus absorption and bioavailability is lower in a vegetarian diet, reducing hyperphosphatemia, a known cause of cardiovascular mortality in CKD; and
  2. Many animal proteins notably DAIRY and ORGAN MEATS are high in phosphates.

By limiting DAIRY to ½ cup/day if at all – PO4 intake is already reduced

 

What About Potassium (in Plant-Based Diets)?

  • Hyperkalemia is the main concern of plant-based diets, and MUST always be monitored for and treated
  • However, appropriate cooking techniques can minimize the amount of potassium absorbed from food

 

Cooking Techniques

Phosphorus, potassium, and sodium are the 3 most difficult minerals to control when kidney function is severely compromised.

  • HOWEVER….

The amount in foods can be reduced by up to 80% by using certain cooking techniques, especially blanching and boiling.

Using frozen or canned foods plus washing can also flush them out in the same proportion.

  • AS SUCH:

Cooking techniques can promote the safe intake of legumes and vegetables, while avoiding hyperphosphatemia or hyperkalemia.

BE AWARE:

By using these techniques certain essential nutrients can be lost, such as Mg and Zn.

Oral supplements can be prescribed, when necessary, to avoid these deficiencies.

Therefore, a healthy diet that ensures the intake of:

  • Essential amino acids
  • Mineral-rich fruits, vegetables, legumes, and dairy products (small portions if at all)

can be maintained keeping the intake of K+, PO4, Na+ in a safe range with appropriate dietary counseling

 

Other Considerations When Recommending a Plant-Based Diet

  • A strict vegetarian diet can be poor in long-chain n-3 fatty acids, zinc, iron, and vitamin B12
  • Osteoporosis: Although some studies indicate a higher risk of osteoporosis in vegetarians than in the general population, differences in bone mineral density between vegetarians and the general population are not clinically relevant. However, osteoporosis and bone-mineral disorders are common among CKD patients and the effects of a vegan diet on the risk of fractures should be evaluated in this population
  • Iron: Although the iron content in vegetarian and non-vegetarian diets is similar, the bioavailability of iron from plants is lower (low heme iron content or scarcely bioavailable iron, e.g., chelated by phytates)]. This can be relevant in CKD patients who have increased hepcidin levels, impairing iron absorption
  • Zinc: Similarly, a diet without an animal source of food can be poor in zinc, as this element is less abundant in plant-based food than in meats, and poorly absorbed because of the presence of fibers and phytate
  • Vitamin D: A vegetarian diet can also be poor in vitamin D, which needs to be monitored and supplemented as needed
  • A vegetarian diet should also be controlled to ensure an adequate consumption of all essential amino acids by a careful combination of legumes and cereals
  • Omega 3: A diet relatively poor in n-3 fatty acids can be offset by increasing the intake of walnuts or flax seeds

 

SPECIFIC PLANT-BASED FOODS GOOD FOR THE KIDNEYS

Beans and Legumes

Rich in:

  • Protein
  • Iron
  • Zinc
  • Fibre (heart-protective)
  • Folate (heart protective)
  • Potassium

Naturally low in heart-damaging nutrients:

  • Saturated fat
  • Sodium
  • Free of cholesterol, and as such heart protective.

Daily recommendation: 2-3 servings per day

Soya

Soy beans are rich in soluble fibre (found in the outer hull):

  • 6g fibre/1 cup cooked soybeans
  • Soluble fibre is proven to assist with lowering of blood cholesterol levels, and controlling of blood glucose (sugar) levels

Soya protein has been shown to assist in lowering blood pressure (a risk factor for CKD).

In addition, soy bean are rich in fermentable fibres which reduce metabolic acidosis, and inflammation – as such slowing the progression of CKD!

  • Daily recommendation: 1 serving per day = 1/3 cup soy beans / 1 serving Soya Life Premium Porridge

 

SOYA LIFE PRODUCTS: AN EASY SOLUTION IN A PLANT-BASED EATING PLAN

In Summary:

PLANTS NOT MEDS: The key to halting progression of CKD might be in the produce market, not in the pharmacy….

When balancing the evidence of the benefits and risk/harms of a vegetarian diet in CKD patients,

a plant-based diet appears to offer important advantages to these patients; and with good nutritional advice a plant-based diet will be safe.

However, it must be recognized that a plant-based diet may pose significant restrictions, and may be difficult to follow by the patients.

 

To Conclude

Dieticians play an important role in individualising/liberalising the diet for our CKD patients by offering counseling on diet richer in plant-derived foods, such a vegetarian, MD or DASH diets with careful monitoring of potential risks (such as hyperkalaemia).

To achieve these goals, involvement of multidisciplinary teams of nephrologists, nephrology nurses, and dietitians who can ensure adequate and safe nutrition to renal patients is mandatory.