Taste Changes in Chronic Kidney Disease

Chronic kidney disease (CKD)  can cause a multitude of symptoms but one that has received limited attention is changes in taste. Taste alterations are often reported by people with CKD and tends to be more common with advancing kidney disease progression. This can have a significant impact on enjoyment of food, food intake, nutritional status and overall quality of life.

 

This blog post will discuss what taste changes are common in CKD, why people with CKD may experience them and ways to help manage them to be able to eat a wide variety of food and bring back the enjoyment of eating.

 

Taste changes in CKD

Reported taste changes can vary and are generally categorised as:

  • No taste
  • Reduced taste
  • Taste disturbances: may find food tastes unpleasant, acidic, bitter, ‘like cardboard’ or ‘metallic’)
  • Exaggerated taste

Some people also report aversions to certain foods particularly meat or food cravings. A high proportion of people also experience dry mouth which can affect the taste buds.

 

Meat aversion in CKD

An aversion to meat is one of the most reported aversions to food products reported by patients with CKD which can be explained by the inability to taste savoury (umami) flavours.

The inability to detect these specific flavours may be related to changes in saliva composition in CKD, general decline in age and possible genetic variations.

 

Food cravings

Food cravings are sometimes reported by people with CKD including the following cravings.

  • Carbohydrate foods: may be due to the difficulty detecting sweet tastes
  • Salty food: may be a response to low salt intake
  • Acidic foods: may be due to the difficulty detecting sour tastes

 

Dry mouth

Dry mouth is a common complaint in CKD, especially in those with more advanced kidney disease. It is caused by the reduction in the flow of saliva which is often seen with changes in fluid levels in the blood.  Those receiving dialysis treatment can particularly experience large fluctuations in these. When the body content of water is reduced by 8% which can occur during one dialysis treatment, saliva flow decreases to almost zero. Poor saliva flow affects the taste buds causing changes in taste perception.

 

Causes of taste changes in CKD

There are several reasons why people with CKD experience taste changes and most of these relate to changes in saliva. Table 1 outlines some of the major changes observed in people with CKD and the effects on taste of the changes.

 

Table 1:

Changes in CKDEffects of change
Reduced saliva flowSome studies have found that people with end-stage kidney disease have a reduced flow of saliva which may be caused by changes in fluid status. This can cause dry mouth which affects the taste buds.
Changes in saliva pHNormal saliva is slightly acidic but some studies have shown that the saliva of people with end-stage kidney disease is more alkaline which can affect taste.
High levels of urea in salivaPeople with end-stage kidney disease have higher levels of urea in their saliva than those with normal kidney function. This affects the perception of bitter taste, causing either an increase or a decrease in perception of bitter taste. It can also cause a metallic taste.
High levels of sodium in salivaThis can increase the salt taste threshold and can therefore cause a salty taste.
High levels of bicarbonate in salivaThis can cause a reduction in the intensity of savoury (umami) taste and may be one of the reasons for lack of interest in meat in many people with CKD.
High levels of  potassium in salivaThis can cause a metallic taste.
Lower levels of zinc in bloodZinc deficiency can be as high as 40% in those receiving haemodialysis treatment. Zinc deficiency can lead to a reduction in overall taste.

 

Management of taste changes in CKD

The most common taste alterations reported by people with CKD are highlighted below with with some tips on how to overcome them:

 

Complete or partial loss of taste

  1. Add extra flavours to food eg pepper, herbs, spices, vinegar, lemon juice
  2. Use condiments such as mustard, mayonnaise, salad dressings and other sauces
  3. Marinate meats/chicken/fish with herbs, spices, olive oil and lemon juice
  4. Trial zinc supplementation
  5. Rinse (don’t drink!) your mouth with sodium bicarbonate mouthwash: you can make your own by dissolving 1 teaspoon sodium bicarbonate (purchase in any supermarket) in 500 mls water

 

Metallic taste

  1. Avoid metallic cutlery
  2. Use glass bakeware or cookware
  3. Limit canned foods
  4. Try peppermints, chewing gum, ginger beer, fruit juices or tea before your meals

 

Bitter taste

  1. Avoid bitter foods such as red meat, coffee, tea, chocolate and tonic water.
  2. Small glass of soda/sparkling water pre meals
  3. Add sweet or sour flavours to foods and drinks to reduce bitter taste eg lemon/lime juice in cooking, vinegar to marinades or salad dressings, honey glazes on meats and vegetables
  4. Try to have foods at room temperature or cold as cold foods have reduced bitter tastes

 

Loss of savoury (umami) taste eg meat

  1. Marinate meat/chicken/fish in citrus juices, vinegar, sweet and sour sauce or wine
  2. Tongue movements (umami taste is enhanced by active tongue and pharyngeal movements eg touching tongue to hard palate and swallowing)

 

Dry mouth

  1. Artificial saliva spray
  2. Regular mouth cleaning and teeth brushing using antibacterial products
  3. Avoid salty foods as this increases thirst
  4. Rinse mouth regularly with water or sodium bicarbonate mouthwash
  5. Suck on chilled/frozen fruit slices
  6. Suck on hard sweets or mints
  7. Chew gum
  8. Acupuncture
  9. Electrostimulation

 

Changes in taste are sadly an unwanted but common symptom of CKD. It can be experienced as a wide-ranging of different taste alterations. There are various ways this can be managed depending on the type of taste change experienced. It is important to discuss any changes in taste you have with your healthcare team who will be able to advise more on the best treatment plan to manage this.

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