Creatinine

What is Creatinine?

Creatinine is a waste product produced after the normal breakdown of muscle tissue. It is made from creatine, a naturally occurring compound in muscle tissue important for energy production during high-intensity exercise or heavy lifting. Creatinine is also produced as a result of protein digestion^[1].

Because nearly all creatinine is excreted in the urine, measuring blood levels can provide important insights into kidney health and how well they are working^[2].

What are Normal Creatinine Levels?

The normal range for creatinine may depend on the testing laboratory but the NHS states that the reference range for men and women is as follows:

Men	59 – 104 µmol/L
Women	45 – 84 µmol/L[3]

Data collected from Forth customers shows that creatinine levels for all age groups are within the normal range. Some research suggests that creatinine levels decrease with age because of declining kidney function^[4]. However, our data does not correlate with this.

What are dangerously high creatinine levels?

A creatinine level above 500 is considered high and indicates severe kidney damage or disease^[5].

What Causes High Creatinine Levels?

High creatinine levels have several possible causes and often indicate an issue with kidney function or other underlying health conditions. Some of the common causes include:

1. Dehydration

   Raised creatinine levels do not always mean there’s an issue with your kidneys, not taking in enough fluid can cause them to rise^[6].

2. High muscle mass

   Having more muscle tissue means you produce more creatinine.

3. Intense exercise

   Intense or strenuous exercise can temporarily raise creatinine levels because of the increased muscle breakdown^[7]. Interestingly, having more muscle tissue can also mean you produce more creatinine.

4. Creatine supplementation

   Supplementing your diet with creatine can cause an increase in blood creatinine levels because creatinine is produced from creatine breakdown. Considering this when taking a creatinine blood test is important because it is not necessarily a marker of kidney dysfunction in this case^[8].

5. High protein intake

   Diets that are high in protein can cause an increase in creatinine levels^[9] because creatinine is a waste product of protein breakdown.

6. Kidney dysfunction

   Because your kidneys filter most of the creatinine out of the blood and remove it from the body in urine, high creatinine levels can signify kidney disease or injury^[10].

7. Liver cirrhosis

   High creatinine levels may be present in people with liver cirrhosis and can be caused by chronic kidney disease or an acute kidney injury^[11].

8. Underlying health conditions

   Some health conditions, such as diabetes, heart disease, and high blood pressure can cause creatinine to rise.

Symptoms of High Creatinine

The symptoms of high creatinine may depend on the condition causing it. Some of the common causes and their symptoms are listed below.

Kidney infection

In severe cases, a kidney infection can cause high creatinine levels and:

• Fever

• Chills

• Foul-smelling urine

• Painful urination

• Feeling or being sick

• Pain in your lower back

Kidney disease

Kidney disease doesn’t usually cause any symptoms until it becomes chronic, then symptoms can include:

• Weight loss

• Poor appetite

• Shortness of breath

• Tiredness

• Blood in your pee

• Swollen ankles, feet or hands

• Itchy skin

• Muscle cramps

• Feeling sick

• Headaches^[12]

Dehydration

Dehydration symptoms include:

• Feeling thirsty

• Dark, strong-smelling pee

• Peeing less often than usual

• Dizziness

• Dry mouth, lips, and tongue

• Sunken eyes^[13]

Reducing Creatinine Levels

There are several things you can do to help lower your creatinine levels:

• Avoid taking supplements that increase creatinine such as creatine because any unused creatine will be turned into creatinine and can give false blood test results.

• If you eat a diet high in protein, try reducing your meat consumption, particularly red meat, and fish.

• Incorporate more fibre into your diet. Some evidence suggests that eating more fibre found in fruit, vegetables, and whole grains lowers creatinine levels in chronic kidney disease patients^[14].

• Intense exercise can cause temporary creatinine rises, if you’re concerned, swapping intense or strenuous sessions with moderate or gentle activities may help to lower your levels.

Can drinking water reduce creatinine?

If your raised levels are caused by dehydration, drinking water will help to correct your hydration status and may fix your high creatinine levels^[15].

The UK government recommends that adults drink 6 to 8 glasses of water or 1.2 litres daily^[16].

What Causes Low Creatinine Levels?

Low creatinine levels are rare and not usually a cause for concern. They may be found in people with low muscle mass, such as the elderly, or in some cases of advanced liver or kidney disease^[17].

Low blood creatinine levels may also be observed in people who follow vegetarian or vegan diets because they lack animal protein^[18].

Pregnancy can also cause low creatinine levels, but they should return to normal after a woman gives birth.

Symptoms of low creatinine

Low creatinine symptoms depend on the underlying cause.

• Low muscle mass

  muscle weakness, frailness, difficulty exercising

• Liver disease

  fatigue, feeling sick, jaundice, pain in the upper right-hand side of the tummy

• Diet

  dizziness, weight loss

Increasing Creatinine Levels

If your diet causes low creatinine levels, and you choose not to eat animal protein, you may benefit from supplementation, especially if you exercise regularly. That’s because research shows that vegetarians (and vegans) have lower creatine stores than meat-eaters^[19]. Inevitably, that means they will have lower creatinine levels.

If low creatinine levels are caused by a muscular disease, treatment will focus on reducing pain and improving quality of life.

Increasing the amount of exercise you do can build muscle mass. Activities could include:

• Walking

• Swimming

• Cycling

• Weight training

Written by Leanne Edermaniger

Based in the UK, Leanne specialises in writing about health, medicine, nutrition, and fitness.

She has over 5 years of experience in writing about health and lifestyle and has a BSc (hons) Biomedical Science and an MSc Science, Communication and Society.