Metabolic acidosis is a condition in which the body has an acid content that is too high to support good health.
An abnormally high acid level in the body is detected with a test that measures a form of carbon dioxide (CO2) that’s dissolved in the blood called serum bicarbonate.
Bicarbonate is a substance called a base, which the body needs to help keep a normal acid-base (pH) balance. This balance prevents your body from becoming too acid, which can cause many health problems.
Healthy kidneys remove acid from the body through urine and they keep the right amount of bicarbonate (base) in the blood. But in CKD, the kidneys can’t remove enough acid, which can lead to metabolic acidosis.
The normal level of serum bicarbonate is 22-29 mEq/L. Kidney experts recommend that patients not have their serum bicarbonate levels fall below 22 mEq/L.
For people with CKD, metabolic acidosis is defined as persistently low bicarbonate levels of less than 22 mEq/L in the blood.
Metabolic acidosis is a common finding in CKD, affecting approximately 15%-19% of patients.
The prevalence of CKD in adults is 15% in the United States and 11-13% globally. As the population ages, that number will likely increase, along with an increase in metabolic acidosis.
Serious long-term problems can result from metabolic acidosis include…
Increased bone loss (osteoporosis): Metabolic acidosis can cause a loss of bone in your body. This can lead to a higher chance of fractures in important bones like your hips or backbone.
Decreased growth in children: Metabolic acidosis prevents the release of growth hormone, which is needed for proper growth.
Progression of CKD: As acid builds up, kidney function decreases. And as kidney function decreases, more acid builds up to cause more kidney damage. This makes CKD worse.
Muscle loss: Excess acid in the body causes muscles to break down, which is called "muscle wasting."
High blood sugar: Excess acid can cause your body to resist the effects of insulin, the hormone in your body that helps keep your blood sugar level from getting too high.
Death: Studies have shown a link between metabolic acidosis and an increased risk for death.
Metabolic acidosis has been identified as an independent risk factor for the progression of CKD.
Metabolic acidosis can cause a variety of unpleasant symptoms such as
Long and deep breaths
Headache and/or confusion
A feeling of being very tired
Vomiting and/or feeling sick to your stomach (nausea)
Loss of appetite
Studies have shown that treatment with sodium bicarbonate (baking soda) or sodium citrate pills, which are base substances, can help keep kidney disease from getting worse. However, you should not take sodium bicarbonate or sodium citrate pills unless your healthcare team recommends them. Another type of treatment that binds excess acid in the bowels may soon be approved for treating metabolic acidosis. You can discuss these treatment options with your healthcare team.
A diet that includes more plant-based proteins than animal-based proteins, along with a high intake of fruits and vegetables, can also help keep acid levels from rising in the blood. Before making any dietary changes, speak with your healthcare team.