ALT: What It Is, Its Low and High Levels, and Treatment

Enzymes are proteins that help speed up chemical reactions in the body. They act as catalysts (breakers) within cells. There are thousands of different types of enzymes, and ALT is one of them. ALT, which stands for alanine transaminase, is an enzyme that can be found primarily in the liver, as well as in the kidneys and other organs. The body uses ALT to convert food into energy. However, having either too little or too much of it can cause certain health problems.

What is ALT?

You may have a blood test for routine check-ups, which will likely include the ALT value. The ALT blood test was previously known as the SGPT (serum glutamic-pyruvic transaminase) test. The ALT value in blood tests measures the amount of ALT present in the blood. Depending on the condition, ALT levels can be high, low, or normal in the blood. A high ALT level in the blood can be associated with liver damage or disease. When liver cells are damaged, ALT is released into the bloodstream. Therefore, ALT can be part of a routine check-up, or a doctor may use it to gain insights into your liver health.

Liver diseases may manifest with high ALT levels before showing any symptoms. This allows for early diagnosis of certain diseases. Additionally, ALT can help distinguish between acute (sudden) liver diseases and chronic (long-term) liver diseases. If you have any of the following symptoms, your doctor may want to check your liver health:

• Nausea or vomiting
• Fatigue
• Loss of appetite
• Jaundice
• Abdominal swelling
• Dark-colored urine
• Pale-colored stools
• Itching
• Swelling in the body (Edema)

In addition to symptoms, being part of a high-risk group may also warrant regular monitoring of your ALT levels. The high-risk groups for liver disease include:

• Family history of liver disease
• Obesity
• Diabetes
• Use or history of using medications that negatively affect the liver
• Hepatitis

What Should the ALT Value Be?

To determine the ALT value, a blood test should first be performed. A nurse or technician will insert a needle into your arm to collect a small sample of blood into a test tube, which is then sent to the laboratory for analysis. The blood collection process typically takes about five minutes, while the results may take until the next day. If the test is being done solely to measure the ALT value, there is no need to fast before the test.

The normal range of alanine transaminase (ALT) in the blood may vary from lab to lab. The commonly used reference range is 7-56 U/L. ALT levels may be higher in men compared to women. The test report will include the reference values used by the laboratory. Additionally, if the ALT value is high or low, the result may be highlighted in pink or bolded.

What is Low ALT?

Low ALT levels are rare and generally do not cause concern. Although the reference value for ALT may differ depending on the laboratory, a value below 7 U/L is typically considered low. Low ALT levels can be associated with vitamin B6 deficiency or chronic kidney disease. Your doctor may ask you to undergo additional tests to determine the cause.

What Are the Symptoms of Low ALT?

Low ALT levels are uncommon and typically do not cause symptoms. However, if symptoms do occur, they can vary depending on the underlying cause. Generally, symptoms of low ALT include:

• Persistent fatigue and weakness
• Numbness in the hands, arms, or legs
• Nausea
• Difficulty concentrating

What Are the Causes of Low ALT?

Low ALT levels may indicate a healthy liver. However, some causes of low ALT levels below the reference range include:

• Vitamin B6 deficiency: Necessary for the proper function of ALT. This is especially common in older adults and people with liver or kidney damage.
• Smoking
• Intense exercise
• Birth control pills
• Hormone therapy
• Kidney diseases

How is Low ALT Treated?

The treatment for low ALT depends on the underlying cause. Your doctor may request additional tests or perform a biopsy to identify the reason for the low ALT levels and develop a treatment plan. For example, if low ALT is due to a vitamin B6 deficiency, supplementation with B6 may be recommended. Additionally, you can increase dietary intake of B6-rich foods such as chickpeas, legumes, nuts, bananas, and avocados.

What is High ALT?

ALT levels can vary due to factors like age, gender, diet, and exercise. Therefore, an abnormal ALT value does not necessarily require immediate concern. High ALT levels are more commonly observed than low ALT levels. ALT levels above 57 U/L are generally considered high. Elevated ALT does not always require treatment, but it may be caused by conditions such as hepatitis, infections, or cirrhosis. However, a high ALT level does not indicate the extent of liver damage. If your ALT level is high, your doctor may recommend additional liver function tests to gain more detailed information.

What Are the Symptoms of High ALT?

High ALT levels typically do not cause symptoms. However, if the high ALT levels are due to liver damage, the following symptoms may be observed:

• Abdominal pain
• Dark-colored urine
• Fatigue
• Itching
• Jaundice (yellowing of the skin or eyes)
• Pale-colored stools
• Loss of appetite
• Nausea and vomiting

What Causes High ALT?

There are many factors that can affect ALT levels. These factors can be immutable, such as gender and age, or they can stem from environmental influences. In general, high ALT levels may be caused by:

• Some pain-relieving medications
• Obesity
• Hepatitis
• Heart failure
• Celiac disease
• Thyroid disorders
• Certain muscle disorders
• Hereditary hemochromatosis (a liver disease due to excessive iron accumulation)

How is High ALT Treated?

There is no direct medical treatment to reduce elevated ALT levels. Treatment options are aimed at addressing the underlying cause. Therefore, the first step is to determine the cause of the high ALT levels. Treatment options for high ALT include dietary changes and exercise. Some recommendations for managing high ALT include:

• Both folate and folic acid may have liver health-improving properties. Folate and folic acid are two different forms of vitamin B9. Folic acid is typically taken as a supplement, while folate is found in certain foods. You can add folate-rich foods such as leafy greens like cabbage and spinach, asparagus, beets, and bananas to your diet.
• Non-alcoholic fatty liver disease is more commonly observed in diets high in fats and carbohydrates. Therefore, by choosing foods rich in healthier fats, such as fish, and natural sugars, such as fruits, you can make healthy dietary changes without drastic modifications to your eating habits.
• Although not definitively proven, coffee has been found to have a protective effect on ALT levels. Drinking one cup of coffee per day may help reduce ALT levels.