Though high alanine aminotransferase (ALT) levels are problematic for people with liver disease, abnormally low levels are also connected to health problems. Read on to find out about the factors beyond liver health that can cause your ALT levels to drop too low and how to increase your levels naturally.

What Does Low ALT mean?

ALT is measured in units per liter of blood or U/L. The most recent comprehensive review concluded that the upper normal limit for ALT should be[5]:

  • 31 U/L for women
  • 42 U/L for men

Until recently, however, 10 to 40 U/L was considered as the normal range for both genders [5].

ALT levels under 7 U/L are considered to be low, though even borderline-low levels (7-16 U/L) might be sub-optimal and point to nutrient deficiencies or other health problems [1, 2, 3].

ALT levels below 7 U/L are low and may point to specific health problems or nutrient deficiencies.

Causes & Conditions Associated with Low ALT

1) Heart Disease

In multiple studies with over one million participants in total, people with low ALT levels were more likely to suffer from heart disease [4, 5, 6].

Two studies of diabetic patients (9,795 and 2,993 participants) found similar results [7, 8].

In the first study, people with ALT levels below 8 U/L were 65% more likely to suffer from a heart attack. In the second, the risk of heart disease began to decline for ALT levels over 30 U/L, especially in women [7, 8].

Extremely low levels may indicate either impaired liver function or an underlying cause that is both reducing ALT and harming the heart [4].

Low ALT levels may point to an underlying disease that is harming both the heart and liver; slightly lower levels might also increase the risk of heart disease.

2) Risk of Dying in Seniors

In the elderly, low ALT levels may indicate an aging liver, increased fragility, and poor nutrition (455 participants, 1,673 participants) [9, 10].

In a meta-analysis of 12 studies with over 200k participants, extremely low ALT in elderly patients (less than 5 U/L) reliably predicted risk of dying due to all causes, as well as from heart disease and cancer [11].

Furthermore, ALT may help the brain heal from stroke by helping cells recover from poor blood flow. This could explain why extremely low levels can be harmful [12].

Low ALT levels in older people may point to liver aging, poor nutrition, and worse health. Since the brain also needs some ALT to regenerate, low levels may slow stroke recovery.

3) Smoking

People who smoked had lower levels of ALT in 2 studies with over 23k healthy participants [5, 13].

However, a study with 500 participants found the opposite trend: smokers had slightly higher ALT levels [14].

Smoking by itself may lower ALT levels while elevating ALT in people who already have certain types of liver disease [15].

For example, in a study of over 6k patients with hepatitis, smoking further increased ALT levels in people that had hepatitis C, but not in those with hepatitis B [15].

Smoking lowers ALT in healthy people but increases it in people with liver disease.

4) Vitamin B6 Deficiency

Vitamin B6 levels often decline with stress, chronic health problems, and poor nutrition. In a 5-week study of 52 hemodialysis patients, low ALT levels were associated with vitamin B6 deficiency. ALT levels improved with daily B6 supplementation, indicating that ALT needs vitamin B6 for normal functioning [16].

5) HELLP Syndrome

HELLP syndrome is a disorder in pregnant women that causes malformed red blood cells, elevated liver enzymes, and high platelets. In one case study, a 28-year-old pregnant woman with high blood pressure, stomach pain, and pregnancy complications (due to newborn heart defects) had ALT deficiency due to HELLP syndrome.

How to Increase ALT

The research about increasing ALT levels is sparse. There are no drugs that are specifically designed for the task since low ALT is typically seen as a good thing.

It’s important to find healthy ways to increase ALT if your levels are low while protecting your liver. For example, drinking too much alcohol increases ALT because it damages the liver. Even if you were to increase your ALT levels this way, the end result would be detrimental.

Vitamin B6, on the other hand, has plently of health benefits and it also increases ALT levels. Therefore, getting more vitamin B6 through diet or supplements would be a good strategy.

We highly recommend consulting a doctor if you are concerned about an abnormally low ALT level before trying any of the following interventions.

We still know little about increasing ALT in people with abnormally low levels. Try out only safe and healthy strategies, such as getting more vitamin B6 and omega-3 fatty acids.

1) Eating More Sugar and Fat?

Supplementing the diets of 76 healthy men with sugar (fructose) for an average of 3 weeks increased ALT levels by an average of 5 U/L in a meta-analysis of 13 trials. Meanwhile, replacing carbs with sugar did not increase ALT levels in 184 healthy male participants [17].

A high-fat diet raised ALT levels in a post-menopausal rats [18].

However, these studies were testing diets to determine if they had a detrimental effect on the liver, which could be seen through increased ALT levels. These interventions are therefore not necessarily healthy ways to increase ALT [17].

2) Vitamin B6

Vitamin B6 has plently of health benefits: it reduces inflammation, supports gut and mental health, and lowers the risk of heart disease. In a 5-week study of 52 hemodialysis patients, low ALT levels were associated with vitamin B6 deficiency. B6 supplementation increased ALT to normal levels [16].

3) If on Hemodialysis – Lose Weight

In a study of 146 patients with chronic kidney disease on hemodialysis, weight loss of about 5% correlated with a 28% increase in average ALT levels [19].

4) Consume More Omega Fatty Acids

Soybean oil, which contains a combination of omega-6 and omega-3 fatty acids, and sunflower oil (omega-6 fatty acids) both increased ALT levels in rats [20].

5) Theoretically Gain Weight

Weight loss reliably reduces ALT, so weight gain may have the opposite effect [21].

It could be especially beneficial in seniors with extremely low ALT levels. Putting on more weight and muscle mass could improve fragility.

However, this hypothesis is purely theoretical and has not been tested in humans or animals.

Want to Learn More?

This post is part of a three-part series about ALT. Learn more about the functions of ALT and why doctors order the test here. If your ALT levels are high, read this post.

Irregular ALT Levels?

LabTestAnalyzer helps you make sense of your lab results. It informs you which labs are not in the optimal range and gives you guidance about how to get them to optimal. It also allows you to track your labs over time. No need to do thousands of hours of research on what to make of your lab tests.

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Low ALT is far less common than high ALT, but it may point to underlying health problems or nutrient deficiencies. Abnormally low levels may increase the risk of heart disease and worsen health in elderly people. Vitamin B6 deficiency is a possible cause, especially in people with kidney disease on hemodialysis.

We know little about healthy ways of increasing abnormally low ALT levels. Most things that increase ALT also damage the liver, such as drinking too much alcohol and eating a lot of sugar and saturated fats.

Among the healthy steps you can take to raise your ALT, consider increasing your vitamin B6 intake, gain muscle mass and weight if you are older and underweight, and get more omega-6 and omega-3 fatty acids in your diet.

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