What does it mean when your ALT levels are low

[Kliner33]

What does it mean when your ALT levels are low Mine was a four and my doctor just proscribed me stuff more my cholesterol. I’m concerned no follow us or anything

[flyinlynn]

You have posted in the Hepatitis C  community you have hepatitis C?

When people have hepatitis C or liver damage occurring they will have elevated liver enzymes.

I was able to find some info about Low ALT test results below 7 the minimum normal copied below.

You doctor is you best option to determine the cause of you below normal ALT. It is a possibility that is normal for you.

Potential Causes of Low ALT

A low ALT without any other signs or symptoms or abnormal test results is usually considered normal. Talk to your doctor for more information. Your doctor will always interpret this test in light of your medical history, signs and symptoms, and other test results.

While low levels are usually not a cause for concern, there are some conditions and factors that may decrease ALT.

1) Vitamin B6 Deficiency

ALT enzyme requires active vitamin B6 to function. Vitamin B6 deficiency is uncommon, but it’s more likely to occur in the elderly, alcoholics, and people with underlying health conditions such as liver, kidney, or inflammatory diseases [4, 5].

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 [6].

Alcoholics with low vitamin B6 levels also have low ALT levels. After one month of abstinence and vitamin B6 supplementation, ALT levels increased [7].

2) Smoking

People who smoked had lower levels of ALT in 2 studies with over 23k healthy participants [8, 9].

However, a study with 500 participants found the opposite trend: smokers had slightly higher ALT levels [10].

Smoking by itself may lower ALT levels while elevating ALT in people who already have certain types of liver disease [11].

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 [11].

Smoking likely lowers ALT in healthy people but increases it in people with liver disease.
3) Regular Exercise

In over 80k young adults, more days per week of either aerobic or strength exercise was associated with low ALT levels within the normal range [12].

It’s not certain, however, whether exercise can decrease ALT below normal.

4) Birth Control Pills or Hormone Replacement Therapy

There are studies that report significant reductions of ALT in women when using oral contraceptives or hormone replacement therapy [13, 14].

5) Chronic Kidney Disease

A study in 142 people with chronic kidney disease found that ALT decreased in proportion to the progression of the disease. It got lower as kidney function declined [15].

In another study, of 100 people, those who had chronic kidney disease had lower ALT levels, and the level dropped as the kidney disease became more severe [16].

Health Effects Associated With Low ALT Levels

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 [17, 8, 18].

Two studies of people with diabetes (9,795 and 2,993 participants) found similar results [19, 20].

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 [19, 20].

These studies have found a correlation, but the relationship here is unlikely to be causal. In other words, there is likely an underlying cause that may be affecting both ALT levels and heart health. Therefore, trying to artificially increase ALT levels will not address the underlying issue and is likely to cause more harm than good.

A couple of studies have found a link between low ALT levels and a higher risk of heart disease. However, this relationship is unlikely to be causal.

2) Mortality in Seniors

In the elderly, low ALT levels may indicate an aging liver, declining kidney function, or poor nutrition (455 participants, 1,673 participants) [21, 22].

In a meta-analysis of 12 studies with over 200k participants, extremely low ALT in elderly (less than 5 U/L) was associated with a higher risk of dying due to all causes, as well as from heart disease and cancer [23].

A study suggests that ALT may help the brain recover from stroke. This could partially explain why extremely low levels can be harmful in the elderly [24].

Low ALT levels in older people have been associated with higher mortality. Low levels in this case likely reflect declining liver and kidney function and/or poor nutrition