Higher blood lactate levels tied to survival, weight changes in ALS
Findings suggest simple blood test may help assess prognosis
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- Higher blood lactate levels in ALS patients were associated with longer median survival and smaller short-term declines in BMI.
- Lower lactate levels were associated with shorter survival and greater short-term BMI decline in ALS.
- Blood lactate levels may serve as a potential prognostic biomarker in ALS, pending further validation.
Blood levels of lactate — a molecule involved in how the body produces energy — may help predict survival and short-term weight changes in people with amyotrophic lateral sclerosis (ALS), according to a new study from Australia and Japan.
Researchers found that patients with lower blood lactate levels had a shorter median survival — about 39 months compared with 49 months — and experienced greater declines in body mass index (BMI) over three months than those with higher lactate levels.
The findings suggest that blood lactate levels may serve as a potential prognostic biomarker — meaning a measurable factor linked to future outcomes — to help identify patients at risk of shorter survival and greater short-term BMI decline.
Lower lactate levels linked to shorter survival in ALS
“Our findings support the hypothesis that lower lactate levels are associated with an increased likelihood of weight loss in ALS patients, faster disease progression and earlier death,” Shyuan Ngo, PhD, professor at The University of Queensland, in Australia, and co-senior author of the study, said in a university news story.
The study, “Blood Lactate as a Prognostic Biomarker for Survival and Weight Loss in Amyotrophic Lateral Sclerosis: An Exploratory–Validation Study,” was published in Annals of Neurology.
ALS is caused by the progressive loss of motor neurons — the nerve cells that control voluntary movement — leading to gradual muscle weakness and increasing difficulty performing everyday tasks.
The exact causes of ALS are not fully understood, but many patients experience metabolic changes, including burning more energy than normal at rest (a state known as hypermetabolism) and unintended weight loss. Previous research has linked these metabolic changes to shorter survival, suggesting they may contribute to disease progression.
Lactate is produced when cells break down glucose for energy under low-oxygen conditions. Although often associated with intense exercise, lactate can also serve as an alternative energy source for tissues, including nerve cells. Previous experimental studies have suggested it may play a protective role in ALS.
Researchers analyze patient data in Australia and Japan
To examine whether lactate levels were linked to clinical outcomes, researchers analyzed data from 110 people with ALS and 86 healthy controls in Australia. They then tested their findings in an independent validation group of 36 people with ALS in Japan.
In the Australian group, people with ALS were older than controls. After adjusting for age and sex, blood lactate levels were significantly higher in ALS patients than in controls. Statistical analyses showed that individuals with higher lactate levels had 2.29 times the odds of having ALS compared with those with lower lactate levels.
The team then identified a cutoff value of 1.05 mmol/L, corresponding to the lowest quartile of lactate levels. Patients whose lactate levels fell below this threshold had significantly shorter median survival — 39 months, compared with 49 months for those with higher levels.
Applying the same cutoff to the Japanese group showed a similar pattern. Median survival was 21 months among patients with low lactate levels, while it had not yet been reached among those with higher levels — meaning more than half were still alive at the time of analysis.
Higher lactate levels tied to slower BMI decline
Finally, the team examined whether lactate levels predicted changes in BMI, a measure based on height and weight. In both ALS groups, higher lactate levels were associated with smaller declines in BMI over three months, suggesting a link between lactate levels and better weight stability.
“Simply put, the more lactate an ALS patient has in their blood, the more likely they are to maintain weight and have a better prognosis,” said Ryutaro Nakamura, MD, PhD, professor at Shiga University and lead author of the study.
“Because weight loss strongly predicts survival in ALS, patients with low lactate levels may benefit from early and intensive nutritional support to improve outcomes,” Nakamura added.
The findings suggest that measuring blood lactate levels could potentially help clinicians assess prognosis and better understand a patient’s metabolic status, though further validation is needed.
However, the study was retrospective and relatively small. Larger studies will be needed to confirm whether blood lactate levels can reliably serve as a prognostic biomarker.
