Leucine supplements and cancer wasting in animal studies
What it found
In rodents with cancer, leucine-rich diets often preserved muscle and reduced some signs of wasting, but one study found faster tumour growth.
All the evidence comes from animals, not people.
What they found
Animal and lab studies
Muscle preservation
In several rat and mouse studies, leucine-rich diets reduced loss of lean body mass and muscle mass. Some also found less breakdown of muscle protein and slightly more protein synthesis.
Heart effects
One study in tumour-bearing rats found that a leucine-rich diet reduced heart muscle breakdown, heart damage and cell death. It did not affect the reduced thickness of the left ventricle.
Inflammation and immunity
Some mouse studies found that leucine-rich diets, often combined with fish oil, lowered pro-inflammatory cytokines and increased anti-inflammatory ones. One study reported improved immune response only when leucine was combined with other nutrients.
Tumour growth
Two rat studies found that long-term leucine supplementation promoted bladder cancer development after exposure to a carcinogen. Another mouse study found that a high-leucine diet increased pancreatic tumour growth compared to no supplementation.
Combination with other treatments
Several studies tested leucine along with exercise or other nutrients like fish oil. In some cases, benefits were seen only with the combined approach, not with leucine alone.
Other findings
Study differences
The included studies used different animal models, doses of leucine, and lengths of feeding. This made it hard for the authors to compare results directly.
What the authors conclude
“Current research indicates that a leucine-rich diet may attenuate CC symptomology; however, these works are difficult to compare due to methodological differences.”
Also in their conclusions
- They say that current research indicates a leucine-rich diet may attenuate cancer cachexia symptoms in rodents, but these works are difficult to compare due to methodological differences.
- They call for further pre-clinical work exploring leucine's potential ability to modulate protein turnover and immune response during cancer cachexia, as well as the impact of additive leucine on tumour growth.
- They advise that if the safety of leucine supplementation is confirmed, prospective human clinical trials are needed.
How it was done
Cancer cachexia is a complex wasting syndrome that cannot be reversed by eating more alone. The authors wanted to see whether leucine, an amino acid that affects muscle protein, might help as an add-on treatment.
The authors searched medical databases for studies on leucine supplementation in animals with cancer cachexia, published between 2001 and 2021. They found 29 papers and included 14 relevant ones, all in rodents.
What it can’t tell you
- All the studies were in rodents, so the results cannot show what happens in people with cancer.
- The studies used different methods and doses, so it is hard to draw firm conclusions about leucine itself.
- Some studies combined leucine with other treatments, so the specific effect of leucine alone is unclear.
Who paid
- Conflicts
- The authors declare no conflict of interest.
- Authors work at
- Baylor University, USA
The paper
- Title
- Leucine Supplementation in Cancer Cachexia: Mechanisms and a Review of the Pre-Clinical Literature
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Beaudry AG, Law ML (2022). Leucine Supplementation in Cancer Cachexia: Mechanisms and a Review of the Pre-Clinical Literature. Nutrients. doi:10.3390/nu14142824Free full textPubMed 35889781DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error