Today I am talking about two amino acids supplements: L-arginine and glutamine. What evidence is to support that these amino acids can help reduce protein losses in kidney disease, specifically IgA nephropathy?
Quick Answer
There is interest in L-arginine and glutamine’s role in the aging of heart and kidney’s. Though evidence is still in it’s infancy. Studies done in mice have shown mixed results with some studies suggesting harm and other’s suggesting benefit. The form of the L-arginine may be a factor. I did not find any studies in humans studying L-arginine or glutamine supplements in IgA nephropathy.
What is IgA nephropathy?
IgA nephropathy is an immune-mediated disease of the kidney. Specifically, immunoglobin A (IgA) accumulates in the kidney leading to inflammation. This inflammation can ultimately lead to reduced kidney function. While the course of IgA nephropathy can be different for everyone, proteinuria (protein in the urine) is not uncommon.
L-Arginine and Glutamine for Body Builders
In 2019, the Journal of Renal Nutrition published this review. The authors looked at safety of these supplements for use in body builders. The specific end point was renal safety. The authors highlight that L-arginine has had mixed results on safety in studies on kidney health. L-arginine appears safe for the general population.
The results of glutamine are very similar for L-arginine. There is interest in this supplement from a kidney health perspective. Glutamine is a common workout supplement. It is likely safe for adults with healthy kidneys. However some studies have reported potential harmful effects on kidney structure and function. For adult body builders with kidney disease glutamine is contra-indicated.
Where do I find information to answer questions about supplements?
One resource I like for information about natural health products is the Licensed Natural Health Products Database. Unfortunately like all government websites, it isn’t the easiest to use.
This database has information about what supplements are approved for use in Canada. And what the supplements have been approved to be used for.
What is L-Arginine?
According the Health Canada Drug Monograph L-Arginine has been approved for use as a supplement to “support a modest improvement in exercise capacity in individuals with stable cardiovascular diseases (CVD)” and as a non-essential amino acid involved in protein synthesis.
Neither of those are related to kidney health, immune function, inflammation or proteinuria. Next stop google scholar.
What new research is there for L-Arginine and kidney disease?
Humans were not subjects of the L-arginine and kidney health studies. Mice or rats were. This tells me that there is interest in this supplement. But it still has a way to go before we will see human trials.
In this article from 2021, the authors explained that the interest in L-Arginine for kidneys is that L-arginine/nitric oxide pathway is a recognized pathway associated with heart and kidney diseases. In this study, the authors fed high vs low L-arginine chow to mice. They found that mice fed more L-arginine had worse proteinuria, accelerated kidney function decline and vascular aging.
In this 2019 mice study, they combined resistance exercise with L-arginine supplementation. They were testing the impacts on inflammatory balance, muscle strength, renal function and renal fibrosis. Exercise alone improved outcomes. The additional of the L-arginine supplement actually stopped these good things from happening.
In this 2019 study of L-homoarginine, mice given high L-homoarginine water to drink had lower levels of proteinuria and better markers of kidney health. The authors of this paper explained that L-homoarginine is not the same as L-arginine. L-homoarginine has an additional methyl group compared to L-arginine.
I didn’t do a full literature review, so there is definitely more research out there. But this tells me that there is interest in the supplement. However these mice studies are showing mixed results. There also seems to be interest in what form of L-arginine might have benefit.
My takeaway for patients or health care providers asking about this supplement would be that research is still new and we just don’t know if it will have benefit. I would also let them know that some studies have shown harm – because that is important too.
What is glutamine?
Glutamine is approved for use in Canada as a non-essential amino acid that can be used in work-out supplements. It can be marketed as “athletic support” or in as an assistant “in the building of lean muscle tissue/mass when combined with regular weight/resistance training and a healthy balanced diet”. To carry these claims the supplement must contain at least 2.6g of protein or amino acids (of which glutamine can be one of).
What new research is there for Glutamine and kidney disease?
My searches for newer articles reporting on glutamine and kidney disease were less fruitful than for L-arginine. I didn’t find any additional studies.
Here is a summary of the evidence presented in the 2019 review on body builders. There were several rat/mouse studies conducted with glutamine. One study reported that glutamine resulted in renal injuries in diabetic rats. Other studies have also reported increases in serum creatinine, glomerular hypertrophy and glomerulosclerosis. The authors also reported that some studies have shown benefit. One study found that IV glutamine improved sepsis induced acute kidney injuries in mice. And other study also reported reduced renal dysfunction.
My take away for patients and other health care providers for glutamine would be the same as for L-arginine. There is interest in the impact of this supplement for kidney disease. The studies were not in humans. Some results were good, some were bad. Some studies report harm. Other reports benefit.
