Over 10% of the adult population suffers from chronic kidney disease (CKD), with the two leading underlying causes of end-stage kidney disease being type II diabetes and hypertension. Dysbiosis of the gut microbiome along with inflammation can play a role as well.
In a new study published Monday in Nutrients, researchers demonstrated the efficacy of a low protein diet and inulin in patients with CKD. Previous research has demonstrated that a high fiber diet can help mitigate disease severity and kidney dysfunction in patients with CKD. Higher dietary fiber intake is linked to better kidney function and a lower risk of inflammation and mortality.
The research team conducted a longitudinal, prospective, controlled, and interventional study on 16 patients. Nine patients followed a low protein diet along with inulin supplementation at 19 g per day and the other seven patients only followed the low protein diet. Laboratory assessments were performed and stool samples were collected for the evaluation of the gut microbiome in all patients. These tests were performed at baseline and again at 6 months. In addition, there was stool testing on 16 healthy individuals to identify a potential dysbiosis between CKD patients and healthy individuals. As a result, the gut microbiome of CKD patients was different from the healthy individuals.
The low protein diet intervention demonstrated a significant increase in Akkermansia and Bacteroides bacteria and a decrease in Christensenella, Clostridia, Lactobacillus, and Pasteurella bacteria. Also, Bifidobacteria was only increased in the inulin supplementation group. If one has more Bacteroidetes bacteria, the individual tends to be leaner. A high Firmicutes:Bacteroidetes ratio has been known to increase the caloric extraction from food and these individuals tend to be more obese. Increasing Bifidobacteria with inulin or prebiotics can optimize this ratio.
The results showed a significant reduction of serum uric acid, C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and plasma NADPH levels in the patients in the inulin group. There was an improvement in SF-36 (physical role functioning and general health perceptions) and a significant increase of serum bicarbonate in both groups. In general, a low protein diet modified gut microbiota and modulated inflammatory and metabolic parameters in patients with CKD. The addition of inulin or using a prebiotic can further improve clinical outcomes in CKD patients.
There is currently no consensus on low-protein diets in renal disease amongst nephrologists.
Low-protein diets have been shown to slow disease progression but many of patients suffer from renal cachexia. High-protein diets may exacerbate renal disease by stimulating cellular hypertrophy and proliferation, glomerular scarring, increasing reactive oxygen species, creating an acid load causing ammonium production, increasing urea formation, causing hypertrophy of renal tubules, and generating aldosterone and angiotensin.
Although many prebiotics are effective, common ones such as inulin, fructooligosaccharides, and galacto-oligosaccharides often require an individual to consume quite a bit, which can lead to undesired gastrointestinal symptoms. Instead, consider using xylooligosaccharides, as it is a unique prebiotic fiber that does not require a large payload and does not have GI side effects. Clinical studies have shown 1.4 grams of xylooligosaccharides to be as effective as 5 grams of inulin. Also, concurrently supplementing along with Bifidobacteria can be helpful and have a synergist effect.
Additional nutrients to consider include fiber, resistant starch, fish oil, phosphatidylcholine, and n-acetyl-cysteine or glutathione. Fish oil supplementation (with a dosing range of up to 10 grams per day) has been shown to decrease protein in the urine as well as protect kidney function and slow the rate of kidney dysfunction.
By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS