A recent Japanese study indicates that eating a low-salt, oat-based fruit granola breakfast may have beneficial effects on blood pressure, cholesterol levels, and gut health in people with moderate chronic kidney disease (CKD). The research was published in the journal Foods.
CKD is a growing global health issue affecting about 843.6 million people worldwide. It is projected to become the fifth leading cause of years of life lost by 2040. Risk factors for CKD include diabetes, obesity, and hypertension. Cardiovascular disease (CVD) often occurs alongside CKD and is the main cause of death among patients with kidney disease.
Dietary changes such as adopting Mediterranean or whole-grain diets have previously been linked to lower CKD risk. Fruit granola, made mainly from oats and containing only 0.24 grams of salt per 50-gram serving, represents a lower sodium alternative compared to typical Western or Japanese breakfasts.
Oats are rich in beta-glucan, a soluble fiber known to reduce LDL cholesterol and blood sugar levels. Earlier observations by the study authors found that fruit granola intake reduced salt consumption and blood pressure while improving gut health in hemodialysis patients.
In this study, researchers recruited adults over age 20 with stable moderate CKD at a university hospital in Japan. Participants replaced their usual breakfast with 50 grams of fruit granola at least five days per week for two months. Clinical tests measured blood pressure, urine markers, lipid profiles, nutritional status, and bowel habits before and after the intervention.
Twenty-four participants completed the study; most were male with an average age of nearly 67 years and had stage G3 CKD due primarily to diabetic nephropathy.
Results showed systolic blood pressure dropped significantly from an average of 128.9 mmHg to 124.3 mmHg after two months on the granola diet; diastolic pressure fell slightly but not significantly. No adverse events occurred during the trial.
There were no changes observed in kidney function measures or liver function tests during the intervention period. However, LDL cholesterol levels and the LDL-to-HDL ratio both declined significantly; HDL cholesterol and triglycerides did not change notably. Ferritin levels also decreased though its clinical importance remains unclear.
Markers related to renal tubular damage improved: urinary N-acetyl-beta-D-glucosaminidase decreased significantly following fruit granola intake. Participants reported better bowel movement frequency and stool quality based on questionnaire responses.
The estimated daily salt intake increased slightly according to spot urine samples—from 8.4 g/day to 9.2 g/day—but researchers noted possible limitations in this measurement method using single urine samples rather than full dietary records.
No significant changes appeared in other urinary markers such as albumin or electrolytes like sodium or potassium.
Researchers concluded that "two months of fruit granola consumption was associated with reductions in urinary markers of tubular damage, lower systolic BP [blood pressure], and improvements in lipid-related and intestinal health markers in patients with moderate CKD." They cautioned that these findings are preliminary: "These findings suggest potential cardiovascular and renal benefits but should be regarded as hypothesis-generating."
The study’s limitations include its small size (24 participants), lack of a control group, short duration (two months), open-label design without blinding, absence of detailed dietary tracking beyond breakfast substitution, exclusive recruitment from one country (Japan), and involvement by a food manufacturer—factors which limit how widely these results can be applied elsewhere.
