Diets containing products made from whole grain oats may improve blood lipid profiles, while diets containing products made from whole grain barley may provide additional benefits for blood pressure and inflammation.
Key Findings
Results
LDL cholesterol concentrations showed a trend toward statistical significance across diets, with reductions in both whole grain groups compared to control.
The trend across diets reached p = 0.0638, falling short of conventional statistical significance
Barley diet lowered LDL cholesterol by 8.9 mg/dL compared to control
Oat diet lowered LDL cholesterol by 11.2 mg/dL compared to control
Study used a 6-week, double-blind, parallel-design, randomized controlled feeding trial with 68 adults
Results
Both whole grain oat and barley diets significantly lowered total VLDL and chylomicron particles compared to the control diet.
The reduction in total VLDL and chylomicron particles was statistically significant (p = 0.0272)
This effect was observed in both the oat and barley diet groups
The control diet contained 0.8 daily servings of whole grain per 2000 kcal
Both whole grain diets contained 4 daily servings per 2000 kcal
Results
The whole grain oat diet significantly lowered total LDL particles, multiple LDL particle subfractions, and increased LDL particle size.
Total LDL particles were significantly reduced (p = 0.0014)
Small LDL particles were significantly reduced (p = 0.0008)
Medium-small LDL particles were significantly reduced (p = 0.0008)
Very small LDL particles were significantly reduced (p = 0.0009)
LDL particle size was significantly increased (p = 0.0451)
Results
The whole grain barley diet significantly lowered diastolic blood pressure compared to control.
The reduction in diastolic blood pressure was statistically significant (p = 0.0388)
This effect was specific to the barley diet group
The barley diet provided 4 daily servings of whole grain barley per 2000 kcal
The trial duration was 6 weeks
Results
The whole grain barley diet significantly lowered vascular cell adhesion molecule (VCAM) concentrations, an inflammation-related marker.
The reduction in VCAM concentrations was statistically significant (p = 0.0320)
VCAM is considered a marker of vascular inflammation relevant to cardiovascular disease risk
This effect was specific to the barley diet and not observed with the oat diet
VCAM reduction suggests potential anti-inflammatory benefits of whole grain barley
Methods
The study used a double-blind, parallel-design, randomized controlled feeding trial design with three dietary arms over 6 weeks.
68 adults were randomly assigned to one of three diet groups
Group 1 (control): 0.8 daily servings of whole grain per 2000 kcal
Group 2 (oats): 4 daily servings of whole grain oats per 2000 kcal
Group 3 (barley): 4 daily servings of whole grain barley per 2000 kcal
Markers of cardiovascular disease risk were assessed before and after the 6-week treatment period
Background
Oats and barley are identified as beta-glucan-rich grains with potential to reduce cardiovascular disease risk factors in adults.
Both grains contain β-glucan, a soluble dietary fiber associated with lipid-lowering effects
The study was designed to compare effects of products made with either whole grain barley or whole grain oats on CVD risk factors
Multiple CVD risk markers were assessed including lipoproteins, blood pressure, and inflammation markers
What This Means
This research suggests that eating foods made from whole grain oats or whole grain barley every day for six weeks can meaningfully improve several markers linked to heart disease risk. The study compared adults who ate a low-whole-grain control diet to those who ate either four daily servings of whole grain oats or four daily servings of whole grain barley. Both whole grain diets reduced levels of VLDL and chylomicron particles, which are types of fat-carrying particles in the blood associated with cardiovascular risk. The oat diet showed particularly notable effects on LDL ('bad') cholesterol particle profiles, reducing the number and shifting the size of LDL particles toward larger ones, which is generally considered a more favorable pattern. The barley diet, on the other hand, showed unique benefits for blood pressure and vascular inflammation, specifically reducing diastolic blood pressure and lowering levels of a molecule called VCAM that is involved in inflammation of blood vessel walls.
This research suggests that while both oats and barley offer heart health benefits, they may do so through somewhat different mechanisms. Whole grain oats appear to work primarily by improving the LDL cholesterol particle profile, while whole grain barley may offer additional advantages for blood pressure regulation and reducing vascular inflammation. These are distinct pathways that both contribute to overall cardiovascular health, suggesting that including either or both grains as part of a regular diet could be beneficial.
The study is notable for being a tightly controlled feeding trial lasting six weeks with 68 participants, which strengthens confidence in the findings compared to studies that rely on self-reported food intake. The differences between the two whole grain diets and the control diet were meaningful in size, with LDL cholesterol dropping by roughly 9 to 11 mg/dL, though the LDL findings just missed conventional thresholds for statistical significance. The results support the idea that specific whole grain foods can provide measurable cardiovascular benefits, and that oats and barley, despite being similar grains, are not interchangeable in all of their health effects.