A clinical trial from the University of Bonn shows that consuming mostly oatmeal for two days can reduce harmful LDL cholesterol by 10 percent in people with metabolic syndrome. The benefits, including changes in gut bacteria, persisted for six weeks. Participants also experienced modest weight loss and lower blood pressure.
Researchers at the University of Bonn conducted a randomized controlled trial published in Nature Communications, examining the effects of a short-term oat-based diet on individuals with metabolic syndrome. This condition involves excess body weight, high blood pressure, elevated blood sugar, and abnormal lipid levels, increasing risks for heart disease and diabetes.
In the study, 32 participants followed a 48-hour calorie-restricted plan consisting almost entirely of oatmeal, consuming 300 grams per day boiled three times daily with minimal additions like fruit or vegetables. This halved their usual calorie intake. A control group reduced calories similarly but without oats.
Both groups saw some improvements from calorie reduction, but the oatmeal group experienced stronger effects. "The level of particularly harmful LDL cholesterol fell by 10 percent for them -- that is a substantial reduction, although not entirely comparable to the effect of modern medications," said Marie-Christine Simon, junior professor at the University of Bonn's Institute of Nutritional and Food Science. Participants in this group lost an average of two kilograms and had slight drops in blood pressure.
The LDL reduction remained noticeable six weeks later. Analysis revealed shifts in the gut microbiome, with increased bacteria producing phenolic compounds like ferulic acid, which may influence cholesterol metabolism positively. "We were able to identify that the consumption of oatmeal increased the number of certain bacteria in the gut," noted lead author Linda Klümpen.
A follow-up six-week phase with 80 grams of oatmeal daily without calorie limits yielded only modest changes, suggesting intensive short-term consumption is more effective. Simon suggested periodic oat-based diets could help maintain cholesterol levels and prevent diabetes, though further research is needed.
The trial involved 68 participants total, with measurements of blood, stool, weight, and blood pressure taken before, immediately after, and at intervals up to six weeks. Funding came from sources including the German Federal Ministry of Education and Research.
