A short-term, calorie-restricted diet heavily focused on oats may significantly lower levels of “bad” cholesterol, according to a recent clinical trial conducted in Germany. The study, published in Nature Communications, found that consuming a diet comprised almost entirely of oats for just two days led to a 10% reduction in LDL cholesterol, with benefits lasting up to six weeks.
Oatmeal and Metabolic Syndrome
Researchers at the University of Bonn investigated the effects of this dietary intervention on individuals with metabolic syndrome – a condition characterized by an increased risk of diabetes and cardiovascular disease. Metabolic syndrome encompasses a combination of risk factors including overweight, high blood pressure, and abnormal glucose and lipid levels.
During the trial, participants followed a calorie-restricted diet for two consecutive days, primarily consisting of oatmeal. Results demonstrated a significant improvement in cholesterol levels compared to a control group who also reduced calories, but without the specific focus on oats. This benefit persisted even six weeks after the intervention concluded.
300 Grams of Oats Daily and Measurable Health Changes
The study protocol involved participants consuming oatmeal boiled in water three times daily, with the option to add fruits or vegetables. A total of 32 women and men completed the intervention, each consuming 300 grams of oats daily for the two-day period, reducing their caloric intake to approximately half of their usual amount.
While both groups in the study experienced benefits associated with calorie restriction, the effects were notably more pronounced in those who consumed oats. “The level of LDL cholesterol, especially harmful, was reduced by 10% in them; Here’s a substantial reduction, although not entirely comparable to the effect of modern medications,” stated Professor Marie-Christine Simon, from the Institute of Nutritional and Food Sciences at the University of Bonn.
Participants also experienced an average weight loss of two kilograms and a slight reduction in blood pressure.
The Role of the Gut Microbiome
The research team discovered that the diet altered the composition of the gut microorganisms. According to Linda Klümpen, the study’s lead author, “We were able to identify that the consumption of oats increased the amount of certain intestinal bacteria.” These bacteria actively participate in food metabolism and generate byproducts that influence various bodily functions.
Some compounds produced by these bacteria enter the bloodstream and can influence cholesterol metabolism. “For example, we were able to demonstrate that intestinal bacteria produce phenolic compounds when breaking down oats,” Klümpen explained. “It has already been shown in animal studies that one of them, ferulic acid, has a positive effect on cholesterol metabolism. This also seems to occur with some of the other bacterial metabolic products.”
The study also identified that other gut microorganisms reduced the presence of the amino acid histidine, which can be transformed into a molecule associated with insulin resistance within the body.
A High Dose in a Short Timeframe is Key
Researchers concluded that the benefits were most evident with a high intake of oats concentrated in a short period, combined with calorie restriction. A parallel intervention, where participants consumed 80 grams of oats daily for six weeks without other limitations, only produced slight improvements.
“A short-term oat-based diet, at regular intervals, could be a well-tolerated way to keep cholesterol levels within the normal range and prevent diabetes,” Simon suggested. Researchers are now planning to evaluate whether repeating this intensive diet every six weeks can generate a sustained preventative effect over the long term.
