Lowering bad cholesterol usually means long-term diet changes or medication. But what if a very short dietary change could make a difference? A new study suggests it might.
Researchers from the University of Bonn found that eating mainly oats for just two days led to a significant reduction in harmful LDL (low-density lipoprotein) cholesterol in people with metabolic syndrome. LDL cholesterol deposits fat along artery walls, forming plaques that narrow blood vessels, and when these plaques rupture, they can trigger clots that cause heart attacks or strokes. The study, published in Nature Communications, showed that
LDL cholesterol fell by about 10 per cent, and the effect was still seen six weeks later.
The research, titled Cholesterol-lowering effects of oats induced by microbially produced phenolic metabolites in metabolic syndrome: a randomised controlled trial, suggests that oats may improve cholesterol not only because of their fibre content, but also by changing gut bacteria in ways that support better lipid metabolism.
The researchers ran two randomised controlled trials involving adults with metabolic syndrome, a cluster of conditions that includes excess weight, high blood pressure, abnormal cholesterol and raised blood sugar, all of which increase the risk of heart disease and diabetes.
One group followed a two-day intensive oat diet, while another tried a six-week moderate oat intake. Both were compared with control diets that either matched calories or reflected a typical Western diet, but without oats.
What participants ate during the two-day oat diet
For 48 hours, participants ate 300 grams of oatmeal per day, divided into three meals. The oats were cooked in water, with only small amounts of fruit or vegetables allowed, and no other foods. Importantly, their overall calorie intake was roughly half of what they normally consumed.
A control group also reduced calories, but without oats, allowing researchers to test whether oats themselves made a difference.
Did oats lower cholesterol levels?
According to the study, while calorie reduction improved health markers in both groups, those
eating oats saw around a 10 per cent drop in LDL (bad) cholesterol, a level considered clinically meaningful. Total cholesterol also fell, along with modest reductions in weight and blood pressure.
The study highlighted that cholesterol levels remained lower even six weeks later, long after participants had returned to their usual diets.
Researchers found that oats changed the gut microbiome, boosting bacteria that break down oat compounds into phenolic metabolites, which are bioactive molecules that can enter the bloodstream and influence cholesterol metabolism directly.
Why smaller amounts of oats over six weeks were less effective
In the second part of the study, participants ate 80 grams of oats daily for six weeks, without cutting calories. According to the researchers, oats appear to be most powerful when consumed in high doses over a short period, especially alongside calorie restriction. A small daily serving may help stabilise cholesterol, but it does not trigger the same microbial and metabolic shift.
Could this become a practical prevention strategy?
The authors suggest that short, intensive oat-based diets repeated at intervals might offer a simple, well-tolerated way to manage cholesterol and reduce diabetes risk, particularly for people with metabolic syndrome.
However, they caution that this approach is not a replacement for medication where drugs are clinically indicated, and larger studies are needed to test long-term safety and effectiveness.
For more health updates, follow #HealthWithBS This content is for informational purposes only and is not a substitute for professional medical advice.
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