• A new study shows that eating an oatmeal-only diet for two days lowered cholesterol levels for six weeks.
• The study found that a sudden influx of oats can lead to beneficial gut microbiome activity and disrupt cholesterol processing at the cellular level.
• A parallel six-week study conducted by the same researchers, which replaced one meal a day with oats, did not observe similar cholesterol reductions.

In clinical trials, people who followed a low-calorie diet consisting primarily of oatmeal for two days experienced long-lasting reductions in LDL (“bad”) cholesterol and total cholesterol levels.

The reduction in cholesterol levels lasted for 6 weeks after the 2-day diet.

LDL levels decreased by 10%, which was less than what could be achieved with drug therapy, but still significant.

The first study investigated the effects of a two-day oatmeal diet, with 32 women and men either on the oatmeal diet or on a standard calorie-reduced diet for the same period of time.

17 people on the oatmeal diet ate 300 grams of oatmeal per day. They were allowed to supplement their cereal with vegetables and fruits. In total, they consumed half as many calories as normal. After two days of oatmeal therapy, dieters returned to their habitual diet without oatmeal.

Those who went on the oatmeal diet lost 2 kg of weight and saw a slight decrease in blood pressure immediately after two days on the diet.

The second study investigated the effects of regularly incorporating oats into the diet. Seventeen people replaced oatmeal with a choice of oatmeal, porridge, oatmeal, smoothie, or baked goods in their daily meals for six weeks while maintaining their typical overall daily caloric intake. The 17 members of the study’s control group did not make any changes to their regular diet, except that they avoided oats.

Researchers found that simply incorporating oats into the daily diet plan did not produce measurable changes in LDL or total cholesterol levels after six weeks.

The implications of this study are that short-term, intensive consumption of oats may be more effective in: reduce cholesterol Rather than incorporating oats into your diet regularly.

Associate Professor Marie Christine Simon, from the University of Bonn, Germany, is the study’s principal investigator. She said the intense exposure to oats provided by the two-day diet produced a strong response by the gut microbiome.

Simon discussed the “dosage and rapid exposure to oat components, particularly the phenolic compounds metabolized by oats.” intestinal flora — can cause more powerful biochemical reactions than modest daily intake. ”

Specifically, she says, “High-dose meals provide much higher amounts of oat phenolics and fiber than a single regular meal. This results in higher levels of substrates ( ferulic acid) for microbial metabolism. ”

This was supported by fecal samples collected for the study, Simon reported. “This high oat load significantly increased phenolic metabolites produced by microorganisms, especially dihydroferulic acid, which is associated with cholesterol reduction.”

Furthermore, Professor Simon suggested that the sudden influx of oats “could cause a rapid change in the metabolic activity of gut microbes, producing more bioactive compounds that can enter the circulation and influence host lipid metabolism.”

Overall, this suggests that phenolics may interfere with cholesterol processing at the cellular level.

Simon was optimistic but cautious about whether repeating the short-term oatmeal diet regularly could help control cholesterol.

“The hypothesis that repeated short-term, high-dose oat interventions may result in recurrent or sustained LDL reductions, particularly if intestinal metabolic pathways are continuously engaged, with effects on body weight and blood pressure, may be scientifically reasonable, but this needs to be tested in future RCTs (‘randomized controlled trials’).

The results of this study do not mean that daily consumption of oats, along with appropriate medications prescribed by your doctor, has no role in controlling your cholesterol levels.

Michelle Ruthenstein, MS, RD, CDCES, CDN; I am a registered dietitian specializing in heart disease. She said, “In a small, tightly controlled setting, it is easier to observe significant short-term changes than the gradual LDL improvements typically seen when oats are incorporated into the daily free-living diet, where many other factors are also involved.”

Dr. Rosenstein cautioned in his study that “follow-up periods based on self-reported habitual intake cannot fully tease out the impact of oats on subtle improvements in overall diet quality and changes in body weight that may also contribute to lower LDL levels.”

“From a real-world perspective, this result remains encouraging,” she says.

“Regularly incorporating moderate amounts of oats along with other soluble fiber sources, plant protein, and overall nutrient adequacy within a heart-healthy dietary pattern remains a practical, evidence-based way to support LDL lowering and cardiometabolic health without the need for extreme or short-term dietary approaches.”
— Michelle Ruthenstein, MS, RD, CDCES, CDN

Rosenstein already recommends oats to clients seeking cholesterol control, but not as a silver bullet, but as one component of a broader, plant-friendly, high-viscosity fiber intake pattern.

She explained that oats also support the gut microbiome by providing beta-glucan. “Meta-analyses have shown that consuming about 3 grams of oat beta glucan, typically two to three servings of oats or oat bran, per day can lower LDL by about 5 to 10 percent,” Rosenstein noted.

“Oats are nothing special,” she added. “Barley has similar LDL-lowering effects as its beta-glucan equivalent, and whole grain rye and other viscous fiber-rich grains also provide modest cholesterol benefits.” These grains also provide other healthy nutrients.