Obesity is characterized by chronic low-grade inflammation, which contributes to the development of cardiovascular disease. While processed foods and beverages high in saturated fats and simple sugars are associated with a higher risk of cardiovascular disease, diets rich in plant-based foods, including fruits, are associated with a lower risk. Findings of a recent report detail the effects of daily apple consumption on inflammation, endotoxemia, and metabolism.

Causes of obesity-associated inflammation include leaky gut, a condition where the intestinal barrier is compromised, leading to increased levels of bacterial endotoxin (toxins that are released when bacteria die) in the bloodstream (called endotoxemia). This increase in endotoxin levels activates white blood cells to secrete pro-inflammatory cytokines such as interleukin (IL)-6 and IL-17. Plant foods such as apples are beneficial for people with obesity because they are rich in bioactive compounds that decrease inflammation and dietary fibers that strengthen the gut barrier.

The researchers recruited 46 participants with overweight and obesity and directed them to avoid foods and beverages rich in polyphenols and/or dietary fibers (e.g., coffee, vegetables, grains, beans, and red/purple/blue fruits) for two weeks. Next, they assigned half of the participants to consume three Gala apples per day for six weeks or to avoid apples. Both groups continued to eat a diet with limited polyphenols and dietary fibers. Participants provided blood samples for the collection of white blood cells and measurement of pro-inflammatory cytokines. After isolating the white blood cells, the researchers stimulated them with endotoxin and measured their response.

Apple consumption decreased plasma C-reactive protein (a pro-inflammatory cytokine) by 17 percent, IL-6 by 12 percent, and endotoxin-binding protein by 20 percent compared with no apple consumption. White blood cells from participants who consumed apples secreted 28 percent less IL-6 and 11 percent less IL-17. While apple consumption increased total antioxidant capacity in blood by 10 percent, it had no effect on cardiovascular disease markers.

These findings suggest that six weeks of daily Gala apple consumption helped mitigate inflammation in those consuming a diet low in polyphenols and fiber, a common feature of the Western diet pattern. Apple consumption may decrease cardiovascular disease risk in those with obesity, even without weight loss.

• Link to full report.