JOY: New Vaccine May Prevent Weight Gain And Stop Obesity, Study Finds

Heat-killed bacteria found in cow’s milk and soil could Aid Weight Loss And revolutionize obesity prevention, offering a safe and accessible solution to combat weight gain and inflammation caused by high-fat, high-sugar diets

New research from the University of Colorado Boulder suggests that a microorganism commonly found in cow’s milk and soil could be key to preventing weight gain and inflammation associated with high-fat, high-sugar diets. The study, published in Brain, Behavior, and Immunity, reveals that mice injected with the bacterium Mycobacterium vaccae (M. vaccae) gained less weight and accumulated less visceral fat — the type of fat linked to heart disease and diabetes — despite consuming a Western-style diet.

Bacteria vs. the Global Obesity Epidemic

The study’s lead researcher, Christopher Lowry, a professor in the Department of Integrative Physiology, believes this discovery could lead to groundbreaking solutions for the global obesity crisis.

“Our studies demonstrate that regular treatment with a single species of bacterium with well-documented anti-inflammatory effects can, unexpectedly, completely prevent excessive weight gain in response to consumption of a Western-style diet,”

Lowry explained.

He added that the research might prompt a fundamental rethinking of obesity’s causes, offering new insights into how inflammation and immune system interactions contribute to weight gain.

How the Study Was Conducted

Researchers fed mice either a standard, nutrient-rich diet or a Western-style diet for ten weeks. The Western-style diet consisted of:

• 40.6% of calories from fat,
• 40.7% from carbohydrates (18.2% from sugar),
• 18.7% from protein.

While both groups consumed the same caloric intake, only some mice received weekly M. vaccae injections. The results were striking: mice on the Western diet without the injections gained significant weight and visceral fat, while the vaccinated group showed no such weight gain, matching the healthy diet group in body weight and fat accumulation.

The Role of “Old Friends” Microbes

Lowry highlighted the concept of “old friends” — microorganisms, such as M. vaccae, that humans co-evolved with but lost contact with due to modern urban lifestyles. These microbes historically regulated our immune systems and prevented excessive inflammation.

“The bacterium we studied was heat-killed, so there’s no risk of infection. Instead, it drives anti-inflammatory and immunoregulatory effects, interrupting the cycle of inflammation, weight gain, and metabolic disorders,”

Lowry said.

The researchers believe that other “old friends” microbes may similarly protect against diet-induced obesity by boosting regulatory T cells (Tregs), immune cells that prevent chronic inflammation and metabolic complications.

Beyond Weight Control: Mental Health Benefits

The benefits of M. vaccae extend beyond weight management. The bacterium decreased neuroinflammation and anxiety-like behaviors in mice, consistent with decades of research showing its ability to promote stress resilience.

“This microorganism prevents stress-induced inflammation and its negative outcomes, such as heightened anxiety and fear responses,” Lowry explained.

Implications for Human Health

While the findings are promising, Lowry emphasized the need for further research to determine if these effects can be replicated in humans.

Future studies will explore:

• Whether M. vaccae can reverse established obesity.
• How its anti-inflammatory properties influence weight gain.
• The potential for developing accessible and affordable treatments for vulnerable populations.

Lowry’s team is already working on commercial applications through Kioga, a new spinout company at the University of Colorado Boulder.

Hope for the Future

With obesity rates and related diseases like type 2 diabetes on the rise, innovative, scientifically-backed solutions are crucial. If proven effective in humans, M. vaccae could revolutionize weight management and reduce the health risks of Western-style diets.

As Lowry concludes,

“There’s something innately attractive about addressing the global obesity epidemic by simply replacing an organism we inadvertently lost through modernization. This research offers hope for a safe, accessible approach to preventing obesity and its complications.”