Lactobacillus rhamnosus GG is a beneficial microorganism, part of a group known as probiotics. These are live bacteria and yeasts that can provide health benefits when consumed in adequate amounts. Discovered in 1983, the GG strain is one of the most extensively researched probiotics globally, due to its ability to function effectively within the human body.
The Uniqueness of the GG Strain
The specific probiotic strain Lactobacillus rhamnosus GG owes its name to the two scientists who first isolated it from the intestinal tract of a healthy human: Sherwood Gorbach and Barry Goldin. Unlike many other bacteria, L. rhamnosus GG is exceptionally resilient. It has a notable capacity to survive the harsh, acidic environment of the stomach and then endure exposure to bile in the small intestine. This resilience ensures that the bacteria can reach the lower gastrointestinal tract alive.
Once in the intestines, the GG strain exhibits a strong ability to adhere to the mucosal lining. It accomplishes this using unique, hair-like structures on its surface called pili, which allow it to attach to intestinal cells. This adherence allows the probiotic to colonize the gut temporarily and influence the intestinal environment. These survival and adhesion capabilities are primary reasons it has been the subject of hundreds of clinical studies.
Primary Health Functions
One of the most well-documented roles of L. rhamnosus GG is in supporting digestive health, particularly in the context of diarrhea. For instance, it is frequently used to help reduce the incidence and duration of diarrhea associated with antibiotic use. Antibiotics can disrupt the natural balance of gut bacteria, and this probiotic helps restore that balance. It has also been shown to be beneficial in cases of infectious diarrhea, such as traveler’s diarrhea and acute gastroenteritis.
Beyond the gut, this probiotic strain has demonstrated an ability to interact with and support the immune system. A significant portion of the body’s immune system is located in the gut, and L. rhamnosus GG can influence immune responses. It has been observed to stimulate the production of certain immune cells and proteins that help regulate inflammation. This interaction helps to fortify the gut’s defensive barrier, making it more difficult for harmful substances to pass from the intestine into the bloodstream.
Another area of investigation for L. rhamnosus GG involves skin health, specifically in relation to atopic dermatitis, a type of eczema. Some studies have explored its use, particularly in infants and children, as a way to manage this inflammatory skin condition. The connection is thought to be rooted in the link between gut health and systemic inflammation, often referred to as the gut-skin axis.
Sources and Proper Dosing
Lactobacillus rhamnosus GG is most reliably found in the form of dietary supplements. While some fermented foods like yogurt contain probiotics, they do not typically contain this specific strain unless it has been explicitly added by the manufacturer. This specificity is important, as the effects of probiotics are strain-dependent, and other L. rhamnosus varieties may not have the same supporting evidence.
When selecting a supplement, the dose is measured in Colony-Forming Units (CFUs), which indicates the number of viable bacteria in each serving. For L. rhamnosus GG, dosages used in clinical studies vary depending on the intended purpose and the age of the individual. For general gut health in adults, doses often range from 1 to 10 billion CFUs taken once or twice daily. For managing specific conditions like antibiotic-associated diarrhea, higher doses may be used.
For children, dosages are lower and should be determined based on the product’s instructions or consultation with a healthcare provider. Taking the supplement with a meal may improve its survival through the digestive tract. Consistency is more important than the specific time of day it is taken for establishing its presence in the gut.
Safety and Potential Side Effects
Lactobacillus rhamnosus GG is widely considered safe for consumption and has been granted “Generally Recognized as Safe” (GRAS) status in the United States. It has a long history of use in infants, children, and adults with a low incidence of adverse effects. When side effects do occur, they are mild and temporary, reflecting the body’s adjustment to new microorganisms in the gut. The most commonly reported effects are minor digestive changes, such as increased gas or bloating, which often subside within a few days.
While it is safe for most people, certain individuals should consult with a healthcare professional before starting any new supplement. People with severely weakened immune systems, such as those undergoing chemotherapy, organ transplant recipients, or individuals with advanced HIV, are advised to avoid probiotic supplements. The concern in these cases is a small risk of the probiotic bacteria entering the bloodstream and causing an infection.
Others who should seek medical advice include individuals with a central venous catheter or patients with short bowel syndrome. These conditions may alter interactions with probiotics, and use should be discussed with a doctor.