Why do probiotic supplements containing certain bacteria benefit human health instead of causing illness?

• A. They introduce beneficial bacteria that help maintain a healthy balance of the gut microbiota.
• B. They increase the acidity of the stomach to destroy all pathogens.
• C. They eliminate all bacteria from the digestive tract, preventing any infections.
• D. They directly attack and destroy human immune cells to prevent overreaction.

Answer: (A)

Verified step by step guidance

1. Understand the role of the gut microbiota: The human digestive tract contains a complex community of microorganisms, including bacteria, that play essential roles in digestion, immune function, and protection against harmful pathogens.
2. Recognize what probiotics are: Probiotic supplements contain specific strains of beneficial bacteria that, when ingested, can help restore or maintain the natural balance of the gut microbiota.
3. Analyze why probiotics benefit health: These beneficial bacteria compete with harmful microbes for nutrients and attachment sites, produce substances that inhibit pathogens, and stimulate the immune system in a balanced way.
4. Evaluate the incorrect options: Increasing stomach acidity to destroy all pathogens is not the primary function of probiotics; eliminating all bacteria would disrupt the microbiota balance and harm health; directly attacking immune cells would be harmful and is not a probiotic action.
5. Conclude that probiotics help maintain a healthy gut microbiota balance, which supports digestion and immune health, rather than causing illness.