Bifidobacterium Animalis

• Bifidobacterium animalis (B. animalis) is naturally found in the intestines of most humans and other mammals. It is anaerobic (does not need oxygen to live) and rod-shaped. It is Gram-positive (turns purple when fixed to a microscope slide and treated with the chemicals crystal violet, iodine, alcohol, and safranin) and produces lactic acid when it eats lactose (milk sugar). The bacteria's name includes what was once known as two separate species, Bifidobacterium animalis and Bifidobacterium lactis (B. lactis). The two are now considered subspecies of B. animalis, but both names are still often used on probiotics products labels.
  
  

Probiotics

• "Probiotic" means "for life" in Greek. Probiotics are dietary supplements that include live, non-harmful bacteria and yeasts that may provide health benefits when ingested. By eating or drinking them, users hope to replace or supplement the bacteria in their gut to improve digestion and provide other health benefits. According to a 2003 article by Natural Solutions Magazine, to be beneficial, a probiotic should include at least 1 billion live bacteria per daily serving, but many probiotic supplements contain far too few live animals to be helpful.
  
  

Probiotic Yogurt

• Yogurt (or yoghurt) is made of milk that is treated with billions of non-harmful bacteria that turn lactose into lactic acid. This thickens and sours the milk. Usually, commercial yogurt is heated to kill the bacteria, but when it is not, it is labeled as "active," "live" or "live-culture" yogurt.
  Probiotics are usually grown on dairy products that are similar to yogurt, but yogurt cannot legally be classed as probiotic unless bacteria that are specifically considered probiotic are added to it. Yogurt, like Activia, that includes live B. animalis can be labeled probiotic.
  
  

Health Claims

• According to "The Probiotics Revolution: the Definitive Guide to Safe, Natural Health Solutions Using Probiotic and Prebiotic Foods and Supplements" by Gary B. Huffnagle (2008), these are some of the health benefits attributed to probiotics use:
  Preventing or treating yeast infections
  Improving cholesterol levels
  Preventing or treating colon cancer
  Stimulating the immune system
  Improving vitamin and mineral absorption
  Reducing constipation
  Improving symptoms of lactose intolerance
  
  Dannon claims on its website (activia.us.com/bifidus.asp) that eating Activia daily for two weeks can improve digestive regularity by slowing the speed at which food travels through the digestive system.
  
  

Scientific Research

• On its website, Dannon names these four peer-reviewed research articles to support the statement that eating Activia is beneficial:
  Berrada N., et. al.; "Bifidobacterium from fermented milks: Survival during gastric transit"; Journal of Dairy Sciences; 1991
  Pochart P, et. al.; "Survival of bifidobacteria ingested via fermented milk during their passage through the human small intestine: an in vivo study using intestinal perfusion"; American Journal of Clinical Nutrition; 1992; 55:78-80
  Arunachalam K.D., et. al.; "Role of bifidobacteria in nutrition, medicine and technology"; Nutrition Research; 1999, Vol 19, 10: 1539-1597
  C. Picard, et. al.; "Review article: bifidobacteria as probiotic agents--physiological effects and clinical benefits"; Alimentary Pharmacological Therapy; 2005, 22:495-512
  
  From these articles, it is not clear whether any company sponsored this research to support commercial claims.