Yogurt and You: What Everyone Should Know About Live Cultures

Yogurt is a popular dairy product produced the world over by the bacterial fermentation of milk. It commonly contains a live and active culture of both Lactobacillus bulgaricus and Streptococcus thermophilus. Some yogurts may also contain Lactobacillus acidophilus and Bifidus regularis (such as Activia, a low-fat probiotic yogurt produced by Dannon).

What are live and active cultures?

They're living organisms! Lactobacillus bulgaricus and Streptococcus thermophilus, two of several underrated "good guys" in the wide world of bacteria, convert pasteurized milk into yogurt by fermenting the milk sugar lactose (a disaccharide consisting of glucose paired with galactose), producing lactic acid as a byproduct. The increased acidity of the solution causes the milk proteins to denature and tangle into the gel-like texture characteristic of yogurt. The increased acidity also prevents the proliferation of potentially pathogenic bacteria within the mixture.

What are the health benefits of yogurt?

For starters, yogurt is rich in protein, calcium, as well as the vitamins D, B-2, B-12, potassium and magnesium. It is a huge source of calcium, accounting for nearly 40% of the Food and Drug Administration's (FDA) recommended daily value. Generally speaking, probiotics also benefit the alimentary canal by regulating digestion, adjusting the microflora of the large and small intestines, and significantly enhancing immune function (namely, increasing the level of gamma interferon, which is a protein that assists white blood cells in fighting off disease).

How does this affect you?