Medically reviewed on June 7, 2018
What is Yogurt?
Yogurt is the general term for a fermented, slightly acidic milk product that contains essentially no alcohol. Most commonly, it is prepared by the addition of live cultures of Streptococcus thermophilus and Lactobacillus bulgaricus to heated whole or skim cow's milk. The mixture is incubated and homogenized to a semisolid. Condensed skim milk or dry milk solids sometimes are added to produce a custard-like texture. If cultures of Lactobacillus acidophilus are added, the product is called acidophilus milk. Yogurt provides a dietary source of calcium and protein, as well as folic acid, magnesium, and zinc.
What is it used for?
Yogurt has been promoted to restore the GI flora after systemic antibiotic therapy and to alleviate anal pruritus, aphthous ulcers, and canker sores. The large number of bacteria in active yogurt (each milliliter of commercial brands contains about 125 million L. bulgaricus and 125 million S. thermophilus) may hasten colonization in the colon, thereby removing the reservoir of yeast infection. More than 3 decades ago, bacterial replacement therapy with live cultures was found to have no established value in the prevention or treatment of such disorders. Yogurt possesses intrinsic antibacterial activity, probably largely because of its lactic acid content. Lactic acid has demonstrated bactericidal activity against some organisms, but this is probably not the only factor in eliminating the bacteria.
Cardiovascular and cholesterol reduction effects
Fat loss and weight loss have been demonstrated with the use of yogurt. Enhanced calcium intake was proposed as the mechanism for this effect. Older studies have demonstrated a cholesterol-lowering effect with yogurt. Surveys suggest yogurt has a protective effect against coronary heart disease and elevated blood pressure.
One human clinical study showed that the addition of yogurt to the diet significantly reduced a marker of bone resorption in menopausal women. Despite the debate that exists regarding the role of supplemental calcium in the prevention of osteoporosis, yogurt remains a recommended source of calcium.
Yogurt also may have some anticancer properties. Yogurt has a protective effect against some cancers in laboratory experiments, but convincing human data are not available.
Yogurt has been used as a substitute for milk for those who are lactose intolerant. Yogurt has been at the center of a controversy regarding milk products that can be tolerated by people with lactase deficiency. Studies are inconclusive. Reports by those with lactose intolerance and other bowel disorders indicate individual responses that often vary from study results.
Yogurt also has been used to prevent recurring vaginal yeast infections. There has been some interest in the direct vaginal instillation of yogurt for the treatment of Candida infections. However, the clinical effects of this therapy have not been defined in well-controlled studies, and this practice cannot be widely recommended, particularly in pregnant women.
What is the recommended dosage?
In addition to its widespread use as a food, yogurt has been studied in clinical trials in amounts of 100 to 200 g/day.
The use of yogurt containing live cultures (probiotic) is not advised in patients at risk for opportunistic infections or in those with badly damaged GI tracts.
Generally recognized as safe when used as food.
None well documented.
Yogurt is not associated with any significant adverse reactions.