A new study has found probiotics may help weight loss surgery patients avoid a vitamin B12 deficiency, which is a common side effect of the procedure.

Researchers at Stanford University School of Medicine followed 44 patients who had gastric bypass surgery. They found that those who received a probiotic supplement everyday for three months following their procedure had a significantly higher weight loss as well as higher levels of vitamin B12 than those who got a placebo pill.

The group who received the probiotics had a 47.6 percent weight loss compared with a 38.5 percent loss in the control group.

Almost two-thirds, or 66 percent, of adult Americans are overweight. Gastric bypass is the most common weight loss surgery because it is associated with fewer complications than other interventions.

Vitamin B12 is important for proper metabolism, the formation of red blood cells and health of the central nervous system.

Probiotics are good bacteria that are known to aid digestion. They can be found in foods like yogurt and other cultured milk products, miso, tempeh, some juices and soy beverages. They can also be taken as a nutritional health supplement.