Probiotics are live cultures which have earned the affectionate title of 'friendly bacteria' due to their potential ability to benefit health through improving the balance of bacteria in the intestines. The use of probiotic bacteria in health has been subject to much research in recent years with some promising results. It may help to prevent and treat infectious diarrhea and reduce the occurrence of antibiotic-induced diarrhea. This may be due to acid production by the probiotic bacteria and also competition resulting in fewer harmful bacteria

Probiotics may also assist in reducing the risk of developing colon cancer, with a number of studies observing lower rates in populations consuming more fermented dairy produce (i.e. yoghurt).

Cholesterol levels may also benefit as probiotic bacteria encourages the liver to use up cholesterol to make bile acid which the bacteria digests, instead of releasing cholesterol into the blood stream.

Currently there is a lot of interest in the use of probiotics to promote remission in Inflammatory Bowel Diseases, (IBD) such as Crohn's Disease, but more work is required to identify the specific strains of bacteria that are beneficial. Further areas of reported improvement include better immune function, control of blood pressure, lactose digestion in the lactose intolerant and symptomatic relief of Irritable Bowel Syndrome (IBS).

Probiotics may sound like a cure-all but their efficacy is dependant on having the right strain of bacteria in high enough numbers. Many different strains exist, commonly members of Lactobacillus and Bifidobacterium species. Their actions may further vary according to the health and genetic make-up of their human host.

Yoghurt is the most common probiotic carrier, and by its very nature, contains live bacteria. These are not necessarily probiotic, however, and to be classified as such they need to be able to survive the digestive process. For example, yoghurt starter bacteria Lactobacillus bulgaricus and Streptococcus thermophilus are not very resistant to conditions in the stomach and small intestine and therefore not considered probiotic.

China has certainly hopped on the probiotic bandwagon in the last two years; around 20 percent of yoghurt products are now probiotic. Yili produce a range of plain and drinking probiotic yoghurt in blue containers of varying sizes with 'LGG' on the front (which stands for the strain of bacteria used). Bright dairy produces 'Abioo' probiotic yoghurt with a distinctive lime green and royal blue packaging. Mengniu make an extensive range of fruity yoghurts in 3-sided pots, with the probiotic initials 'LAB' on the bottom left-hand corner.

Additional sources of probiotics include Korean kimchi and German Sauerkraut - both pickled vegetables using probiotic bacteria in the preservation process. Kefir is a sour fermented milk drink commonly consumed in Mongolia, made by incubating bacterial plugs (kefir grains) with cow's or goat's milk.

Optimise your friendly bacteria intake by including one probiotic yoghurt product daily - add it to cereal in the morning, grab a pot and a straw as a snack on the move or make smoothies by blending together fresh fruit, yoghurt and ice.

This nutrition-related column is written by Nina Lenton, a qualified dietitian living in Beijing and working at Bayley and Jackson Medical Center. Contact her at nina.lenton@bjhealthcare.com.

(China Daily 05/23/2007 page14)