I tend to buy live-culture yogurts, because I read that they contain "healthy bacteria". What does this mean and are such yogurts and yogurt drinks beneficial to our health?
Conventional remedy
Probiotic drinks are those containing live cultures such as lactobacillus and bifidobacterium, which enhance intestinal health by impairing the growth of harmful gut bacteria and by lining the intestinal wall, to prevent unwanted bugs attaching to it.
Studies of children suggest probiotics help reduce the duration of diarrhoea. Children taking probiotics on an ongoing basis suffer less from viral-type gastroenteritis. Evidence is also beginning to emerge of probiotics' ability to influence the immune system. Elderly people given bifidobacterium, for example, show enhanced levels of interferon, the naturally occurring antiviral agent.
Lactobacillus has been shown to reduce both the severity and duration of infant diarrhoea. The addition of the probiotic to oral hydration solutions benefits children with acute diarrhoea and has helped bring about earlier hospital discharge.
Probiotics also help reduce the effects of diarrhoea caused by broad-spectrum antibiotics. Other conditions that seem to benefit include ulcerative colitis, in which probiotics may help to maintain disease remission; irritable bowel syndrome; and recurrent vaginal infections.
Lactose intolerance is now a recognised cause of stomach symptoms such as flatulence, diarrhoea, abdominal pain and cramping. This is due to poor enzyme function within the gut, and there is some evidence that probiotics replenish an enzyme called beta-galactosidase, which helps to restore the body's utilisation of the lactose contained in milk and dairy products.
A recent Finnish study has supported the hypothesis that some intestinal bacteria play important roles in preventing allergic disease. Researchers investigated whether Lactobacillus rhamnosus could prevent eczema. They enrolled more than 150 pregnant women with personal or family histories of hay fever, eczema or asthma.
Each mum-to-be took two capsules of lactobacillus a day for two to four weeks before delivery, then carried on for another six months. Breastfed children were then given lactobacillus with their mothers' milk; bottle-fed babies were given a suspension of the bacterium.
The children were followed up for two years; the results showed a 50 per cent reduction in cases of eczema.
Because of their mothers' medical histories, the children had an increased genetic susceptibility to allergic disease. That the probiotic helped strongly suggests that the normal flora of the gut might have a role in preventing allergies.
There is growing evidence that probiotics are a useful therapy. But further studies are required to clarify their role in relation to specific clinical conditions, and the dosage of each probiotic, before they could be routinely prescribed. - Dr Muiris Houston
Alternative remedy
Pure live yoghurt, containing L. bulgaricus or S. thermophillus, can be of great benefit to your health. A lot of commercially available "yogurts" would not qualify as yogurt, live or otherwise.
This is largely down to commercial factors such as the addition of stabilisers, which prevent the bacteria eating the fruit in fruit yogurts, and the addition of sugars, artificial sweeteners, colouring agents and preservatives, which provide a long shelf life. The lesson is to read food labels carefully.
If you suffer from a dairy intolerance, yogurts will not be good for your health. Dairy intolerance is a relatively common problem, and it is not overcome by the fermentation process. In fact, eating yogurt may make the symptoms worse.
Don't despair however. You can get pure live yogurts from specialist shops or by choosing particular brands from good supermarkets. A way to test if a yogurt is live is to try to use a few tablespoons of it as a starter culture for your own yogurt. If you can, it is live; if you can't, it is not. The quality of any starter culture is critical to a yogurt's health-giving properties. Some cultures cannot survive the digestive process, particularly the encounter with stomach acid.
So, if you are not dairy intolerant and can be guaranteed the viability of the cultures, then yogurt is good for you - but don't expect too much from the more commercial brands. Also, there are some good brands of soya-based products with live cultures that may be worth giving a try. To find out more, read any of Leon Chaitow's books. - Maria Costello
Maria Costello (061-316693) is a Limerick-based nutritional therapist
The advice in this column is not intended as a substitute for advice received directly from a medical doctor or alternative practitioner. Individuals should receive a thorough diagnosis before embarking on treatment