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Next in Q & A Thursday, Emma has asked about using probiotic supplements after having antibiotics – do they work and what’s the most effective and inexpensive way of taking them?

Probiotics include supplements like Inner Health and Yakult. They contain bacteria or other microorganisms that have a beneficial effect on health.

The official definition from the World Health Organisation is that probiotics are:

Live microorganisms which when administered in adequate amounts confer a health benefit on the host

Gut flora

While some people find it a disturbing thought, there are currently millions and millions of bacteria in your digestive tract. In fact there are about ten times the number of microorganisms in your digestive tract as there are cells in your body. It’s estimated our gut contains about 500 different species in total, although 90 percent come from only 30 – 40 species.

Probiotics seem to live in a symbiotic relationship with us, and we definitely derive a number of benefits from their presence. This is one of the nutrition topics where research is still relatively new, however it’s believed probiotics:

• break down otherwise undigestible carbohydrates, producing short chain fatty acids in the process
• prevent harmful bacteria from colonising the gut and causing disease
• are involved in the immune response, reducing the likelihood of allergies and auto-immune conditions
• prevent inflammatory bowel disease
• may improve the absorption of some minerals
• can produce a number of vitamins, including vitamin K and B12

In short, probiotics help to normalise the functioning of your gut, they produce certain nutrients and they help balance our immune system.

What changes your gut flora?

The balance of bacteria in your digestive system can be affected by:

• antibiotic use
• use of specific drugs, such as antacids and gastric acid inhibitors.
• stress
• a high fat and low fibre diet
• diarrhoea and gastro-intestinal upsets

Should you take probiotics after taking antibiotics?

There is evidence that taking antibiotics can affect the number and balance of probiotics in your system, causing bloating, abdominal discomfort and diarrhoea. If this is you, then a course of probiotics after antiobiotic therapy can be useful.

To encourage the healthy growth of probiotics, you also need to eat plenty of prebiotic foods, such as fruit, vegetables and legumes. These act as a food source for the probiotic bacteria and encourage the establishment of a healthy colony.

Contrary to some suggestions it seems on recent evidence that probiotic bacteria do survive the digestive process to take up residence in the intestines.

What to take?

When it gets down to brands, the story starts getting a bit trickier. Most vitamin companies produce at least one type of probiotic and (of course) everyone believes there’s is the best. But . . . most of them haven’t been extensively trialled, there’s little independent information on product comparisons and most of the trials so far have been run by the vitamin companies themselves.

Plus there’s still a lot we don’t know about probiotics. While the most well known is Lactobacillus acidophillus, there are a range of other species that exist and it’s likely that a balance of these microflora produces the optimal effect. It’s also likely the probiotic supplement which will minimise allergies is different from the one to be used after antibiotics, and so on. It’s a big area of research, but there’s still a lot we don’t know.

When choosing a probiotic:

• it’s important they’re kept in a the fridge
• they should be packaged in either dark coloured bottles or plastic containers to minimise exposure to light
• they should have a foil seal, underneath the lid, to minimise exposure to air
• on current research it’s believed the Lactobacillus acidophillus and Saccharomyces boulardii species are the most important for restoring balance after antibiotic use

What is Q & A Thursday?

This post is part of Q & A Thursday – a weekly burst of blogging, where you get to dictate the subject matter. Q & A Thursday is all about simple, practical and sensible answers to food, diet and health dilemmas sent in by readers. If you have a question you’d like answered, then either leave a comment or send me an email. For more information you can take a look at the Q & A Thursday archives.

13 September, 2007