Nutrition – Gut reactions

Reach for a pint of milk in a supermarket and you'll find that the dairy counter has been bugged. Probiotic drinks such as Actimel and Yakult, as well as the supermarket's own versions of these, seem to promise instant health from 'gulps of goodness'.

Will this help?

Reach for a pint of milk in a supermarket and you’ll find that the dairy counter has been bugged. Probiotic drinks such as Actimel and Yakult, as well as the supermarket’s own versions of these, seem to promise instant health from ‘gulps of goodness’.


The question is, how good are these supercharged yogurts and do cyclists really need them? The makers of one probiotic product claimed it takes oxygen into your body – something which would certainly appeal to tired, lactate saturated muscles. However, this is an impossibility since the bacteria in the drinks are anaerobic which means they would die in the presence of oxygen!

Bacteria boost

Say the word ‘bacteria’ and most people think disease, putrefaction and decay. So it’s hard to imagine swallowing billions of bacteria on purpose – and a logical reaction is to reach for the bleach. However there is absolutely no doubt that a healthy gut can help boost your immune system and improve the absorption of nutrients from the food you eat.

When you are born, your gut is completely sterile. Then you become infected and bacteria begin to colonise, finding their own particular niches suitable for growth, along the entire length of your gut. Soon it becomes a thriving mass and you end up with around ten times more bacterial cells than the number of cells in your entire body! The average weight of the bacterial mass in women is around 800g (the weight of about eight apples) and 1kg in men.

A few of these bacteria are potentially harmful but are effectively crowded out by the good, or ‘probiotic’ bacteria. These carry out a wide range of functions. Some manufacture essential B vitamins (needed to help release the energy from carbohydrate, so especially important for cyclists), produce digestive enzymes or substances which can help to neutralise carcinogenic compounds.

It’s a fierce world in your gut, though, and the good and bad bacteria are constantly competing. The delicate balance can be upset by everything from emotional stress to fatigue. A particularly hard ride not only challenges your endurance, but can leave your insides in chaos. A course of antibiotics or cycling in a different country and sampling new foods can jolt the system and change your microbial mix. When pathogenic (bad) bacteria outnumber the probiotics, the effect can range from tiredness, mild diarrhoea and abdominal bloating to more serious problems such as ulcers or cancer.

An obvious way to restore or maintain the right balance is to gulp down probiotics – an idea which has been turned into a multi-million pound industry.

Special strain

Each brand contains its own specially cultured strain of bacteria, similar to that which exists naturally within our gut. It all sounds very simple, but bacteria are delicate and only a few strains are able to thrive in the human digestive tract. These include the Bifidobacterium and those from the Lactobacillus family. These live in our bowels but in order to get there, must travel through the stomach and small intestine. Most are destroyed by the highly acidic conditions in the stomach. If they do survive the journey, and get to the bowel, they must be able to latch on to its walls and multiply.

Only strains of bacteria which can survive, attach and reproduce are of any value as a probiotic. The bacteria in ‘bioactive’ yogurts do not usually survive the journey. While natural yogurt is a good food, the bacteria it contains will not contribute to those in the lower gut.

Probiotic products need to contain at least 10 million of the right type of bacteria (such as L Casei immunitas or Bifidobacterium bifidum) to be effective. But the little pots of useful bacteria also come loaded with sugar, cheap fillers and colourings – making a cleverly marketed health product not so healthy. Yakult have recently produced a ‘sugar free’ version but this contains the artificial sweetener aspartame, which is to be avoided.

No nasties

If you want the bacteria without the nasties, a better choice would be probiotic supplements. The BioCare range includes Bio-Acidophilus which contains an impressive 8 billion Lactobacillus and Bifidobacterium mix.


Another effective way to increase the number of friendly bacteria in your large bowel is to take prebiotics. These are found naturally in foods such as bananas, leeks, onions, garlic, tomatoes, chickpeas and sunflower seeds. Prebiotics are basically a picnic for friendly gut bacteria which are not destroyed by the high acidity in the stomach. But, if you suffer from bloating, constipation, or have taken a course of antibiotics, there is a case for taking a more concentrated prebiotic supplement. If you want to make sure you get the full package, there are now synbiotics which contain both the good probiotic bacteria and prebiotics which feed them.