Positive Health Online

Over the last 10-15 years, probiotics have undergone something of an image transformation. Not so long ago most medics considered them to be a quack remedy on a par with snake oil, with no proof of efficacy. Fast forward to 2012, hundreds of scientific studies later and probiotics are now being recommended by gastroenterologists and on national TV (Channel 4 The Food Hospital) as part of an effective treatment for IBS-induced hair loss.

Probiotic is a Greek word which means "for life". The health benefits of cultured and fermented foods have a long history dating back to ancient civilizations. It wasn't until the early nineteenth century however, that a culture of Streptococcus Thermophilus and Lactobacillus bulgaricus was officially developed by Metchnikoff, the head of the Pasteur Institute in Paris, who proposed it as a tonic for the bowel.

In addition to specific immune related functions, some of the researched effects of probiotics are:

• Synthesis and absorption of B vitamins[1] including B3, B6, biotic and folic acid;.
• Synthesis of vitamin K;
• Recycling of oestrogen involved in female hormone imbalance;
• Manufacture of lactase,[2] the enzyme that digests lactose in dairy products.
• Absorption of minerals, particularly iron and calcium. This is good reason to take a probiotic when supplementing minerals;
• Relief of constipation by helping to form soft, bulky and well lubricated stools which pass through the colon swiftly. A four week Canadian study in which probiotics were given to 70 people with chronic constipation found that 89% reported an improvement in symptoms;[3]
• Binding of cholesterol in the gut, to lower excess levels;[4]
• Prevention of travel bugs. A study by Professor Glenn Gibson, head of microbiology at Reading University showed that taking probiotics for five days before and during travel abroad resulted in a 30 percent reduced likelihood of picking up bugs.[5]
• Supportive of healthy digestive function;
• Management of inflammation;
• Prevention/treatment of atopy in children;[6,7]
• Production of antimicrobial substances which destroy yeasts and bacteria. Some species produce anti-tumour substances;
• Detoxification of harmful substances;
• A recent review  discusses the link between obesity and changes in the composition and metabolic function of gut microbiota/ There is evidence to show that different strains of bacteria are found in the guts of overweight people compared to lean people.  Gut microbes change according to the type of diet eaten and certain types (which can be passed from one generation to another) will affect the physiology of the host and influence weight gain.  

Barrier Defences
At a recent lecture organized by the Natura Foundation, I was reminded about the importance of flora, not only in the gut, but on other body barriers such as the skin, lungs, eyes, ears, nose and throat. These are the first line of defence against the external environment and healthy flora should form a thick protective layer over the barriers.  This means infection causing pathogens cannot gain entry and activate the immune system. Allergies and intolerances are also less likely to occur.

Causes and Effects of Imbalanced Bacteria
A certain amount of unhealthy gut bacteria is a given but the ratio between good and bad is what is important. If the good bacteria are found in large enough quantities in the human gut, the undesirable, disease causing bacteria will be kept in check.[8] A balance favouring the unhealthy bacteria is known as dysbiosis. Dysbiosis is a factor in many common conditions, including, for example, rheumatoid arthritis, allergy, IBS, diabetes, obesity and chronic fatigue syndrome.

Smoking, unhealthy food choices, medications and environmental pollution all negatively affect bacterial balance.  Of the medications, antibiotics, steroids (e.g. cortisone, ACTH, prednisolone, the Pill, HRT) are particularly destructive to the bowel flora. Chemotherapy will mean intensive probiotic therapy is needed.

Stress will interfere with barrier repair because it alters the pH in favour of a medium which encourages unhealthy bacteria. Stress also stimulates enzymes that eat away at the gut lining.

The best way to assess the state of the flora is to check the stools! A healthy stool should be cylindrical in shape, not at all sticky, break up easily when flushed and have no odour. If this is not the case, your bowel flora probably need improving. A diet rich in vegetables and soluble fibre (oats, wholegrain rice, spelt, rye bread) will help. However grains do not suit some people's digestive systems and IBS sufferers cannot tolerate too much fibre. A probiotic supplement can be useful.

Probiotic Supplements
Choose a probiotic that is effective i.e. contains a high number of bacteria and proven strains that are resistant to stomach acid and will adhere to the intestinal wall. A capsule or powder is generally preferable to a yoghurt drink which often has sugar added. The species of probiotic is, for example Lactobacillus acidophilus or Bifidobacterium lactis and there are lots of different strains within the species, for example L. acidophilus DDS-1. This means that two acidophilus supplements will be different.

When to take Probiotics
The ideal time to take probiotics is on an empty stomach at least half an hour before breakfast or in the evening before bed, at least 2 hours after food.

The consensus amongst probiotic specialists is that it is worth taking a probiotic concurrently with a course of antibiotics and continuing the probiotic for a few weeks afterwards, rather than waiting until the antibiotics are finished before starting the probiotics. A gap of a few hours should be left between the probiotic and antibiotic when they are being taken simultaneously.

References
1. Alm L et al. Effect of Fermentation on B Vitamin Content of Milk in Sweden. Journal of Dairy Sciences 65: 353-359. 1982.
2. Alm L, Journal of Dairy Sciences. 64(4): 509-514. 1981.
3. Koebnick C, Wagner I, Ising K, Stern U. Ernaehrungs-Umschau 48: 392-396. 2001.
4. Marteau PR. Probiotics in clinical conditions. Clinical Reviews in Allergy and Immunology
 22 (3):255-73. 2002.
5. Black FT et al. Prophylactic efficacy of Lactobacilli on travellers diarrhoea. Conference in international travel medicine 1, Zurich, Switzerland. Berlin. Springer 333-5. 1989.
6. Viljanen M et al. Probiotic effects on faecal inflammatory markers and on faecal IgA in food allergic atopic eczema/dermatitis syndrome infants. Pediatr Allergy Immunol 16(1): 65-71.
7. Kirjavainen PV et al. Aberrant composition of gut microbiota of allergic infants; a target of bifidobacterial therapy at weaning? Gut 51(1): 51-55. 2002.
8. Collado MC et al. The impact of probiotics on gut health. Curr Drug Metab. Jan;10 (1):68-78. 2009.