Probiotics & Prebiotics - Do they really work?

Probiotic with cereals

Our first impression of bacteria is how deadly or infectious they are bit it is only a very small amount of them that are bad. For instance, out of 2500 strains of Salmonella only two of them cause trouble. Moreover, some bacteria such as E Coli, only causes havoc when ingested through the mouth. It normally lives in our guts' micro flora.

Things go wrong if they become too comfortable and over populate the micro flora. Here is where the bacteria in probiotics come to the rescue. These 'good' bacteria help keep the population of the others in place. Overpopulation produces excessive gases (hydrogen sulphide, H2S) hence bloating, diarrhoea, cramps and other symptoms of great discomfort.

What are Probiotics and Prebiotics?

Probiotics alive

Schrezenmeier & De Vrese (Am J Clin Nutr 73 (Suppl) 361s-364s 2001) define a probiotic as: 'A preparation or product containing viable, defined micro organisms in sufficient numbers, which alter the micro flora of the host intestine and, by that, exert beneficial health effects on the host'. Meanwhile, prebiotics are nutrients and constituents of food which our gut flora feed upon, thus increasing their numbers. Prebiotics include fructo-oligosaccharides, which are found naturally in many plants including leeks, onions, wheat, garlic, chicory root and artichokes.

The 1908, Nobel Prize-winning scientist Elie Metchnikoff of the Pasteur Institute in Paris provided the first evidence that microorganisms may be responsible for the health-promoting effects of fermented milks. After observing that Bulgarian peasants lived to ripe, old ages, Metchnikoff became convinced that their health and longevity were linked to microbes in the soured milk they copiously drank. He suggested that disease-causing 'bad' bacteria could be eliminated by ingesting large amounts of Bulgarian sour milk, which contained a beneficial 'good' bacterium later identified as Lactobacillus bulgaricus.

Probiotics may be found in live yoghurts or specially formulated powders, supplement pills or probiotic drinks which contain one or more of the strains of these bacteria. With food processing, pollution and antibiotic therapy, the numbers of bacteria living naturally in our gut are reduced, and research has shown that active consumption of bacteria increases the size of intestinal colonies, thereby improving digestion of food. Moreover, numerous studies have also shown that with optimal numbers of 'good' bacteria, the immune system is improved, increasing our ability to fight disease. Probiotics may also have a role in reducing the severity of food allergies and intolerances, and may help reduce severity of symptoms in both osteo- and rheumatoid arthritis.

Health Benefits of Probiotics

  • Managing Lactose Intolerance:

Because Lactic Acid Bacteria (LAB) convert lactose into lactic acid, their ingestion helps lactose intolerant individuals tolerate more lactose than what they would have otherwise.

  • Prevention of Colon Cancer:

In laboratory investigations, LAB have demonstrated anti-mutagenic effects thought to be due to their ability to bind with (and therefore detoxify) carcinogenic substances formed in cooked meat. Lower rates of colon cancer among higher consumers of fermented dairy products have been observed in some population studies.

  • Cholesterol Lowering:

Animal studies have demonstrated the efficacy of a range of LAB to be able to lower cholesterol levels, presumably by breaking down bile in the gut, thus inhibiting its re-absorption (which enters the blood as cholesterol).

  • Lowering Blood Pressure:

Several small clinical trials have shown that consumption of milk fermented with various strains of LAB can result in modest reductions in blood pressure.

  • Improving Immune Function and Preventing Infections:

Probiotics are thought to have several beneficial effects on immune function. They may protect against harmful bacteria overgrowth and there is evidence to suggest that they may improve immune function by encouraging production of cells in our body whose main function is to protect us against infections and cancers. Clinical trials have also demonstrated that probiotics may decrease the incidence of respiratory tract infections and dental caries in children. LAB foods and supplements have been shown to be effective in the treatment and prevention of acute diarrhoea; decreasing the severity and duration of rotavirus infections in children as well as antibiotic associated and travellers diarrhoea in adults.

  • Reducing Inflammation:

Probiotic foods and supplements have been found to modulate inflammatory and hypersensitivity responses, an observation thought to be at least in part due to the regulation of cytokine function. Clinical studies suggest that they can prevent reoccurrences of Inflammatory Bowel Disease in adults, as well as improve milk allergies and decrease the risk of atopic eczema in children.

  • Improving Mineral Absorption:

It is hypothesized that probiotic lactobacilli may help correct mal absorption of trace minerals, found particularly in those with diets high in phytate content from whole grains, nuts, and legumes.

  • Prevents Harmful Bacterial Growth Under Stress:

In a study done to see the effects of stress on intestinal flora, rats that were fed probiotics had no occurrence of harmful bacteria latched onto their intestines compared to rats that were fed sterile water.

Dead or Alive! Alive better

In one of its surveys the independent magazine 'Which?' reported that only 5-15% of bacteria in products tested survived all the way to the consumer! So is this a waste of money and false advertisement?

Luckily it is not an entirely 'yes' answer, because scientists demonstrated that the immune system in subjects given dead 'good' bacteria still responds. In California and Jerusalem irradiated probiotics (irradiation kills all living bacteria) where given to mice with gut inflammation.

The treatment reduced the inflammation in a similar way to giving "live" bacteria, and the researchers concluded that irradiated probiotics were just as effective.

According to the BBC, Professor Eyal Raz, one of the study authors, said: "Our goal was to address whether the metabolic activity of probiotics was mandatory for their protective effect." The team believes that part of the body's immune system called the "innate" immune system responded to the bugs, regardless of whether they were dead or alive. This immune response might be damping down the overactive response within the gut.

However, experts say that the presence of live rather than inactivated bacteria in the gut has several advantages. Firstly, the simple fact that they are occupying space and attached to the gut wall denies that space to harmful bacteria, particularly if their numbers increase over time.

Find out more about:

Food & Lactose Intolerance

Food intolerance is the inability to completely break down food resulting in cramps, bloating, wind, diarrhoea etc. Lactose Intolerance (milk) is the most common form and affects half the world population. Food Allergy is not Lactose Intolerance. A guide is provided.

Food & Milk Allergy

Food allergy is caused when the immune system mistakenly responds to food proteins thinking they are harmful substances. Symptoms include vomiting, itching, rash, and hives. Allergies in children are very common, but treatment with digestive enzymes may prove very helpful.

Coeliac or simply Wheat Sensitive?

In Coeliac Disease, gluten causes damage to the small intestines, however, more people are wheat sensitive. This shows negative in blood tests. Read how to diagnose and avoid false negative screening results.

Baby Colic

Baby colic is very distressing to both the baby and the parents. However, studies conclude that half the babies suffer due to lactase deficiency. This is easily treated by neutralising milk with lactase enzyme.

IBS or Simply Food Intolerance?

Medical studies confirmed 50% of patients diagnosed with Irritable Bowel Syndrome may in fact be Lactose Intolerant. Omitting dairy products from their diet, or treating it with enzymes has helped them start a new life. Since IBS symptoms are similar to LI, diagnosis can be confusing.

Carbohydrate Intolerance and Obesity

The inability to break down starch and other sugars leads to bloating, wind, cramps, diarrhoea, etc. Now there is evidence that obesity may be related to carbohydrate intolerance. There is some good news with the help of digestive enzymes