Regular probiotic supplementation has been shown to maintain intestinal health and enhance natural immune system response by stimulating the body’s production of Natural Killer and T- cells.


By helping to increase the number of healthy bacteria in the gut, probiotics improve digestion and can reduce bloating, gas, constipation and diarrhoea. But how?

Some strains like Lactobacillus acidophilus create lactic acid, which then reduces the pH (alkaline level) of the intestine. This speeds up the digestive process and allows stools to pass through the colon more quickly, which in turn reduces the incidence of constipation.


When the digestive system is overrun by harmful bacteria, the gut cannot absorb all the food – and the result is diarrhoea. Probiotics are therefore a natural alternative to over-the-counter remedies that can have unwanted side effects.


There is evidence that as we age the body becomes less efficient in digesting food and extracting nutrients from it. A healthy level of probiotics can aid nutrient absorption by improving digestion. They do this by producing more of the enzymes that break down food.


Probiotics aid the digestion of fat and some strains like Bacillus coagulans have been shown to help lower LDL (the ‘bad’ form of cholesterol) and increase HDL levels (the good form).


Since better digestion improves metabolism, the result might translate to better energy levels. However, the research on probiotics and improved energy show mixed results. In some cases supplementation with probiotics does improve energy and in others it does not. Researchers believe that this is due to the significant difference in microbiome make-up between individuals.
The conclusion from this – and indeed the research generally – is that a probiotic supplement with multiple strains is likely to be more effective, because this increases the probability that it will include the strains that most benefit you.


We’ve seen that pharmaceutical antibiotics can negatively disturb probiotic balance. But some strains of probiotic (like Lactobacillus bulgaricus) can act as natural antibiotics.
In documented research, the strain Lactobacillus acidophilus DDS-1 has been shown to produce the natural antibiotic-like substance acidophilin, which kills pathogenic bacteria like salmonella and E. coli.
Dr Khem Shahani, from the University of Nebraska and the developer of L. acidophilus DDS-1, has demonstrated that it has a similar antibiotic effect to streptomycin (a strong antibiotic), but that the effect was selective – killing just the pathogenic bacteria.


Candida albicans the mouth, intestinal tract and vagina.

Candida yeast in normal amounts helps with digestion and the absorption of nutrients. But when candida overproduces, symptoms may appear that include chronic fatigue, hormonal imbalances, mood disorders and thrush, which itself causes itching and discomfort.

Left unchecked, candida overgrowth breaks down the walls of the intestinal lining and penetrates into the bloodstream. This releases by-product toxins and other toxins from your system, causing leaky gut syndrome and can even infect membranes around the heart or brain.

Researchers have identified sugar-rich Western diets, together with excessive use of antibiotics, as a reason for the big increase in candida yeast infections. Candida thrives on food sugars and vaginal candidiasis often follows antibiotic therapy. Other contributing factors include birth control pills and cortisone drugs.

Probiotics – and especially Lactobacillus acidophilus and Bifidobacterium bifidum – can stimulate the production of white blood cells in the body that combat candida yeast and fungal infections. A 1990 report in the Lancet recorded that women with candida were cleared of the condition with a course of L. acidophilus.


Both Lactobacillus bulgaricus and L. acidophilus DDS-1 (note that L. here – and usually elsewhere – is shorthand for lactobacillus) have been shown in laboratory studies to inhibit tumour growth and help block the formation of carcinogenic compounds. The collaborative research was conducted by Nebraska’s Dr Shahani and the Sloan Kettering Institute in New York. Anti-tumour effects have also been detected in L. casei and Streptococcus thermophilus.

The mechanism for this potential effect is not totally clear but was investigated in a 2008 paper by M T Liong on pro- and pre-biotics and colon cancer in the International Journal of Molecular Sciences.

Probiotics ... In-vivo and molecular studies have demonstrated encouraging outcomes, mainly attributed to its antimicrobial effects against carcinogen- producing microorganisms, anti-mutagenic properties, and alteration of the tumor differentiation processes.
Prebiotics ... also possess protective effect against colon carcinogenesis, mainly attributed to production of short chain fatty acids upon fermentation by gut microflora, and alteration of gene-expressions in tumor cells.
Synbiotics ... (combination of probiotic and prebiotic) has been found to exert a synergistic effect in improving colon carcinogenesis compared to when both were used individually.”

In addition, nitrites used in food processing can be converted to carcinogenic (cancer causing) nitrosamines in the digestive tract. L. acidophilus has been shown in vitro to inhibit this chain of events.


Osteoporosis is the loss of bone density. L. acidophilus improves the ability of the body to absorb and metabolise calcium and is therefore potentially an important element in a dietary regime aimed at improving bone density. In addition L. acidophilus synthesises vitamin K, which is needed for calcium to be transported to form bone. A probiotic supplement following an antibiotic course is therefore especially important for women at risk of osteoporosis.


Parkinson’s is the second most common neurodegenerative disease. Researchers at Caltech University have confirmed (December 2016) that changes in the composition of gut bacteria are contributing to – or might actually cause – the deterioration in motor skills that characterises Parkinson’s disease.

The initial clue was that 75 percent of people with Parkinson’s have gastrointestinal (GI) abnormalities, primarily constipation and bloating. And, says lead researcher Sarkis Mazmanian, these GI problems often precede the motor symptoms by many years.

Although the study was in mice – as inevitably so many preliminary studies are – the implications are that improving gut flora could be a way to cut the risk of this incurable disease. It is early days, however, as the researchers have yet to identify particular strains of probiotic that would form part of a preventative strategy.

Nevertheless, a preliminary conclusion is that a multi-strain probiotic is a logical defensive choice. This could be coupled with an anti-inflammatory nutritional supplement, since it’s known that another characteristic of Parkinson’s patients is the presence of inflammatory molecules called cytokines within the brain.


Glucose is the blood sugar that comes, not just from refined sugar, but from metabolising carbohydrate foods. It is released into your bloodstream during digestion. Insulin from the pancreas helps break down these sugars and move them from your blood into your cells to create energy.

Research published in the US National Institutes of Health (NIH) Library of Medicine indicates that probiotic supplementation – specifically Lactobacillus and Bifidobacterium strains – can help maintain optimal blood glucose levels.

High blood sugar levels are part of a dangerous condition known as metabolic syndrome. Metabolic syndrome combines high blood sugar, high blood pressure, high cholesterol, and increased levels of adipose (body fat) tissue, especially around the tummy. This type of fat releases toxic chemicals that further increase inflammation within
body tissue.

Metabolic syndrome conditions very significantly increase your risk for stroke and heart attack, as well as diabetes. The NIH has published studies showing that probiotic supplements can help reduce the risks for these diseases.


The British Journal of Nutrition noted that the intestinal flora of fatter people differs from thin ones. Could rebalancing their microbial status lead to weight loss?

To test this hypothesis, researchers recruited 125 overweight men and women. The subjects followed a 12-week weight-loss diet, followed by a further 12-week period aimed at maintaining body weight. Throughout the study, half the participants took 2 capsules daily containing probiotics from the Lactobacillus rhamnosus family, while the other half received a placebo.

After the 12-week diet period, researchers observed an average weight loss of 4.4 kg in women in the probiotic group and 2.6 kg in the placebo group.

After the 12-week maintenance period, the weight of the women in the placebo group remained the same, but the probiotic group continued to lose weight, up to a total of 5.2 kg.
Therefore women consuming probiotics lost twice as much weight over the 24-week period of the study. Researchers also pointed out that the appetite-regulating hormone leptin decreased as did the intestinal bacteria that characterise obesity.

The possible reason? Probiotics may act by altering the permeability of the intestinal wall. By keeping certain pro-inflammatory molecules from entering the bloodstream, the probiotics might help prevent the chain reaction that leads to glucose intolerance, type 2 diabetes and obesity.

A meta-analysis in the International Journal of Food Sciences and Nutrition summarised 25 randomised human trials on the impact of probiotic consumption on body weight and BMI in over 1,900 healthy adults. They found taking probiotics did reduce Body Mass Index (BMI) and body weight.

Taking more than one type of probiotic for a period of 8 weeks or more resulted in the most weight loss. Other studies have shown that subjects who supplement with probiotics can experience a measurable reduction in overall belly fat.
The potential for probiotics to contribute to achieving a healthy weight is logical, given the essential role of gut bacteria in breaking down food and nutrients.


Traveller’s Diarrhoea (aka “Montezuma’s Revenge”) is a quite frequent and unpleasant accompaniment to the otherwise joys of foreign travel. It is an infection of the stomach and intestines that is primarily caused by unaccustomed bacteria in the foods and water consumed – the normal culprit being the enterotoxigenic E. coli.

Preventative strategies of course include washing your hands or carrying a hand sanitiser, using bottled water to clean your teeth, not eating salads washed in local water and not eating raw foods. But the Journal of Nutrition also recommends a multi-strain probiotic taken two weeks before and during the trip as a good way to cut the risk.


The mouth contains hundreds of species of bacteria. In addition, putrefying bacteria in the gastro-intestinal tract can cause halitosis (bad breath). One outcome of an increased level of ‘good’ bacteria has been found to be improved oral health and a reduction in incidence of bad breath.


According to the World Health Organisation (WHO), stress is the fourth leading cause of disability worldwide and the 2015 Stress in America survey indicates worryingly increasing levels of stress in adults – to the point where 78% reported experiencing at least one symptom of stress and 24% incidents of extreme stress.

We have seen the importance and strength of the gut/brain signalling mechanism. In stressful conditions, the brain reacts and sends signals to several parts of the body, including the ‘second brain’ of the gut and vice versa.

There are now dozens of studies that confirm probiotics can have a role in lowering the damaging effects of stress, to the extent that one researcher has coined the term ‘psychobiotics’.

University Health News, which compiles health studies, reported on a 2015 randomised, double-blind, placebo-controlled trial (the gold standard for human trials). The trial randomly assigned patients with major depressive disorder to receive either probiotic supplements or placebo. The probiotic consisted of 2 billion CFUs each of Lactobacillus acidophilus, L. casei, and Bifidobacterium bifidum.

After eight weeks, patients who received the probiotic had significantly decreased total scores on the Beck Depression Inventory, a widely used test to measure the severity of depression, compared with placebo. In addition, they had significant decreases in systemic inflammation as measured by C Reactive Protein levels, significantly lower insulin levels, reduced insulin resistance, and a significant rise in glutathione, the body’s key antioxidant.

In another controlled study reported in Applied and Environmental Microbiology, a probiotic given to medical students in the 8 weeks prior to their examinations reduced stress among the

Lead author Dr Kouji Miyazaki said:

“The probiotic Lactobacillus casei Shirota can relieve many aspects of the stress response, especially gastrointestinal dysfunction.
“These findings indicate that the stress responses are controlled by probiotics ... through the brain-gut axis. Thus, the probiotic strengthens the resilience of our stress response system.”


Health on the outside is a reflection of health on the inside, so many people taking a course of probiotics report better skin tone.

German researchers noted that eczema patients consistently had very low levels of lactobacilli and that a 10 week course of probiotic supplements including L. acidophilus alleviated the condition – although other studies have showed no similar benefit. Skin fungal conditions like athlete’s foot may well respond positively.


Recent research shows that many health problems, including colitis (inflammation of the colon), weight gain, asthma, diabetes and even depression are linked to an imbalance of probiotics.

Colitis in particular can lead to the cell walls of the intestines becoming permeable (leaky gut), increasing the chance of digestive upset and negative reactions to gluten and dairy products.

An imbalance of healthy bacteria combined with a leaky gut is now linked to an increased risk of diabetes and heart disease. And, due to the direct gut brain connection, an imbalance can also lead to neurological problems that include depression and even migraine.

One study has also suggests a link between good bacteria and seasonal allergies, particularly with hay fever.

Perhaps the best summary of benefits – albeit in medical language – is from The Journal of Clinical Gastroenterology 2011 titled 'Impact of probiotics on colonizing microbiota of the gut’:

“Increased levels of Bifidobacterium and Lactobacillus in the gut correlate with numerous health endpoints. Microbiota changes due to probiotic intake include ...

•  Decreasing pathogens and their toxins
•  Altering bacterial community structure to enhance evenness
•  Stabilizing bacterial communities when perturbed (eg. with antibiotics)
•  Promoting a more rapid recovery from a perturbation.”