Can taking probiotics help with weight loss?

The microbiota of obese individual has been shown to have a reduced diversity and composition of gut microbiota, differing from that of lean individuals. The gut microbiota is a living environment which plays an important role in the immune system, as a modulator of energy balance (homeostasis) and deposition of fat. Restoring the richness and variety of the microbiota has been shown to improve the integrity of the gut, reduce inflammation and alter the metabolic defects which result in obesity.

What is a probiotic?

Probiotics are live microorganisms – bacteria and yeast, which are good for health and the digestive system. They help with food digestion, vitamin production and eliminating disease-causing cells.

Probiotics can be found in such foods such as yogurt, fermented foods, honey and apple cider vinegar. Probiotics are also available as therapeutic supplements used to treat conditions such as constipation, diarrhoea, acid reflux, eczema, and obesity. The most common therapeutic bacteria belong to groups called Lactobacillus and Bifidobacterium, but other bacteria may also be used as probiotics, and also yeasts such as Saccharomyces boulardii.

Probiotics and Obesity

Probiotics exert an anti-obesity effect. They do this by modulating the microbiota, lowering insulin resistance and suppressing appetite by increasing feelings of satiety. Several studies have shown probiotics and prebiotics display potential therapeutic effects on body weight, waist circumference, BMI, the distribution of fat, lipid profile and inflammation.

The microbiome

The gut microbiota include the bacteria which reside in the gastrointestinal tract (GI), from the mouth to the small and large intestine. The residential inhabitants of the human gastrointestinal tract are various and considered crucial for human health, offering protective, structural and metabolic functions. These include:

• Protection. They do this by displacing harmful bacteria, competing for nutrients and producing factors which are anti-microbial.
• Developing the immune system and inducing immunoglobulin A (IgA) – the first line of defence against invading bacteria and viruses.
• Reinforcing mucosal barrier function. Preventing toxins and harmful bacteria from entering the bloodstream. 
• Synthesizing beneficial nutrients – vitamin K, folate and biotin
• Supporting the absorption of nutrients – magnesium, calcium and iron ions.
• Metabolizing dietary compounds and non-digestible foods - producing short-chain fatty acids.

The majority of microbes are found in the large intestine and their growth is reliant on the human diet – specifically non-digestible carbohydrate. These compounds are called prebiotics.

Prebiotics

Prebiotics have the ability to alter the composition and function of the microbiota.

Prebiotics influence the growth and activity of beneficial microorganisms – bacteria and fungi. They are a group of nutrients, such as fructo-oligosaccharides and galacto-oligosaccharides (GOS) obtained from food which are degraded by the microbiota energy (food for microbes).

Short-chain fatty acids

The digestion of prebiotics produce short-chain fatty acids (SCFAs), which are absorbed and circulate in the blood, supporting the gastrointestinal tract distant and  organs. SCFA’s support the immune system and decrease the pH of the colon.

Short-chain fatty acids; propionate, acetate, and butyrate, offer positive effects in the body.

• Propionate is an energy source - synthesizing glucose and lipids in the liver.
• Acetate is used as a substrate in the synthesis of cholesterol. Click Here for why we need cholesterol. 
• Butyrate is used as an energy source for the epithelial cells of the intestine.

How do probiotics effect obesity?

Probiotics restore the microbiota to a “lean gut microbiota”. They do this by:

• Modulating the composition of the gut microbiota composition and metabolism.
• Offering an antimicrobial activity. Reducing the growth of pathogenic microorganisms and their ability to adhere to the intestinal mucosa and epithelium (intestinal wall).
• Reduce intestinal permeability. Leaky gut is a basic term referring to a "loose intestinal wall" which allows toxins and bacterial substances to enter the bloodstream. Intestinal permeability is associated with metabolic diseases. Click Here for further reading

The microbiota is associated with food intake, satiety and energy balance.

Restoring the gut microbiota

Prebiotics, probiotics and symbiotic (a combination of both) can be used to help rescue the gut. 

Probiotics to use

Several probiotics used either alone, or in combination, have been shown (in animal models) to be successful species for reducing weight and fat accumulation. These include:  Lactobacillus (e.g., L. Casei strain Shirota (LAB13), L. Gasseri, L. Rhamnosus, L. Plantarum) and  Bifidobacterium (e.g., B. Infantis, B. Longum, and B. Breve B3) species.

Types of prebiotics

There are many prebiotics – the majority are oligosaccharide carbohydrates (OSC’s). They can be found in fruit, vegetables, grains, seeds and supplemental forms. Some examples include: 

• Vegetables: garlic, onions, shallots, leeks, asparagus, artichoke, beets, Brussels sprouts, savoy cabbage, fennel and snow peas, konjac root, burdock root, yacon root. 
• Fruits: apples, watermelon, grapefruit, nectarine, persimmon, plums, pomegranate, ripe bananas, dates, prunes, raisins, cocoa.
• Grains: barley, oats, wheat bran
• Seeds: flaxseeds
• Seaweed: sushi, and supplements such as spirilina and algae
• Inulin: as a supplement 

The diet

The diversity of the gut microbiota determines the effectiveness of obtaining energy from food during digestion. The food eaten influences the population and diversity of the gut microbes.

To support optimal gut health include prebiotic food - vegetables, legumes, fruit, bread, cereals, nuts, seeds and inulin. Probiotic foods such as fermented foods such as yoghurt, kefir, sauerkraut, tempeh, kimchi, miso, kombucha and pickled vegetables.

The bottom line

For long-term weight-loss goals to be achieved and maintained, sustainable lifestyle and diet changes need to be employed, with the goal being to improve over-all health.

References

1. https://www.nccih.nih.gov/health/probiotics-what-you-need-to-know
2. Probiotics: How Effective Are They in the Fight against Obesity? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412733/
3. The gut flora as a forgotten organ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1500832/
4. Dietary intervention impact on gut microbial gene richness https://pubmed.ncbi.nlm.nih.gov/23985875/
5. Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6463098/
6. https://www.immunology.org/public-information/bitesized-immunology/receptors-and-molecules/immunoglobulin-iga
7. Gut Microbiota and Obesity: A Role for Probiotics https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893459/
8. The Role of Probiotics and Prebiotics in the Prevention and Treatment of Obesity https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6470608/
9. Intestinal permeability – a new target for disease prevention and therapy https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4253991/