- Can Probiotics Really Help with Weight loss?
Can Probiotics Really Help with Weight loss?
Probiotics have been touted as a treatment for everything from asthma and allergies to diabetes and even skin ageing. While there is much hype – there are also some encouraging findings from clinical studies across a range of conditions – including their use in aiding weight loss and in the fight against obesity. We examine the evidence to separate the facts from the hype.
So What Are They Exactly?
Probiotics are micro-organisms – such as bacteria and yeasts – that can provide health benefits when consumed. While some bacteria are bad for us, most are harmless and many actually help us stay healthy. In fact without them our digestive functions, our immune system and our health in general would be at risk.
Our bodies are home to as many as 100 trillion microbes – more cells in our bodies are foreign microbes than are human DNA. Most of these microbes live in our gut, supporting our digestion and our immune system, fighting infection and regulating our metabolism. They even influence our cravings, our mood and our mental health .
While Scientists are a long way from understanding exactly how each of the different strains and species – of which there are many- interact and influence our health, they are in agreement that a ‘normal and healthy’ microbiome is one that is a diverse and balanced ecosystem – and that many health conditions – including obesity and diabetes lack this diversity and ‘balance’ of probiotic bacteria.
How Can Probiotics Help with Weight Loss?
Taking Probiotics can help replace desirable strains and species of bacteria and microbes in our gut to rebalance our biome with these beneficial strains of microbes – inorder to increase the health and diversity of our microbiota.
There are clear differences in the makeup of gut flora in overweight or obese people compared with normal lean people (4, 5, 6). Overweight and obese people tend to have less diversity in their microbiota, as well as higher proportions of Firmicute bacteria compared with Bacteroidetes (the reverse is true in people of a normal, healthy weight).
Our gut microbiota can affect our body weight in a number of ways, such as
- Our metabolism; both the energy we extract from food and also the energy we burn
- The health and permeability of our gut lining and associated inflammation
- Our cravings, as a result of our bodies signals for hunger and satiety 
Probiotics are thought to be able help reduce and maintain a healthy body weight by altering our gut microbiota to affect each of these . However it is a hugely complex area that is not yet fully understood and there continues to be much research.
Probiotics For Metabolism and Energy Absorption
Changes to the gut flora in overweight or obese people can affect their metabolism, including how much energy is absorbed from food, how much is used and how much is stored. In clinical studies the microbiota in obese people were found to increase the amount of energy extracted from their diet when compared to lean people consuming the same diet.
Another early but promising area of research has been investigating how alterations to the gut microbiome can reduce fat absorption. 
In a recently published study specific bacteria were identified (8) that encourage energy and fat absorption – and that a typical western diet is thought to promote the growth of these microbes so that, over time, the presence of these microbes can lead to higher levels of energy absorption, weight gain and obesity.
Probiotics To Reduce Body Fat and Weight Gain
In a study at Karolinska Institutet, Sweden, published in 2010, the team of researchers were able to reduce fat storage in mice with the probiotic Lactobacillus paracasei .
The probiotics were found to increase the levels of the protein ANGPTL4 which resulted in a reduction in body fat stored.
Probiotics To Treat Obesity Induced Inflammation
Obesity is closely linked to chronic inflammation in the body and the brain, and it is widely thought that by improving gut health, probiotics may help reduce chronic inflammation and as a result prevent obesity and other diseases (4, 5).
Probiotics to Suppress Appetite and Cravings
In a study in 2013 at the National Institutes of Health, Maryland USA, probiotics were found to effectively treat obesity and weight gain in mice by promoting the release of GLP-1 – a hormone that encourages the release of insulin and promotes the feeling of satiety (or fullness) to reduce over consumption. Increased levels of GLP-1 are also thought to help burn calories and fat (8, 9).
Meanwhile In study published in the british-journal-of-nutrition investigated the impact of a Lactobacillus rhamnosus on weight loss in both men and women . The study – a double-blind, placebo-controlled, randomised trial, found that the probiotic taken over a 24 week period helped the Women in the study lose body weight and fat mass together with the appetite-regulating hormone leptin. However the probiotic was not found to have any beneficial effect on the men in the study.
What Evidence Supports the Use of Probiotics for Weight Loss?
To date most clinical studies examining the effect of probiotics on weight loss in humans have been largely inconsistent.
There is only one significant review that we’re aware of – that has found probiotics to have a significant effect on the weight of the participants.
In a review of 14 randomized control trials published in 2016, a collaboration between French and Israeli researchers Drora, Dickstein, Dubourg and Paul, 14 studies in adults were examined (9 of the studies included a probiotic dairy food, and 5 of a probiotic single strain supplement).
The authors found probiotics did have a significant bearing on the subsequent weight of the participants, the majority of whom were overweight or obese. The probiotics evaluated included the species Probiotic species included were Lactobacillus acidophilus, L casei, L plantarum, L gasseri, L rhamnosus, . bulgaricus, Bifidobacterium infantis, B lactis, B longum, B breve, Streptococcus thermophilus, and Saccharomyces cerevisiae.
In animal studies however the results are much more exciting, with certain strains of bacteria linked to weight gain and others to weight loss .
Notable studies include research at Washington University School of Medicine in St. Louis where gut bacteria from obese mice were transplanted into the gut of sterile lean mice; who as a result quickly gained weight leading to obesity (6).
In another study where sterile mice received gut microbes from obese and lean humans, the mice that received microbes from obese people gained weight while the mice that received microbes from lean people did not .
Our View: Should You Take Probiotics For Weight Loss?
Probiotics can influence your weight in a number of ways, including
- Metabolism: The amount of energy or calories you absorb from food, and fat you store.
- Cravings and appetite by influencing the hormones and proteins your body releases.
- Inflammation: probiotics can also help to reduce inflammation in your body and your brain, which can affect obesity.
However clinical studies while promising – are to date inconsistent and different strains of probiotics may have different effects. Scientists and doctors have stated that there is no reason for healthy adults to take probiotics – however research seems to suggest they may have some benefits if you are overweight or obese – or suffering from digestive problems and systemic inflammation.
It is worth noting though that probiotics alone will not offer much benefit – and that if you are serious about improving the health of your gut microbiome you need to consider what you eat – avoiding processed foods, excess sugar, stimulants and toxins and including more vegetables and prebiotic fibre in your diet.
Last of all – don’t forget your lifestyle is equally important – so make sure you are getting regular exercise, a full nights sleep each night and avoid excessive stress.
- Gough, E., Shaikh, H. and Manges, A.R., 2011. Systematic review of intestinal microbiota transplantation (fecal bacteriotherapy) for recurrent Clostridium difficile infection. Clinical infectious diseases, 53(10), pp.994-1002.
- Nazarii Kobyliak, Caterina Conte, Giovanni Cammarota, Andreana P. Haley, Igor Styriak, Ludovit Gaspar,corresponding author Jozef Fusek, Luis Rodrigo, and Peter Kruzliakcorresponding author. 2016. Probiotics in prevention and treatment of obesity: a critical view. Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4761174/
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- Ogawa, A., Kobayashi, T., Sakai, F., Kadooka, Y. and Kawasaki, Y., 2015. Lactobacillus gasseri SBT2055 suppresses fatty acid release through enlargement of fat emulsion size in vitro and promotes fecal fat excretion in healthy Japanese subjects. Lipids in health and disease, 14(1), p.20.
- Yadav, H., Lee, J.H., Lloyd, J., Walter, P. and Rane, S.G., 2013. Beneficial metabolic effects of a probiotic via butyrate-induced GLP-1 hormone secretion. Journal of Biological Chemistry, 288(35), pp.25088-25097
- Pannacciulli, N., Bunt, J.C., Koska, J., Bogardus, C. and Krakoff, J., 2006. Higher fasting plasma concentrations of glucagon-like peptide 1 are associated with higher resting energy expenditure and fat oxidation rates in humans–. The American journal of clinical nutrition, 84(3), pp.556-560.
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