Gut Flora Plays a Role in Body Weight

Anne Seccombe

“Supplementing with probiotics such as acidophilus, bifidus and lactobacilli may assist in maintaining a normal weight or losing weight in overweight or obese individuals”

“There is a lot of uncertainty as to whether individual probiotic supplements are effective.  There is a lot of variability between the strains both in terms of their effects in the body, their care prior to ingestion and whether or not they can survive the acidic environment of the stomach and remain alive in the intestine for long enough to do their job.  Some strains need to be stored in the refrigerator.  A simple way of increasing the numbers of beneficial bacteria in your digestive system is to reduce the amount of sugar and refined carbohydrates in your diet and eat lots of fresh vegetables, a moderate amount of fresh fruit, whole grains and legumes (which often contain d-chiro inositol).  You can also use fresh fermented milk products such as kefir and naturally fermented, unpasteurised soy products such as tamari, tempeh and natto to re-seed your gut with beneficial micro-organisms

There are two major phyla or families of bacteria which inhabit our intestines and help to digest the food that we eat.  They are Firmicutes and Bacteroides.

Researchers have discovered that obese people have a different ratio of these gut flora to lean people.  It turns out that the microbes in the Firmicutes family have a larger arsenal of enzymes at their disposal to digest complex carbohydrates, making them much more efficient at what they do and allowing for more energy to be derived from the same amount of food. So this lends credit to those people who eat less than their acquantainces, whilst doing the same amount of exercise and still tend towards the heavier end of the scale.  We have traditionally put this down to individual rates of metabolism, however gut flora may also play a large part.

A related study found that lean people had a larger population of Bacteroides group microbes, comprising 20% of their gut flora, than obese people who only had 5% of these less efficient microbes.

All is not lost, however, whilst we share a core variety of gut microbes with our family even amongst identical twins there are differences and it is these deviations from the core set of microbes that can influence whether a person is lean or obese.  It is also possible to alter the composition of the gut flora through dietary changes.  When obese people followed either a low fat or a low carbohydrate diet for a year, the amount of Bacteroides microbes increased from 5% to 15% of total stool volume.  This means that if you follow a reduced fat/carbohydrate diet for a year you significantly improve the ratio of gut flora to be more in line with that of lean individuals and in theory, will then obtain less energy from carbohydrate-based foods.  Unfortunately researchers in the UK have failed to find the same effect with a shorter term study of 4 weeks, so it is likely that to obtain the benefits described the diet would need to be followed strictly for at least one year.

Kirsi Laitinen, a nutritionist and senior lecturer at the University of Turku in Finland presented findings at the European Congress on Obesity earlier this month which  found that supplementing with lactobacilus and bifidobacterium, commonly available probiotics, when a woman is pregnant from the first trimester continuing until she stops breast feeding exclusively (or 6 months post-partum) reduces excess fat around the abdomen in particular and total body fat percentages in general.  Women who received probiotic supplements and nutritional counselling specific to pregnancy had 1-2 % less body fat on average than women who received either a placebo and nutritional counselling or no counselling or probiotics whatsoever.  In fact, the study found that only 25% of the women who received the probiotic supplement were found, on review one year later to have central obesity (a BMI of 30 or above or a waist circumference of 80cm of greater) compared with 43% in women who received only dietary counselling but no probiotics and 40% in women who received neither nutritional counselling nor probiotic supplements.

Another Finnish study, this time on children, found that disturbances in the gut flora actually preceded children becoming overweight.  Children who had a greater percentage of bifidobacteria in their gut remained of normal weight, whilst overweight children were found to have only half the amount of bifidobacteria as their leaner cohorts.  In addition, overweight children were found to have more than twice the amount of staphylococcus aureus bacteria in their stools as their leaner cohorts.

Studies have found that probiotics may be beneficial to many aspects of our health, including:

  • Managing Lactose Intolerance – Some strains of bacteria convert lactose into lactic acid, so supplementation can increase the threshold of lactose that a lactose intolerant person can tolerate – say that 3 x fast!).
  • Lowering Risk of Colon Cancer – Population studies have found that cultures that consume fermented dairy products such as kefir have a lower incidence of colon cancer.  Laboratory studies indicate that this may be due to lactobacillus bulgaricus’ ability to bind to heterocyclic amines, carcinogenic substances which are formed when meat is charred and by inhibiting an enzyme called beta-glucuronidase which can form carcinogens in the gut.
  • Lowering cholesterol
  • Lowering blood pressure
  • Improving Immune System Function – Increasing the number of Ig-A containing plasma cells, T-lymphocytes and Natural Killer cells and increasing the rate of phagocytosis.
  • Preventing Infections – It is thought that this occurs through competitive inhibition.  Studies have found that probiotic supplementation reduces the number of dental caries in children as well as the number of respiratory infections.
  • Treating Peptic Ulcers - Through inhibiting the bacterium heliobacter pylori which causes the ulcers.
  • Reducing Inflammation – Through down-regulating bacteria-produced inflammatory cytokines.  Studies found that probiotics caused a reduction in C-Reactive Protein (CRP) a common inflammatory marker which is commonly elevated in women with PCOS.
  • Reducing the Risk of Allergy Development – Probiotics help to train your immune system distinguish between good proteins (antigens) and bad proteins (pathogens) and to respond appropriately – killing pathogens but not over-reacting to antigens.  It is when this process goes awry that allergies can develop.
  • Improving the Absorption of Trace Minerals – especially in those whose diets are high in grains, legumes and nuts.
  • Producing Vitamin K and some B Group Vitamins – B Group vitamins are very important for carbohydrate metabolism, so of particular importance to women with PCOS.
  • Relieving the symptoms of IBS and ulcerative colitis, reducing the severity of antibiotic-associated diarrhorea and the severity and duration of rotavirus in children and acute diarrhoea in travellers.

If you decide that you do want to take a probiotic supplement, you may want to consider the bacillus coagulans strain  as it is available as a spore so it has a long shelf life, doesn’t need refrigeration and can even tolerate warm temperataures.  They are also robust enough to survive the acidic environment of the stomach and reach the small intestine and remain active there for long enough to do some good.

More Information:

Kalliomaki M, Collado MC, Salminen S, Isolauri E.  Early differences in fecal microbiota composition in children may predict overweight. American Journal of Clinical Nutrition, Vol. 87, No. 3, 534-538, March 2008

http://www.ajcn.org/cgi/content/abstract/87/3/534

http://www.ajcn.org/cgi/content/full/87/3/534

Turnbaugh PJ, Hamady M, Yatsynenko T, Cantarel BL, Duncan A, Ley RE, Sogin ML, Jones WJ, Rose BA, Affourtit JP, Egholm M, Henrissat B, Heath, AC, Knight R, Gordon JI.  A core gut microbiome in obese and lean twins. Nature 457, 480-484 (22 January 2009) | doi:10.1038/nature07540; Received 29 June 2008; Accepted 14 October 2008; Published online 30 November 2008

http://www.nature.com/nature/journal/v457/n7228/full/nature07540.html

Duncan SH, Lobley GE, Holtrop G, Ince J, Johnstone AM, Louis P, Flint HJ. Human colonic microbiota associated with diet, obesity and weight loss. International Journal of Obesity (2008) 32, 1720–1724; doi:10.1038/ijo.2008.155; published online 9 September 2008

http://www.nature.com/ijo/journal/v32/n11/abs/ijo2008155a.html

Turnbaugh PJ, Ley RE, Mahowald MA, Magrini V, Maddis E, Gordon JI.  An obesity-associated gut microbiome with increased capacity for energy harvest Nature 444, 1027-131 (21 December 2006) | doi:10.1038/nature05414; Received 8 October 2006; Accepted 7 November 2006

http://www.nature.com/nature/journal/v444/n7122/abs/nature05414.html

http://www.newscientist.com/article/dn10837-your-gut-reaction-influences-your-weight.html

http://www.nutraingredients.com/Research/Probiotics-may-help-women-regain-their-figures-after-pregnancy

17th European Congress on Obesity, Amsterdam, the Netherlands, May 6-9, 2009

http://www.eurekalert.org/pub_releases/2009-05/eaft-sip050609.php

http://en.wikipedia.org/wiki/Probiotic

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One Response to Gut Flora Plays a Role in Body Weight

  1. Christina says:

    Well done

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