The metabolic syndrome is a cluster of disorders that includes aberrations to blood sugar control, lipid imbalances, abdominal obesity, inflammation, insulin resistance and reduced force output from skeletal muscle. The cause of the metabolic syndrome is thought to result from consumption of the Western diet, a diet characterised by high intakes of sugar, processed fats, processed meats and salt. These metabolic poisons are contained in foods absent of micronutrients, and this causes the perfect storm for the development of metabolic disease. Obese individuals have altered gut bacteria when compared to lean individuals, including lower levels of beneficial bifidobacteria which can increase levels of less desirable strains. Some evidence suggests that the disrupted intestinal milieu is a contributory factor in the development of the metabolic syndrome because gut bacteria are important in harvesting energy from food, reducing inflammation and producing satiety inducing foods such as short chain fatty acids.
Scientists are interested in how modulation of gut bacteria affects the symptoms and development of the metabolic syndrome. By understanding the bacterial changes caused by consumption of a Western diet, it may be possible to favourably manipulate of the bacterial colonies within the gut, and cause health benefits that prevent or reverse the metabolic syndrome. Supplementation of prebiotics (food for bacteria) is one way that the gut bacteria can be favourably modulated. Fructooligosaccharides (FOS) and galactooligosaccharides (GOS) have been shown for example to favourably change the bacterial profile of the gut and provide health benefits. In particular these prebiotics may preferentially increase the growth of the beneficial bifidobacteria and lactobacilli. The health benefits of FOS and GOS may include the ability to regulate food intake and body weight, as well as providing improvements in blood glucose homeostasis, blood pressure regulation and lipid metabolism.
A recent study1 investigated the effects of a GOS mixture [Bi2muno(B-GOS)] on markers of metabolic syndrome in 45 overweight adults with more than three clinical symptoms of metabolic syndrome. For 12 weeks subjects received either GOS supplements or a maltodextrin control. This was then followed by a 4 week washout period, before switching to the opposing treatment. Consumption of GOS was associated with increases in bifidobacteria in faeces of the subjects compared to a control, suggesting that favourable changes to microbiota in the gut had occurred. Consumption of the GOS supplement was also associated with reductions in calprotectin and C-reactive protein (both accepted markers of inflammation) and increases in immunoglobulin A. Reductions in plasma insulin, total cholesterol and the total to high density lipoprotein (HDL) ratio were also seen in the GOS group at 12 weeks. Therefore the GOS supplementation appears to have beneficial effects on markers of the metabolic dysfunction.
As more is understood about the bacteria in the gut, the link between microbes and disease becomes more clear. Changes to the gut bacteria that include reductions in specific strains of bacteria may have an influence on health. While research into fibre compounds such as FOS and GOS are continuing, the link between food quality and gut bacterial colonisation profiles is more well established. High quality diets not only provide the host with adequate nutrition, but also provide nutrients for the bacteria in the gut. Fibre was once believed to provide bulk to the chyme in the gut, but this viewpoint is now outdated. Many varieties of fibre, while not directly absorbed by humans, are used as foods by the bacteria in the gut. Both FOS and GOS fall into this category of bacterial food sources which explains their ability to alter the bacterial colony profiles of the gut. It is interesting that the link between fibre and health, and the role of bacteria in this interaction, has been overlooked for so long.
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