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  • Alison J

Fructans for Brain & Gut Health

There is a lot of discussion surrounding carbohydrates and how they convert to sugar in your body. Carbs are bad, don’t eat carbs! Carbs are not the enemy and can be extremely beneficial for your health, as long as you are consuming them as whole food and not in a highly processed form such as refined sugars and wheat.

This article discusses the benefits of fructans, a form of carbohydrate, on our health. Fructans are found in plants and are a type of fermentable fibre that arrive in the large intestine relatively intact. Food sources of fructans include chicory, Jerusalem artichokes, asparagus, leeks, onions, garlic & bananas.

Method of Action

Fructans are indigestible by the human body, and arrive in the large intestine where they have been shown to function as prebiotics for the beneficial bacteria, lactobacilli and bifido-bacteria.

The fructans in your food are fermented by these residential intestinal bacteria to generate short chain fatty acids (SCFA), providing food for the host. This glycolytic process is defined as the anaerobic Embden-Meyerhof-Parnas (EMP) pathway, which allows the creation of adenosine triphosphate (ATP) without the need for oxygen. ATP is the energy molecule found within every cell in your body, without it your cells wouldn’t be able to function.

Fructans and our Health

Studies have shown that a diet which includes fructans can have a positive impact on the health of the gut and the brain.

Gut Health

Unlike protein digestion and amino acid fermentation which have been linked to colon cancer, fructans are considered pre-biotics and are beneficial to the health of the colon. The SCFA produced from the fermentation of fructans increases the colon’s resistance to pathogens, improves the integrity of the intestinal wall, reduces inflammation, and improves immune function.

Studies on the effect of gut health from the increase of dietary fructans in infants right through to the elderly have shown positive results. Infants showed a bifidogenic effect when added to baby formula, as did paediatric cancer patients when fructans were increased in the diet. In healthy adults there was a significant increase in beneficial bacteria with some studies showing a decrease in the potentially harmful Clostridium bacteria. This reduction would reflect the reduced colonic PH which favours the growth of beneficial bacteria inhibiting the growth of pathogenic bacteria. Studies in the elderly show that including fructans in the diet at controlled doses benefited both sexes with constipation as well as those suffering from antibiotic related diarrhoea, by increasing the beneficial bifidobacteria. Prebiotics have been shown to reduce mucosal inflammation by the production of mucin, a physical barrier for the intestinal wall thereby assisting with diarrheal disorders as well as improving the microbial mass of stools to assist those with constipation.

Brain Health

With 90% of the cells in the human body being microbial in origin it is worth investigating the relationship between our gut and the central nervous system. One of the SCFA produced through the fermentation of fructans is butyrate. Most of the butyrate produced in the colon provides over two thirds of the colonic cells with their energy needs. Excess leaves the intestine via the portal vein to the liver though some enters the blood stream via the distal colon and is allowed to circulate freely throughout the whole body including the brain.

Reduced glucose availability in the brain is thought to contribute to mitochondrial dysfunction in neurological diseases such as Alzheimer’s. It has been hypothesised that if sufficient butyrate levels could be reached in the brain, it could act as an energy substrate, directly affecting energy metabolism and increasing mitochondrial activity. A recent study on dietary fructo-oligosaccharides on mice concluded that these fructans could attenuate the development of Alzheimer’s disease due to their systematic antioxidant effects.

Over 70% of autistic children have been shown to suffer from gastrointestinal issues, with the degree directly related to the autism severity. Studies of the microbiome of autistic patients shows significantly reduced numbers of Bifidobacteria than the control group. The prebiotic effect of fructans has been shown to increase the bifidobacteria in these patients and reduce the severity of their autism.


The benefits of including fructans regarding the general health of the gut are clear. Studies that examine the use of fructans to medicinally treat both brain disorders and illnesses of the gut are extremely promising but as yet inconclusive, more research is required to fully understand the importance of nutritional intervention in these areas.


Bourassa, M., Alim, I., Bultman, S., & Ratan, R. (2016). Butyrate, neuroepigenetics and the gut microbiome: Can a high fiber diet improve brain health? Neuroscience Letters, 625, 56–63.

Corpet, D., Yin, Y., Zhang, X., Rémésy, C., Stamp, D., Medline, A., Archer, M. (1995). Colonic protein fermentation and promotion of colon carcinogenesis by thermolyzed casein. Nutrition and Cancer, 23(3), 271–81.

Finegold, S., Dowd, S., Gontcharova, V., Liu, C., Henley, K., Wolcott, R., Youn, E., Summanen, P., Granpeesheh, D., Liu, M., Molitoris, D., Green, J. (2010). Pyrosequencing study of fecal microflora of autistic and control children. Anaerobe, 16(4):444-53. doi: 10.1016/j.anaerobe.2101.06.008

Gropper, S., & Smith, J. (2012). Advanced Nutrition and Human Metabolism (6th ed.). Belmont, CA: Wadsworth.

Jurtshuk, P.(2012).Medical Microbiology. 4th edition. Retrieved from:

Meyer, D., & Stasse-Wolthuis, M. (2009). The bifidogenic effect of inulin and oligofructose and its consequences for gut health. Eur J Clin Nutr, 63(11), 1277–1289. Retrieved from

Pereto, J. (2011). Encyclopedia of Astrobiology. Berlin, Heidelberg: Springer-Verlag

Todar, K. (2012). Today’s Online Textbook of Bacteriology. Retrieved from

Yen, C., Wang, C., Wu, W., & Chen, H. (2015). Fructo-oligosaccharide improved brain beta-amyloid, beta-secretase, cognitive function, and plasma antioxidant levels in d-galactose-treated Balb/cJ mice. Nutritional Neuroscience.

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