VEGA News Item

Bacteria have Nutritional Qualities in Health - 04/03/2014

Significance of Plant-Based Diets in the Very Young

Nutrition is a study entangled in many disciplines and studies that have lingered in the era of genetics and microgenetics over the years. They have made progress in this time.

The effect of food on mood and other physiological manifestations has become clearer and no doubt will emerge more in future, despite being absorbed in arguments over the microbiota in the gut.

Therefore the gut absorption will interest us more clearly and will become apparent despite interests attempting to suppress the knowledge, and commercial objectives to slow the progress. Therefore it behoves us to look to the future and introduce it to our culture, knowledge and production of wholesome food, keeping a good balance of nutrition and the human microbiome.

Diseases for which intestinal microbiota is associated, and symptoms of aberrations, with summaries of multiple studies that support an association with microbiota are shown in the tables below (from de Vos, W. M. and de Vos, E. A. (2012), Role of the intestinal microbiome in health and disease: from correlation to causation. Nutrition Reviews, 70: S45–S56. doi: 10.1111/j.1753-4887.2012.00505.x - Nutrition and the Human Microbiome: 24th Marabou Symposium, Stockholm, Sweden).

New parents cannot be expected to meet this measure of the health of their babies until the required disciplines have been set up for the experts. But they can be watchful for their 2-5 year old’s urine, faeces and breathing, and obviously attend routine medical check-ups and discuss everything with their doctors and nurses. They should pay attention to the new mother, who should not neglect the bodily effect on her metabolism and should return to good health and weight after the birth. These will make food consumption as important in the baby’s health as the imposition of demands by commercial interests, which are not necessarily advantageous. For example, the pressure to use sugar, salt and certain fats. The tendency to over-eat should be resisted and the return of a good figure made highly desirable, so that defects in her metabolism can be reliably corrected.

Table 1. Intestinal microbiota-associated diseases, syndromes, or other aberrations, with summaries of multiple studies that support an association between the microbiota and the indicated aberration.


Most relevant observations and potential correlation

Crohn's disease

Diversity decrease – reduced Faecalibacterium prausnitzii

Ulcerative colitis

Diversity decrease – reduced Akkermansia muciniphila

Irritable bowel syndrome

Global signatures – increased Dorea and Ruminococcus

Clostridium difficile infection

Strong diversity decrease – presence of Clostridium difficile

Colorectal cancer

Variation in Bacteroides spp. – increased fusobacteria


Altered diversity – specific signatures

Celiac disease

Altered composition, notably in small intestine

Type 1 diabetes

Signature differences

Type 2 diabetes

Signature differences


Specific bacterial ratios (Bacteroidetes/Firmicutes)


Table 2. Indications for associations between the microbiota and health aberrations, provided as an alphabetical listing of the aberrations suggested to be associated with the intestinal microbiota, along with support for such an association.

Disease or aberration

Type of support

Alzheimer's disease

Microbiota in a mouse model of Alzheimer's disease


Analysis of plaques in humans

Autistic spectrum disorders

Analysis of mucosa in children with autism spectrum disorders

Chronic fatigue syndrome

Cultured microbiota in patients with chronic fatigue syndrome

Colic babies

Longitudinal analysis of colic babies cohort

Cardiovascular disease

Cardiovascular-diseased mice and microbial metabolism

Depression and anxiety

Probiotic intervention in stressed mice


Analysis of elderly and high frailty scores

Graft-vs-host disease

Review of human data on graft-vs-host disease

Multiple sclerosis

Involvement of microbiota in mice with multiple sclerosis

Nonalcoholic fatty liver disease

Effect of choline depletion in humans

Parkinson's disease

Role of enteric nervous system and review of Parkinson's disease development

Rheumatoid arthritis

Microbiota as predisposing factor in rheumatoid arthritis

Retrovirus infection

Mouse retrovirus infection relies on microbiota

Poliovirus infection

Mouse microbiota promotes poliovirus infection

The mammalian gut is colonized by a dense and complex microbial community that has a major influence on nutrition and health. The main energy sources for microbial growth in the large intestine of man and farm animals, and also in the rumen, are plant-derived fibre and polysaccharides. Our research employs molecular community analysis, anaerobic microbiology, metabolic profiling and genome data to identify the roles of particular bacteria in the microbial community of the human large intestine. A particular focus is the microbial colonization and degradation of insoluble substrates such as plant cell walls and resistant starch particles (Walker et al 2008), The different groups of micro-organisms that colonize the mammalian gut vary widely in their ability to utilize different carbohydrate sources, reflecting differences in the organization of their degradative enzyme systems, uptake systems and energy metabolism. These differences are now being revealed by analysis of draft genome sequence information from key fibrolytic gut bacteria (Flint et al 2008, Rincon et al 2010). Recently a series of human dietary intervention studies have allowed us to gain unique information on the dynamics of the gut community in response to dietary change, and on the occurrence of inter-individual variation in key bacterial species that appears to influence the fermentation of dietary resistant starch (Duncan et al 2007, Walker et al 2011).

At the same time we are trying to understand the factors that determine metabolic outputs from the gut community. We have been investigating phylogenetic groups responsible for key functions, such as butyrate and propionate formation and lactate utilization, in the human large intestine, using a combination of cultural and molecular approaches. A long-standing line of work (reviewed by Louis & Flint 2009) has defined the major groups responsible for butyrate production in the human colon, including Roseburia spp., Eubacterium rectale, and bacteria related to E. hallii that can convert lactate to butyrate (Duncan et al 2004). Gut pH appears to play an important role in the ecology of these organisms (Duncan et al 2009). Recent work has defined the substrate preferences of another important butyrate-producer Faecalibacterium prausnitzii (Lopez-Siles, in prep) and the new lactate-utilizing species Anaerostipes coli (Allen-Vercoe et al, in prep). These are among the 10 most abundant bacterial species detected in the human intestine by 16S rRNA sequence analysis (Walker et al 2010). In addition we are currently examining the ability of different isolated strains and species to release and transform phenolic compounds present in plant cell wall material.

The ultimate aim is to use this information to understand and enhance the health benefits of plant derived fibre, including the development of new prebiotics. At the same time this work promises to explain why different individuals show contrasting responses to added fibre in their diets that range from intolerance (eg. in some IBS sufferers) to health enhancement. 


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