Five scientists from the Riddet Institute, which specialises in food and nutritional research, presented the latest Whanganui Science Forum seminar at Davis Lecture Theatre. Their topic was "It's a small world" as they explained the micro-organisms that live in the human gut. FRANK GIBSON got the inside story.
It is easy to see the human body as a mechanism that has evolved to support the brain.
The body protects the brain and moves it away from danger. The body keeps the brain in touch with the outside world. The body finds nutrition to keep the brain and its support functions working.
But after this talk, my ideas may change.
Your gut microbiome is the community of several hundred trillion micro-organisms that exists in the tube joining your mouth to your anus.
These organisms have about 150 times more genes than human cells. The community has a mass of about two kilograms, and the makeup of this community varies according to diet, age, physical health and hereditary factors -- and it is unique to everyone.
Changes in this community profoundly affect the functioning of the rest of the body.
The microbiome works so closely with the human cells of the body that it is now regarded as an organ of the body. I begin to think that although the brain is where the managers work, the chief executive and owners have their offices in the gut.
Events in the first few hours and days of the life of a baby have profound and permanent effects upon its future. The gut of a newborn is sterile and takes several years to develop into a mature system, and this developing community depends upon nutrition, inherited characteristics and -- possibly most importantly -- on bacteria acquired from contact with the microbiome of other animals and humans.
Dr Elizabeth Rettedal was asked how a healthy gut could be engendered in a baby born by caesarean section, and she advocated that, assuming the mother to be healthy, a hand should be wiped on the mother's rectal area and this should then be wiped on to the skin of the child. This may sound gross, but it has the effect of transferring a healthy microbial system to the child.
Robust constitutions: Getting dirty is good for kids' immune systems. Photo/file
Starting life with a healthy gut microbiome reduces propensity to allergies, obesity and possibly autism. There is evidence that modern life is just too clean -- kids who play in the dirt tend to be healthier.
The microbiome breaks down certain nutrients in food that human enzymes cannot tackle -- an important example is dietary fibre from plants. Without the correct bacteria present in the microbiome, this is not fully digested and may cause lack of uptake of some nutrients and reduction in substances such as butyrate, which has anti-inflammatory and possibly anti-cancer properties.
Infections and the use of antibiotics in young children can have irreversible effects in the adult microbiome. Such changes can cause reduced resistance to problems such as allergies and Crohn's disease and increase susceptibility to obesity and diabetes.
Research has shown possible links between microbiome function and brain function problems such as depression and Parkinson's disease.
Dr Eric Alterman's area of specialty is fermented foods, his main area of study being fermented dairy products such as cheese and yoghurt.
He had a simple message -- do not trust commercials. He quoted the Foundation of Innovation in Medicine, which states that 95 per cent of functional foods are making claims unsupported by clinical data. He also pointed out that new varieties of probiotics are emerging with high health benefits but these benefits are very strain dependent.
Unless your yoghurt has the right strain of probiotic it may not be having any positive effects.
Lactobacillus fermentum is one of the most recent recent additions to the range of premium probiotics. However, the strain Lactobacillus fermentum AGR 1487 reduces the effectiveness of the gut lining in preventing immune system problems, while Lactobacillus fermentum AGR 1485 has potential anti-tumour properties while improving the effectiveness of the gut lining.
Dr Wayne Young is investigating the links between the microbiome and brain function. Putting mice into an open area makes them stressed and they will hide at the edges of the area until they become calmer. The same mice, when dosed with certain probiotics will be less stressed and will venture into the open more readily.
Research has shown that the microbiome has effects on areas of the pre-frontal cortex which, in humans, are associated with schizophrenia and autism. A test involving people looking at positive and negative images found that the length of time that people looked at the images was affected by ingestion of probiotics.
Explanation of these effects is at an early stage but there are hints that they are linked to metabolism of some amino acids by the microbiome. A byproduct of this process is serotonin. Low serotonin levels have been associated with depression and anxiety.
Dr Jane Mullaney's work is mainly with diabetes. Her message was that although many diseases had strong links to heredity, they were triggered by environment.
Environment can affect the genetic structure of the microbiome with resulting changes in the way genes are expressed.
Interestingly, a drop in the diversity of the genes in the microbiome is often seen before the symptoms of the disease appear.
This set of talks gave a vast amount of information. The messages to take away? Avoid stress and unhealthy environments. Do not eat rubbish. Getting muddy is good for kids. And do not always believe what it says on the packet.
Frank Gibson is a semi-retired teacher of mathematics and physics who has lived in the Whanganui region since 1989.
