the gut changes through the ages

The way we are born, vaginal or C-section, has a big impact on our gut composition and health not only during childhood but also later in life. For instance, children born vaginally get bacteria found in the mother’s birth canal and faeces and therefore the gut bacteria of mothers and babies born this way are more similar.

However, children born through C-section get more bacteria found on the skin of their mothers, doctors and nurses and so in the early days these children have less similar gut bacteria to their mothers [1].

Some studies found that children born through a C-section have a higher risk of allergies or a higher risk of obesity later in life [2], [3]. While these are important results, it is important to bear in mind that these findings are just associations and not direct causal relationships and there is plenty you can do to support gut health throughout early life. 

Breastfeeding plays an important role in the developing gut of babies because it gives them lots of good gut nutrients and prebiotics from the mother, strengthens the immune system and helps create that special bond between mother and child. At this stage, the bacteria in babies’ guts are more of Bifidobacteria type which is specialised in breaking down the sugars found in mothers’ milk. There are now some great formula formulations, which try to mimic the prebiotic element of breastmilk.

Alongside the introduction of solid foods in babies’ diets, the diversity of gut bacteria escalates and gradually starts resembling that of an adult [1]. At this stage, it is important to slowly introduce gut-loving foods, including a variety of different plant-based foods and  fibre-rich ones that would boost the diversity of the gut bacteria and eventually the health of the child. 

The prescription of antibiotics is a common way to treat childhood bacterial infections. However, they may disrupt a child’s gut bugs long-term. If they are unavoidable, there are ways to restore the gut community after an antibiotics course such as probiotics supplementation (specific probiotics have been formulated for use after antibiotics) or through probiotic foods, such as yoghurts and kefir or fibre-rich foods. 

At this stage, teenagers tend to become more aware of their appearance, and how they are perceived by others and also have some pretty big life decisions to make, not to mention school exams. This often leads to stress or anxiety which, interestingly, can affect their gut bacteria too through the gut-brain axis.

Indeed, a lot of research suggests that our moods affect our gut bugs or vice-versa through the chemicals these bugs send/receive to and from the brain. As diet is a major contributor to what our gut looks like, one way we might be able to support these anxiety bursts during teenage years would be to make slow improvements to our diets by adding more fibre and plant-based diversity. Read more on this here.

Of course, at this stage hardly any teenager would say a big YES, PLEASE to a bowl of beans and salad. But what we are starting to realise is that fibre-rich foods not only influence our moods but our appearance too [4], maybe that bowl of beans is not that bad after all. Making some simple swaps can help teenagers increase their fibre gradually and knowing how important gut health is may go someway in providing an incentive. 

Think early twenties: student life, living away from home, sleepless nights, parties or ready meals at odd times. While these are fond and great memories that last a lifetime. Forming a long-term habit of these at this stage in life may not be the kindest way to treat our gut companions. Although the gut bacteria are generally stable at this time, they can still undergo changes depending on what we eat. For instance, switching to a heavy meat-based, processed food diet leads to the loss of bacteria. The ones that can deal with those important plant-based fibres [5]. Heavily processed foods have a negative impact on our gut microbes [6]. So home cooking can help us take back control of how much and what we eat and is often cheaper. 

Our gut bugs are also tuned to day-night cycles. And so the night bugs are usually dealing with body repair while we are sleeping. Eating or drinking during the night or having lots of late nights can mess up this perfect orchestration. As well as affect our moods and especially our body weight control mechanisms [7]. 

Pregnancy comes with lots of changes in women’s bodies which ultimately may impact the health of the future mother and baby. These include having more of specific species. Such as Firmicutes, and increases in hormones can also alter the make up of your microbes. While these changes are generally normal in pregnancy as they prepare the woman for giving birth and nurturing the baby. Too much of these is not great because of the potential risks of gestational diabetes or a child’s growth problems [8]. Antibiotic use during pregnancy may also affect the mother’s gut health or immune system. But there is plenty that can be done to support gut health throughout pregnancy.

Pregnancy results in changes to digestion, namely, things tend to slow down to maximise nutrient absorption from food. This can ultimately result in constipation. Which as well as being uncomfortable can also disrupt the balance of bacteria in your gut. Consuming enough fibre and water and keeping active can help ease constipation. All great ways to have a happy mind and gut. The mother, the baby (and let’s not forget those trillions of gut microbes) will be so grateful for these tiny changes in daily routine. 

Menopause is another stage in women’s lives where their bodies go through major transformations. Generally, there is little information on what the gut bacteria look like and what they do at this stage in life. A study showed that giving probiotics to postmenopausal women led to improved bone health [9]. Another showed that short-term intake of soy-isoflavonoids (oestrogen-like molecules) can cause changes. A study into postmenopausal women showed how it helped decrease gut bacteria numbers.  Those that promote inflammation and are more common in obese postmenopausal women [10].

Your gut bacteria play an important role in how your body breaks down and gets rid of oestrogen too. So if something is out of balance here, it may influence menopausal symptoms. 

As people age, the risks of old age conditions, like heart disease, mobility problems or dementia and the increased use of medication go up. Together with these, the gut microbes change as well. Becoming less diverse and possibly losing many important functions we are now beginning to learn. If older people find it difficult chewing, have mobility restrictions (preventing them from cooking their own food) or aren’t motivated to cook alone. Then this may reduce the quality of their food, including those of a plant-based or fibrous nature. Which in turn has an effect on gut bacteria.

In addition, as we age, our ability to produce bile decreases [12]. Bile is important to emulsify fats for digestion and absorption. It plays a crucial role in the balance of the bacteria in our guts. If our fats aren’t properly broken down, this can have a negative impact on the bacteria in our gut [13]. 

Of course, this is not the case with all older people. For instance, those who live close to 100 or beyond seem to have gut bacteria more similar to those of younger people, and less similar to those of people in their late 70s or 80s [11]. What is special about these people is that their diets are rich in fibre, poor in animal fats and they benefited from increased physical activity. This healthy lifestyle was probably maintained throughout their entire lives. The more interesting thing is that those who live in care homes had a less diverse gut bacteria and worse mental and general health than those who were living in a community surrounded by friends and family [11]. Maybe living in a nurturing community would be the answer to good gut and long healthy life? 

1. Kundu, P., Blacher, E., Elinav, E. and Pettersson, S., 2017. Our gut microbiome: the evolving inner self. Cell, 171(7), pp.1481-1493. 
2. Yuan, C., Gaskins, A.J., Blaine, A.I., Zhang, C., Gillman, M.W., Missmer, S.A., Field, A.E. and Chavarro, J.E., 2016. Association between cesarean birth and risk of obesity in offspring in childhood, adolescence, and early adulthood. JAMA pediatrics, 170(11), pp.e162385-e162385. 
3. Bager, P., Wohlfahrt, J. and Westergaard, T., 2008. Caesarean delivery and risk of atopy and allergic disesase: meta‐analyses. Clinical & Experimental Allergy, 38(4), pp.634-642. 
4. Salem, I., Ramser, A., Isham, N. and Ghannoum, M.A., 2018. The gut microbiome as a major regulator of the gut-skin axis. Frontiers in microbiology, 9. 
5. David, L.A., Maurice, C.F., Carmody, R.N., Gootenberg, D.B., Button, J.E., Wolfe, B.E., Ling, A.V., Devlin, A.S., Varma, Y., Fischbach, M.A. and Biddinger, S.B., 2014. Diet rapidly and reproducibly alters the human gut microbiome. Nature, 505(7484), p.559. 
6. Hall, K.D., Ayuketah, A., Brychta, R., Cai, H., Cassimatis, T., Chen, K.Y., Chung, S.T., Costa, E., Courville, A., Darcey, V. and Fletcher, L.A., 2019. Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell metabolism. 
7. Parkar, S.G., Kalsbeek, A. and Cheeseman, J.F., 2019. Potential role for the gut microbiota in modulating host circadian rhythms and metabolic health. Microorganisms, 7(2), p.41. 
8. Edwards, S.M., Cunningham, S.A., Dunlop, A.L. and Corwin, E.J., 2017. The maternal gut microbiome during pregnancy. MCN. The American journal of maternal child nursing, 42(6), p.310. 
9. Narva, M., Nevala, R., Poussa, T. and Korpela, R., 2004. The effect of Lactobacillus helveticus fermented milk on acute changes in calcium metabolism in postmenopausal women. European Journal of Nutrition, 43(2), pp.61-68. 
10. Nakatsu, C.H., Armstrong, A., Clavijo, A.P., Martin, B.R., Barnes, S. and Weaver, C.M., 2014. Fecal bacterial community changes associated with isoflavone metabolites in postmenopausal women after soy bar consumption. PLoS One, 9(10), p.e108924. 
11. Biagi, E., Rampelli, S., Turroni, S., Quercia, S., Candela, M. and Brigidi, P., 2017. The gut microbiota of centenarians: signatures of longevity in the gut microbiota profile. Mechanisms of ageing and development, 165, pp.180-184. 
12. Bertolotti, M. , Gabbi, C. , Anzivino, C. , Crestani, M. , Mitro, N. , Del Puppo, M. , Godio, C. , De Fabiani, E. , Macchioni, D. , Carulli, L. , Rossi, A. , Ricchi, M. , Loria, P. and Carulli, N. (2007), Age‐related changes in bile acid synthesis and hepatic nuclear receptor expression. European Journal of Clinical Investigation, 37: 501-508. doi:10.1111/j.1365-2362.2007.01808.x 
13. Ridlon, J.M., Kang, D.J., Hylemon, P.B. and Bajaj, J.S., 2014. Bile acids and the gut microbiome. Current opinion in gastroenterology, 30(3), p.332. doi:10.1097/MOG.0000000000000057