What do exercise and a diet high in fibre have in common? We’ve known for some time now that both of these are good for our gut health and decrease our risk of colon cancer. However, it seems as though there may something extra that fibre and exercise have in common, and it comes as a fatty acid called butyrate. This link between exercise, fibre and gut health will be explored, and you’ll see that the effects travel as far as the brain.
What actually is butyrate and what does it do?
Butyrate is a short chain fatty acid produced by our gut bacteria as they break down foods that are high in fibre. Resistant starches are a type of fibre, that are some of the best fuels for these butyrate producing bacteria (Bourassa 2016). These starches come in foods such as legumes, oats and starches that are cooked and cooled like potato and rice salads.
Now butyrate is an important fuel for the cells of our colon. In fact it supplies up to 70% of their energy (Bourassa 2016). Keeping your colon cells healthy is thought to be one of the reasons why higher butyrate levels decrease your risk of colon cancer by 50% (Matsumoto et al, 2008).
However, the benefits of butyrate go well beyond reducing our risk of colon cancer. This is because healthier gut membranes improve their integrity (how closely they bond together) allowing them to act as a better barrier, which has flow on effects to improving our immunity and reducing inflammation (Ji Wang et al, 2018).
What’s the evidence on exercise and gut health?
Most of the interest on the effect of exercise on butyrate levels started back in 2008. Matsumoto and colleagues showed that butyrate levels, and the bacteria that produce butyrate, were higher in rats that exercised versus a sedentary control.
In 2014 a group of Irish researchers found that professional rugby players had a greater diversity of gut microbiota than a group of sedentary controls (Clarke et al, 2014). However a signifiant limitation in this study was that professional athletes eat very differently than the general population. And these results could possibly be related to their diet and not their activity.
We had to wait until late last year when a group from the University of Illinois designed a study that looked at the impact of aerobic exercise on butyrate. Previously sedentary individuals were asked to exercise three times a week for a 6 week period (Allen et al 2017). What they found was that there is a link between butyrate, exercise, and gut health in humans.
Much like the rodent study back in 2008 they found that aerobic exercise increases the levels of butyrate along with the colonies of bacteria that produce butyrate. Interestingly this effect was most pronounced in lean subjects. The overweight group did still increase the colonies of the butyrate producing bacteria (not to the extent of the lean group) but they didn’t see an increase in butyrate levels in their stools.
Exercise and gut health can also improve your brain!
Now here is where it really gets interesting. The term “your gut is your second brain” has been well used over the last decade. This has been used to explain that the enteric nervous system of the gut is not only quite complex, but it also has the capacity to signal the brain via many neurotransmitters.
We know that butyrate can cross the blood brain barrier and it is well known to suppress HDAC (Histone deacetylase; Bourassa 2016). Now HDAC inhibitors will increase the expression of BDNF (Brain-derived neurotrophic factor) in the brain. This is important for memory and learning as BDNF is like fertiliser for the brain. It helps your brain cells grow in number and connections!
So where’s the research at?
An interesting experiment, albeit in mice, was published back in 2013 where mice were given an object recognition memory task that is usually not enough to form in either their short or long term memory (Intlekofer et al, 2013). They had a sedentary group and a group that was exercising 3 weeks before the task. They also had a sedentary and exercising group that was injected with butyrate.
The non-butyrate injected sedentary mice could not successfully remember the task 24 hours post initial exposure However, both the sedentary/butyrate injected group and the exercise group could. And when it came to remembering the task 7 days after the initial exposure, it was only the butyrate group that could.
It is important to know that the exercise group only did so for the 3 weeks leading up to the task, and not during the 7 days after the task. This highlights that to get the improved learning outcome, continual exercise exposure is needed.
This mechanism of increased BDNF release via butyrate is probably why we see that children who are fed a high fibre diet perform better in cognitive tasks than those on a low fibre diet (Bourassa 2016). And it could also be the reason why it shows promise in the treatment of neurodegenerative diseases (Bourassa 2016).
We also know that aerobic exercise has an effect on increasing BDNF levels, and this may be why individuals have a 20% improvement in learning tasks (Winter et al, 2007). So it makes sense to eat a high fibre diet and exercise at the same time right?
Take home points about exercise and gut health:
- It appears as though aerobic exercise continues to benefit our health in many different ways, and improving our gut health is another reason to be active. Aerobic exercise of around 30 to 60 minutes a few times a week can give you this benefit to your gut.
- Improve the diversity of your microbiota through eating foods that are high in butyrate producing fibre such as legumes, oats and potato salads.
- Combine this with regular exercise to improve the butyrate production of your gut as this have effects that travel to your brain.
- And while there is still much more research to be done, it seems to indicate that by doing this you are improving your capacity to learn and remember things, along with decreasing your risk of developing neurodegenerative conditions such as Alzheimer’s.
About the Author
I attended an insightful evening at SAHMRI on depression. I don’t want to sound all melancholic at the start of this blog. However, quantitatively speaking, Australia is the unhappiest country in the world (per capita). We also have the highest prescription rate/use of antidepressants in the world (per capita).
Now I am really sounding melancholic.
Why do we have high rates of depression?
I was really saddened that Australia, a wonderful, optimistic, culturally diverse nation is so depressed. Are we trying to put a band-aid on by taking an antidepressant with the notion that quote un-quote “she’ll be right mate”? Are we ill-informed by our health & medical team? Or does one think or feel that a pill is the only way to remission? Or are we literally still stuck in time?
Maybe my past tense reference was justified…
Here’s the problem…
Depression is so much more complex than the first hypothesis from the 50s, which brought us the discovery of the first antidepressant, Fluoxetine (Prozac). The problem is that all that has changed in the last forty years is that we now have ten or more antidepressants rather than just one. The reason I am so passionate about the right co-care and management is because of the side effects of these medicines. For example, the growth factors in antidepressants can contribute to obesity, another morbidity that inundates our health care system.
So what can we do to help treat depression?
Recent advances have shown that our genes can be switched off by our environment, sedentary lifestyles and psychologically stressful events. This includes our BDNF (brain derived neurotrophic factor) genes, which are the fertilisers for our brain. They help protect and grow our neurons. However, positively, we can also switch this gene on by exercising and meditating. Therefore our actions and choices can potentially lead to melancholy or greater health.
I guess this is more of a personal release than an education problem solving blog. Please pardon the lack of clarity/direction. But it many ways I feel this is the current position we are in.
It all starts with the little things:
- Move more…
- Find space, breathe, form boundaries and find silence/solitude…
- Hug more…
- Connect more (interpersonally)…
- Connect with nature…
- Nourish your body… (remember where amino acids are derived from… FOOD. And what do amino acids make? Neurotransmitters!)
Running is not for everyone!
I was recently on a running track alongside a busy highway when I received a spray of abuse from a passenger in a car. It’s not the first time it has happened – actually it’s surprisingly common. Obviously it didn’t hurt me, and I suppose it comes out of the joy within an action that bears no consequence. Whatever. I don’t really get it…but it leaves me thinking every time. In a twisted way it motivates me. I start to think about how I would respond if the abuser actually had the gaul to do it NOT from a car driving 80kph in the opposite direction to me!
So, with tongue slightly in cheek – and without wanting to be labelled an internet tough guy – I leave my response to destiny in the hands of cyberspace.
Here’s why you’re better off undertaking some physical activity than riding shotgun in a passenger vehicle:
Today’s Western lifestyle is toxic for our brains.
The continual stress of rushing around, meeting deadlines, feeling guilty about not spending enough time with the family and poor sleep habits elevate levels of a hormone called cortisol in our bodies. While this hormone can actively destroy our memory faculties, some surprising research has shed light on a simple way to correct this decay. And it’s not what you might expect. (more…)
This year I decided that I want to exercise more, but not because I want to lose weight! I hear many resolutions at the beginning of a new year to shed unwanted kilos. These are made with the notion that effort will be required, with resolve for active pursuit. There’s a good chance that you know someone who began the year with this goal, and their plan of attack may well have included exercise. I’m not writing with any advice on maintaining this resolution into the new year, but instead am wanting to put a new spin on why a sustained exercise regime may be important to you over the coming year.
I’m interested in enhancing my ability to absorb and retain information. This doesn’t come through as a common resolution, particularly in relation to an exercise program. As in the title of this post, accumulation of wisdom is often assumed to be resultant from being around for a while! Yet even though we have embarked on a new year with fresh expectations to change our world, reality is that most of us return to surroundings of familiar stimuli, generally in the form of routine. On the whole, routine is a positive aspect to lifestyle – it affords us proficiency and efficiency in what we do. However, too much routine also has the potential to rob us of learning capacity through understimulation of the brain’s learning centre. This may be the product of carrying out days and weeks fulfilling familiar tasks that do not challenge the mind with enough stimulus to form growth of new brain cells.
Brain-derived neurotrophic factor (BDNF) is a protein found in the brain with the role of building the circuitry of cells by which the brain functions. It is responsible for ensuring adequate storage space for any new information that is to be taken on board. In the absence of BDNF, new information is rejected from the brain in the same way that items are rejected from an overflowing storage locker. It simply won’t fit! Deficiency of BDNF causes cellular breakdown within the brain, which brings about a scattering of messages and a reduced ability to focus.
Clinical evidence is now showing us that exercise not only increases the presence of BDNF in the brain, but that there is a close correlation with the accumulation of exercise. Higher exercise levels (frequency and duration) are associated with higher levels of BDNF in the Hippocampus – the long term storage area of the brain where memories are filed – effectively creating more storage space in the brain via the addition of new storage units. So the essence of learning is much the same as the resolution to lose weight – effort is required to make yourself smarter! Don’t leave it to chance through the ticking away of another year in the hope that time on earth will bring about wisdom. Exercising is a proactive approach to build and fill brain cells with new information that will ensure you end the year wiser than you began.