Do you need extra support to maintain those pesky resolutions? Read on!

It’s that time of year again, folks. As the Labrador puppy of hope runs headlong toward the closed glass door of inevitability, millions of otherwise rational adults indulge in a practice commonly referred to as “making new year’s resolutions”. However, despite initial confidence, most participants will fail to maintain their resolutions.

Following on from David’s piece on new year’s day, I’d like to take this opportunity to provide much-needed moral support (“outside interference”?) to those who are looking to beat the odds and stick to their resolutions. And what better way to provide incentive than by giving examples of how three common new year’s resolutions can positively affect your brain and your immune system.

1.     Eat healthily
This seems like a good place to start. Cut out all that high fat, high salt, junk food and start chowing down on carrots and quinoa. We all know that our diet can affect our weight, but how can diet change our brains or our immune system?

One way diet can affect both is by changing the composition of the bacteria inhabiting our gastrointestinal tract – also known as the microbiome. Currently a hot topic in various biological disciplines, changes in the microbiome have been associated with changes in all sorts of human functions, including immunity and even behaviour. For example, increases in dietary fibre change the composition of the microbiome, which increases levels of short-chain fatty acids (SCFAs). Though still debated, SCFAs are widely considered to have beneficial effects promoting weight loss, reducing obesity and maintaining insulin sensitivity. Micronutrients, such as vitamins, are also important in immune responses and may be partly responsible for the increased vaccine responses seen in people aged 65-85 who increase their fruit and vegetable intake to around 5 portions per day.

If you’re interested in protecting your brain, there are strong associations between diabetic insulin resistance and Alzheimer’s disease. Many physicians are now promoting the adoption of low-sugar, low-calorie diets to help slow down cognitive dysfunction and promote neuronal plasticity. Alternatively, you* could just supplement your high fat, high sugar diet with cinnamon and be fine**.

* If you’re a male Wistar rat living under highly restricted and controlled laboratory settings.

** “‘Fine’ has variable definitions. ‘Fine’ is unacceptable.” – Spock

2.     Get more sleep
This one is more intuitive. Going without sleep for prolonged periods is fatal, and sleep affecting behaviour is something familiar to all of us. However, in addition to the acute effects that we all observe after a bad night’s sleep, there is increasing evidence that chronic sleep deprivation can negatively impact immunity and brain function. Part of this may be attributed to the clearance of toxic metabolites from the brain during sleep. One group last year discovered that beta-amyloid (a protein associated with the plaques that form on the brain in Alzheimer’s disease) is actively removed from brain tissue during sleep. Another study showed that patients with sleep apnoea were more likely to die from sepsis than those who enjoy undisturbed sleep. The biological processes behind these correlations are even less well-understood than those linking diet to behaviour and, well, it's getting late so we really ought to move on...

3.    Exercise
Physical activity can certainly influence mood via the release of hormones, but exercise can also have long-term effects on immune responses and cognitive function. For example, access to a running wheel reduced anxiety behaviour in mice and increased risk-taking (in the form of staying out in the open). Something to consider, perhaps, if your resolutions include going on new adventures.

If weight-loss is your goal, exercise will probably do you more good than Roux-en-Y gastric bypass surgery (RYGB) which, one recent study suggests, increases the “rewarding effects” of alcohol. While this seems appealing in the short-term (just me?), it may result in the breaking of yet another common resolution.

Finally, if you want to be fighting fit immunologically, you can start by getting... umm... fighting fit. Physical exercise is known to affect many aspects of immune function and can reduce some of the inflammation associated with obesity. But I'll leave you with one caveat. Endurance-type exercise can lead to the release of cardiac troponins. The reasons for the release of this compound are still unclear, but it does have the quirky side-effect of mimicking the chemical symptoms of a heart attack. Which is why, if you go for a long run for the first time in ten years, break your ankle and get taken to the ER, they may tell you that you’re also having a heart attack. Which you probably aren’t.

I'm not into exercise. If God wanted me to bend over, he'd put diamonds on the floor.

On which heartening note, I'll end my highly selective, whirlwind tour of recent papers that support your año nuevic attempts at self-betterment. Now please excuse me while I run to the store, buy vegetables and go to bed early.