Why we should be brain ‘reddy’

Humphry Davy invented the first electric light more than 200 years ago (for those wanting an edge in their local pub trivia, it was 1802).

Prior to this, there was no way of experiencing significant amounts of blue light once the sun set for the day.

Oil lamps, the invention of which dates to 4500 BCE, had very low blue-light content, and fire and candles are very red-light dominant.

Nature also provided sources of blue light after dark, in the form of the moon and stars, but at very low levels. The only other way to see it was in lightning – but too brief to have meaningful effects.

The advent of artificial blue light in the past two centuries has been very helpful for progress, if you view industrialisation, productivity and technological advances as such, of course. But it has been a double-edged sword: we are increasingly realising that creating an artificial day after sundown is problematic for our physiology.

The most obvious example of this is the disruption to our circadian (daily) rhythm, with all the attendant impacts on sleep. Blue light interferes with melatonin production and this hormone needs to accumulate to prepare our body for sleep.

Its suppression is not the best situation, including for our brain, which requires the healing powers of sleep to remain healthy in the short and long term.

How about red light, though? Well, this wavelength has negligible effects on melatonin. Sitting around a fire at night – something we have done for millennia –shouldn’t impact sleep.

So, the absence of effect is a positive thing, but does being bathed in red light provide any inherent benefits? Increasing research supports the notion that red light boosts mitochondrial function.

For those of you who have a vague recall of high school biology, these tiny little organelles are colloquially known as the powerhouses of the cell. Without them, we simply would not survive.

As an interesting aside, mitochondria are thought to have arisen from a bacterium entering the cell perhaps about two billion years ago. Instead of being digested, they formed a stable relationship with the cell – one of the very first examples of symbiosis (a mutually beneficial arrangement).

Mitochondria are as critical for the brain as for the rest of the body. One of the emerging theories behind Alzheimer’s disease is that it is the consequence of a neuroenergetic crisis or, to put it simply, the brain runs out of energy.

This theory has led to the development of so-called ‘red-light therapy’ – also known as photobiomodulation – in which red light is used to stimulate mitochondria and improve energy production.

Red-light therapy comes in many guises, including screens and red-light bathing beds. For brain health, however, it generally is in the form of a helmet worn on the head, which has attached a number of red-light emitters.

The theory goes that the red light can pass through the skull and enter the cells in the outer cortex of the brain, stimulating the mitochondria within. Research is preliminary, but encouraging, with small studies showing benefits for cognitive function in healthy brains and those with early clinical Alzheimer’s disease. Importantly, it also appears very safe, with no suggestion of harm from the treatment.

Photobiomodulation is one of a number of neurostimulation techniques that show promise for improving cognitive function, with the others involving stimulation through magnets or small electrical currents. This is certainly an area I am keeping a close eye on.

 Kailas Roberts is a psychogeriatrician and author of Mind Your Brain: The Essential Australian Guide to Dementia, available at bookstores and online. Visit yourbraininmind.com or uqp.com.au