Most of us know that what we eat has a significant effect on the health of our bodies, but few of us pay much attention to how our food choices also affect our minds. Specific nutrients, foods, and the overall dietary pattern can dramatically alter cognitive function and our emotional health. This month, as a back-to-school special, we're looking at smart nutrition and how to feed your brain.

Let's begin by laying out key factors that affect cognitive health and function, namely:

• Neurotransmitter synthesis
• Inflammation
• Blood sugar regulation and energy production
• Cardiovascular health and cell membrane health
• Gut health.

Some of these are straightforward, while other factors are interconnected in multiple, complex ways.

Neurotransmitter synthesis

For the brain and nerves to function properly, we need to have the right ingredients and conditions to synthesise appropriate amounts of neurotransmitters including dopamine and serotonin. Key nutrients here include B vitamins, essential fatty acids, phosphatidylserine, and protein. Other nutrients and probiotics are also implicated in neurotransmitter production and can affect nerve signalling and cognitive function.

Inflammation

Inflammation is also a factor in cognitive health as undesirable inflammation can cause degeneration of brain tissue and nerve tissue and impair cognitive and emotional well-being. Inflammation is linked with blood sugar regulation, with poorly managed diabetes resulting in damage to the brain and nerves. Inflammation can also affect the health of cell membranes, which may impair communication between cells and their ability to control what substances enter and leave the cells.

Blood sugar regulation

Poor blood sugar regulation and insulin resistance can also reduce the energy available to brain cells. As the brain is the body's hungriest organ, it also produces a significant amount of free radicals. These oxidative substances can cause damage to brain cells unless they are neutralised by antioxidants.

Cardiovascular health

Cardiovascular health is also key for cognitive health as the brain relies on healthy cerebrovascular blood flow to deliver nutrients and oxygen and to remove metabolic waste and toxins. Inflammation, blood pressure irregularities, and damage to blood vessels in the brain can result in stroke or transient ischemic attack (TIA), which may permanently damage parts of the brain, causing cognitive impairment or even death.

Gut-brain axis

Finally, there is now a wealth of evidence supporting the existence of the gut-brain axis, whereby brain activity can affect gut health and gut health can affect brain function. This is partly due to the production of neurotransmitters by bacteria in the gut, and to the effects of things such as psychological stress and depression on digestive function.

Putting it all together

What does this all mean in terms of dietary choices? Well, for one thing, it is important to understand that how and what we eat can influence the factors outlined above.

A diet for brain health is likely, therefore, to support optimal blood sugar regulation, energy production, inflammatory and immune system processes, cardiovascular and cell membrane health, gut health, and the neurotransmitter production. While this might seem like a lot to ask, such a diet is not out of reach for most of us.

Some key things to focus on include ensuring that your diet:

• Contains plenty of plant-based foods (for fibre, energy, and phytonutrients)
• Includes very little saturated fat (typically found in meat and animal products)
• Contains no trans fats (which contribute to cardiovascular disease and poor brain health)
• Is low-sodium (to help manage blood pressure and cerebrovascular health)
• Includes plenty of lean protein (from legumes, nuts, and seeds, for instance)
• Features good sources of polyunsaturated fatty acids (like omega-3 docosahexanoic acid)
• Is rich in antioxidants, including fat-soluble antioxidants.

Smart Nutrition

Let's look at some specific nutrients that have been associated with cognitive health, starting with omega-3 fatty acids.

Omega-3 fatty acids can help support normal inflammatory processes, cell membrane health, the health of the endothelium (inner lining of blood vessels) to support healthy blood flow in the brain, and cellular communication for proper brain function. Omega-3 may also help inhibit the formation of amyloid plaques associated with cognitive decline. Docosahexanoic acid (DHA) and eicosapentanoic acid (EPA) are long-chain omega-3 fatty acids that have been linked in some studies to psychological well-being and to learning ability, concentration and memory.

To support brain health, include plenty of EPA and DHA in your diet, through fortified foods, algal oil, and oily fish. Nuts and seeds can also provide the shorter-chain fatty acid linoleic acid that is able to be converted in DHA and EPA.

Antioxidant nutrients are also key to cognitive health, with lipid-soluble nutrients such as lutein, lycopene, astaxhanthin, vitamin E, and vitamin A important for helping to protect the fatty cell membranes from free radical damage. Water soluble antioxidants such as vitamin C are also vital for brain health. These nutrients are typically found in brightly coloured fruits and vegetables, as well as nuts, seeds, wholegrains, and legumes.

Soluble and insoluble fibre are other important elements in a diet for good brain health. This is because these two types of fibre help support blood sugar regulation by slowing down the release of sugar from food, in addition to supporting the health of the gut microbiome, i.e. the bacteria in the gut.

Select bacteria (probiotics) feed on the fibre in plant foods and produce essential nutrients including fatty acids, vitamins, and neurotransmitters that then affect brain health. Conversely, a poor microbiome can have adverse effects on brain function by increasing the production of pro-inflammatory substances and by compromising levels of essential neurotransmitters, as well as inhibiting the absorption of vital nutrients and energy.

Supplements for brain health

There is mounting evidence that certain nutrients can support brain health in various ways. These include:

• Theanine (found in tea), an amino acid that can promote a feeling of calm concentration and relaxed focus
• Curcumin (found in turmeric), an antioxidant that helps protect brain cells, possibly against premature cognitive decline
• Proanthocyanidins (found in foods such as berries), powerful antioxidants that help protect brain blood vessels
• Phosphatidylserine (found in soy and sunflower seeds), a phospholipid that supports nerve cell membranes, myelin, and energy and neurotransmitter production
• Probiotics, especially Bifidobacterium longum, which may help protect brain cells and promote psychological and cognitive well-being.

The takeaway is that to be smart about brain health you need to do more than just pop a pill or two. Instead, cognitive and emotional health is best served by eating a nutritious diet that supports overall health, and perhaps adding in select supplements to make up any unavoidable dietary shortfalls should you need.