Generalised Anxiety Disorder - Food for the Brain

About Anxiety:

Anxiety is experienced by everyone at some point in their lives and can often be triggered by important life events, financial pressures, relationship issues and more. However, there are some that suffer with ongoing symptoms of anxiety, where even after the stressful situation has disappeared, they continue to experience both physical and psychological symptoms. These may include1:

  • Nervousness, worry, fear
  • Palpitations
  • Panic attacks
  • Problems concentration
  • Dizziness
  • Problems sleeping/insomnia 

Anxiety is also a symptom of a range of diagnoses, such as panic disorder, phobias, PTSD and social anxiety disorder. It is estimated to affect up to 5% of the UK population and it is more common in women than men2

How Conventional Medicine Treats Anxiety:

Generalised Anxiety Disorder (GAD) is the title of its official diagnosis and it is most commonly treated with antidepressants, called selective serotonin reuptake inhibitors (SSRIs), as well as talking therapies like cognitive behavioural therapy (CBT). Conventional medicine hasn’t identified a clear cause for anxiety, however, some research shows that there are a variety of factors3 that can lead to a GAD diagnosis:

  • Imbalance in brain chemicals such as serotonin and noradrenaline, both of which play an important role in regulating mood
  • Genetic influences – research shows you’re up to 5 times more likely to develop an anxiety disorder if you have a close relative with the condition4
  • Overactivity in parts of the brain that are involved with emotions and our survival, such as the amygdala 
  • Having experienced significant trauma, such as abuse, bullying and accidents
  • Having a history of drug or alcohol abuse
  • Having a long-term condition that involves suffering with pain, such as arthritis

Nutrition and Anxiety; What Works

Balance Blood Sugar Levels

Our brain is one of the most energy hungry organs in the body that needs a continuous supply of fuel, which is mediated by our blood sugar levels. This is so that the brain can carry out important functions, such as the production of neurotransmitters, communication between brain cells, learning, memory and so much more. Eating the wrong types of food can lead to peaks and troughs in our blood sugar levels, which can cause shortfalls in fuel to the brain and lead to symptoms of dizziness, panic, palpitations, worry and nervousness, all of which are symptoms of anxiety. 

The brain’s main source of fuel is glucose – a simple sugar. However, we need this sugar to be steadily available throughout the day. Eating foods that are too high in ‘quick-releasing’ sugars will lead to blood sugar levels spiking and then dipping too low, too quickly. This is because our digestive system doesn’t have to do very much to extract the sugars from these types of foods. Baked goods, refined grains (white rice, white bread), confectionery, fizzy drinks, chocolates, cereal bars, juices and anywhere else that you find refined sugars, contain quick releasing sugars. 

In a systematic review that investigated 12 studies with data on 12,626 people with type 2 diabetes, there were significant and positive associations between having diabetes and anxiety5. Diabetes is diagnosed when someone is no longer able to metabolise carbohydrates and sugars, as a result of insulin resistance. This is a consequence of eating foods that are high in quick-releasing sugars, which can lead to the blood sugar imbalances that you see in people with diabetes. However, it’s worth noting that you don’t have to be diabetic to experience poor glycemic control. 

Key Action:

Choose slow releasing carbohydrates like pulses, root vegetables, brown rice, brown bread and pseudo-grains like quinoa.

To further help balance blood sugar levels, pair these carbohydrate sources with protein rich foods such as eggs, fish, poultry and meat. 

Support the Gut Microbiome

Our gut has tens of trillions of microorganisms, including at least 1000 different species of known bacteria with more than 3 million genes (150 times more than human genes), weighing up to 2kg. Scientists say that we are just as bacteria as we are human6, highlighting their importance to the basic functioning of the body. One of the gut microbiome’s most important roles is in protecting the tissue and cells in the lining of the digestive tract, where a complex network of nerves are located that directly communicate with the brain. These nerves are able to function separately from the central nervous system, which is why the gut is often called the second brain. Optimal communication between the gut and the brain is vital for good mental wellbeing, and this starts with a healthy microbiome. 

Another curious function of the gut microbiome is to produce neurotransmitters. For example, up to 90% of serotonin, the ‘good mood’ neurotransmitter, is created in the gut by bacteria7. This then proceeds to be communicated via the vagus nerve to the brain where it exerts its effect on the brain’s neurochemistry – pretty fascinating stuff! 

In a recent study8, after intense antibiotic treatment in a group of mice, there were a large number of gut bacteria metabolites that were significantly depleted compared to the control group. ⁠These specific gut metabolites were identified to play a pivotal role in the tryptophan-serotonin pathway, as well as in sleep-wake cycles. Whilst serotonin is mostly known for being the ‘happy’ neurotransmitter, it also plays an important role in sleep. The researchers found that in the gut bacteria-depleted mice, there was almost no serotonin and a high frequency of movement between sleep-wake cycles, meaning less optimal sleep. ⁠This is just one of the many ways our gut bacteria can influence neurochemistry, and it helps to know that by eating the right foods, we can have a significant positive impact on the ecology of our gut, and consequently our mental wellbeing. 

Key Action:

In order to support a healthy ‘gut-brain communication’, it’s important to avoid foods that will lead to imbalances in the ecosystem of our gut. Foods that are highly processed and sugary, as well as alcohol and unnecessary medications (for example, overuse of painkillers and antibiotics), can have a negative impact on gut bacteria.

Instead, aim to eat a ‘rainbow’ of vegetables. Eating a wide variety of different coloured vegetables, ensures you’re providing your gut bacteria with a range of prebiotic fibres and plant pigments to feed on, which are full of antioxidants. This will provide optimal fuel to encourage diversity of bacteria species and strains, which can help to prevent anxiety and low mood. 

In addition, eating fermented food such as sauerkraut, natural live yoghurt and fermented soy like miso and tempeh, also help to provide a natural source of probiotics or good bacteria, helping keep the gut populated with optimal levels of bacteria strains that have a positive impact on health.


Avoid caffeine

Coffee has many health-promoting benefits, including its high levels of antioxidants. However, some people simply do not handle caffeine very well. For example, we know that certain genetic variations can predispose someone to be very resistant to caffeine9 – meaning that they can enjoy various cups of coffee a day, including one before bed, and feel absolutely normal.  On the other hand there are others that are hopeless at processing caffeine and feel jittery for hours, even after just one coffee. Either way, when we look at the mechanism of caffeine and the biological effects it has on the body, it’s easy to see why caffeine may not be the best thing to consume if you’re prone to anxiety. 

Caffeine stimulates the production of cortisol and adrenaline, which are two hormones that are specifically geared to stimulate the nervous system into ‘fight or flee’ mode. When we’re in fight or flee mode, the body gets ready to deal with a stressful and potentially life threatening situation. Our heart rate goes up, sugar stores are liberated from the tissues of our body to be used for quick energy, and our blood circulation moves away from our digestive tract to our muscles, so that they are well-equipped to ‘fight or flee’. These are all conducive to stimulating anxiety and prevent the nervous system from settling and switching back into ‘rest and digest’, the gear we want to be in most of the time for our body to function at its best. 

But perhaps where caffeine has the most negative impact, is in preventing optimal sleep, which can be a pivotal risk factor for someone that has anxiety. In a systematic review10 of epidemiological studies and randomized controlled trials on the effect of caffeine on sleep, it was found that caffeine reduced total sleep time, sleep efficiency and prolonged sleep latency. Slow-wave sleep – which is our most restorative phase of sleep – was also reduced and arousals were increased. 

Key Action:

Instead of coffee, try hot drinks that are soothing and calming for the nervous system, like herbal teas, which are naturally caffeine free. If you like the taste of coffee and can’t imagine not starting your day without it, why not give decaf a go. It’s important to note, however, that if you’re used to having a lot of caffeine every day, it’s vital to gradually reduce. The caffeine withdrawal symptoms are real!

Try magnesium

This mineral is a balm for the nervous system. Whilst it plays a role in hundreds of enzymatic reactions in the body, one of magnesium’s primary functions is to prevent over-excitation in the brain and the nervous system. It does this by inhibiting something called the NMDA receptor, which normally receives an excitatory signal from the neurotransmitter glutamate11. In cases of magnesium deficiency, this inhibitory process doesn’t happen, which can lead to the brain becoming overactive, causing symptoms of anxiety. 

In cases of chronic stress, magnesium also helps to protect a part of the brain, called the hippocampus, that is particularly sensitive to ongoing stress in both the environment and the physical body. The hippocampus is responsible for stimulating the production of cortisol from the adrenal glands, which is of course necessary for our health. The problem is when this function is constantly stimulated, the hippocampus can become desensitized. This means that the normal negative feedback loop, where cortisol is downregulated when it reaches peak, no longer functions properly, and we’re left with chronic stress and anxiety. Magnesium, miraculously, not only helps to suppress the hippocampus from instructing the adrenals to produce cortisol, but it also reduces the responsiveness of the adrenal glands to these instructions12. So, all in all, magnesium has a global positive effect on the nervous system. 

Key Action:

There are many different types of magnesium and it’s important to get the right combination and right dosage to feel its impact. Magnesium citrate and oxide can cause diarrhoea if taken in excess and are for this reason poorly absorbed.

Magnesium l-threonate, magnesium glycinate and magnesium taurate are the three that are most recommended for the brain and the nervous system. Having between 400mg-800mg a day in separated doses is advised for optimal impact.

However, please note that excessive magnesium does have some side effects, such as dizziness, low blood pressure and arrhythmia, so it is always best to work with a nutrition or healthcare practitioner to guide you through all your specific needs. 

Try l-theanine

L-theanine is a non-essential amino acid that is one of green tea’s bioactive compounds. It is known for its ability to stimulate the production of GABA, one of the brain’s most important ‘inhibitory’ neurotransmitters that prevent over-excitation of the brain and helps to induce feelings of calm and relaxation. L-theanine has also been shown to trigger alpha-wave activity in the brain, which is known for meditative states of awareness that can enhance creativity and focus. 

Key Action:

Up to 400mg a day can be taken in separate doses to help with both mild and severe anxiety13. Be sure to take it away from food and with a small carbohydrate snack such as an oat cake or a piece of fruit. This helps to ensure that there isn’t any competition for absorption between other amino acids.