Factors In Diets That Can Affect Mood

In these times, it’s never been more important to look after our mental and physical health. Understanding how our lifestyle, including our diet, can influence the way we feel plays a big role in improving our overall health. For example, diets that rely heavily on saturated fat, sugar, and processed foods, are more prone to cause a negative impact on both physical health and mood, making conditions like depression and anxiety more likely. Diets that are centered around a diverse range of foods such as plants, lean meats, whole grains, and healthy fat products are proven to actually help protect our mental health, and can even be a useful part of a treatment plan to help depression.

So…What factors can affect our mood?

Blood Sugar

Many people may be suffering from symptoms of common mood disorders, such as depression and anxiety, without realizing that variable blood sugar could be the culprit. Evidence shows that there is a strong relationship between glycemic highs and lows, and mood. Symptoms of poor glycemic regulation have been shown to closely mirror mental health symptoms, such as irritability, anxiety, and worry. This should come as no surprise, as the brain runs primarily on glucose. The Journal of Medicine and Life conducted research that showed that depression occurrence is two to three times higher in people with diabetes, than in people without. This is partly due to prominent blood sugar highs and lows. One study found that inconsistent blood sugar levels among those with diabetes were associated with lower quality of life and negative moods. Among diabetics, higher blood glucose, or hyperglycemia, has historically been associated with anger or sadness, while blood sugar dips, or hypoglycemia, has been associated with nervousness.

How to solve this?

  1. Reduce and manage stress 

Stress has been shown to have a negative effect on the regulation of blood glucose. Specifically, hormonal changes during acute and chronic stress can affect glucose balance.

  1. Increase intake of protein and fiber

Protein and fiber both have low glycemic index (GI), which means that they have a low impact on blood sugar levels.

  1. Reduce intake of sweet beverages and refined carbs

A diet high in refined carbohydrates, including sweet beverages, has a high GI value and is associated with unstable blood sugar regulation.

The Gut

Our intestines contain over 1,000 different types of microorganisms, known as the gut microbiota. Their job is to digest nutrients, produce vitamins and hormones, and are even involved in our mental health. This is due to the gut-brain axis, which is the way the gut communicates with the brain. The vagus nerve is responsible for this communication through the cells of the immune system by releasing chemicals into the blood. This is important because it allows us to understand that what eat can have a direct connection to our emotions and mood.

The gut can contribute in positive ways to support our mental health. They produce several compounds during their metabolism, which are beneficial to our mood, such as short chain fatty acids, which have anti-inflammatory characteristics, and Tryptophan, an amino acid used to produce serotonin, which is a hormone heavily involved in mood. A diet high in processed foods can often lead to a decrease in diversity as the microorganisms are not being well nourished. In the end, this increases a person’s chance of developing depression as a bacterial imbalance can cause inflammation.  

As a result, it is very important that we nourish the trillions of microorganisms that reside in our gut to help protect our mental health. The main way we can achieve this through our diet is by trying to make it as varied as possible by including a range of fruits, vegetables, wholegrains, beans and legumes, and nuts and seeds. Remember, a diverse diet means a diverse microbiota, which means a happier body, mind, and being.


Statistics have shown that depression is associated with extremely high levels of inflammation in the body. One factor that contributes to this is diet. A nutrient poor diet is known to increase inflammation. Inflammation can have several negative impacts that affect our mental health including:

  •  Damage to the neurons in the brain, therefore increasing the risk of developing depression.
  • An increase in circulating cytokines, which are chemicals released by the immune system that contribute to inflammation. They can affect our emotions by changing the release of serotonin and dopamine, our “happy hormones”. Cytokines can also affect the stress response, which can contribute to anxiety.
  • Decreasing the volume of the hippocampus, a part of the brain involved in learning, memory, and mood.

However, there are foods that help reduce inflammation and can improve our mental health. Polyphenols, a type of phytochemicals known for their anti-inflammatory and antioxidant properties, are able to protect the neurons in the brain from damage caused by inflammation. Foods that are high in polyphenols include many fruits and vegetables, such as berries and spinach, coffee and even dark chocolate, which has the added bonus of releasing endorphins when we eat it, helping to boost our mood.

The facts show that food can influence our mood, and it is up to you to let it affect you in a positive or negative way. 


  1. Penckofer S, Quinn L, Byrn M, Ferrans C, Miller M, Strange P. Does glycemic variability impact mood and quality of life?. Diabetes Technol Ther. 2012;14(4):303–310. doi: 10.1089/dia.2011.0191
  2. Gonder-Frederick LA. Cox DJ. Bobbit SA. Pennebaker JW. Mood changes associated with blood glucose fluctuations in insulin-dependent diabetes mellitus. Health Psychol. 1989;8:45–59.
  3. Butler, M.I., Morkl, S., Sandhu, K.V., Cryan, JF., Dinan, T.G. (2019), ‘The Gut Microbiome and Mental Health: What should we tell our patients?’ Canadian Journal of Psychiatry, 64
  4.  Rieder, R., Wisniewski, P.J., Alderman, B.L., Campbell, S.C (2017), ‘Microbes and mental health: A review’, Brain, Behaviour and Immunity, 66, pp. 9-17
  5.  Firth, J., Marx, W., Dash, S., Carney, R., Teasdale, S.B., Solmi, M., Stubbs, B., Schuch, F.B., Carvalho, A.F., Jacka, F., Sarris, J. (2019), ‘The effects of dietary improvement on symptoms of depression and anxiety: A meta-analysis of randomised controlled trials’, Psychosomatic Medicine, 81

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