Stress and Diet: what is their relationship?

The relationship between stress and nutrition is an important area of research in health and nutrition science. The interaction of these two parameters is more complex than we might imagine, as both stress can affect our eating habits and nutrition can, in turn, affect our ability to manage stress.

What do we really mean by ‘stress’?

Stress is our body's natural biochemical response when faced with a potential threat or danger. When we are under stress, a special system in our body called the sympathetic nervous system is activated. This system sends signals to various organs to prepare the body for action. For example, the heart starts beating faster, muscles contract to be ready for a reaction and we are alert. It is what we call the fight or flight response.

Along with the activation of the sympathetic nervous system, a more complex mechanism called the hypothalamic-pituitary-adrenal axis (HPA axis) comes into play. This is a communication system between the brain and the adrenal glands, two small glands located above the kidneys. The process starts when the hypothalamus, a small but critical part of the brain, senses the presence of stress and sends signals to the pituitary gland, another endocrine gland in the brain. The pituitary gland, in turn, releases specific hormones that are carried through the blood to the adrenal glands. There, they respond by producing key stress hormones, such as cortisol and adrenaline, which prepare the body to cope with the situation.

This process has been in place since the beginning of human existence and is aimed at survival. However, when stress becomes chronic, it can affect health in a variety of ways, including metabolic disorders, increased risk of cardiovascular disease and weakened immune systems.

Can stress affect what we consume?

The answer is yes! In what way? Stress can affect our appetite and the food choices we make. Some experience appetite suppression, while others resort to eating as a means of relief. It is observed that most of them experience increased cravings for foods rich in sugar, fat and salt. Eating such foods can provide temporary relief due to the neurochemical reactions they cause, such as the release of dopamine in the brain, a substance associated with joy and pleasure. This can lead to a vicious cycle of emotional eating - guilt and remorse - further eating.

As a consequence, anxiety can contribute to weight gain. In addition, gastrointestinal disorders, such as stomach pain, bloating, constipation or diarrhoea, are common in times of stress and may lead to the exclusion of various foods, with negative consequences for nutrition and general health.

Can diet have a positive effect on stress?

Nutrition provides the body with a variety of nutrients related to regulating neurotransmission, maintaining good mood, improving blood circulation and normal brain function, factors that contribute to more effective stress management. In fact, certain nutrients have been shown to contribute to better brain function and mental resilience.

To begin with, magnesium is essential for regulating neurotransmission and relaxing muscles. Its deficiency is associated with increased cortisol production and symptoms of anxiety. Foods rich in magnesium are for example nuts (almonds, walnuts, sunflower seeds) and green leafy vegetables. Also, omega-3 fatty acids play an important role in reducing inflammation and stabilising neurotransmitters. They help to reduce cortisol and improve mood. They are found in fatty fish (salmon, mackerel, sardines), flaxseed, chia seeds and walnuts. In addition, B vitamins are essential for the functioning of the nervous system and the regulation of energy metabolism. Their deficiency can lead to fatigue, irritability and increased stress. Rich sources are meat, fish and legumes. Particularly important is tryptophan, an amino acid and a precursor molecule of serotonin, the hormone of joy. Increased tryptophan intake is associated with better mood and reduced stress. It is found in turkey, beef, eggs, dairy products and bananas.

But can diet have a negative influence on stress?

Our diet can exacerbate symptoms of anxiety and stress through various physiological mechanisms.

Alcohol and Caffeine

Consumption of substances such as alcohol and caffeine can significantly affect the functioning of our nervous system and our ability to manage stress. Alcohol, for example, directly affects the central nervous system by reducing serotonin levels. At the same time, it disrupts the sleep cycle, especially the REM (Rapid Eye Movement) stage, which is critical for emotional recovery and balancing cortisol levels. When this stage of sleep is affected, problems such as irritability, reduced concentration and a strong reaction to stressful situations can occur. Caffeine, on the other hand, enhances the body's response to stress by causing the release of stimulant hormones such as adrenaline and norepinephrine. This can lead to increased heart rate, higher blood pressure and activation of the hypothalamic-pituitary-adrenal axis. In people with high caffeine sensitivity, which can be detected through genetic analysis, this effect is more pronounced, causing nervousness, insomnia and worsening of anxiety symptoms.

Processed Carbohydrates 

Eating foods rich in processed carbohydrates and added sugars, such as white bread, sweets, soft drinks and packaged juices, can cause sharp fluctuations in blood glucose levels. These fluctuations lead to reactive hypoglycemia. When sugar levels drop sharply, the body perceives this as an “emergency” and secretes stress hormones, such as adrenaline and cortisol, to bring glucose back to normal levels. This process can cause symptoms such as irritability, fatigue, confusion and an increased stress response.

So what is the conclusion?

The relationship between stress and nutrition is a two-way street and is extremely important for our well-being. A key indicator of the body's ability to adapt to stress is heart rate variability (HRV). HRV measures the variations in the time interval between two consecutive heartbeats, meaning it focuses not only on the number of beats per minute, but on how constant or variable the pattern is. In particular, it reflects the balance between the sympathetic nervous system (activated in stressful situations) and the parasympathetic nervous system (associated with relaxation and recovery).

In this context, implementing anxiety management strategies such as breathing exercises, physical activity and adequate sleep combined with a healthy diet can help improve HRV and overall stress management. At our centre, we offer the possibility of measuring HRV, giving a comprehensive picture of the body's physiological response to stress and providing personalised recommendations for its improvement.

So, what you can do from today:

• Limit caffeine consumption after 14:00, if there is a high sensitivity

• Enhance your diet with omega-3 fats, magnesium and B vitamins

• Walk daily for at least 15 minutes

• Try 5 minute breathing exercises before bedtime

Citations

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