Skip Carbs to Improve Mental Health
The growing interest in low-carbohydrate or no-carbohydrate diets has made news for their benefits for physical health, but there are benefits to reducing carbohydrate intake for mental health as well. People with anxiety, depression, bipolar disorder, and other mental disorders have found relief in changing their diets. Why would what you eat affect your brain chemistry and your feelings?
- High blood glucose levels can increase brain glucose levels in a toxic way. High levels of glucose in the brain can lead to formation of dysfunctional proteins called “advanced glycation end products,” or AGEs, which accumulate in the brain and cause neuron toxicity and inflammation. This inflammation and neurotoxicity can definitely impact mental well-being.
- High levels of insulin in the blood directly effects the blood-brain barrier. Having high levels of insulin at a constant rate or with many repeated spikes can cause the insulin receptors on the surface of the blood-brain barrier to become damaged and less sensitive. Less working insulin receptors on the blood-brain barrier mean that less insulin is passing into the brain, which is harmful because the cells inside the brain need insulin to process the glucose it needs to turn glucose into energy. This is called “cerebral glucose hypometabolism” and has been linked to neurodegenerative disease (such as Alzheimer’s and Parkinson’s disease).
- Diets high in sugar cause high levels of inflammation in the brain. High sugar consumption triggers an inflammation cascade which causes the release of inflammatory Inflammation is a leading cause of neurological and psychiatric diseases.
- High-sugar diets encourage oxidative damage (free radicals). If the cells receive more sugar than they can handle, cells release reactive oxygen cells (or free radicals). These free radicals are neutralized by our body’s antioxidants, but as the free radicals roam the body, they damage cellular DNA and cell components. Free radicals can damage the blood-brain barrier and result in higher permeability of the barrier for substances that should not get through.
- Too much sugar damages our cellular mitochondria. The mitochondria in our cells generate energy and are essential to cellular and body health. Our brains use about 20% of the body’s supply of energy, and too much sugar damages the mitochondria of brain cells. Not enough energy to the brain results in impaired brain health.
- Stress hormones released by high-carb intake affect your mental wellbeing. As soon as the spike from high carbohydrate intake is gone and the “crash” follows, your body releases adrenaline and other stress hormones up to 5 hours after consuming too many carbohydrates. This contributes to the panicky feelings of hypoglycemia and can cause anxious feelings, irritability, shaking, difficulty concentrating, and a cycle of craving more carbohydrates.
- Carbohydrates affect your neurotransmitters. Neurotransmitters (like serotonin, dopamine, GABA, glutamate) can be disrupted by high carbohydrate intake. A pathway called the kynurenine pathway regulates the activity of the neurotransmitters. Neurotransmitters are responsible for emotions and also emotional dysregulation that is found in many psychiatric disorders. As too many carbohydrates disrupt the pathway, it forces the brain into an “emergency mode” where it signals the kynurenine pathway to steal tryptophan (the building block for serotonin) away from serotonin and melatonin to produce more glutamate. Serotonin, melatonin, and GABA levels all decrease as dopamine increases, and glutamate—the neurotransmitter that can causes excitotoxicity when in excess in the brain—increases and damages the brain.
- High sugar diets reduce the brain’s ability to respond appropriately to stress. Brain-derived neurotrophic factor (BDNF) is a molecule involved in neuroplasticity, or the ability of the brain to respond and recover from stress. BDNF is reduced when the brain is receiving too much sugar.
The link between carbohydrates and brain health has been well-studied, and though many people thrive on low-carb or no-carb diets, the answer is not a “one size fits all” diet. The best takeaway from learning how sugar impacts your brain and your emotions is to check-in with how you’re feeling and how certain foods make you feel, so you can find a healthy balance in your diet that leads to a better mood.