Metabolic Health and ADHD: Understanding the Connection

Key Takeaways

• The relationship between blood sugar balance, metabolic health, and ADHD is complex and multidirectional.
• Balanced meals, regular movement, good sleep, and stress management support metabolic and mental health.

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Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that affects how someone pays attention, controls impulses, and stays organized. Rather than a weakness, ADHD is a different way of thinking. It comes with both challenges and unique strengths. Common symptoms of ADHD include difficulty focusing, hyperactivity, impulsive behaviors, restlessness, and distractibility. People living with ADHD are often highly resilient, creative, and can hyperfocus on certain tasks. According to data from the National Center for Health Statistics in 2023, 15.5 million US adults have ADHD.¹

The causes of ADHD are not fully understood, but researchers continue to uncover different factors that may contribute to its symptoms and development. Among these factors are blood glucose and insulin resistance. Understanding the connection between blood glucose and ADHD may be beneficial for effective symptom management. Let’s take a closer look at the proposed mechanisms linking blood sugar with ADHD.

The Impact of Blood Sugar Fluctuations on ADHD Symptoms

Glucose, the simplest form of sugar, is the brain’s preferred energy source. Unlike other areas of the body, the brain can’t store glucose for later. This means it needs a consistent flow of sugar to function at its best. There is no evidence that sugar consumption itself is related to ADHD.² However, rapid fluctuations of glucose in the brain (alternating between spikes and crashes) prevent the brain from making neurotransmitters (like dopamine, serotonin, and norepinephrine).

When blood sugar spikes (for example, after drinking a large soda), this glucose flux overstimulates the brain, leading to hyperactivity and restlessness. A blood sugar crash, on the other hand, can result in sluggishness or inattention. Low blood glucose levels also trigger the release of cortisol, which can cause feelings of irritability and frustration. Further, low blood sugar can increase cravings for sugar and caffeine, leading to a ride on the blood sugar roller coaster.

Insulin Resistance and Its Role in ADHD

When you eat a high-sugar meal or snack, your blood sugar rises. Usually, this triggers the production of insulin. Insulin is a hormone produced by the pancreas that clears glucose from the blood by moving into the body’s cells. Insulin resistance occurs when the cells don’t respond normally to insulin. If you are insulin resistant, a normal amount of insulin will not effectively move glucose into cells. To compensate, your body has to make extra. This can eventually cause your pancreas to burn out and increase your risk for type 2 diabetes.

Research in both adults and children shows a link between insulin resistance and ADHD. A Swedish study of 5.5 million adults found that those with ADHD were more than twice as likely to have type 2 diabetes.³ In children and adolescents, studies have found a higher prevalence of diabetes and elevated A1c among people with ADHD compared with those without.⁴ And children may be at risk before they are even born. A retrospective birth cohort study of over 37,000 children found that children of mothers with type 1 or type 2 diabetes during pregnancy were 25%-50% more likely to have ADHD.⁵

Even without a diagnosis, there may be a correlation between impaired insulin signaling and the severity of ADHD symptoms. Insulin resistance in the brain could impair dopamine signaling⁶, leading to both ADHD symptoms and dysregulation of appetite. A cross-sectional study of adults found that 46% of patients with type 2 diabetes exhibited ADHD-like symptoms, even though fewer than 14% had been diagnosed with ADHD.⁷ A case-control study found that the severity of ADHD symptoms was higher in children with type 1 diabetes, an autoimmune condition characterized by insulin deficiency.⁸

Brain Glucose Metabolism and Cognitive Function

Because the brain can’t store glucose, it relies on a constant stream of carbs to maintain the production of essential neurotransmitters. These neurotransmitters help to regulate both behavior and cognitive function. Serotonin, in particular, plays a vital role in impulse control,⁹ while dopamine and acetylcholine support attention.¹⁰ Cognitive performance declines when the brain does not have enough glucose to make these neurotransmitters.

Beyond neurotransmitter production, reduced glucose metabolism in certain parts of the brain is observed in people with ADHD. In one study, 75 adults were given intravenous glucose and asked to complete a task in which they pressed a button when they heard a particular noise. Positron-emission tomography (PET) scans were taken of their brains to see where the glucose was used in the brain. Adults with ADHD had reduced glucose metabolism in the prefrontal cortex and premotor cortex, parts of the brain involved in attention and motor control.¹¹ This demonstrates how altered glucose utilization in certain parts of the brain may contribute to hallmark symptoms of ADHD. Common ADHD medications, such as methylphenidate, work by stimulating parts of the brain that are usually underactive.

Dietary Strategies for Stabilizing Blood Sugar

Whether you have ADHD or not, good nutrition is key when it comes to balancing your blood sugar and preventing insulin resistance. Therefore, diet can play a significant role in mental health. Follow these simple dietary strategies to promote stable blood sugar:

• Choose low-glycemic index foods: The glycemic index is a measure of how quickly a food raises blood sugar levels. Foods with a higher glycemic index are digested and absorbed quickly. These foods tend to be high in sugar and low in fiber, and include things like birthday cake, white bread, and sweeteners. On the other hand, foods with a lower glycemic index are digested more slowly and are typically higher in fiber. These include most fruits, vegetables, beans, and whole grains. Choosing low-glycemic index foods can prevent rapid rises in blood sugar.
• Avoid “naked” carbohydrates: The body digests carbs more quickly than fats or proteins. Eating a carb with other foods can slow digestion and, as a result, the release of sugar into the bloodstream. Pair your carbs with protein and healthy fats. For example, spread peanut butter on toast, add Greek yogurt to breakfast cereal, or dip tortilla chips in guacamole.
• Avoid excessive sugar intake: Reducing your sugar intake is the best way to lower the glycemic index of the foods you eat and avoid naked carbs. Dessert is fine in moderation, but it can be easy to overconsume. Consider smaller portions of your favorite desserts or lower-sugar alternatives, like yogurt parfaits or fruit smoothie popsicles.

Lifestyle Interventions to Support Blood Sugar and ADHD Management

Beyond diet, lifestyle changes may also support both blood sugar balance and ADHD symptom management. Here are some things to try (as a bonus, these are all things that support overall wellbeing, too!):

• Physical activity: Research consistently shows that exercise improves insulin sensitivity and blood sugar control.¹² Interestingly, these improvements can result from either aerobic activity or resistance training. Physical activity can also improve symptoms of ADHD, including impulsivity, attention, executive functioning, and task switching.¹³ The Physical Activity Guidelines for Americans recommend 150 minutes of moderate-intensity physical activity per week (think: brisk walking, cycling, or stair climbing) and two muscle-strengthening activities per week.¹⁴
• Adequate sleep: Sleep restriction negatively impacts glucose metabolism, leading to elevated plasma glucose levels and reduced insulin sensitivity.¹⁵ While inadequate sleep may cause or mimic ADHD, ADHD may also make it hard to fall asleep or sleep through the night.¹⁶ Everyone’s sleep needs are different, but most adults should aim for 7 to 9 hours per night. Establish a consistent sleep schedule and practice good sleep hygiene by limiting screens before bed and using your bed only for sleeping. Consult with a doctor or sleep specialist if you have trouble sleeping.
• Stress management techniques: When you are stressed, to prepare your body for “fight or flight,” your body releases the hormones cortisol and adrenaline. These hormones can cause blood sugar levels to rise. Chronic stress resulting in consistent hyperglycemia (high blood sugar) can increase the risk for insulin resistance and diabetes.¹⁷ Research also indicates that higher levels of perceived stress are associated with ADHD symptoms.¹⁸ Everyone is different, but practice stress management techniques like mindfulness, meditation, or spending time in nature to balance blood sugar and reduce ADHD symptoms.

The Bottom Line

ADHD is a complex condition influenced by many factors, and growing research suggests that blood sugar balance and metabolic health may play a role in how symptoms show up. While more research is needed to better understand the multidirectional link between metabolic health and ADHD, diet and lifestyle interventions can help increase insulin sensitivity, improving the health of your body and brain. As always, individual needs vary, so work with a healthcare provider to tailor strategies to meet your unique needs.

Learn More With Signos’ Expert Advice

Blood sugar health seriously affects how you feel and how well your body functions. That’s why it’s so important to understand how different things affect your blood sugar levels. 

Signos CGM empowers you to improve your health by keeping track of your diet, exercise, sleep habits, and blood sugar. Knowledge is power, and a CGM can give you specific information about how your habits affect your health. 

Signos has a team of health experts who compile evidence-based nutrition information to help you improve your health and wellness. Check out the resources here.