What You'll Learn
This article breaks down recent research on Huntington's disease (HD)—a genetic neurodegenerative disorder—to explain how the brain and body "talk" to each other when someone has HD. You’ll learn about the key ways this communication goes wrong, and simple lifestyle changes (like diet and exercise) that might help manage symptoms and support overall health.
A Quick Look at Huntington's Disease
HD is caused by a faulty gene (a repeated "CAG" segment in the HTT gene) that makes a harmful protein called mutant huntingtin (mHtt). This protein builds up in the brain, damaging cells—especially in the striatum, a region controlling movement and thinking. Over time, this leads to:
- Motor symptoms: Involuntary jerky movements (chorea), muscle stiffness (dystonia), and balance problems.
- Non-motor symptoms: Cognitive issues (trouble with memory or decision-making), mood swings, and psychiatric symptoms.
But HD isn’t just a "brain disease." It also harms other parts of the body: muscles waste away, metabolism goes haywire (unexplained weight loss despite eating more), gut health suffers, and even the heart and blood vessels can be affected.
Why This Research Matters
Scientists used to focus mostly on the brain in HD. But new studies show the rest of the body plays a big role too. The brain and body are constantly sending signals back and forth (like hormones, immune molecules, and even tiny particles called "extracellular vesicles"). When HD disrupts these signals, it can make both brain and body symptoms worse. Understanding these "cross-talk" problems could lead to better ways to manage HD—including lifestyle changes.
How HD Breaks Brain-Body Communication
Research highlights several key "messengers" that go wrong in HD:
1. Mutant Huntingtin (mHtt) Spreads Through the Body
The harmful mHtt protein doesn’t stay in the brain. It can leak into the bloodstream and travel to organs like the liver, muscle, and gut. In animal studies, mHtt from HD mice even damaged organs in healthy mice connected to them (a technique called parabiosis). This suggests mHtt might "spread" disease beyond the brain.
2. Chronic Inflammation
HD revs up the immune system, leading to high levels of inflammatory molecules (like cytokines) in the blood. These molecules can harm brain cells and worsen symptoms like fatigue and mood issues. For example, HD patients have higher levels of immune markers linked to cognitive decline.
3. Broken Gut-Brain Axis
The gut and brain communicate closely via nerves, hormones, and gut bacteria (microbiome). In HD:
- Gut bacteria get imbalanced ("dysbiosis"), leading to inflammation and digestive problems (like bloating or diarrhea).
- Toxins from imbalanced gut bacteria may leak into the blood and reach the brain, worsening damage.
- Animal studies show fixing gut bacteria with fiber or probiotics can improve HD symptoms like memory problems.
4. Muscle Weakness and "Muscle-Brain" Signals
Muscles normally send helpful signals to the brain (like molecules called "myokines" that support brain health). In HD:
- Muscles waste away (cachexia), even early in the disease.
- Mitochondria (the "powerhouses" of cells) in muscles don’t work well, leading to fatigue and high lactate (a waste product) during exercise.
- Weak muscles send fewer of those helpful signals to the brain, creating a "vicious cycle" of more weakness and brain damage.
5. Hormone Imbalances
HD messes with hormones that regulate hunger, stress, and metabolism:
- Cortisol (stress hormone): Levels rise in HD, worsening muscle loss and brain cell damage.
- Ghrelin (hunger hormone): HD patients often feel hungrier but still lose weight, partly due to ghrelin imbalances.
- Cholesterol metabolites: A brain cholesterol byproduct (24S-hydroxycholesterol) drops in HD, linked to faster brain shrinkage.
Lifestyle Steps to Support Brain-Body Health in HD
While there’s no cure for HD yet, research suggests diet and exercise can help fix some of these broken communication pathways. Here’s what we know:
Diet: Nourish Your Gut and Brain
- Focus on a Mediterranean-style diet: Rich in fruits, veggies, whole grains, fish (omega-3s), and olive oil. This supports gut bacteria, reduces inflammation, and may slow cognitive decline.
- Add fiber: High-fiber foods (oats, legumes, fruits) feed healthy gut bacteria, which produce short-chain fatty acids (SCFAs) that calm inflammation and support brain health.
- Avoid extreme diets: Fasting or very low-calorie diets helped some HD mice, but HD patients already struggle with weight loss—so these are risky without strict medical supervision.
- Stay hydrated and manage weight: Even small weight loss can speed HD progression. Work with a dietitian to ensure you’re getting enough calories and nutrients.
Exercise: Move Safely to Boost Muscles and Mood
Exercise is tricky in HD—too much can worsen fatigue, but too little speeds muscle loss. The key is gentle, consistent movement:
- Aerobic exercise: Brisk walking, swimming, or cycling (30 minutes, 3x/week) improves heart health, boosts mitochondria, and may slow brain shrinkage.
- Strength training: Light weights or resistance bands help keep muscles strong, which sends better signals to the brain.
- Avoid overexertion: HD muscles tire easily. Stop if you feel pain or extreme fatigue. Work with a physical therapist to create a personalized plan.
What We Still Need to Learn
Research is ongoing! Gaps include:
- How exactly gut bacteria affect HD symptoms in humans (most studies are in mice).
- The best "dose" of exercise for different HD stages (early vs. advanced).
- Whether combining diet and exercise works better than either alone.
Key Points to Remember
- HD affects both the brain and body—their communication breakdown worsens symptoms.
- Inflammation, gut imbalances, muscle weakness, and hormone issues are key culprits.
- A Mediterranean diet, fiber, and gentle exercise may help support brain-body communication.
- Always work with your healthcare team before starting new diets or workouts.
Talk to Your Doctor
This research offers hope, but everyone’s HD is different. Ask your doctor:
- How can I safely add more fiber or omega-3s to my diet?
- What type of exercise is best for my current symptoms?
- Could a referral to a dietitian or physical therapist help?
You’re not alone—small lifestyle changes, guided by your care team, can make a big difference in managing HD.
This article is based on research published in the International Journal of Molecular Sciences (2024).