🔥 Vet Nutrition 2025: Why High-Starch Feeds Trigger Inflammation in Horses 🐴⚠️

Author: Dr Duncan Houston, BVSc

While grain and starch-rich feeds have long been used for energy, recent research shows they may be pro-inflammatory and harmful, especially in certain horses. A new study out of Sam Houston State University reveals how high-starch diets increase levels of interleukin-1β (IL-1β), a powerful inflammatory marker. In this 2025 article, Dr Duncan Houston explores the dangers of high-starch diets and how to feed your horse with inflammation in mind. 🐎🧠

🧬 What Is Interleukin-1β (IL-1β)?

IL-1β is a cytokine—a chemical messenger released during inflammation. In humans, it’s linked to chronic disease and even neuroinflammation associated with conditions like Alzheimer’s. In horses, elevated IL-1β signals systemic inflammation and internal stress. 🔬

📊 What the Study Found

The research was conducted in two trials and published in The Horse. Here's what they discovered: 🧪

Trial 1: Normal Weight vs. Overweight Horses

• 📅 Horses were fed hay and steam-rolled barley for 14 days
• ⚠️ Overweight horses showed immediate IL-1β increase
• 🧬 Normal weight horses also had elevated IL-1β—but after 14 days

Trial 2: Younger vs. Older Horses

• 📅 Horses aged 12–14 and 20–23 fed hay, barley, and concentrate for 36 days
• 🔥 Older horses had significantly higher IL-1β levels than younger horses

📉 What This Means for Your Horse

The findings suggest:

• ⚠️ Overweight and older horses are more sensitive to inflammatory effects of starch
• 📈 Even normal, fit horses show increased inflammation over time

Systemic inflammation can lead to digestive issues, joint problems, metabolic dysfunction, and cognitive decline. 🧠💥

🥣 Where Is Starch Found in the Diet?

• 🌽 Corn, oats, barley
• 🍞 Commercial sweet feeds and high-energy concentrates
• 🥖 Molasses-based products

These feeds are fine for hard-working performance horses with high caloric needs—but risky for:

• 🧓 Horses over age 15
• ⚖️ Overweight or easy keepers
• 🧬 Horses with EMS or PPID (Cushing’s)

🧠 Dr Duncan Houston’s Advice

"Feeding grain to the wrong horse is like fueling a campfire with gasoline. It sparks inflammation, risk, and long-term damage. Go forage-first." 🐴🔥

✅ Vet-Recommended Feeding Strategies (2025)

• 🌿 Base the diet on forage: High-quality hay or pasture should make up 75–90% of intake
• 🥕 Add low-starch, high-fat feeds (e.g., beet pulp, rice bran, flaxseed)
• ⚖️ Use body condition scoring to adjust calories
• 📊 Monitor inflammation in seniors and EMS-prone horses

💡 Signs Your Horse May Be Reacting to a High-Starch Diet

• 💥 Irritability or mood changes
• 🧠 Cognitive decline or forgetfulness in seniors
• ⚠️ Flare-ups of laminitis or joint swelling
• 📉 Sudden weight gain or metabolic crashes

🔚 Final Thoughts: Feed for the Long Haul

We now know that high-starch diets do more than just spike blood sugar—they drive inflammation that can impact every part of your horse’s health. Choose low-starch feeds, forage-first diets, and consult with your veterinarian about age- and weight-appropriate nutrition. 🐎❤️

Need a custom feeding plan for your older or easy-keeper horse? Visit AskAVet.com or download the Ask A Vet app for expert support. 📱🌾