Hello Runner,
Welcome back to your weekly moment of endurance nutrition!
Happy Weekend!
How are you?
I'm fine!
I had a good week, with lots of work and a return to training.
My last weekend was SUPER intense. I volunteered at the Barcelona Triathlon on Friday, handing out race numbers, and on Sunday, during the race, I helped at the hydration stations, handed out medals, collected chips, and had paella for lunch with the athletes.
I loved being part of that world and getting to know both pro athletes and sportspeople up close.
On Saturday, I spent the whole day at a really interesting conference on precision medicine, and in the evening I had my flight to Lisbon. Unfortunately, my flight was canceled at the last minute, and I ended up not going to Portugal. I missed the nutrition conference in Estoril. I was sad, but I was happy that I was able to help at the Triathlon.
It was so crazy that I went four days without training because I didn't have the time or the conditions. But last Monday, I was back in action again.
Today's topic is Antioxidants → when they help and when they hinder adaptation to exercise.
This is a topic that leaves many runners confused and with questions. I confess that even I have been confused. This email will clarify when antioxidants are helpful, when they may interfere, and how to use them wisely in your daily nutrition as a runner.
Antioxidants are often promoted as essential for health, recovery, and performance. You’ll find them praised in articles, recipes, supplements, and almost every “healthy eating” recommendation for athletes/runners. And yes — they do play an important role in reducing damage caused by exercise and supporting the body’s defenses.
However, the relationship between antioxidants and training adaptation isn’t as straightforward as “more is better.” In fact, when consumed at the wrong time or in excessive supplemental form, antioxidants may actually reduce some of the beneficial training responses that runners work so hard to gain.
Before getting straight to the point, I want to explain some basic concepts.
What Antioxidants Are
During exercise, the body produces free radicals — unstable molecules that create oxidative stress. Think of this as a natural “wear and tear” process that happens when your muscles work. A certain amount of oxidative stress is normal and even necessary to stimulate adaptation.
Antioxidants are compounds that neutralize excessive free radicals. Your body produces some on its own, and you also get them through food. They act like a protective shield to limit cell damage, support recovery, and promote long-term health.
Some of the most well-known antioxidants include:
Vitamin C (citrus fruits, kiwi, strawberries, peppers)
Vitamin E (nuts, seeds, avocado, vegetable oils)
Polyphenols (berries, cocoa, tea, coffee, olive oil, herbs, colorful vegetables)
Carotenoids (carrots, tomatoes, sweet potatoes, leafy greens)
Selenium (Brazil nuts, seafood, eggs)
→ A simple rule: the more naturally colorful your plate, the more antioxidants you’re getting.
Food vs Supplements: Not the Same Impact
Antioxidants obtained through whole foods provide a moderate, balanced effect. They come packaged with fiber, water, vitamins, and minerals that work together naturally.
Antioxidant supplements, on the other hand, deliver large, concentrated doses. And that’s where the issue appears.
High-dose supplements can reduce oxidative stress too much. This may “block” some of the signals your body uses to adapt to training — such as increasing mitochondria (energy production), improving endurance, and strengthening muscle function.
→ Food supports the process.
→ Large supplement doses can interfere with it.
When Antioxidants Help Runners
Antioxidant intake can be beneficial for:
General health and recovery
Reducing inflammation during very heavy training phases
Supporting immune function when sick, run-down, or traveling
After races or very hard sessions, when recovery is the priority
During high-stress periods, poor sleep, or an intense life load
→ This is when you can increase antioxidant-rich foods (and occasionally supplements if needed), because the focus is on recovery rather than maximizing training adaptation.
When Can They Reduce Training Adaptation
Right after regular training sessions — especially endurance training — your body uses oxidative stress as a signal to adapt and improve. If you neutralize that stress immediately with high antioxidant doses, you interrupt that process.
This effect is mainly associated with supplements, not food.
So, the key point:
→ Avoid high-dose antioxidant supplements right after training if your goal is to build fitness, speed, and endurance.
Aim to let the body respond naturally to training first.
TIPS
Practical Guidance for Runners
Here are simple recommendations you can start using today:
1. Prioritize food-based antioxidants daily
2–3 servings of fruit + 2–3 servings of vegetables a day is a solid target. The more variety, the better.
2. Include antioxidants regularly, but not obsessively
Spread them through meals — breakfast, lunch, dinner — rather than loading them right after training every day.
3. Best time to increase antioxidant intake
After a race or a very intense training day
During heavy training weeks or taper week
When feeling run-down or fighting off a cold
In the evening on training days, if supplementing
4. If using supplements
Avoid taking high-dose vitamin C or E within 2–3 hours post-training
Reserve them for specific periods (travel, overreaching weeks, and extremely busy days when you can't stick to your diet properly)
Prefer short-term, targeted use — not daily long-term use
5. Don’t fear fruit sugar
Fruit is not the enemy for runners. Its benefits far outweigh the tiny sugar content.
Simple Examples to Add Antioxidants (Without Overthinking)
Breakfast: Greek yogurt + berries + walnuts
Lunch: Rainbow salad (tomato, spinach, carrots, peppers, olive oil)
Pre-run snack: Banana or a small handful of dried fruit
Dinner: Sweet potato with herbs and vegetables on the side
After a race or tough session: Berry smoothie or tart cherry juice
These choices support recovery and long-term performance — without interfering with training adaptations when used wisely.
What Not To Do
Don’t take vitamin C + E supplements daily “for recovery”
Don’t rely on powders or pills instead of food
Don’t panic about antioxidants — it’s about timing, not restriction
As you can see, you can't go wrong with antioxidants.
If you’re unsure how to apply this to your own training, I offer 1:1 personalized nutrition coaching for runners. Reply “INFO” and I’ll share the details.
Track of the week 🎧️
This week's Track of the Week is a song I recently discovered, and I loved the beat. Perfect for a casual run.
Still My Desire - Extended Mix by Jimmi Harvey
Wishing you a great weekend and week ahead!
Here’s to health and good runs⚡️
Ana Paula Alonso