This is the most well-known category, and for good reason.
What to notice:
Frequent bloating and gas after meals
Diarrhea or constipation (or alternating between them)
Abdominal pain or cramping
Nausea after eating
Greasy, foul-smelling stools (indicates poor fat absorption)
Why it happens: In sensitive individuals, gluten can trigger inflammation in the gut lining, disrupting normal digestion and nutrient absorption.
2. Brain Fog and Difficulty Concentrating
Many people with gluten sensitivity report feeling like they're thinking through molasses.
What to notice:
Difficulty focusing on tasks
Forgetfulness
Feeling mentally "slow" or foggy
Trouble finding words
Why it happens: The gut-brain connection is real. Inflammation in the gut can affect cognitive function, and some researchers believe gluten peptides can cross the blood-brain barrier in sensitive individuals.
3. Fatigue and Low Energy
Feeling tired after a gluten-containing meal is a common red flag.
What to notice:
Overwhelming fatigue, especially after eating
Feeling tired even after a full night's sleep
Energy crashes during the day
Why it happens: If your gut is inflamed and not absorbing nutrients properly, your body isn't getting the fuel it needs. Plus, chronic inflammation itself is exhausting.
4. Headaches and Migraines
Recurrent headaches, especially after meals, can be a clue.
What to notice:
Frequent headaches, particularly after eating
Migraines that don't respond well to typical treatments
Headaches accompanied by other digestive symptoms
Why it happens: Inflammation and immune responses can trigger headaches in susceptible individuals.
5. Skin Issues
Your skin often reflects what's happening inside your body.
What to notice:
Dermatitis herpetiformis – An intensely itchy, blistering rash (specifically linked to celiac)
Eczema or psoriasis flare-ups
Unexplained dry skin or rashes
Acne that doesn't respond to typical treatments
Why it happens: Inflammation and immune complexes can deposit in the skin, causing various dermatological issues.
6. Joint Pain and Inflammation
Unexplained aches and pains that come and go.
What to notice:
Achy joints without a clear cause
Stiffness that improves with movement
Inflammation that seems to flare after meals
Why it happens: Systemic inflammation from gluten sensitivity can affect joints throughout the body.
7. Mood Disturbances
Anxiety, depression, and irritability can all be linked to what you're eating.
What to notice:
Unexplained anxiety or feelings of dread
Depressed mood
Irritability or mood swings
Feeling "off" emotionally without reason
Why it happens: Inflammation affects neurotransmitter function, and the gut produces about 95% of your body's serotonin.
8. Hormonal Imbalances
For women especially, gluten sensitivity can affect reproductive hormones.
What to notice:
Irregular menstrual cycles
Severe PMS
Unexplained infertility
Miscarriages
Why it happens: Chronic inflammation can disrupt the delicate balance of reproductive hormones.
9. Anemia and Nutrient Deficiencies
If you're eating well but your blood work shows deficiencies, your gut may not be absorbing nutrients properly.
What to notice:
Iron-deficiency anemia (low ferritin)
Vitamin B12 deficiency
Vitamin D deficiency
Unexplained weight loss
Why it happens: Inflammation in the small intestine (especially in celiac disease) damages the villi responsible for nutrient absorption.
10. Autoimmune Conditions
Having one autoimmune condition increases your risk of developing others.
What to notice:
Hashimoto's thyroiditis
Type 1 diabetes
Rheumatoid arthritis
Psoriasis
Any other autoimmune diagnosis
Why it happens: There's a strong genetic link between celiac disease and other autoimmune conditions. If you have one, you're at higher risk for others.
The "Gluten Challenge" – Why You Shouldn't Self-Diagnose
If you suspect gluten sensitivity, here's what many people do wrong: they stop eating gluten, feel better, and assume that's proof.
The problem: To get properly tested for celiac disease, you need to be consuming gluten for at least 6-8 weeks before testing. If you've already eliminated it, you'll have to go back on it to get accurate results—and that can be miserable.
The right approach:
Keep eating gluten until you've been tested (if you choose to pursue testing)
See a doctor for proper evaluation
Consider keeping a food and symptom diary
What to Do If You Suspect Gluten Sensitivity
Step 1: See a Doctor
Start with your primary care provider. They can order:
Blood tests for celiac disease (tTG-IgA, EMA, etc.)
Genetic testing (HLA-DQ2 and HLA-DQ8)
Referral to a gastroenterologist for possible endoscopy
Step 2: Keep a Detailed Food Diary
Write down:
What you eat
When you eat it
Any symptoms that follow
How severe they are
Step 3: Consider an Elimination Diet (Under Guidance)
If testing is negative but symptoms persist, a supervised elimination diet can help identify triggers.
Step 4: Work with a Dietitian
If you do need to go gluten-free, a dietitian can help you do it healthfully—because gluten-free doesn't automatically mean healthy.
Foods That Contain Gluten
Gluten is found in:
Wheat (including spelt, farro, semolina, durum)
Barley
Rye
Triticale (a wheat-rye hybrid)
Hidden sources to watch:
Soy sauce (unless labeled gluten-free)
Salad dressings
Soups and broths
Processed meats
Beer
Oats (unless certified gluten-free—they're often cross-contaminated)
The Bottom Line
Gluten sensitivity is real, and its symptoms can affect nearly every system in your body. If you recognize several of these warning signs, it's worth exploring with a healthcare provider.
Remember: Proper testing matters. Don't self-diagnose and eliminate gluten before getting tested—you may miss the chance for an accurate diagnosis.
Whether or not gluten is your issue, listening to your body's signals is always the right move.
