🔵 Early supportive evidence (large real-world survey)

Study at a glance

• Participants: 5,286 adults
• Condition: Range of chronic symptoms (digestive, skin, neurological, respiratory and more)
• Study type: Large observational survey
• Duration: Outcomes assessed after 3 months

What was done

People who had taken a food-specific IgG test were advised to reduce or remove foods identified by the test.

After approximately 3 months, they reported:

• How closely they followed the diet
• Whether their symptoms improved

What improved

• 72% of participants reported a noticeable improvement in symptoms
• Among those who followed the diet strictly, this increased to 75.8%

Additional findings:

• 68% of those who improved reported benefits within 3 weeks
• 77.7% experienced a return of symptoms when foods were reintroduced

In practical terms, this means many people reported feeling better after removing foods identified by the test, with symptoms often returning when those foods were reintroduced.

Key takeaway

Around 3 in 4 people who followed an IgG-guided diet reported an improvement in their symptoms, with many noticing changes within a few weeks.

What this means

This large real-world study suggests that many people with chronic symptoms report improvement after removing foods identified by IgG testing. The return of symptoms on reintroduction strengthens the idea that specific foods may play a role for some individuals.

🔵 Evidence strength

Early supportive evidence (large observational survey)

Full citation

Hardman and Hart 2007 IgG survey study

Hardman G, Hart G.
Dietary advice based on food-specific IgG results.
Nutrition & Food Science. 2007;37(1):16–23.

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