New food intolerances in menopause: what is actually happening

Intolerance and allergy are different things

Food allergy is an immune reaction, usually IgE-mediated, producing hives, swelling, breathing difficulty or anaphylaxis, typically within minutes and reproducibly with tiny amounts.

Food intolerance is a digestive problem: the food is not broken down or absorbed properly, producing bloating, wind, pain and altered bowel habit, usually dose-dependent and delayed by hours.

The distinction matters because they are investigated differently, and because allergy testing is not the right tool for intolerance — a point that commercial testing exploits heavily.

Why it appears now

Gut motility changes as progesterone becomes erratic and then falls, altering how long food spends in each part of the digestive tract. Fermentation of a given food depends heavily on that transit time.

The gut microbiome shifts after menopause, and which bacteria are present determines what is fermented and how much gas is produced.

Irritable bowel syndrome frequently worsens or first presents in midlife, and it changes the threshold at which normal fermentation is felt as pain — visceral hypersensitivity rather than a change in the food.

Lactose intolerance genuinely can emerge in adulthood, as lactase production declines with age in most of the world's population.

Test before you eliminate

This is the most consequential practical point. Coeliac disease serology requires gluten to be in the diet to be reliable, and testing after gluten has been removed produces false negatives.

Removing gluten first and testing later is the single most common reason a coeliac diagnosis is delayed by years, and coeliac disease matters: it causes iron deficiency, bone loss and nutrient malabsorption, all of which compound the changes of menopause.

So the order is: test, then trial an elimination if testing is negative.

What tests are not useful

IgG food sensitivity panels are widely sold and are not supported by allergy or immunology bodies for diagnosing intolerance. IgG antibodies to food reflect exposure, not intolerance, and healthy people without symptoms test positive to many foods.

Hair analysis, applied kinesiology and vega testing have no evidence base for this purpose.

The consequence is not just wasted money: these panels typically return long lists that lead to unnecessarily restricted diets, which cause their own nutritional problems and make the real cause harder to identify.

When to see someone

Ask for coeliac serology, full blood count, ferritin and thyroid function before removing any food group, and keep eating gluten until the coeliac test is done.

See a dietitian for a structured elimination, such as a low-FODMAP approach, which has evidence for irritable bowel syndrome but is complex and not intended to be permanent.

Seek prompt assessment for blood in the stool, unexplained weight loss, a persistent change in bowel habit over three weeks, or difficulty swallowing.