Acne Nutrition · The Foundational Guide

Acne Nutrition: how food, supplements, and functional labs actually clear adult acne.

Acne nutrition is the practice of using food, targeted supplements, and lifestyle interventions to address the internal drivers of acne (hormones, gut, blood sugar, minerals, inflammation) rather than working only on the surface of the skin. A trained acne nutritionist uses functional lab testing to identify which of these systems is actually driving each person's breakouts, then builds a protocol from those results.

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Adult acne is almost never a skincare problem. It's a downstream symptom of an internal imbalance, which is why even the most expensive skincare routines rarely produce lasting results in adults. Acne nutrition starts from that premise. The work is to identify which internal system is producing the breakouts (each person's driver is different, even when the breakouts look identical) and correct it with food, supplements, and lifestyle change. When the underlying driver is addressed, the skin clears, and it stays clear because the root cause is no longer producing the symptom.

What you actually need to know

The four things that matter most.

01 · Foods with the strongest research links to acne

Refined sugar and high-glycemic foods, conventional dairy (especially skim milk and whey), industrial seed oils. Individual sensitivities vary and are best identified via testing rather than guessing.

02 · Supplements with the strongest evidence

Zinc (especially picolinate at 30 mg daily), vitamin A as retinyl palmitate, omega-3s, vitamin D when deficient, species-specific probiotics. Hormone-specific support (DIM, vitex, calcium-d-glucarate) when matched to the right hormone pattern.

03 · Why generic acne diets fail

Every case of adult acne has a different driver. The same elimination diet will clear one woman's skin and do nothing for another. Personalization is the entire game, and personalization requires lab data.

04 · What a credentialed acne nutritionist actually does

Reviews health history, orders relevant functional labs (HTMA, GI-MAP, DUTCH), interprets results in the context of your symptoms, and builds a phased nutrition and supplement protocol with weekly support and adjustments.

How Katie Stewart Wellness does this

Our approach.

Katie Stewart, RHN, FDN-P trained at the Canadian School of Natural Nutrition and is a Functional Diagnostic Nutrition Practitioner. She's spent 10 years specializing exclusively in adult acne and has personally reviewed over 4,000 functional lab panels. Katie Stewart Wellness has cleared 3,000+ women in 15 countries using this model. The 1:1 program is called The Clear Skin Solution; for women not ready for 1:1, the courses library covers the same five-pillar system at lower price points.

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FAQ · The questions we hear most

Acne Nutrition FAQs

The most common questions about how acne nutrition actually works and whether it's right for your skin.

What is acne nutrition?

Acne nutrition is the use of food, supplements, and lifestyle changes to address the internal drivers of acne rather than relying on topical or pharmaceutical suppression. It's based on the principle that adult acne is almost always a downstream symptom of an internal imbalance (gut, hormones, blood sugar, minerals, inflammation) and the most reliable path to clear skin is to identify and correct that imbalance.

Which nutrient deficiencies cause acne?

The most common deficiencies linked to acne are zinc, vitamin A, vitamin D, magnesium, omega-3 fatty acids, and selenium. Mineral imbalances (especially the copper-to-zinc ratio) are also major drivers and show up clearly on an HTMA test. Most adults eating a standard Western diet are deficient in at least three of these.

What's the best diet for clear skin?

The diet pattern with the strongest evidence for clear skin is a whole-food, anti-inflammatory diet built around quality protein at every meal, plenty of cruciferous and leafy vegetables, healthy fats (olive oil, avocado, wild fish), low-glycemic carbohydrates, and minimal seed oils, refined sugar, and conventional dairy. There's no one universal acne diet because individual food sensitivities vary.

Should I cut dairy for acne?

For most people with adult acne, yes, at least temporarily. Conventional dairy (especially skim milk and whey protein) raises IGF-1, which stimulates the oil glands and worsens hormonal acne. A 60 to 90 day dairy elimination is one of the easiest and most informative experiments. If skin clears, dairy was a driver. If nothing changes, it wasn't.

Should I cut gluten for acne?

Only some people. Unlike dairy, gluten doesn't have a universal acne-driving mechanism. But gluten sensitivity (separate from celiac disease) is real, and when present, it drives gut inflammation that surfaces as breakouts. The most efficient way to know is to test (GI-MAP and IgG food panel) rather than guess.

Can a nutritionist actually clear acne?

A credentialed acne nutritionist working with functional lab data can clear most cases of adult acne, including hormonal, post-pill, and gut-driven forms. At Katie Stewart Wellness, the 1:1 program (The Clear Skin Solution) has historically cleared 65% of clients within 6 months and 85% within 9 months. Results depend on driver complexity, protocol adherence, and time.

From the blog.

Recent articles from Katie and the team on acne nutrition, all evidence-based and written from clinical experience with 3,000+ clients.

Browse all acne nutrition articles