Gut, Immune & Vitamin D Foundations

Four guides on digestion, microbes, immune function and vitamin D — written to help you ask better questions, not to sell you a detox.

What you get

A 62-page reading edition plus all four guides as separate PDFs.

• How to Fix Your Gut — 14 pages
• How to Understand Your Gut Microbiome — 15 pages
• How to Build a Bulletproof Immune System — 15 pages
• Vitamin D: The Hormone You Make From Sunlight — 15 pages

Some of what is inside

• What a stool test can and cannot tell you, and why names are not diagnoses
• Why more microbial diversity is not universally better
• Why correcting a deficiency helps and megadosing a sufficient person usually does not
• Vitamin D as a hormone: what current guidance says, and why the upper limit is a ceiling rather than a target
• The gut red flags that mean stop self-managing and get assessed

Who this is for

Anyone who has been sold a gut protocol and wants to know which parts are supported. It is deliberately unexciting where the evidence is unexciting.

A note on how these are written

Every guide follows the same four moves: it names the popular claim, states what the evidence actually supports, gives you something specific to do, and tells you when to stop. You will find hedges in here. Where the research is thin, it says so. If you want certainty and secrets, these are the wrong books.

Not sure yet? Read one first, free.

The Home Workstation Audit is a free six-page guide cut straight from this library — same voice, same hedges, same "here is when to stop" section at the end. No card, no trial. If you do not like how it reads, you have spent ten minutes and you know not to buy this.

And if a file ever fails to download or arrives corrupted, email us and it is fixed or refunded. Nothing on this page affects your rights under the Australian Consumer Law.

Instant download

Your files are emailed to you the moment payment clears, and are also on the confirmation page. Read on phone, tablet, laptop or e-reader, and print any page you want beside you.

Educational material only. Not medical advice, diagnosis or treatment, and not a substitute for individualised care from a professional who knows your circumstances. Copyright 2026 DeeperKnowledge. Personal use only — not for resale or redistribution.