Could nutrient deficiencies be keeping your blood sugar high?

Why micronutrients genuinely matter for blood sugar, but are a supporting player alongside diet and your diabetes care, not a replacement for it.

77 min · 3 min readExpert: Dr. Peter Osborne|Watch episode|

Original episode: Mar 4, 2026

Editorial profile:Functional nutritionNutrient deficienciesGluten sensitivity
Contested / minority view — this is not established medical practice, and standard care remains the foundation. Nothing here is a proven treatment.
Current scientific status:A contested reframing of type 2 diabetes as primarily a micronutrient-deficiency disease; micronutrients may play a supporting role, but this is not established treatment and does not replace standard diabetes care.

What this episode covers

  • Despite the title, this is not about one nutrient: it argues that many vitamins and minerals run the cellular machinery that handles glucose.
  • Zinc and magnesium help make insulin, chromium supports the insulin receptor, and deficiency may therefore worsen blood sugar control.
  • Some diabetes medications deplete nutrients (metformin lowers vitamin B12), but the wider claim that diabetes is mainly a deficiency disease goes beyond the evidence.

Confidence in this episode

Everything about how much to believe this episode, in one place.

Overall confidence:Low–Moderate

Individual nutrients do play real roles in blood sugar and some trials show modest benefits, but the speaker's argument that diabetes is largely a deficiency disease, and that carbohydrate restriction misses the real issue, is not the prevailing view.

Evidence at a glance
Mechanistic evidenceStrong
Human clinical evidenceLimited
Clinical certaintyLow
✓ Consistent with established evidence
  • Vitamins and minerals such as magnesium, zinc, and chromium are genuinely involved in insulin production and glucose handling.
  • Metformin is well recognized to deplete vitamin B12, which is worth monitoring.
  • Supplements cannot compensate for a poor diet — the speaker says this himself.
Less certain
  • That nutrient deficiencies are the main cause of type 2 diabetes.
  • That supplements meaningfully change the course of diabetes, rather than modestly shifting numbers.
  • The high vitamin D doses and the intracellular test the speaker recommends.
  • The claim that type 2 diabetes is "100% reversible" for everyone.

Why it matters

If you are doing 'everything right' and your numbers still will not move, it is reasonable to ask whether something else is going on. Nutrient status can be a worthwhile piece of the puzzle, particularly if you have a documented deficiency or take medications known to affect nutrient levels. But the honest framing is that nutrients support the machinery; diet, weight, activity, and your medical care remain the engine. Getting this order wrong can cost you time, money, and in some cases safety.

What stands out

  • Not one deficiency — despite the title, the episode is about many micronutrients and blood sugar, not a single nutrient (the episode's own content).
  • Supplements can't outrun diet — the speaker says it himself: you cannot out-supplement the foods driving insulin resistance (his own framing).
  • Medications can deplete nutrients — metformin is well recognized to lower vitamin B12, which is worth discussing with your doctor (established).
This is one of multiple expert perspectives. The full topic combines them into clear guidance.Explore full topic →

Best-supported action

The single highest-leverage move from this episode, anchored in the strongest evidence the speaker presents.

Where to start

Small low-friction starters covering the main moves from this episode.

  • Tell your doctor about every supplement you take.
  • Ask what your fasting glucose and A1C numbers actually mean for you.
  • Prioritize whole foods over ultra-processed ones.

Other supported actions

Further actions discussed in this episode, ordered from strongest to weakest evidence. This is one expert's view, the full topic compares and ranks across experts.

  • Focus first on the foundations — overall diet quality, movement, sleep, and weight — which remain the strongest levers for blood sugar.Strong evidence
  • If you take metformin, ask your doctor about checking your vitamin B12, since this depletion is well recognized.Moderate evidence
  • If you're considering supplements such as magnesium or vitamin D, discuss testing and dosing with your doctor rather than self-prescribing.Limited evidence

Full context, impact ratings, and timing — available in related topics

Questions to take to your doctor

Questions worth asking based on this episode
  • Given my medications, could any supplement I take push my blood sugar too low?
  • Given I'm on metformin, should we check my vitamin B12 level?
  • Given my numbers, what should I focus on first to improve my blood sugar?

Full doctor prep with ranked questions available in the full topic page

This is one expert perspective. The full topic ranks actions across multiple experts.Explore full topic →

Context

How this expert sees it

Functional-medicine practitioner who often interprets fatigue, nerve symptoms, digestive problems, and brain fog as possible signs of nutrient deficiencies. He places greater emphasis than mainstream medicine on specialised testing and targeted supplementation, and sells some of the tests and supplements he recommends.

What we don't know yet

This episode does not prove that nutrient deficiencies cause type 2 diabetes, or that supplements can treat it. The studies cited are mostly small or short, and the average effects on blood sugar are modest, largely in people who were already deficient.

The speaker argues that focusing primarily on carbohydrate restriction misses a more important issue — micronutrient status. This is not the prevailing scientific view, where dietary pattern, weight management, physical activity, and medications remain the cornerstone of treatment. His claim that type 2 diabetes is '100% reversible' is also overstated: remission is possible for many, especially early on, but it is not guaranteed.

Some doses discussed (such as 8,000 to 10,000 IU of vitamin D daily) exceed standard upper limits and need medical supervision. The episode also promotes the speaker's own intracellular nutrient test and supplement guide. None of this is a reason to change or stop your diabetes treatment on your own.

Overall evidence profile: real mechanistic research plus small and short human trials with modest average effects, combined with the speaker's clinical experience and commercial interests, not large trials showing supplements treat diabetes.

Where people go wrong

  • Adding berberine, alpha-lipoic acid, or other blood-sugar-lowering supplements while on diabetes medication, without telling your doctor.This can cause hypoglycemia — blood sugar low enough to be dangerous.
  • Treating supplements as the main fix while diet and lifestyle stay the same.The speaker agrees this does not work; supplements are at best an add-on, not the foundation.

What to expect over time

  • Before you startThe first step is knowing your actual numbers and telling your doctor what you take; nothing else is safe to judge without that.
  • First weeks to monthsThe trials cited ran about 4 to 16 weeks and showed modest average improvements, mostly in people who were deficient.
  • Long termLasting blood sugar control comes from diet, weight, movement, and your medical care, not from a supplement stack.
This is one expert's perspective. The full topic shows where experts agree and disagree.Explore full topic →