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Biomarker reference

Nutrients & electrolytes

India's most common and most overlooked gaps: the ones that quietly cost you hours of clarity everyday.

Micronutrient markers cover the deficiencies that are most common in India and most often overlooked, largely because their symptoms — fatigue, poor concentration, low mood, hair shedding, breathlessness on exertion — are exactly what a demanding job is assumed to cause. Three dominate the Indian picture. Vitamin B12 deficiency follows directly from predominantly vegetarian diets, since the vitamin occurs almost exclusively in animal foods. Vitamin D deficiency is widespread despite abundant sunlight, because skin pigmentation, indoor work, clothing and particulate pollution all reduce how much the skin actually synthesises. Iron deficiency is common and, crucially, shows up in ferritin long before haemoglobin falls — so a standard anaemia screen misses the entire symptomatic phase that precedes anaemia. Each of these is cheap to identify and straightforward to correct once seen.

01

Why are these markers read together?

No marker in this group means much on its own. Nutrients & electrolytes covers 17 of the measurements in the Peak Brain panel, and a physician reads them as a pattern — one value at the edge of a reference range means something quite different depending on what the others are doing.

  • Ferritin must be read alongside hs-CRP. Ferritin rises with inflammation regardless of iron status, so a normal value in an inflamed person can hide real deficiency.
  • B12 and homocysteine are functionally linked. Serum B12 measures total circulating B12, most of which cells cannot use; homocysteine rises when the usable fraction is short, catching cases a normal B12 would miss.
  • Iron status distorts HbA1c. Iron deficiency can raise HbA1c by a few tenths of a percent with no change in glucose — enough to move someone across a diagnostic threshold on the basis of an iron problem.
02

What does this group explain?

  • Fatigue and brain fog that persist despite adequate sleep, in someone whose routine blood count reads normal.
  • Why vegetarian and predominantly vegetarian diets need active monitoring rather than assumption, particularly for B12 and long-chain omega-3.
  • Whether a supplement regimen is actually reaching tissues, which cannot be inferred from the dose on the label.
03

Nutrients & electrolytes: marker explanations

Ferritin

Ferritin is the protein the body uses to store iron, and the amount circulating in blood is proportional to how much iron is held in reserve.

Vitamin D (25-OH)

Vitamin D is measured as 25-hydroxyvitamin D, the circulating storage form, which reflects combined intake from sunlight, diet and supplements over the preceding weeks.

Vitamin B12

Vitamin B12 is required for red blood cell formation, DNA synthesis and the maintenance of the myelin sheath around nerves.

04

Also measured in this group

These markers are included in the panel and read alongside the ones above. They have no standalone reference page, because outside the context of a full panel there is little useful to say about them individually — and a page that exists only to fill a URL is worse than no page.

  • Active B12what cells can actually use
  • Serum ironoxygen delivery
  • TIBCcarrying capacity
  • UIBCthe unused capacity
  • Transferrin saturationiron availability
  • Serum calciumbone and nerve
  • Ionised calciumthe active fraction
  • Serum magnesiumthe standard read
  • Phosphorusbone partnership
  • Sodiumfluid balance
  • Potassiumnerve and heart rhythm
  • Chlorideacid-base balance
  • Vitamin A (retinol)vision and immunity
  • Vitamin Emembrane antioxidant
05

Who reviews this group

Reviewer assignment follows speciality. Pages in this group are assigned to Dr. RS Pradhan (MD) and Dr. Arjun (MD, DM), and each page carries a byline naming its reviewer and the date of review.

Nutrients & electrolytes: common questions

Why is vitamin D deficiency common in a sunny country?

Sunlight availability and vitamin D synthesis are different things. Higher skin melanin needs several times longer exposure for the same production, indoor work removes most midday sun, clothing covers the skin that would synthesise it, and urban particulate pollution attenuates the relevant UVB wavelengths. Deficiency alongside abundant sunshine is the norm, not a paradox.

Can I be iron deficient with a normal haemoglobin?

Yes, and this is the most common way iron deficiency is missed. Haemoglobin only falls once stores are largely exhausted, so ferritin can be low — with the fatigue, hair shedding and poor exercise recovery that accompany it — while a full blood count reads entirely normal.

Should I just supplement rather than test?

For B12 in a vegetarian diet, low-dose supplementation is reasonable regardless. For iron and vitamin D it is not: iron supplementation is unhelpful when the cause is inflammation and harmful in undiagnosed iron overload, and the high-dose vitamin D regimens widely sold in India can cause toxicity without monitoring.

The programme

One marker rarely answers the question.

Peak Brain draws a full blood and urine panel at your home, has a licensed physician read every marker together rather than one at a time, and turns what they find into a ranked 90-day protocol with a retest at the end.

How the programme works