The Paradox of Plenty

Modern diets deliver calories and convenience, but micronutrient density has declined. Soil depletion, food processing, and narrow crop selection mean your supermarket produce carries fewer minerals than your grandparents' did. Add digestive issues, plant-heavy eating, or medication, and deficiency becomes likely.

Four gaps stand out: B12, magnesium, iodine, and K2. Not uncommon; not dramatic; but meaningful.

Vitamin B12: The Absorption Problem

B12 is abundant in animal products—meat, fish, dairy, eggs. But abundance doesn't mean absorption. B12 requires intrinsic factor, a protein your stomach lining makes. Age reduces it. Metformin and acid-blockers interfere with it. Vegan diets lack it entirely.

Deficiency creeps: fatigue, brain fog, neuropathy (nerve damage). By the time you feel symptoms, the deficit is substantial.

Who's at risk: Vegans, people over 60, those on long-term acid-blockers or metformin, anyone with pernicious anemia or celiac disease.

Fix: Animal products (3 oz fish = 3 mcg, more than your daily need). B12 supplements as cyanocobalamin or methylcobalamin work; injections bypass absorption entirely. A simple blood test (serum B12 or methylmalonic acid) tells you where you stand.

Magnesium: The Depletion Champion

Magnesium runs 600+ enzymatic reactions: muscle contraction, nerve signaling, energy production, protein synthesis. Modern processing strips it from grains; phytic acid in plants binds it; stress and alcohol burn it.

The RDA is 310–420 mg depending on age/sex. Most people consume 200–250 mg.

Deficiency signals: muscle cramps, poor sleep, tension, constipation, arrhythmias.

Best sources: Leafy greens (spinach, kale), seeds (pumpkin, sunflower), nuts (almonds), whole grains, legumes. Absorption varies—take with food, not with calcium supplements (they compete).

Supplementation: Glycinate and threonate absorb well and don't cause loose stools like magnesium oxide. 200–400 mg daily is reasonable for most; more if you train hard.

Iodine: Essential but Narrow Sources

Iodine is needed for thyroid hormone synthesis. Insufficient iodine causes goiter (enlarged thyroid), hypothyroidism, and developmental delays in children. It's not trendy, but it's critical.

Most iodine in developed nations comes from iodized salt and dairy (where cows eat iodine-rich feed). If you've cut salt or gone plant-based, you're vulnerable.

Seaweed is iodine-rich but inconsistently so—sometimes 100 mcg, sometimes 10,000 mcg per sheet. Too much iodine can trigger autoimmune thyroid issues in susceptible people.

Simple fix: Iodized salt or a multivitamin with 150 mcg iodine. Test if concerned (TSH and free T4 are standard screening).

Vitamin K2: The Forgotten Activator

K2 activates proteins that deposit calcium into bone and teeth, not soft tissue. K1 (from leafy greens) is abundant; K2 is not. K2 comes from fermented foods, grass-fed dairy, and certain cheeses.

Low K2 is linked to arterial calcification and poor bone quality despite adequate calcium intake.

Sources: Natto (fermented soy, ~100 mcg per serving), aged cheeses, grass-fed butter, sauerkraut. Most people get minimal K2 from food.

Supplementation: 45–180 mcg daily (K2 MK-7 form) is safe and inexpensive. Particularly useful if you take supplemental calcium or vitamin D.

Common Deficiency Patterns

Certain populations face higher risk:

  • Vegans and vegetarians: B12 (always), iron (sometimes), potentially K2 and iodine if diet is narrow
  • People over 60: B12 (absorption declines), magnesium, vitamin D, iodine
  • Those on medications: Metformin and acid-blockers reduce B12; some statin drugs deplete CoQ10; diuretics deplete magnesium and potassium
  • High-stress or high-training: Magnesium, B vitamins, zinc (burned through in stress and recovery)
  • Plant-exclusive: Iodine (unless iodized salt or seaweed), K2, potentially iron (plant iron is poorly absorbed)

Knowing your pattern helps target supplementation.

Testing and Timing

Don't guess. A comprehensive metabolic panel and micronutrient testing (available through functional medicine or your primary care doctor) takes the guesswork out. Once you know your status, supplementation becomes targeted and cost-effective.

Absorption improves with food—take fat-soluble vitamins (D, K2, E) with meals containing fat. Water-soluble B vitamins can go with or without food, though morning dosing often works better for energy-related ones (they fuel cellular metabolism).

Start supplementation conservatively. A single micronutrient often has compounding effects; adding multiple at once makes it hard to identify which helps and which causes side effects.