| Vitamin D3 |
Oily fish, egg yolk, beef liver |
UVB synthesis is blocked by glass, sunscreen and cloud, and is negligible in the UK Oct–Apr. Low status remains common. |
| Vitamin B12 |
Meat, fish, shellfish, dairy, eggs |
Absent from plant foods; absorption declines with age, low stomach acid and long-term PPI or metformin use. |
| Folate (B9 as 5-MTHF) |
Liver, spinach, kale, legumes |
Heat-sensitive and reduced by storage and cooking; active 5-MTHF is of particular interest for common MTHFR variants. |
| Magnesium |
Pumpkin seeds, dark chocolate, almonds, spinach |
Stripped by food processing and reduced by soil depletion; many adults do not meet recommended intakes. |
| Iodine |
Seaweed, white fish, dairy, eggs |
Plant-based diets are frequently deficient and UK dairy iodine has fallen; kelp-derived iodine is a natural, reliable source. |
| Zinc |
Oysters, red meat, crab, pumpkin seeds |
Phytates in wholegrains and legumes can reduce absorption by up to 50% from plant sources. |
| PQQ |
Fermented soy (natto), green tea, parsley |
Dietary intake is typically under 1mg/day; clinical doses (10–20mg) are far higher than food provides. |
| Boron |
Raisins, almonds, avocado, prunes |
Intake may be low in diets limited in fruit, nuts and vegetables; boron supports bone and mineral metabolism. |
