Subclinical Nutritional Deficiencies

The rarity of classical deficiency diseases today has produced the false assumption that modern diets provide adequate nutrition. Doctors receive little training in identifying subclinical nutritional deficiencies. Subclinical deficiencies produce real symptoms — typically a partial rather than full clinical picture — and impair the body's capacity for repair, longevity, and immune protection. Subclinical biotin deficiency can manifest as brittle nails, nail ridges, and hair loss. Subclinical vitamin A deficiency can cause reduced night vision, corneal problems, and thickened skin. Subclinical vitamin B1 (thiamine) deficiency can present as anxiety and nervous tension.