Interseasonal vitamin deficiency: How to recognize it by symptoms, what are its dangers, and what tests to take

The off-season is a period when the body is especially vulnerable. Temperature changes, decreased sunlight, stress, viral loads, and depleted vitamin reserves after winter or summer often lead to latent vitamin deficiencies. These may not manifest immediately, but gradually affect the immune system, nervous system, hormonal balance, and overall well-being.

What is interseasonal vitamin deficiency?

This is a condition of deficiency of vitamins, minerals and microelements, which occurs most often in spring and autumn , when:

• the quality of nutrition is declining,
• vitamin stores (D, B, C, iron, magnesium) are depleted,
• the functioning of the gastrointestinal tract and the absorption of nutrients are disrupted,
• the load on the nervous and immune systems increases.

Important: most often it is not just one vitamin , but a complex deficiency.

Main symptoms (self-diagnosis checklist)

🧠 Nervous system

• chronic fatigue, apathy
• irritability, anxiety
• deterioration of memory and concentration
• insomnia or shallow sleep

➡️ Possible deficiencies: B vitamins, magnesium, vitamin D

🛡 Immunity

• frequent colds and viruses
• long recovery period
• herpes, exacerbation of chronic infections

➡️ Possible deficiencies: vitamin D, C, zinc, selenium

Skin, hair, nails

• dry skin, cracks, peeling
• hair loss, brittleness
• nail splitting

➡️ Possible deficiencies: iron, biotin (B7), zinc, vitamin A, E

Heart and blood vessels

• rapid heartbeat
• dizziness
• cold hands and feet
• low or unstable blood pressure

➡️ Possible deficiencies: iron, magnesium, potassium, vitamin B12

Gastrointestinal tract and metabolism

• bloating, unstable stool
• decreased appetite or cravings for sweets
• heaviness after eating

➡️ Possible deficiencies: B-complex, zinc, enzymes, vitamin D

What tests should be taken if vitamin deficiency is suspected?

Basic checklist

1. Complete blood count
   (anemia, inflammation, oxygen metabolism)
2. Ferritin
   🔴 is a key marker of iron stores
   (more important than just “iron in the blood”)
3. Vitamin D (25-OH D)
   🔴 is one of the most common deficiencies in Europe
4. Vitamin B12
5. Folic acid (B9)
6. Magnesium (preferably intracellular)

Extended diagnostics (as indicated)

• Zinc, selenium
• Vitamin A, E
• Homocysteine
• C-reactive protein
• Gut microbiota analysis
• Bioresonance diagnostics (assessment of absorption and hidden deficiencies)

Why it’s important not to take vitamins at random

• Vitamins may not be absorbed due to gastrointestinal problems.
• Some deficiencies mask others
• Excess vitamins A, D, and iron can be toxic.
• Symptoms may be related not only to vitamins, but also to:
  • parasitic load
  • chronic inflammation
  • hormonal imbalances

👉 That’s why diagnosis is always more important than self-treatment.

General recommendations for the off-season

• sleep and recovery mode
• warm, easily digestible food
• liver and intestinal support
• reducing sugar and ultra-processed foods
• gentle detox support
• individually selected vitamins and microelements after tests

Interseasonal vitamin deficiency isn’t a sign of weakness or “aging.”
It’s the body’s signal that it needs support, attention, and proper prevention.

Regular diagnostics, a conscious approach to nutrition, and personalized recommendations help you maintain energy, immunity, and mental clarity year-round.

With care for your health,
ANS Clinic