Does increased vitamin D (Vit D) cause Acute Mountain Sickness (AMS)?

Vitamin D and Acute Mountain Sickness (AMS)

There is no evidence that increased vitamin D levels cause Acute Mountain Sickness (AMS), and vitamin D supplementation has not been shown to either prevent or worsen AMS in clinical studies.

Understanding Acute Mountain Sickness

Acute Mountain Sickness (AMS) is a condition that occurs when individuals ascend to high altitudes too quickly without proper acclimatization. The primary cause is hypoxia (reduced oxygen) due to decreased barometric pressure at altitude, not vitamin D status 1.

Key Risk Factors for AMS:

• Rapid ascent to altitudes above 2,500m
• Prior history of altitude sickness
• Low home elevation
• Poor physical conditioning
• Intense exercise upon arrival at altitude
• Higher maximum and sleeping altitudes 2

Vitamin D and AMS: Current Evidence

The available guidelines and research do not establish any causal relationship between vitamin D levels and AMS:

• High Altitude Travel Guidelines make no mention of vitamin D as a risk factor or treatment consideration for AMS 2
• Clinical nutrition guidelines for neurological conditions note insufficient evidence to recommend vitamin D therapy for various conditions, but do not link vitamin D to AMS 3
• Studies examining AMS prevention have focused on:
  • Proper acclimatization through staging at intermediate altitudes 4
  • Medications like acetazolamide and dexamethasone 2
  • Controlled ascent rates 2, 1

Antioxidant Studies and AMS

Some research has investigated antioxidant supplementation for AMS prevention with mixed results:

• One small study (n=18) found that antioxidant supplementation (including vitamins C and E) reduced AMS symptoms 5
• However, a larger, more rigorous double-blind randomized controlled trial (n=83) found no benefit from antioxidant supplementation for AMS prevention 6

Vitamin D Metabolism Considerations

While vitamin D is not directly linked to AMS, some relevant points about vitamin D metabolism at altitude include:

• Vitamin D levels can be affected by various factors including skin pigmentation, age, and body composition 3
• Obesity may affect vitamin D metabolism and bioavailability 3
• Inflammation (which can occur with AMS or infections at altitude) may temporarily decrease 25-(OH)D levels as it can act as a negative acute-phase reactant 3, 7

Prevention of AMS

The most effective strategies for preventing AMS include:

1. Gradual ascent: Limit ascent to less than 400m/day when above 2,500m altitude
2. Staging: Two days of staging at 3000m or 3500m before ascending higher reduces AMS incidence
3. Rest days: Include a rest day for every 600-1200m gained
4. Medication: Acetazolamide (125mg twice daily starting 24 hours before ascent) is the primary pharmacological preventive measure
5. Proper hydration: Maintain adequate fluid intake and avoid alcohol 2, 4

Treatment of AMS

For those who develop AMS:

• Descent of more than 300m as soon as possible for serious illness
• Oxygen supplementation if available
• Acetazolamide for mild symptoms
• Dexamethasone for more severe symptoms (limited to 2-3 days)
• Nifedipine (20mg three times daily) may be used to treat High Altitude Pulmonary Edema when descent is impossible 2, 1

Conclusion

Based on current evidence, vitamin D status is not implicated in the development or prevention of AMS. The focus for preventing and treating AMS should remain on proper acclimatization strategies, controlled ascent rates, and appropriate medication use when indicated.