Surgery and Vitamin C levels and Cognition

We are  investigating the effects of Anaesthesia on Vitamin C, Vitamin B12 levels and Cognition.

NIIM is conducting a clinical trial on the effect of anaesthesia on cognitive function. This study aims to investigate the correlation between vitamin C and B12 levels and cognitive function in surgery patients.

Low levels of vitamin C and B12 in the blood have been linked with impaired cognitive functioning. Post-surgical cognitive impairments are extremely common, possibly explained by a reduction in plasma vitamin C and vitamin B12 concentrations after anaesthesia.

Aim of the Study:

In this study we want to find out:

  • The relationship between vitamin C and vitamin B12 concentrations and cognition post-surgery.
  • The effects of anaesthesia on vitamin C and vitamin B12 plasma concentrations post-surgery.
  • A possible way of reducing post-operative cognitive decline.


Blood tests and cognitive testing will be undertaken 1-2 weeks prior and post to surgery. Participants will be required to fast for 8-12 hours prior to testing. All testing will take about 90 minutes.

  1. The blood test will measure plasma vitamin C and vitamin B12 levels.
  2. Cognitive testing will involve paper and pen and computer tests:
  • Symbol Digit Modalities Test (SDMT)
  • Hopkins Verbal Learning Test-Revised (HVLT-R)
  • Mini Mental State Examination (MMSE)
  • Swinburne University Computerised Cognitive Assessment Battery (SUCCAB consisting of eight computer-based tasks)

Inclusion criteria:

You’ll be eligible, if you are:

  • Planning to undergo surgery
  • Must not be taking antidepressants, antipsychotics, anxiolytics, illicit drugs or any cognitive enhancing drugs.
  • Have good comprehension of written and spoken English

What will I need to do?

Participants will be required to come to NIIM in Hawthorn for cognitive testing and a blood test 1-2 weeks prior and 1-2 weeks post surgery to their scheduled surgery. Testing will take about 90 minutes.

Privacy and confidentiality

Your personal data will be known only to the study team. All data collected will be de-identified before analysis and stored securely in locked files at the NIIM clinic. No personal data will be divulged in publication.

Can I access test results?

After the study when all data has been collected and analysed, you can receive a summary of the de-identified study results.

Who should I contact if I have any questions about the study?

NIIM Research Department
Phone: 03 9804 0646
Email: research@niim.com.au