Heavy Metal Index
Ask the IndexAboutIndex Pro

Nutritional status of selenium in Alzheimer's disease patients

Cite this pageVersion history

This small case-control study compared dietary selenium intake and selenium in plasma, red blood cells and nails between older adults with Alzheimer’s disease and cognitively normal controls in Sao Paulo, Brazil. Patients had significantly lower selenium in all three tissues and lower intake, but most controls were also below the plasma reference range. The authors relate the low values to low soil selenium in Sao Paulo state.

Key numbers

  • Plasma selenium, mean (SD): 32.59 (21.99) µg/L in patients (n = 28) versus 50.99 (21.07) µg/L in controls (n = 29) (Table 1, p. 804).
  • Erythrocyte selenium: 43.74 (23.02) µg/L versus 79.16 (46.38) µg/L (Table 1, p. 804).
  • Nail selenium: 0.30 (0.14) µg/g versus 0.40 (0.13) µg/g (Table 1, p. 804).
  • Energy-adjusted dietary selenium: 40.99 (11.23) µg/day versus 48.91 (15.50) µg/day, against a reference of 45 µg/day (Table 1, p. 804).
  • Below the plasma reference range of 60 to 120 µg/L: 89.3% of patients and 75.9% of controls (Table 1, p. 804).
  • Control-patient differences significant at P < 0.005 (Table 1).

Methods (brief)

Participants aged 60 and over without supplement use were recruited from university hospital clinics. Intake came from a 3-day food record using a software database with Brazilian selenium data. Plasma, erythrocyte and nail selenium were measured by hydride generation atomic absorption spectroscopy with a commercial serum reference material for accuracy checks.

Evidence fitness

Supports the observation that low selenium status was common in this older Brazilian clinical population, and offers biomarker values for comparison. It cannot establish whether low selenium contributes to Alzheimer’s disease or results from it, and the groups differed in mean age.

Limitations

Very small sample; controls were younger (71.2 versus 80.6 years); intake estimates depend on food composition data; detection limits are not reported; oxidative stress was not measured.

Update history

No substantive edit history is available in this build. The full commit record is available in git.

Referenced by