Increased beta-carotene and vitamin C intakes may reduce dementia risk

According to a new German study, low blood beta-carotene - and vitamin C concentrations may be associated with a higher risk of losing brain functions.

In this observational study, blood concentrations of vitamin C, vitamin E, beta-carotene, lycopene and coenzyme Q10 were measured in 74 participants with mild cognitive impairment and 158 healthy age- and gender-matched controls (1). The study results show that blood vitamin C and beta-carotene concentrations were significantly lower in the dementia sufferers than in the control group, even after adjusting for school education, intake of dietary supplements, smoking habits, body mass index and alcohol consumption. No associations were found for vitamin E, lycopene and coenzyme Q10.

The researchers commented that these findings indicate a significant association between vitamin C and
beta-carotene plasma levels and dementia risk. The hypothesis that antioxidants may have beneficial effects on the underlying changes associated with the development of dementia was said to be very important and supports the promotion of higher dietary intake of antioxidant-rich foods. Long-term data would be needed to give further insight into this association.

Oxidative stress is believed to play a central role in the development of Alzheimer’s disease (AD), the most common form of dementia among older people. Antioxidants may prevent the onset of AD, as high dietary intake of vitamin C and E has been reported in large epidemiologic studies to be linked with lower risk of the disease (2, 3). Some publications found a significant association between vitamin E intake and cognitive decline and dementia (4, 5). Other studies did not support an association between combined use of vitamin E and C supplements and lower risk of AD (6).

1. von Arnim C. A. et al. Dietary antioxidants and dementia in a population-based case-control study among older people in South Germany. J Alzheimer’s Dis. Published online June 2012.
2. Engelhart M. J. et al. Dietary intake of antioxidants and risk of Alzheimer disease. JAMA. 2002; 287(24):3223–3229.
3. Morris M. C. et al. Vitamin E and vitamin C supplement use and risk of incident Alzheimer disease. Alzheimer Dis Assoc Disord. 1998; 12:121–126.
4. Morris M. C. et al. Vitamin E and cognitive decline in older persons. Arch Neurol. 2002; 59:1125–1132.
5. Morris M. C. et al. Dietary intake of antioxidant nutrients and the risk of incident Alzheimer disease in a biracial community study. JAMA. 2002; 287:3230 –3237.
6. Masaki K. H. et al. Association of vitamin E and C supplement use with cognitive function and dementia in elderly men. Neurology. 2000; 54:1265–1272.