Specifically, it was noted that those with the highest intakes of β-carotene were observed to have lower risks of declining scores of cognitive function across all three cognition tests utilised in the study, in the report published in the journal 'Nutrients'. This negative association was also observed for α-Carotene in one of the three cognitive function tests.
“To date, some studies have examined the associations of α-carotene and β-carotene with cognitive function. However, to our knowledge, most of the previous studies have mainly focused on the plasma level of carotenes with cognitive function,” the researchers from Sun Yat-sen University and Hangzhou Medical College state, highlighting the relevance of their research.
With an increasingly aging population, the incidence of cognitive decline among the elderly is becoming ever-more prevalent. It has been reported that factors such as obesity, lack of physical activity, and smoking are risk factors for the associated conditions of mild cognitive impairment (MCI) and Alzheimer’s. Additionally, a lack of nutrition has been established as an important risk factor, with vitamin B12 exhibiting protective properties as a result of methylation reactions in the DNA of neurones within the brain.
The provitamin A carotenoids named α-Carotene and β-carotene can be converted in the body to vitamin A. Despite the established antioxidant properties of vitamin A within the central nervous system, which has been observed to also offer protection against cognitive decline, the potential effects of its precursors of dietary α-carotene and β-carotene have not been thoroughly explored.
As a result, the present study looked to assess the relationship between intake of dietary α-carotene and β-carotene and cognitive function in elderly people.
Researchers recruited participants screened from those involved in NHANES to obtain a sample of 2,009 over the age of 60 with available data on cognitive function.
Data was obtained from the 2011-2012 and 2013-2014 NHANES cycles, with dietary α-Carotene and β-Carotene intakes measured by 24 h dietary recall interviews. Cognitive function was assessed utilising cognitive tests including the Consortium to Establish Registry for Alzheimer’s disease (CERAD W-L), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST).
It was observed that those with the highest intakes of β-carotene demonstrated lower risks of CERAD W-L decline as well as AFT decline.
In males, it was analysed that there was a decreased risk of AFT decline associated with both α-carotene and β-carotene intakes. Whilst in women, a decreased risk of CERAD W-L decline was associated with dietary α-carotene, as well as decreased risks of CERAD W-L and AFT following higher intakes of β-carotene.
Whilst previous studies have mirrored the findings observed here, the mechanism in which the α-Carotene and β-Carotene reduce this risk of cognitive decline has not yet been defined.
“Dietary carotene intake reduced the progression of atherosclerosis, stroke, and other oxidative impairments, which are risk factors for cognitive decline.”, the researchers discuss, indicating a possible route of action.
“Another hypothesis is related to the antioxidant function of plasma α-carotene and β-carotene through dietary intake, which can promote the formation of gap junctions between cells and can be converted to vitamin A.”, they add.
Whilst the large sample paired with the use of objective measurements ensured validity to the results, it is worth noting that due to the study design used, cause and effect cannot be established based on this study. Therefore, further RCTs are required to investigate this relationship further.
“Association of Dietary α-Carotene and β-Carotene Intake with Low Cognitive Performance in Older Adults: A Cross-Sectional Study from the National Health and Nutrition Examination Survey”
Qiya Zhong, Wen Sun, Yao Qin and Huadong Xu.