Document Type

Journal Article

Publication Title

Clinical Nutrition

Publisher

Elsevier

School

Nutrition and Health Innovation Research Institute / School of Medical and Health Sciences

RAS ID

58430

Funders

AR is supported by a Research Training Program (RTP) scholarship. SRRS is supported by an NHMRC Investigator Grant (GNT1197315). The salary of LCB is supported by an NHMRC of Australia Emerging Leadership Investigator Grant (ID: 1172987) and a National Heart Foundation of Australia Post-Doctoral Research Fellowship (ID: 102,498). The salary of CPB is supported by a Royal Perth Hospital Research Foundation ‘Lawrie Beilin’ Career Advancement Fellowship (ID: CAF 127/2020) and the Western Australian Future Health Research and Innovation Fund (ID: IG2021/5).

Grant Number

NHMRC Numbers : 1172987, GNT1197315

Comments

Rajendra, A., Bondonno, N. P., Murray, K., Zhong, L., Rainey-Smith, S. R., Gardener, S. L., ... & AIBL Research Group. (2023). Habitual dietary nitrate intake and cognition in the Australian Imaging, Biomarkers and Lifestyle Study of Ageing: a prospective cohort study. Clinical Nutrition, 42(8), 1251 - 1259. https://doi.org/10.1016/j.clnu.2023.05.022

Abstract

Background & aims

Dietary nitrate improves cardiovascular health via a nitric oxide (NO) pathway. NO is key to both cardiovascular and brain health. There is also a strong association between vascular risk factors and brain health. Dietary nitrate intake could therefore be associated with better cognitive function and reduced risk of cognitive decline. This is yet to be investigated. The aim of this study was to investigate the association between habitual intake of dietary nitrate from sources where nitrate is naturally present, and cognitive function, and cognitive decline, in the presence or absence of the apolipoprotein E (APOE) ε4 allele.

Methods

The study included 1254 older adult participants of the Australian Imaging, Biomarkers and Lifestyle Study of Ageing who were cognitively normal at baseline. Plant-derived, vegetable-derived, animal derived nitrate (not including meat where nitrate is an allowed additive), and total nitrate intakes were calculated from baseline food frequency questionnaires using comprehensive nitrate databases. Cognition was assessed at baseline and every 18 months over a follow-up period of 126 months using a comprehensive neuropsychological test battery. Multivariable-adjusted linear mixed effect models were used to examine the association between baseline nitrate intake and cognition over the 126 months (median [IQR] follow-up time of 36 [18–72] months), stratified by APOE ε4 carrier status.

Results

In non APOE ε4 carriers, for every 60 mg/day higher intake of plant-derived nitrate at baseline there was an associated higher language score [β (95% CI): 0.10 (0.01, 0.19)] over 126 months, after multivariable adjustments. In APOE ε4 carriers, there was an associated better episodic recall memory [0.24 (0.08, 0.41)] and recognition memory [0.15 (0.01, 0.30)] scores. Similar associations were seen for the intakes of vegetable-derived and total nitrate. Additionally, in APOE ε4 carriers, for every 6 mg/day higher intake of animal-derived nitrate (excluding meat with nitrate as an allowed additive) at baseline there was an associated higher executive function score [β (95% CI): 1.41 (0.42, 2.39)]. We did not find any evidence of an association between dietary nitrate intake and rate of cognitive decline.

Conclusion

Our results suggest that habitual intake of dietary nitrate from sources where nitrate is naturally present impacts cognitive performance in an APOE genotype contingent manner. Further work is needed to validate our findings and understand potential mechanisms underlying the observed effects.

DOI

10.1016/j.clnu.2023.05.022

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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