Tammy Scott

Prof. Tammy Scott


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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23 August 2017 in Nutrients
Verified
Journal Article
Open access
PDF file
TSTammy Scott
Tammy Scott
HRHelen Rasmussen
Helen Rasmussen
Oliver ChenOliver Chen
Oliver Chen
EJElizabeth Johnson
Elizabeth Johnson
Lutein is selectively incorporated into the macula and brain. Lutein levels in the macula (macular pigment; MP) and the brain are related to better cognition. MP density (MPD) is a biomarker of brain lutein. Avocados are a bioavailable source of lutein. This study tests the effects of the intake of avocado on cognition. This was a six-month, randomized, controlled trial. Healthy subjects consumed one avocado (n = 20, 0.5 mg/day lutein, AV) vs. one potato or one cup of chickpeas (n = 20, 0 mg/day lutein, C). Serum lutein, MPD, and cognition were assessed at zero, three, and six months. Primary analyses were conducted according to intent-to-treat principles, with repeated-measures analysis. At six months, AV increased serum lutein levels by 25% from baseline (p = 0.001). C increased by 15% (p = 0.030). At six months, there was an increase in MPD from baseline in AV (p = 0.001) and no increase in C. For both groups, there was an improvement in memory and spatial working memory (p = 0.001; p = 0.032, respectively). For AV only there was improved sustained attention (p = 0.033), and the MPD increase was related to improved working memory and efficiency in approaching a problem (p = 0.036). Dietary recommendations including avocados may be an effective strategy for cognitive health.

1 June 2017 in The American Journal of Clinical Nutrition
Verified
Journal Article
Closed access
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ARAnnie J Roe
Annie J Roe
SZShucha Zhang
Shucha Zhang
RBRafeeque A Bhadelia
Rafeeque A Bhadelia
EJElizabeth J Johnson
Elizabeth J Johnson
ALAlice H Lichtenstein
Alice H Lichtenstein
TSTammy Scott
Tammy Scott
Background: There is a potential role of choline in cardiovascular and cerebrovascular disease through its involvement in lipid and one-carbon metabo

5 July 2017 in BMC Nephrology
Verified
Journal Article
Open access
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DDDavid A. Drew
David A. Drew
BKBang-Bon Koo
Bang-Bon Koo
RBRafeeque Bhadelia
Rafeeque Bhadelia
DWDaniel E. Weiner
Daniel E. Weiner
SDSarah Duncan
Sarah Duncan
MSMark J. Sarnak
Mark J. Sarnak
Patients treated with dialysis have high rates of brain infarcts, brain atrophy, and white matter disease. There are limited data regarding the presence of more subtle damage to brain white matter. In the Cognition and Dialysis Study, we compared brain structure using diffusion tensor imaging in hemodialysis (HD) patients to individuals without known kidney disease, using tract based spatial statistics (TBSS) to compare Fractional Anisotropy (FA) and Mean Diffusivity (MD). Statistical comparison of each overlaid voxel was age controlled using a permutation based corrected p value of <0.05. Thirty-four HD patients and twenty six controls (52 vs 51 years for HD vs control) had adequate magnetic resonance imaging for analysis. The HD group had fewer women (38% vs 23%) and a higher prevalence of diabetes (29% vs 8%), heart failure (29% vs 0%) and clinical stroke (15% vs 0%). Hemodialysis patients had significantly lower FA across multiple white matter fiber tracts, with fronto-temporal connections, the genu of the corpus callosum and the fornix more significantly affected than posterior regions of the brain. Similarly, HD patients had significantly higher mean diffusivity in multiple anterior brain regions. Results remained similar when those with a prior history of stroke were excluded. In HD patients, there is more white matter disease in the anterior than posterior parts of the brain compared to controls without kidney disease. This pattern of injury is most similar to that seen in aging, suggesting that developing chronic kidney disease and ultimately kidney failure may result in a phenotype consistent with accelerated aging.

20 January 2021 in British Journal of Nutrition
Verified
Journal Article
Closed access
PDF file
MMMarshall G. Miller
Marshall G. Miller
NTNopporn Thangthaeng
Nopporn Thangthaeng
GRGrant Rutledge
Grant Rutledge
TSTammy Scott
Tammy Scott
Barbara Shukitt-HaleBarbara Shukitt-Hale
Barbara Shukitt-Hale
Functional changes in the brain during ageing can alter learning and memory, gait and balance – in some cases leading to early cognitive decline, disability or injurious falls among older adults. Dietary interventions with strawberry (SB) have been associated with improvements in neuronal, psychomotor and cognitive functions in rodent models of ageing. We hypothesised that dietary supplementation with SB would improve mobility and cognition among older adults. In this study, twenty-two men and fifteen women, between the ages of 60 and 75 years, were recruited into a randomised, double-blind, placebo-controlled trial in which they consumed either freeze-dried SB (24 g/d, equivalent to two cups of fresh SB) or a SB placebo for 90 d. Participants completed a battery of balance, gait and cognitive tests at baseline and again at 45 and 90 d of intervention. Significant supplement group by study visit interactions were observed on tests of learning and memory. Participants in the SB group showed significantly shorter latencies in a virtual spatial navigation task (P= 0·020,ηp2= 0·106) and increased word recognition in the California Verbal Learning test (P= 0·014,ηp2= 0·159) across study visits relative to controls. However, no improvement in gait or balance was observed. These findings show that the addition of SB to the diets of healthy, older adults can improve some aspects of cognition, but not gait or balance, although more studies with a larger sample size and longer follow-up are needed to confirm this finding.

1 January 2019 in Journal of Alzheimer’s Disease
Verified
Journal Article
Closed access
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JTJirayu Tanprasertsuk
Jirayu Tanprasertsuk
EJElizabeth J Johnson
Elizabeth J Johnson
MJMary Ann Johnson
Mary Ann Johnson
LPLeonard W Poon
Leonard W Poon
PNPeter T Nelson
Peter T Nelson
TSTammy Scott
Tammy Scott
Background: Centenarian studies are important sources for understanding of factors that contribute to longevity and healthy aging. Clinico-neuropathological finding is a key in identifying pathology and factors contributing to age-related cognitive decline and dementia in the oldest old. Objective: To characterize the cross-sectional relationship between neuropathologies and measures of premortem cognitive performance in centenarians. Methods: Data were acquired from 49 centenarians (≥98 years) from the Georgia Centenarian Study. Cognitive assessment from the time point closest to mortality was used (<1 year for all subjects) and scores for cognitive domains were established. Neuropathologies [cerebral atrophy, ventricular dilation, atherosclerosis, cerebral amyloid angiopathy (CAA), Lewy bodies, hippocampal sclerosis (HS), hippocampal TDP-43 proteinopathy, neuritic plaque (NP) and neurofibrillary tangle (NFT) counts, Braak staging, and National Institute on Aging-Reagan Institute (NIARI) criteria for the neuropathological diagnosis of Alzheimer’s disease (AD)] were compared among subjects with different ratings of dementia. Linear regression was applied to evaluate the association between cognitive domain scores and neuropathologies. Results: Wide ranges of AD-type neuropathological changes were observed in both non-demented and demented subjects. Neocortical NFT and Braak staging were related to clinical dementia rating. Neocortical NFT and NP, Braak and NIARI staging, cerebral and ventricular atrophy, HS, CAA, and TDP-43 proteinopathy were differentially associated with poor performance in multiple cognitive domains and activities of daily living. Conclusion: AD-type pathology was associated with severe dementia and poor cognition but was not the only variable that explained cognitive impairment, indicating the complexity and heterogeneity of pathophysiology of dementia in the oldest old.

6 September 2018 in Nutrients
Verified
Journal Article
Open access
PDF file
SBSherman Bigornia
Sherman Bigornia
TSTammy Scott
Tammy Scott
WWWilliam S William
William S William
KTKatherine Tucker
Katherine Tucker
Polyunsaturated fatty acid (PUFA) consumption is recommended as part of a healthy diet, but evidence of the impact of individual species and biological concentrations on cognitive function is limited. We examined prospective associations of PUFA erythrocyte composition and dietary intake with measures of cognitive function among participants of the Boston Puerto Rican Health Study (aged 57 years). Erythrocyte and dietary PUFA composition were ascertained at baseline and associated with 2-year scores on the Mini-Mental State Exam (MMSE) (n = 1032) and cognitive domain patterns derived from a battery of tests (n = 865), as well as with incidence of cognitive impairment. Erythrocyte and dietary n-3 PUFA were not significantly associated with MMSE score. However, total erythrocyte and dietary n-3 very-long-chain fatty acids (VLCFA), and intake of individual species, were associated with better executive function (P-trend < 0.05, for all). There was evidence that greater erythrocyte n-6 eicosadienoic acid concentration was associated with lower MMSE and executive function scores (P-trend = 0.02). Only erythrocyte arachidonic acid (ARA) concentration predicted cognitive impairment (Odds Ratio = 1.26; P = 0.01). Among Puerto Rican adults, we found that n-3 VLCFA consumption may beneficially impact executive function. Further, these findings provide some evidence that n-6 metabolism favoring greater ARA tissue incorporation, but not necessarily dietary intake, could increase the risk of cognitive impairment.