The effect of weight loss on circulating biomarkers of brain health and executive function

Obesity is associated with deficits in cognitive function, particularly within the domain of executive function (EF). EF refers to higher order cognitive processes that regulate our ability to sustain attention, inhibit subconscious tendencies, remember and manipulate information for immediate use, and remain cognitively flexible. Deficits in EF in overweight and obese individuals may impact the success of weight loss and maintenance efforts. Therefore, understanding the biological links between obesity and EF, as well as the ability to reverse EF deficits with weight loss, is imperative. The first study aimed to determine the effect of weight loss in overweight and obese, middle-aged and older adults on serum brain-derived neurotrophic fact (BDNF), S100 calcium binding protein B (S100B), and glial fibrillary acidic protein (GFAP). Serum samples (n=21; 50-75 years, BMI 25-40 kg/m2) were pooled from two prior weight loss studies. Fasting blood measurements were taken before and after 8- or 12-weeks of hypocaloric diet-induced weight loss (1200 or 1500 kcal/d). Body Mass Index (BMI), body weight, waist circumference, and percent body fat (All p<0.001) decreased with weight loss. Serum BDNF (p=0.871), S100B (p=0.898), and GFAP (p=0.506) did not change following weight loss. The second study aimed to determine the correlation between the magnitude of change in serum BDNF, S100B, and GFAP and the magnitude of improvement in EF performance on three computer-based tests. Participants (n=8; 50-75 years, BMI 25-40 kg/m2) completed 4-weeks of hypocaloric diet-induced weight loss (1200 or 1500 kcal/d), followed by 4-weeks of weight maintenance (hypocaloric diet + steps/d goal). Fasting blood and EF measurements were completed at baseline, and weeks 4 and 8. BMI (p=0.001), body weight (p=0.001), waist circumference (p=0.002), and percent body fat (p=0.001) decreased from baseline to week 8. Serum BDNF (p=0.359), S100B (p=0.277), and GFAP (p=0.585) did not change following weight loss. Go/No-Go (GNG) errors of commission (p=0.009) and AX-Continuous Performance Test (AX-CPT) correct response time (p=0.041) decreased following the weight loss. The change in serum GFAP was inversely correlated with GNG errors of omission (r=-0.716, p=0.046) and AX-CPT correct hits (r=-0.737, p=0.037), and positively correlated with AX-CPT correct response time (r=0.859, p=0.006). In conclusion, although weight loss does not influence serum BDNF, S100B, or GFAP levels, it may have a positive effect on inhibitory control in overweight and obese, middle-aged and older adults. Further research is needed to understand the relationship between serum BDNF, S100B, and GFAP and executive function.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Human Nutrition, Foods, and Exercise

Department dc:contributor.department

Human Nutrition, Foods and Exercise

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2020

Author dc:creator

• Herra, Lindsay Marie

Chair dc:contributor.committeechair

• Davy, Kevin P.

Committee members dc:contributor.committeemember

• Davy, Brenda M.
• Katz, Benjamin D.
• Zabinsky, Jennifer S.

• Obesity
• older adults
• cognitive function
• executive function
• brain-derived neurotrophic factor (BDNF)
• calcium binding protein B (S100B)
• glial-fibrillary acid protein (GFAP)

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:26233

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/106747