Interaction of Vitamin B12 and Ancestral Genetic Background with Adiposity in Children

Wilnerys Colberg HernándezMentors: José R. Fernández PhD & David Allison PhD

Obesity

What is obesity?Excess body fat accumulated to the magnitude that it may have an adverse effect on health. Obesity is determined differently in adults  and children.

• BMI = weight(kg) / height²(m²)• BMI • BMI percentile   

Why is this a concern?• Increasing prevalence• Obesity is associated with numerous health problems 

• Heart disease, high blood pressure, diabetes,      metabolic syndrome, cancer, etc.  

• Shortening individuals’ lives• 70% obese children become obese adults 

(Zhao, J. et.al, 2011)

Obesity prevalence in children

Etiology of obesity

Say hi to Gordy!

http://theblueprintforlife.com/forum/topics/the-vicious-cycle-of-childhood-obesity

• Obesity is a complex disease• Individuals respond differently

  What do we know of the etiology of obesity?• Through the years there has been controversy 

The contribution of environmental and behavioral might sound simple…

Behavioral

Environmental

Obesity

Genetic

Nature VS Nurture

(Kimm, S. et. al, 2003)

Complex enough?

• The etiology is still not completely understood but,• Scientific research are beginning to explore these factors

• Efforts focusing these factors and its affect on adiposity

• I took interest understanding how these factors interact to influence adiposity

Obesity

Genetic

Behavioral

Environmental(McAllister, E. et.al, 2009)

• Scientists have made great advances identifying several genes that might be implicated and have found association between race/ethnicity  

Lets start by…

Obesity

Genetic

Genetic variation

Ancestral Genetic Background (ADM):• ADM describes the genomic variation between populations. 

• Examination of DNA variations based on genetic markers• European, African, Amerindian

• Genetic Background affects how our bodies capture, store, and release energy from food.

How do we capture individuals consumption of food?

Obesity

Genetic

(Darvasi, A. et.al, 2005)

• Today there is an emerging trend to understand how nutrients affect body composition.

• Personalized nutrition advice • Which nutrient(s) should we target? 

Nutritional Components

Obesity

Environmental(Abete, I. et.al, 2011)

Behavioral

Nutrient -> Vitamins -> B12

Vitamin B12

B12 is touted as an energy enhancer, metabolism booster & fat burner

Is this true?

• Relationship between vitamin B12 and excess body fat is unclear. • Found in animal based foods and fortified food.• Essential for growth, development, producing blood cells, nervous system function.• Regulation of protein and enzymes in metabolism. 

Obesity

Environmental(Baltaci, D. et.al, 2012)

Behavioral

Objective

To  evaluate  if  the  interaction  of  dietary  Vitamin  B12 consumption and ADM influences  levels of body fat among children from a multi-ethnic sample. 

Obesity

GeneticEnvironmental

Behavioral

Methodology

• Subjects from a cross-sectional cohort study :• Sample of 319 children.• Males and females of age 7 to 12 years.• Children were recruited from Birmingham, Alabama.• Pubertal stage assessed by pediatrician according to the criteria of Marshall and 

Tanner.• Not taking medication known to affect body composition.• Measurements were performed between 2004-2008 at Nutrition Obesity research 

Center & the Department of Nutrition Sciences at UAB.• Anthropometric measures:

• Pubertal status (breast, genitalia, and pubic hair development)• Height (cm) - (stadiometer)• Weight (kg) - (scale-tronix 6702W)

Methods…

• Body composition• Dual-energy x-ray absorptiometry (DXA)

• Dietary Measures:• Two 24-hour diet recalls administered by a registered dietitian using triple-pass method• Total calories• B12 dietary intake ()• Other B vitamins

• Ethnicity:• Reported by parents or guardian

• Genetic Measures:• Genetic Admixture assessed by ancestry informative markers

• Amerindian, African, and European

Statistical Analyses

Log Total Fat Covariates B12 Intake African

AdmixtureB12 * Afr.

Adm.

Covariates:Total Calories, Height, Age, Sex, Tanner

Model #1

• Analyses were performed using SAS software version 9.3 • Multiple regression model

•  To estimate the relationships among variables in interest

Multiple Regression Models

Resting Energy

ExpenditureCovariates B12 Intake African

AdmixtureB12 * Afr.

Adm.

Covariates:Total Calories, Weight, Age, Sex, Tanner

Model #2

Model #3

BMI Covariates B12 African Admixture

B12 * Afr. Adm.

Covariates:Total Calories, Age, Sex, Tanner

Total Lean Covariates B12 African Admixture

B12 * Afr. Adm.

Covariates:Total Calories, Age, Sex, Tanner

Model #5

Model #4

Log Total Fat Covariates **Other B -

vitaminsAfrican

AdmixtureB vitamins * Afr. Adm.

Covariates:Total Calories, Height, Age, Sex, Tanner

**B-vitamins:Thiamin, Niacin, B6, Riboflavin, Folate & pantothenic acid

Multiple Regression Models

Results: model #1

Variable Mean

Total Calorie 1892.22  469.71

Total Fat 8864.19  5686.29

Height (cm) 139.45  10.64

Weight (kg) 36.55  9.53

Age  9.55  1.57

Pubertal Stage 1.50  0.74

Vitamin B12 4.51  2.72

Male 53.11%

     European American 37.89%

     African American 33.23%

     Hispanic American 26.40%

Mixed Race/Ethnicity 2.48%

Table 1. Baseline Descriptive Statistics

* Standard Deviation **Percentage of total sample (n=319)

Table 3. Percent of Variability Explained

Model R-squared % variability explained

Covariates + Afr. Adm. 0.3131 ____

Covariates + Afr. Adm. + B12

0.3199.68%

Covariates + Afr. Adm. + B12 + Interaction

0.34032.72%

Variables Parameter estimate P-value

African Admixture -0.053 0.7184

B12 0.064 0.0008

B12 & Afr. Adm. -0.082 0.0036

Table 2. Parameter Estimates for Interaction and Simple Effect Terms

P-value for model

0510152025303540

4

4.5

5

5.5

6

6.5

7

7.5

8

0 0.2 0.4 0.6 0.8 1 B12 intake (µg)

Log

Body

Fat

Fig 1. 3D representation of the interaction of B12 with African Admixture on Body Fat

Results: model #1

African ADM

Results: model #1

0 5 10 15 20 25 30 35 404

4.5

5

5.5

6

6.5

7

7.5

8

00.20.40.60.81

B12 intake (µg)

Log

Body

Fat

Fig 2. 2D representation of the interaction of B12 with African Admixture on Log Body Fat

Afr. ADM

Results:

Results: model #5None of the other B-vitamins had any significant associations

Model Dependent Variables Independent Variables

Parameter Estimate P-Value

2 Resting Energy

Afr. ADM. -90.49 0.0808

B12 -9.94 0.1412

interaction 12.72 0.1987

3 BMI

Afr. ADM. 0.29 0.7312

B12 0.25 0.0238

interaction -0.31 0.0591

4 Lean Mass

Afr. ADM. 293.87 .07578

B12 -50.17 0.6851

interaction 176.12 0.3333

Discussion/Conclusion

• This study demonstrates that the differences  in body fat observed  in  children  may  be  explained  in  part  by  the interaction  of  dietary  micronutrients  with  individuals’ ADM. 

Fig. 2 2D representation of the interaction of B12 intake & Afr. Adm with Log body fat

• Also, the mechanism by which the interaction of B12 and Afr. Adm. does not seem to be related to resting energy expenditure since no significant association was found in the regression model.

• Further study is needed to understand how individuals’ ancestral background and nutrient consumption may contribute to adiposity levels.

• This study may help our understanding of the etiology of obesity, hopefully for the development of nutritional intervention strategies.

Discussion/Conclusion

Acknowledgments

• NSF (EPSCoR : 1158862)• SSG• University of Alabama at Birmingham• Universidad Metropolitana• Dr. José Fernández• Dr. Hemant Tiwari • Michelle Brown Bohan PhD• Kenneth P. Kell M.Eng• Keith E. Pearson

Any questions???