amp Obesity Julia Humphrey Central Washington University Objectives Understand the difference between natural and manufactured glutamate Acknowledge the potential relationship between MSG ID: 296596
Download Presentation The PPT/PDF document "Monosodium Glutamate" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Monosodium Glutamate & Obesity
Julia Humphrey
Central Washington UniversitySlide2
Objectives
Understand
the difference between natural and manufactured glutamate
Acknowledge the potential relationship between MSG
&
appetite
Learn the
e
ffects of MSG during pregnancy & in
offspring
Know how much MSG is consumed & where it is hiddenSlide3
What is Monosodium Glutamate (MSG)
Favor enhancer/food additive largely used in the food industry
Responsible for umami/savory taste
When detected by taste buds, it signals the protein presence in the diet
Thought to mainly be in Asian cuisine
Hidden in many processed foodsUsed in place of sodiumSlide4
Natural vs. Processed Glutamate
MSG is the manufactured salt of glutamic acid
Glutamate is the sodium salt of glutamic acid
Key to the savory umami
taste
Glutamate in natureL-glutamic acidExists as part of proteins
Broken down as a part of protein digestion
Natural constituent to fermented foods
MSGD-glutamic acidRefined, can be readily absorbed into circulationNot bound to proteins, levels spike upon consumptionPossibility of “toxicity” = MSG sensitivitySlide5
MSG & Obesity History
1960s
Debons
et al.
Systemically administered MSG in mice found a pattern of obesity & hypothalamic damage
This lead to MSG admin. as the most widely used model to induce obesity in rats
I
nduces
a lesion of arcuate nucleus in hypothalamus Slide6
MSG & Obesity
Experimental studies in rats
The
arcuate
nucleus proposed as an important site of leptin actionLeptin produced by adipose cells Essential in maintenance of appetite, energy homeostasis, & body weight
MSG
administered subcutaneously in newborns
Lesion of the hypothalamic nucleusLeptin action reduced likely as a result of lack of leptin receptors in
arcuate nucleusSlide7
Obesity, voracity, and short stature: the impact of glutamate on the regulation of appetiteHermanussen
et al. 2006
Purpose
Effects of oral administration of MSG in pregnant rats and offspring
Subjects/Methods
32 pregnant rats, day 14 of pregnancy divided into 4 groupsGroup 1 (n=8): no extra MSG
Group 2 (n=8): 2.5 g MSG per day
Group 3 (n=8): 5.0 g MSG per day
Group 4 (n=8): no extra MSG during pregnancy offspring injected with 4mg/g MSGOffspring killed half at day 30 and rest at day 90Slide8
Results
Maternal feeding with 5 g/d resulted in severe birth weight reduction (p < 0.01)
Leptin
levels reduced in
MSG-fed groups
(p < 0.05)MSG-fed animals contained more body fat at day 30 and 90 than controls (p < 0.05) Impaired glucose toleranceInsulin resistance
Obesity, voracity, and short stature: the impact of glutamate on the regulation of appetite
Hermanussen
et al. 2006
2.5 and 5 g/day MSG consumption showed marked voracity
AppetiteSlide9
Monosodium glutamate versus diet induced obesity in pregnant rats and their offspringAfifi
and Abbas 2011
Purpose
Compare oral administration of large doses of MSG with high calorie
diet in
pregnant rats & offspringSubjects/Methods90 female rats randomly divided into 3 groups
Group 1 (n=30): normal chow 4.5% fat
Group 2 (n=30): normal chow + 100 g/kg MSG
Group 3 (n=30): high fat chow 31% fatSlide10
Subjects/MethodsFemale rats allowed to mate and further divided into groups
C10 (n=10): control
preg
sacrificed on 10
th
dayMSG10 (n=10): MSG treated preg sacrificed on 10th dayHC10 (n=10): high calorie preg
sacrificed 10
th
dayC20 (n=10): control preg sacrificed on 20th dayMSG20 (n=10): MSG treated preg
sacrificed 20th dayHC20 (n=10): high calorie preg sacrificed 20th dayOffspring of female rats
CO (n=10): control preg offspring sacrificed 10th dayMSGO (n=10): MSG preg offspring sacrificed 10
th
day
HC (n=10): high calorie
preg
offspring sacrificed 10
th
day
Monosodium glutamate versus diet induced obesity in pregnant rats and their offspring
Afifi
and Abbas 2011Slide11
C10
C20
HC10
HC20
MSG10
MSG20
Body weight (g)
236.4 ± 6.5
255.6 ± 7.4
301.6 ± 5.9309.6 ± 8.0237.4 ± 6.0
245.4 ± 5.3Abdominal fat (g)
13.6 ± 0.05
13.6 ± 0.04
44.6 ± 0.49
45.0 ± 0.56
57.6 ± 0.39
58.0 ± 0.5
Blood glucose
(mg/dl)
84.2 ± 1.2
79.2 ± 1.0
118.2
± 3.2
122.6 ± 2.9
120.0 ± 2.2
125.0 ± 2.5
TAG
(mg/dl)
147.4
± 13.0163.7 ± 15.0210.6 ± 4.0221.4 ± 5.0200.3 ± 5.0223.3 ± 3.0TC (mg/dl)85.2 ± 3.086.5 ± 2.0102.7 ± 2.0107.5 ± 3.0103.2 ± 1.0108.6 ± 2.0Number of offspring4.5 ± 0.64.7 ± 1.03.3 ± 0.53.3 ± 0.52.0 ± 0.81.8 ± 1.0
Monosodium glutamate versus diet induced obesity in pregnant rats and their offspring
Afifi
and Abbas 2011Slide12
MSG Consumption
FDA
Considers MSG as a food additive
“generally
recognized as safe
”Not required to list amount of MSG in Nutrition Facts panelLarge variation in MSG consumptionUK (1991): 580 mg/d general
4.68 g/d in extreme users
China (2010): 3.8 g/dThailand (2012): 4.0 g/dJapan & Korea (1990’s): 1.2-1.7 g/dSpeculated intake is up to 10 g/dSlide13
Consumption of MSG in relation to incidence of overweight in chinese adults: China Health and Nutrition Survey
He et al. 2011
Subjects
Longitudinal open-cohort, ongoing, nationwide survey 1991-2006
10,095
Chinese men and women 18-65
yr
Methods
MSG consumption dietary data both in the household & individualAll food purchases, home production, and processed snack foods were weighed and recorded24-hour recall for 3 consecutive daysMSG intake for each household member estimated based on the proportion of each individual’s food consumption
MSG intake separated into quintilesChi square test Slide14
ResultsMean cumulative MSG intake 1.8 g/dMSG positively associated with BMI in dose-response manner (p < 0.01
)
Highest MSG quintile 33% more likely to be overweight
Higher BMI, income, lower physical activity
Pilot
StudyExamine association between MSG and serum leptinMSG intake positively related to serum leptin
concentrations
Serum
leptin concentration increased by 0.45 ng/mL with every 1-g increase in MSG intakeConsumption of MSG in relation to incidence of overweight in chinese
adults: China Health and Nutrition SurveyHe et al. 2011Slide15
Limitations to Studies
Majority on pregnancy & neonatal outcome is in rodents
Not ethical to perform on humans
MSG dose is very large compared to actual consumption in
humansSlide16
Is MSG Safe During Pregnancy?
Animal
studies
Result of maternal MSG consumption
Low birth weight in offspring
Increased insulin resistance in offspringLeptin
levels reduced in
offspringLeptin resistance in pregnant ratIncreased abdominal fat in pregnant ratPlacental barrier Controls
the passage of glutamate from maternal plasma to fetus, metabolizing it before it reaches the fetal circulationMSG-sensitivityHeadaches, nausea, numbness, weakness when consuming MSG containing foodsWant to consume fresh unprocessed as much as possible during pregnancyConsult doctor Slide17
“Hidden” MSG
Not labeled as MSG
Hydrolyzed (anything), glutamate, glutamic acid, yeast extract, soy sauce, soy protein, gelatin, flavors, flavoring, bouillon, broth, seasonings,
etc
Found in common food items
Processed cheese, salad dressings, meat & vegetable stocks/broth, soups, vegetable dips, condiments, chips, pasta sauceFast food: KFC
Increase in MSG production
Increase in processed foods = increased
consumption200 tons per year in 1969800 tons per year in 2001Possible that exposure in utero could be a contributing factor to increasing obesity ratesSlide18
Conclusion
Obesity is a multifactorial disease
Related to diet, physical activity, genetics, environment
Like sugar and fat consumption MSG may simply be one factor in the mix
Would like to see national study in U.S
Difficult since NHANES does not provide MSG infoSlide19
Resources
Afifi
MM, Abbas AM. Monosodium glutamate versus diet induced obesity in pregnant rats and their offspring
.
Acta
Physiologica Hungarica 2011;98;2:177-188
Collison
K,
Makhoul N, Zaidi M, Inglis A, Andres B, Ubungen R, Shoukri M, Al-Mohanna
A. Interactive effects of neonatal exposure to monosodium glutamate and aspartame on glucose homeostasis. Nutrition & Metabolism 2012;5;58:1-13Diemen V, Trindade M. Effect of the oral administration of monosodium glutamate during pregnancy and breast-feeding in the offspring of pregnant
Wistar rats. Acta Cirurgica Brasileria
2010;25;1:37-42
Friedler
B, Grimm V. Prenatal monosodium glutamate (MSG) treatment given through the mother’s diet causes behavioral deficits in rat offspring
. International Journal of Neuroscience
1984;23:117-126
He
K, Du S,
Xun
P, Sharma S, Wang H,
Zhai
F,
Popkin
B. Consumption of monosodium glutamate in relation to incidence of overweight in Chinese adults: China Health and Nutrition Survey (CHNS).
American Journal of Clinical Nutrition
2011;93:1328-36
Hermanussen
M, Garcia AP, Voigt M, Salazar V,
Tresguerres
JAF. Obesity, voracity, and short stature: the impact of glutamate on the regulation of appetite.
European Journal of Clinical Nutrition 2006;60:25-31Insawang T, Selmi C, Cha’on U, Pethlert S, Yongvanit P, Areejitanusorn P, Boonsiri P, Khampitak T, Tangrassmeeprasert R, Pinitsoontorn C, Prasongwattana V, Gershwin M, Hammock B. Monosodium glutamate (MSG) intake is associated with the prevalence of metabolic syndrome in a rural Thai population. Nutrition & Metabolism 2012;9;50:1-6Yu T, Zhao Y, Shi W, Ma R, Yu L. Effects of maternal oral administration of monosodium glutamate at a late stage of pregnancy on developing mouse fetal brain. Brain Research 1997:195-206 MSG Truth website http://www.msgtruth.org/avoid.htm. Accessed July 12, 2013Names of ingredients that contain processed free glutamic acid (MSG) http://www.truthinlabeling.org/hiddensources.html . Accessed July 12, 2013 Glutamic Acid - It Is Not MSG or Monosodium Glutamate http://www.edenfoods.com/articles/view.php?articles_id=207. Accessed July 12, 2013Slide20
What are your thoughts? Questions?