Preserving Muscle Mass, Strength and Performance in Free-living Older Adults

218 Pages·2013·4.5 MB·English

Preserving Muscle Mass, Strength and Performance in
Free-living Older Adults: A Focus on
Dietary Protein Quantity, Distribution and Dairy Products

Samaneh Farsijani

School of Dietetics and Human Nutrition
McGill University, Montreal
Quebec, Canada

April, 2017

A thesis submitted to McGill University in partial fulfillment of the requirements of
the degree of Doctor of Philosophy

© Samaneh Farsijani, 2017
ABSTRACT
The loss of muscle mass and strength or physical function with aging, known as sarcopenia, is an
important predictor of frailty, disability and loss of autonomy. Among etiologic factors, inadequate
protein intake may contribute but the effect of its mealtime distribution remains to be shown. As
well, the role of dairy products as important sources of protein and other nutrients has been scarcely
studied in longitudinal studies.
The global objectives of this thesis are: (1) to examine the extent to which total protein intake and
mealtime protein distribution are associated with lean mass (LM) and appendicular LM (aLM) and
their 2-y changes; (2) to examine the cross-sectional and longitudinal relationships between
mealtime distribution of protein intake and physical performance; and (3) to investigate the
association between total dairy intake and changes in body composition, physical performance
over 3 years, using the NuAge database (Quebec Longitudinal Study on Nutrition and Aging) in
free-living men and women aged 67-84 y. Dietary data were extracted from 2 sets of three
nonconsecutive 24-h food recalls collected at baseline (T0) and after 2 years (T2). Participants’
protein intake was adjusted to their energy intake using the nutrient residual energy-adjustment
method. Protein distribution across meals was calculated as the coefficient of variation (CV) of g
protein ingested per meal, with lower values reflecting the evenness of protein intake. In Study 1,
body composition data were analyzed in 351 men and 361 women with available dual-energy X-
ray absorptiometry data at T0 and 2-y follow-up. In Study 2, two functional composite scores
(muscle strength: handgrip, arm and leg; and mobility: timed up-and-go, chair stand, normal and
fast walking speed) were analyzed in 827 men and 914 women over 3 years. In Study 3,
participants (n=1499) were assessed for their total dairy intakes (milk, cheese, yogurt and dairy‐
based desserts). Frailty was defined according to Fried et al. 2001 criteria. In all studies, mixed
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model analysis was used to examine trajectories of muscle mass, strength and mobility across time,
by sex, as conditioned by studied variables (i.e., protein quantity, distribution and total dairy
intake), adjusted for potential covariates.
Results from Study 1 showed that an even protein intake distribution across meals, independent of
the total protein amount, was associated with higher LM and aLM in both older men and women
throughout follow-up. But neither protein quantity nor distribution affected the rate of LM loss in
either sex. In Study 2, more even distribution of protein intake was associated with higher muscle
strength, but not mobility function, in both sexes throughout follow -up (3 years), independently of
the total protein intake. The physical performance decline over 3 years was not affected by protein
intake distribution in either sex. Study 3 showed independent associations between higher dairy
consumption and higher LM and a better mobility score throughout follow -up in both sexes.
Higher dairy intake was inversely associated with body fat in women, while the association was
positive in men. Additionally, the risk of pre -frailty/frailty was lower among high dairy consumers
in men. However, time-dependent changes in body composition, muscle strength or physical
performance were not related to dairy intake in either sex.
Our studies support that specific nutritional approaches, e.g., higher and a more evenly distributed
protein intake as well as higher dairy intake, are independently associated with higher muscle mass
and better physical function, but not with their changes over a short (2 -3 years) follow-up period,
in well-functioning older adults. However, even at the same rate of decline, having a higher lean
mass and strength may delay reaching the sarcopenic threshold. Longer -term and larger
observational and clinical trials are warranted to support future recommendations.

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RESUME
La perte de masse et de force musculaire et une fonction physique amoindrie avec l’âge, appellee
sarcopénie, est considérée comme un prédicteur important de la fragilité, d’invalidité, et de perte
d’autonomie. Parmi les causes possibles, un apport insuffisante en protéines peut contribuer l’effet
de sa distribution aux repas reste à être démontré. De plus, le rôle des produits laitiers comme
source importante de protéines et autres nutriments n'a guère été étudié dans des études
longitudinales.
Les objectifs globaux de cette thèse sont les suivants : (1) examiner dans quelle mesure l'apport
total en protéines et la distribution des protéines aux repas sont associés à la masse maigre (LM)
et à la LM appendiculaire (aLM), et à leurs changements sur 2 ans; (2) examiner la relation
transversale et longitudinale entre la distribution de l'apport en protéines aux repas et la
performance physique; et 3) étudier l'association entre la consommation totale de produits laitiers
et les changements dans la composition corporelle et la performance physique sur 3 an s, en utilisant
la base de données NuAge (Étude longitudinale québécoise sur la nutrition et le vieillissement)
chez les hommes et les femmes vivant en communauté, de 67 -84 any.
Les données alimentaires ont été extraites de 2 séries de trois rappels de 2 4 heures non-consécutifs,
collectés au début (T0) et après 2 ans (T2). L'apport en protéines des participants a été ajusté à leur
apport énergétique en utilisant la méthode résiduelle d'ajustement pour l’énergie (14, 15). La
répartition des protéines aux repas était calculée comme le coefficient de variation (CV) des
grammes de protéines ingérées par repas; les valeurs les plus faibles reflétant la régularité de
l'apport en protéines. Dans l'étude 1, les données sur la composition corporelle ont été analysé es
chez 351 hommes et 361 femmes ayant des données d'absorptiométrie à rayons X à double énergie
disponibles au T0 et suivi T2. Dans l'étude 2, deux scores composites fonctionnels (force
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musculaire : préhension, bras et jambe, mobilité : “timed -up-and-go”, lever de chaise, vitesse de
marche normale et rapide) ont été analysé chez 827 hommes et 914 femmes sur 3 ans. Dans l'étude
3, l’apport total en produits laitiers (lait, fromage, yogourt et desserts à base de lait) a été analysé
chez 1499 participants. La fragilité a été définie selon les critères de Fried et al. 2001 (16). Dans
toutes les études, l'analyse de modèles mixtes a été utilisée pour examiner les trajectoires de la
masse musculaire, de la force et de la mobilité au cours du temps, selon le sexe, telles
qu’influencées par les variables étudiées (quantité de protéines, distribution et consommation
totale de produits laitiers), et ajustées pour les covariables potentielles.
Les résultats de l'étude 1 ont montré qu'une distribution plus uniforme de l 'apport en protéines aux
repas était associée à un LM et un aLM plus élevés chez les hommes et les femmes âgés tout au
long du suivi, et ce, indépendamment de la quantité totale de protéines. Cependant, ni la quantité
ni la distribution des protéines n'ont affecté le taux de perte de LM. Dans l'étude 2, une répartition
plus égale de l'apport en protéines était associée à une force musculaire plus élevée (mais pas à la
mobilité), chez les deux sexes et tout au long du suivi de 3 ans, indépendamment de la pri se totale
de protéines. Le déclin de la performance physique sur 3 ans n'a pas été affecté par la distribution
de l'apport protéique. L'étude 3 a démontré des associations indépendantes entre une
consommation laitière plus élevée et un LM plus élevé ainsi qu’un meilleur score de mobilité tout
au long du suivi, chez les hommes et les femmes. Une consommation laitière plus élevée était
inversement associée au taux de graisse corporelle chez les femmes, alors que l'association était
positive chez les hommes. D e plus, le risque de fragilité / pré -fragilité était plus faible chez les
grands consommateurs de produits laitiers, chez les hommes. Cependant, les changements dans la
composition corporelle, la force musculaire ou la performance physique au cours du temp s
n'étaient pas été liés à l'ingestion de produits laitiers, ni chez les hommes ni chez les femmes.
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Nos études soutiennent que les approches nutritionnelles spécifiques, par exemple, une
consommation de protéines plus élevée et plus uniformément distribuée, ainsi qu'une
consommation plus élevée de produits laitiers, sont indépendamment associées à une masse
musculaire plus élevée et à une meilleure fonction physique, mais pas avec leurs changements sur
une courte durée (2-3 ans) de suivi, chez les personnes âgées. Cependant, au même taux de déclin,
d’avoir une masse et une force musculaire plus élevées peuvent retarder l'atteinte du seuil
sarcopique. Ceci étant, des études d’intervention de plus longue durée sont justifiées pour soutenir
des recommandations futures.
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ACKNOWLEDGMENTS
Writing this part of my thesis is the most desirable part, as I can express my sincere feelings
originated deep from my heart without any challenge of searching for the right references or using
a citation manager software. It is a great pleasure to thank the many people who made this journey
possible for me.
First and foremost, I would like to thank my supervisor, Dr. Stéphanie Chevalier, who has been a
wonderful mentor and teacher, thank you for always trusting me andb elieving in me during every
moment of my PhD journey. I am always grateful that you warmly welcomed me in your lab.
Thank you for your supports, encouragement, and thoughtful scientific discussions that helped me
become a better researcher.
My sincere thanks go to my committee members, Dr. Katherine Gray-Donald and Dr. Jose A
Morais, for their great advice and comments on my manuscripts. I would also like to recognize all
the NuAge cohort participants, who made this work possibl,e and also special thanks to the entire
NuAge research team, especially Dr. Hélène Payette, Dr. Pierrette Gaudreau, Dr. Bryna
Shatenstein for all their helps in revising my manuscripts. I would like to thank Dr. Raman
Agnihotram for his statistical consultations and for patiently erviewing my analyses.
I have always believed that people are placed in our life for reasons, and Dr. Hope Weiler is for
sure one of them. Thank you for all the genuine advice and for your kindness, you ared efinitely
my role model. I will always be grateful to Dr. Errol Marliss for being there to help me, I learned
a lot from his professionalism and caring about colleagues, and also for his kind helps in revising
my manuscripts. I owe my gratitude to Ms. Marie Lamarchefo r kindly accommodating myl ast-
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minute requests for favors. I am grateful to Dr. Terry Comb, who took the time to share his
knowledge of protein biochemistry.
I would like to thank my dear friends, whom I met in Canada, Shima Sadeghi, Negar Tabatabaei,
Niloofar Hariri, Nadjmeh Nikpour, Kathryn Jacob, Catherine D'Aguiar and Maryam Razaghi, for
the joyful gatherings and for all their emotional supports and inspirations.
Lastly, and most importantly, I wish to thank my parents, Shahla Yousef Niaz and Hassan
Farsijani. They raised me, taught me, and loved me. Thank you with all my heart and soul for all
the supports you have provided me over the years. Thank you for encouraging me to trust my ideas
and follow my ambitions above the cultural barriers and geograp hical constrains. I am truly blessed
to have the most amazing brother, Behzad, sister, Somayeh and brother -in-low, Hadi, who always
supported and helped me throughout my training years. Thank you for spending hours over the
phone talking to me to make sure I am the least homesick. I am grateful for the new addition to
my family, my lovely niece, Bahar, for always making me smile, waking up every morning to see
your cute pictures always makes my day. I would like to end my acknowledgement with thanking
my dear Husband, Sina, for being understanding, sympathetic, patience, and encouraging through
this process. Our scientific discussions have inspired me a lot and had a great impact on my
research quality.
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DEDICATION

To my mom and dad…
for their kindness, devotion,
and endless support.
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CONTRIBUTION OF AUTH ORS
For manuscript 1 , the candidate designed the study (with Dr. Stéphanie Chevalier) , analyzed food
recalls, performed statistical analyses, made major data interpretation, was the primary author, and
wrote the first draft of the manuscript . Dr. José A. Morais , Dr. Hélène Payette , Dr. Pierrette
Gaudreau, Dr. Bryna Shatenstein and Dr. Katherine Gray -Donald designed the NuAge st udy and
conducted the research. Dr. Raman Agnihothram, provided statistical c onsultations on longitudinal
data analysis. Dr. Stéphanie Chevalier, provided consultation for statistical analyses, data
interpretation and revisions of the manuscript. The NuAge study was supported by the Canadian
Institutes for Health Research ( CIHR; MOP-62842) and the Quebec Network for Research on
Aging (RQRV), a network funded by The Fonds de recherche du Québec – Santé (FRQS).
For manuscript 2, the candidate designed the study (with Dr. Stéphanie Chevalier), analyzed food
recalls, performed data preparation and statistical analyses, made major data interpretation, was
the primary author, and wrote the first draft of the manuscript. Dr. José A. Morais, Dr. Hélène
Payette, Dr. Pierrette Gaudreau, Dr. Bryna Shatenstein and Dr. Katherine Gray-Donald designed
the NuAge study and conducted the research. Dr. Raman Agnihothram, provided statistical
consultations on longitudinal data analysis. Dr. Stéphanie Chevalier, provided consultation for
statistical analyses, data interpretation and revisions of the manuscript.
For manuscript 3, the candidate analyzed food recalls, performed data preparation and statistical
analyses, made major data interpretation, was the primary author, and wrote the first draft of the
manuscript. Dr. José A. Morais, Dr. Hélène Payette, Dr. Pierrette Gaudreau, Dr. Bryna Shatenstein
and Dr. Katherine Gray-Donald designed the NuAge study and conducted the research. Dr. Raman
Agnihothram, provided statistical consultations on longitudinal data analysis. Dr. Stéphanie
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