Biofortification of Plant-Based Food Products and Applications to the Athlete
Date
2023-12-15
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0001-6216-3276
Type
Thesis
Degree Level
Doctoral
Abstract
Introduction: A diet relying more heavily on plant-based food products and less on animal-based products has been promoted to feed a growing world population in a sustainable fashion. One concern with such a dietary pattern is iron bioavailability, as plant-based sources of iron contain phytic acid, a compound that binds to cations such as iron, limiting absorption.
Objectives: The objectives of this research are to examine the efficacy of a biofortified pea protein (bred to have low phytic acid, and therefore high iron bioavailability) on nutritional intake and iron status in vulnerable athlete populations.
Methods: In study one, a pilot trial evaluated the acceptability of an experimental high-protein supplement (made from field peas with high iron bioavailability) and the feasibility of data collection measures in a group of female runners. Before and after an 8-week supplementation protocol, participants were assessed for iron status, body composition, and exercise performance. Participants were randomized to consume either a protein concentrate derived from regular peas, a protein concentrate derived from low phytic acid peas, or an isocaloric control (i.e., maltodextrin). Participants also consumed 500 mg of vitamin C daily throughout the trial to enhance iron absorption. The incidence of adverse effects thought to be related to the supplement (eg. Bloating, constipation, cramping) were assessed at weeks two, four, six, and eight. With feasibility confirmed, in study two, 28 female runners underwent the same measures as outlined in study one (iron status, body composition, and exercise performance) before and after being randomly assigned to consume either maltodextrin, regular pea protein, or low phytic acid pea protein along with 375 mg of vitamin C for eight weeks. In study three, the habitual dietary intake of macronutrients and key micronutrients (including iron) of 31 elite para cyclists was determined using a food frequency questionnaire. Risk of inadequacy was assessed using the estimated average requirement cut-point method and intakes were compared to daily recommended intake values. Lastly, in study four, four individuals with spinal cord injuries that were recreationally active were assessed for bowel function, iron status, body composition, and exercise performance before and after an 8-week intervention in which they supplemented with 40 g of low phytic acid pea concentrate and 125 mg vitamin C twice daily.
Results: In study one a high degree of compliance was observed for all supplements (maltodextrin= 99.2 ±0.9% compliant; regular pea= 96.3 ±2.1% compliant; low phytic acid= 97.8 ±2.3% compliant). No differences in the incidence of adverse effects between the maltodextrin and pea groups were evident (p=0.53,) nor were any symptoms severe enough to cause the individual to withdraw from the study. Study two found a modest, though statistically non-significant, increase in ferritin was observed for the two pea groups (regular pea= 14.4% increase from baseline; low phytic acid= 5.1% increase from baseline), compared to the maltodextrin group who had a decrease in ferritin (2.2%). Protein (p=0.03) and iron (p=0.01) intakes were significantly higher in the regular pea group compared to the maltodextrin group. No other differences in dietary intake were observed (p>0.05). In study three, athletes consumed most nutrients in excess of the daily recommended intakes with the exception of iodine (males=87% recommended dietary allowance; females=62% recommended dietary allowance) and fibre for men (84% adequate intake). The predicted risk of inadequacy was noted for iodine (89% and 83% risk of inadequacy for females and males, respectively) and vitamin D (84% and 83% risk of inadequacy for females and males, respectively). In study four, no differences were apparent in exercise performance or markers of iron (ferritin and hemoglobin); however, iron intakes increased from baseline to week six (p=0.047) and protein intakes trended toward increased from baseline to week eight (p=0.07). Scores of bowel dysfunction were largely unaltered in three participants, but one individual had a marked improvement.
Conclusion: Biofortified peas are well tolerated in both female runners and individuals with spinal cord injuries. Consumption of biofortified peas did not have any negative effects on nutrient intake, iron status, or exercise performance in these populations of active individuals. Thus, they have the potential to improve nutrient quality and health measures in vulnerable athlete populations. Larger doses or longer trials may be required to induce meaningful changes to iron status.
Description
Keywords
Iron, vegetarian, physical activity
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Kinesiology
Program
Kinesiology