The vegetarian lifestyle in the United States has increased significantly over recent decades. With this growth trend, it has become necessary to assess the pros and cons of vegetarian diet patterns, particularly with respect to nutrition adequacy and chronic disease concerns.

The vegan diet engenders more concern than other common vegetarian lifestyles because it seeks to replace all nutrient-rich animal food products with only plant foods. Consequently, there are concerns of compromised protein, calcium. vitamin D, vitamin B12, n-3 fatty acid, zinc, and iron status. Moreover, because of typical vegan diet phenomena such as low BMI, low protein intake, low circulating estrogen, alongside potentially compromised calcium and vitamin D status, osteoporosis is the major chronic disease concern in vegan lifestyle practice. This study therefore proposed that a well-developed and validated food frequency questionnaire (FFQ), can be effectively used as an assessment tool to address the nutrition-related concerns pertaining to vegans.

The study was an observational study, with a four-phase purpose: (a) Developing a quantitative vegan FFQ de novo, (b) Validating the FFQ against three 24- hr diet recalls, (c) Evaluating specific nutrient intake adequacy among vegans, according to standards of the US Dietary Reference Intakes (DRIs), (d) Determining possible diet-disease association by comparing the FFQ assessment with bone test values.

Samples of 50, 100, and 30 vegans were used for the FFQ-development phase, the validation and nutrition assessment phases, and the the osteoporosis-risk phase, respectively.

Based on Pearson’s correlation coefficients (r=0.38-0.61), the vegan FFQ was valid for 6 nutrients. Comparison of mean observed intakes with the US DRIs demonstrated intakes above the recommended for protein, iron, and n-3 fatty acid; but below the recommended for vitamin D. The EAR cut-point probability approach demonstrated higher than 80% adequacy for intakes of protein, n-3 fatty acids, and iron; and lower than 5% adequacy for intakes of vitamin D.

Regression models showed no association between bone test values and the nutrients of interest. However, significant association was observed between bone test values and specific FFQ support questions; and descriptive data observations suggest that this sample of vegans may not be at high risk for osteoporosis.




School of Public Health

First Advisor

Sujatha Rajaram

Second Advisor

Ella Haddad

Third Advisor

John Kelly

Fourth Advisor

Synnove Knutsen

Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Vegetarians -- United States; Diet, Vegetarian; Osteoporosis; Bone Density; Nutrition Assessment; Nutritional Requirements.



Page Count

xxi; 209

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


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