Micronutrient Testing, Supplement Use, and Knowledge Gaps in a National Adult Population: Evidence from Saudi Arabia

<b>Background:</b> Micronutrient deficiencies, particularly of vitamin D, vitamin B12, and iron, are prevalent worldwide and contribute significantly to morbidity. In Saudi Arabia, these deficiencies are increasingly recognised as public health challenges, yet comprehensive data on prevalence, risk factors, and public awareness remain limited. <b>Objectives:</b> This study aimed to determine the prevalence of laboratory-confirmed deficiency and testing for vitamin D, vitamin B12, and iron among adults in Saudi Arabia; to identify associated sociodemographic, lifestyle, and clinical factors; and to assess public knowledge and attitudes regarding micronutrient status. <b>Methods:</b> A cross-sectional survey was conducted in 2025 among adults residing in Saudi Arabia. Data were collected using a structured, self-administered questionnaire covering demographics, lifestyle, chronic disease history, laboratory testing and supplementation, and knowledge and perceptions regarding micronutrient deficiency. Descriptive statistics, chi-squared tests, and network analysis were used to identify associations and patterns. <b>Results:</b> A total of 1652 participants were included (52.6% female; mean age 41.3 ± 10.2 years). The prevalence of laboratory-confirmed deficiency was 7.6% for vitamin D, 5.5% for vitamin B12, and 7.0% for iron. Most participants had never been tested for these micronutrients. Vitamin D deficiency was significantly associated with gender, age, education, marital status, physical inactivity, and the presence of chronic conditions. Similar patterns were observed for vitamin B12 and iron. Public knowledge was primarily sourced from social media and internet sites; 38.1% of participants considered vitamin deficiency a public health concern, and 96.4% supported awareness campaigns. <b>Conclusions:</b> Micronutrient deficiencies remain common and under-recognised among adults in Saudi Arabia. There is a critical need to improve public awareness, expand routine laboratory testing, and develop targeted interventions to address identified risk groups and knowledge gaps. Our study is the first study to investigate the status of three key micronutrients (vitamin D, vitamin B12, and iron) in a single large sample. We also employed network to explore the complex factors associated with micronutrient deficiencies.