Iron is present in plant and animal-derived foods but the fractional absorption of iron from plant foods (that is the percent of iron absorbed from a consumed quantity) is often low (approx 10%) compared to iron from animal sources 25%-30%. It is therefore more challenging for vegans and vegetarians to achieve the Reference Nutrient Intake (RNI) for iron (8.7 mg/day for men over 18 and women over 50, 14.8 mg/day for women aged 18-50), and they are likely to absorb less of that iron and therefore are more likely to become iron depleted.~Plants do not synthesise vitamin B12 and unless fortified, plant-derived foods and beverages do not contain any vitamin B12. the RNI for vitamin B12 in the UK is 1.5 µg/day, therefore it is crucial that vegans and vegetarians take B12 supplements if they don't consume B12-fortified foods or find other ways of incorporating this vitamin into their diets.~The HARVEST study is a 17-week randomised, controlled, double-blinded, parallel dietary intervention study conducted at the Quadram Institute Clinical Research Facility (QI CRF), Norwich, UK. Investigators are seeking vegan or vegetarian women (18 to 50 years old) to test two interventions, iron-specific recipes and B12 biofortified plants grown in a kitchen garden. There are a total of 4 visits (1 screening visit, 2 2-hours visits and 1 short visit). Investigators will assess blood samples for serum ferritin, serum B12 and other iron and B12 biomarkers. Investigators will ask the participant to complete lifestyle questionnaires regarding their dietary pattern, fatigue level and satisfaction and impression of the study tools.
Veganism and vegetarianism have clear benefits where they have a lower risk of many health issues. However, they also have a higher risk of nutrients and vitamin deficiency such as iron and vitamin B12. Iron can be found in plant-based food but in varying quantities, whereas vitamin B12 is mainly found in red meat, thus vegans and vegetarians can only take this vitamin in supplements such as tablets. In this study, the investigators are testing two interventions, the consumption of recipes with a certain iron amount to increase iron levels, and the consumption of vitamin B12 biofortified plants to increase serum B12 levels in vegan and vegetarian participants.