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.

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.

Inclusion Criteria:

1. Women over 18 years with a regular menstruation cycle (>21 and <40 days).
2. Has followed a vegan or vegetarian diet that does not include the consumption of meat or fish for at least 1 year.
3. Willing to remain on their background diet for the duration of the study.
4. Those who are on a routine regimen of iron and/or vitamin B12 supplements must maintain the same doses 3 month prior to the study and during the duration of the study.
5. Non-anaemic, haemoglobin (Hb) concentration ≥120 g/L.
6. SF >15 µg/L and <60 µg/L [WHO uses the following cut-offs for context: below 15 µg/L indicates iron deficiency, 16-40 µg/L indicates borderline deficiency, and 41 - 150 µg/L is normal].
7. Body Mass Index (BMI) between 18.5 - 40 kg/m2.
8. Live within 40 miles of the Norwich Research Park.
9. Willing to consume plants grown in the hydroponic unit (e.g., spinach, rocket, mizuna) if they agreed to have a unit.
10. Access to a smartphone or online platform a well as access to the internet.

Exclusion Criteria:

1. Those who have known allergies to the hydroponically grown salad greens (spinach, rocket, mizuna).
2. Flexitarian (consumes meat intermittently) vegetarian.
3. Those with menstruation cycle time periods of <21 or >40-days
4. BMI at screening visit < 18.5 kg/m2 (underweight) and > 40 kg/m2 (severely obese).
5. Those diagnosed with or undergoing treatment for anaemia.
6. Currently pregnant, lactating or trying to conceive.
7. High alcohol consumption, consuming more than 2 drinks per day, can elevate the risk for iron overload.
8. Current smoker or has only ceased in the last 6 months.
9. Diagnosed medical conditions that may impact the study outcomes will be considered on an individual basis.
10. Those with an eating disorders, which may impact the study outcome.
11. On, or about to start, a diet programme such as the 5:2 programme (5:2 programme is where an individual would eat normally for five days a week, and fast for two days a week by reducing calorie consumption).
12. Unable to give written or verbal informed consent.
13. Individuals who cannot understand the written instructions/questionnaires.
14. Unwilling to give GP contact details.
15. Participating in another dietary intervention study or has given blood in another research study during the last 3 months.
16. Any person related to or living with any member of the study team.
17. Those who are part of the Line Manager/supervisory structure of the Chief Investigator.
18. Those who have been asked to self-isolate or have been diagnosed with COVID-19 in the last 14 days. However, participants can be rescreened 7 days after the isolation period.