The research area that focuses on the links between nutrition and health, nutrition and the immune system as well as nutrition-related public health interventions, which often falls into the gap between the agricultural and health domains. The rationale of this project is to study the influence of beneficial diets on the immune system of pre-diabetic patients and its potential to counteract infections. A clinical, an in vitro (cell systems) and an in vivo (animal model) approach will be used to study the influence of a seaweed bioactive supplement and a diet rich in components from a Mediterranean diet on a Salmonella typhimurium infection in prediabetic subjects. At the end of this project, we will provide evidence on the potential of these nutritional interventions to counteract infection, which are of high relevance to the society to reduce the burden of type 2 diabetes (T2DM) and obesity. This research is part of an ongoing research project funded by the Research State Agency (Spain), Health Research Board (HRB, Ireland) and the Medical Research Council (MRC-UKRI, UK) via the NUTRIMMUNE' Grant of the Joint Programming Initiative a Healthy Diet for a Healthy Life (JPI-HDHL).

The aim of this study is to evaluate the effects of different diets on gut health, immune and metabolic markers, in individuals aged between 18-65 years who are defined as pre-diabetics and adults in general good health.

About 45 volunteers will take part in this study and they will then be randomly assigned a volunteer number and placed in one of three study group for a total of 12 weeks:

1. Normal Healthy Diet group (N=15): Participants aged 18-65 years in general good health will be following the Eatwell booklet advice*and NICE/NHS guidelines (https://www.nice.org.uk/).
2. Placebo group (N=15): Participants aged 18-65 prediabetics will take 2 capsules/day (750mg Maltodextrin placebo comparator) before each of the two main meals without any advice on the diet to follow.
3. Seaweed Group.: Participants aged 18-65 prediabetics will take 2 seaweeds brown extract capsules/day (information detailed in the safety product sheet, total dose of 700 mg before each of the two main meals. All participants will be advised on product storage and use conditions prior to use to ensure product consistency throughout the period of the study.

At baseline (week 0), week 6, week 12 and week 16, volunteers will be required to visit the University of Roehampton to provide fasted blood, saliva, stool and first pass urine samples and have blood pressure, body fat and weight measured.

During the study period, they will be asked to complete some questionnaire to assess your gastrointestinal symptoms along with daily stool habits and diet habits.

Inclusion criteria

• Adults aged between 18 and 60 years, with
• Fasting blood glucose level of 5.6-6.9mmol/L or impaired HbA1c (HbA1c level of 5.7%-6.4%)
• Fasting blood glucose level below 5.6mmol/L or HbA1c level below 5.7%.
• For intervention purposes, eligible participants are also required to have a mobile phone and be able to read and speak English.

Exclusion criteria

• People with a current diagnosis or clinical history of T2DM
• People with comorbid conditions that may limit participation in the study, such as a history of an acute cardiovascular event, uncontrolled hypertension, cancer or major psychiatric or cognitive problems.
• People who are already participating in a weight loss programme
• People receiving drug treatment for pre-diabetes (eg, metformin)
• People with a history of long-term use of medicines known to influence glucose metabolism (eg, corticosteroids)
• People with elevated liver enzymes (alanine aminotransferase ≥300 IU/L, aspartate aminotransferase ≥300 IU/L)
• People who take antibiotics or bacterial agents (Probiotics) within 1 month
• Pregnant women, women ready for pregnancy, and nursing mothers