Single center, double-blind, randomized controlled cross-over trial with four treatments and four time points.

The study has three primary objectives. The first primary objective is to confirm the reduction of postprandial glycemic and insulinemic response after consumption of 500 ml glucose-free apple juice compared to 500 ml untreated apple juice as could be shown in a previous study

Single center, double-blind, randomized controlled cross-over trial with four treatments and four time points.

The study has three primary objectives. The first primary objective is to confirm the in a previous study shown reduction of postprandial glycemic and insulinemic response after consumption of 500 ml glucose-free apple juice compared to 500 ml untreated apple juice.

The second primary objective is to show the reduction of postprandial glycemic response after consumption of 250 ml glucose-free apple juice compared to 250 ml untreated apple juice.

The third primary objective is to show the reduction of insulinemic response after consumption of 250 ml glucose-free apple juice compared to 250 ml untreated apple juice.

Secondary objectives include safety aspects, specifically the occurrence of diarrhoea in all four treatment groups, differences between treatment groups on the Bristol Stool Forms Scale, gastro-intestinal symptoms and laboratory parameters. In addition, gluconate excretion and excreted portion of ingested gluconate are of interest as well as faecal pH.

Inclusion Criteria:

1. Males aged ≥ 18y
2. Impaired fasting glucose (IFG)
3. Written informed consent
4. Consent to collect stools and urine four times for three days

Exclusion Criteria:

1. Subjects currently enrolled in another clinical study
2. Subjects having finished another clinical study within the last 4 weeks before inclusion.
3. Subjects having participated in the study HB-RCT1-2015
4. Hypersensitivity, allergy or idiosyncratic reaction to apple, apple juice or other apple containing food
5. Acute or chronic infections
6. Renal insufficiency
7. Gastrointestinal illness
8. No stools of type 5-7 of Bristol Stool Form Scale within the last week before inclusion
9. History of gastrointestinal surgery
10. Known fructose intolerance
11. Overt diabetes mellitus
12. Endocrine disorders
13. Any disease or condition which might compromise significantly the hematopoietic, renal, endocrine, pulmonary, hepatic, cardiovascular, immunological, central nervous, dermatological or any other body system with the exception of the conditions defined by the inclusion criteria
14. History of hepatitis B and C
15. History of HIV infection
16. History of coagulation disorders or pharmaceutical anti-coagulation (with the exception of acetylsalicylic acid)
17. Regular medical treatment including OTC, which may have impact on the study aims (e.g. gluconic acid-containing OTCs, antidiabetic drugs, laxatives etc.)
18. Major cognitive or psychiatric disorders
19. Subjects who are scheduled to undergo hospitalization during the study period
20. Eating disorders (e.g. anorexia, bulimia) or special diets (e.g. vegan, vegetarian)
21. Present drug abuse or alcoholism
22. Legal incapacity

The test products (verum and control) are similar in flavour, color, texture, appearance and identical in packaging to ensure the double-blind, controlled design of the study.