Effect of Vitamin D Supplementation on Glucose Tolerance in Subjects at Risk for Diabetes With Low Vitamin D.

NCT ID: NCT01726777

Last Updated: 2015-09-17

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE2
• Total Enrollment: 71 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2012-10-31
• Study Completion Date: 2015-09-30

Brief Summary

Type 2 diabetes (T2D) is an increasingly common and serious condition. Studies show that low vitamin D levels are associated with increased diabetes risk and that vitamin D may protect against diabetes by reducing chronic inflammation and improving insulin sensitivity and insulin secretion. However, no studies have been able to show that vitamin D actually reduces post-prandial blood glucose levels, the most clinically relevant marker of diabetes. Previously the investigators have shown that cheddar cheese and low-fat cheese can be fortified with high levels of vitamin D and that this cheese is at least as a effective as vitamin D supplements in raising blood vitamin D levels.

The main purpose of this study is to see whether vitamin D enriched cheese can improve oral glucose tolerance (reduce blood glucose 2 hours after consuming a drink containing 75g sugar) in people who have low vitamin D levels and are at risk for developing T2D.

Other aims are to determine the effect of vitamin D may on insulin sensitivity, insulin secretion, markers of inflammation, blood cholesterol levels, and safety markers such as urinary calcium excretion.

Detailed Description

Type 2 diabetes (T2D) is an increasingly prevalent and serious condition whose risk appears to be increased by low serum vitamin D concentrations. Epidemiological studies show an association between increased diabetes risk and low serum vitamin D and studies suggest that vitamin D may protect against diabetes by reducing chronic inflammation and improving insulin sensitivity and insulin secretion. Although clinical studies show some of these effects, no studies have been able to show that vitamin D supplementation reduces post-prandial blood glucose, the most clinically relevant marker of diabetes and dysglycemia. Previously, the investigators showed that cheddar cheese and low-fat cheese can be fortified with high levels of vitamin D3 (28,000IU/ 30g portion) and that, in this form, it is at least as a effective as vitamin D3 supplements in raising serum vitamin D concentrations. Since post-prandial glucose is most sensitive to changes in insulin sensitivity the main purpose of this study is to determine the effect of vitamin D supplementation on oral glucose tolerance (ie. serum glucose 2h after 75g oral glucose) in individuals who are at risk for developing T2D. Secondary objective are to determine the effect of vitamin D supplementation on insulin sensitivity, insulin secretion, inflammatory markers, blood lipids and markers of safety including serum parathyroid hormone levels and urinary calcium excretion.

Conditions

Type 2 Diabetes Mellitus; Vitamin D Deficiency

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: QUADRUPLE

Study Groups

Control

30g normal cheddar cheese once per week

Group Type: PLACEBO_COMPARATOR

Control

Intervention Type: DIETARY_SUPPLEMENT

Normal cheddar cheese

Vitamin D

30g cheddar cheese containing 28,000IU vitamin D once per week

Group Type: EXPERIMENTAL

Vitamin D

Intervention Type: DIETARY_SUPPLEMENT

Vitamin D3 supplemented cheddar cheese

Interventions

Control

Normal cheddar cheese

Intervention Type: DIETARY_SUPPLEMENT

Vitamin D

Vitamin D3 supplemented cheddar cheese

Intervention Type: DIETARY_SUPPLEMENT

Other Intervention Names

Vitamin D3

Eligibility Criteria

Inclusion Criteria

• male or non-pregnant, non-lactating females, aged 18-75
• volunteered to participate by signing the consent form
• BMI <40kg/ m2
• vitamin D insufficient, defined as: serum 25(OH) vitamin D3 (25(OH)D) concentration ≤65nmol/ L
• increased risk for diabetes, defined as: FINDRISC score >10 for Caucasians or >6 for non-Caucasians OR presence of metabolic syndrome
• dysglycemia, defined as:fasting serum glucose 5.6 to 6.9 mmol/L, inclusive OR HbA1c 0.054 to 0.064, inclusive
• systolic blood pressure ≤150/95 mmHg if not being treated for hypertension or ≤140/90 mmHg if on treatment for hypertension.
• taking no prescription drugs, or stable (for at least 6 weeks) dose of birth control pill, or drug(s) used to treat hypertension, hyperlipidemia, depression or other mental illness or hypothyroid.
• taking no supplements, or stable (for at least 6 weeks) dose of supplement(s).

• history of renal failure or liver disease
• serum creatinine >1.8 times upper limit of normal (ULN)
• serum aspartate or alanine transaminase (AST,ALT) >3 times ULN
• current use of drug or drugs to treat diabetes or use of steroids or pancreatic enzymes
• within 6 weeks of randomization, change in dose of supplements or drug(s) used to treat hypertension, hyperlipidemia, depression or other mental illness or hypothyroid.
• use of antibiotics within 3 months.
• medical or surgical event requiring hospitalization within 3 months of randomization
• presence of any condition affecting nutrient absorption
• intolerance to cheese
• plan to travel outside Canada for more than 14 consecutive days during the trial

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 75 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Dairy Farmers of Canada

OTHER

Sponsor Role: collaborator

Public Health Agency of Canada (PHAC)

OTHER_GOV

Sponsor Role: collaborator

University of Toronto

OTHER

Sponsor Role: lead

Responsible Party

Thomas Wolever

Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Thomas MS Wolever, DM, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Toronto

Locations

University of Guelph

Guelph, Ontario, Canada

Glycemic Index Laboratories

Toronto, Ontario, Canada

Institut de recherches cliniques de Montréal

Montreal, Quebec, Canada

Countries

Canada

Other Identifiers

UTRS-27546

Identifier Type: -

Identifier Source: org_study_id