Effect of Amount and Type of Dietary Carbohydrates on Risk for Cardiovascular Heart Disease and Diabetes

Conditions

Cardiovascular Diseases, Overweight

Keywords

Blood Pressure, Diabetes, Nutrition, Dietary Carbohydrate, Lipoproteins, Insulin Resistance

Brief summary

Cardiovascular disease (CVD) and diabetes are health conditions that are strongly influenced by a person's diet. Although the best diet to prevent CVD and diabetes is uncertain, reducing intake of saturated and transunsaturated fats is known to help lower cardiovascular risk. However, even diets low in these fats can vary widely in other energy providing nutrients, particularly carbohydrates. This study will determine the effects of a higher versus lower carbohydrate diet, each with a high or low glycemic index (GI) composition, on risk factors for CVD and diabetes.

Detailed description

A healthy diet can have a remarkable effect on a person's overall health. Research has consistently confirmed the association between diet and serious health problems, including heart disease, diabetes, high blood pressure, and gastrointestinal disorders. Most healthy diets aimed at disease prevention promote a low intake of fats, but the optimal diet to prevent CVD and related disorders is uncertain. Recent emphasis has turned to the influence of carbohydrate consumption on risk of CVD and diabetes. Carbohydrates comprise a wide range of foods, which are categorized by their absorption rate, also known as glycemic index (GI). There is much current debate over how the level and type of dietary carbohydrates affect cardiovascular health. This study will determine the effects of a higher versus lower carbohydrate diet, each with a high or low GI composition, on risk factors for CVD and diabetes. Potential participants will attend three screening visits that will include questionnaires, clinical measurements, and blood and urine tests. Participants will then undergo an 8-day run-in phase to become familiar with the feeding patterns of four different diets: high carbohydrate with high GI, high carbohydrate with low GI, low carbohydrate with high GI, or low carbohydrate with low GI. During the run-in, participants will be provided all of their food, snacks, and calorie-containing beverages. Participants will also complete a daily food diary, symptoms questionnaire, medical and social history, and daily weigh-in. After meeting with a dietician to review progress, eligible participants will be randomly assigned to one of eight sequences of the four diet plans. Participants will follow each of the four diet plans for 5 weeks, with a period of at least 2 weeks separating each plan. During each dieting period, participants will be provided all of their food and snacks and most beverages. All participants will be required to eat at least one on-site meal per day, 5 days per week. Participants will keep a daily food diary and will undergo weekly blood pressure measurements for the first 3 weeks of each dieting period. Assessments will occur in the fifth week of each of the four dieting periods and will include symptoms and satiety questionnaires, blood pressure measurements, and a blood draw. One month following the completion of the last dieting period, participants will receive nutritional counseling on the prevention of CVD.

Azuka Amaka Ngige, Hailey Miller, Stephen P. Juraschek, Erin D. Michos, Edgar R. Miller

Circulation2025-11-03

10.1161/circ.152.suppl_3.4363227

Higher Carbohydrate Amount and Lower Glycemic Index Increase Hunger, Diet Satisfaction, and Heartburn in Overweight and Obese Adults in the OmniCarb Randomized Clinical Trial.

Wu Y, Juraschek SP, Hu JR, Mueller NT, Appel LJ, Anderson CAM, Miller ER.

2021-08-014 citations

10.1093/jn/nxab128

Effects of carbohydrate quality and amount on plasma lactate: results from the OmniCarb trial

Jiun‐Ruey Hu, Yingfei Wu, Frank M. Sacks, Lawrence J. Appel, Edgar R. Miller et al. (7 authors)

BMJ Open Diabetes Research & Care2020-08-0112 citations

10.1136/bmjdrc-2020-001457

Effect of type and amount of dietary carbohydrate on biomarkers of glucose homeostasis and C reactive protein in overweight or obese adults: results from the OmniCarb trial

Stephen P. Juraschek, Edgar R. Miller, Elizabeth Selvin, Vincent J. Carey, Lawrence J. Appel et al. (7 authors)

BMJ Open Diabetes Research & Care2016-11-0113 citations

10.1136/bmjdrc-2016-000276

Effect of glycemic index and carbohydrate intake on kidney function in healthy adults

Stephen P. Juraschek, Alex R. Chang, Lawrence J. Appel, Cheryl A.M. Anderson, Deidra C. Crews et al. (8 authors)

BMC Nephrology2016-07-0829 citations

10.1186/s12882-016-0288-5

Effects of High vs Low Glycemic Index of Dietary Carbohydrate on Cardiovascular Disease Risk Factors and Insulin Sensitivity

Frank M. Sacks, Vincent J. Carey, Cheryl A.M. Anderson, Edgar R. Miller, Trisha Copeland et al. (13 authors)

JAMA2014-12-16231 citations

10.1001/jama.2014.16658

Interventions

BEHAVIORALHigh carbohydrate and low glycemic index (GI) diet

The high carbohydrate and low GI diet will require 58% of daily calories to be from carbohydrates and will be composed of meals with a GI of less than 45 on the glucose scale.

BEHAVIORALLow carbohydrate and low GI diet

The low carbohydrate and low GI diet will require 40% of daily calories to be from carbohydrates and will be composed of meals with a GI of less than 45 on the glucose scale.

BEHAVIORALHigh carbohydrate and high GI diet

The high carbohydrate and high GI diet will require 58% of daily calories to be from carbohydrates and will be composed of meals with a GI of greater than 65 on the glucose scale.

BEHAVIORALLow carbohydrate and high GI diet

The low carbohydrate and high GI diet will require 40% of daily calories to be from carbohydrates and will be composed of meals with a GI of greater than 65 on the glucose scale.

Study design

Allocation

RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

PREVENTION

Masking

TRIPLE (Subject, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

30 Years to No maximum

Healthy volunteers

Yes

Inclusion criteria

* SBP of 120 to 159 mmHg and DBP less than 100 mmHg at study entry (mean over three screening visits) (note: participants with stage 2 hypertension \[SBP greater than 160 mmHg or DBP greater than 100 mmHg\] based on the mean over three screening visits will be excluded, as will participants with a mean SBP greater than 170 mmHg or DBP greater than 105 mmHg at any one visit) * Overweight or obese, as defined by a body mass index (BMI) greater than 25 kg/m2 * Willing to eat at least one on-site meal per day, 5 days per week, and willing to eat study diets and nothing else during controlled feeding periods Medication

Exclusion criteria

* Symptomatic ischemic heart disease (e.g., angina pectoris) * Regular use of medications that raise or lower BP during the 2 months prior to study entry * Use of a lipid lowering agent in the 3 weeks prior to study entry * Unstable dose of hormone replacement therapy, thyroid hormone replacement therapy, and psychotropic medications known to cause weight gain or affect the outcome variables (unstable is defined as a change in dose within 2 months of study entry) * Use of insulin, oral hypoglycemic agent, lithium, oral corticosteroid, anti-psychotic drugs, weight loss medications, nitrate, or digitalis Medical History

Design outcomes

Primary

Measure	Time frame
Systolic blood pressure (SBP), Low Density Lipoproteins (LDL) cholesterol, High Density Lipoproteins (HDL) cholesterol, triglycerides, and insulin sensitivity	Measured at Week 5 of each dieting period

Secondary

Measure	Time frame
Diastolic blood pressure (DBP); apolipoproteins B, CIII, A-I, and Very Low Density Lipoproteins (VLDL); and LDL with apolipoprotein CIII	Measured at Week 5 of each dieting period
Beta cell response, glucose effectiveness, and fructosamine; postprandial glucose, insulin, lipids, and hormone levels	Measured at Week 5 of each dieting period
Overall CVD risk using risk equations	Measured at Week 5 of each dieting period

Countries

United States

Outcome results

None listed