effects of potato resistant starch intake on insulin sensitivity, related metabolic markers and satiety

Conditions: Insulin Sensitivity; Lipid Metabolism; Resistant Starch; Potato

Summary: the objective of this study is to assess whether intake of baked and then chilled potatoes over a 24-h period, compared to intake of isocaloric, carbohydrate (cho)-matched foods low in fiber and resistant starch (rs), will increase insulin sensitivity, breath hydrogen and satiety, and decrease hunger and free fatty acid (ffa) levels in overweight or obese men and women at risk for metabolic syndrome and diabetes mellitus.

this randomized, two-period crossover study will include one screening/baseline visit (visit 1) and two 24-h treatment periods (treatment period 1: visits 2 and 3 and treatment period 2: visits 4 and 5). a minimum 7-d washout will occur between the treatment periods.

Eligibility criteria:
inclusion criteria: 1. subject is a male or female, 18-74 years of age, inclusive. 2. subject has a bmi of ≥27.0-39.99 kg/m2 at visit 1. 3. subject has a waist circumference ≥40 in for men and ≥35 in for women at visit 1. 4. subject has a rating of 7 to 10 on the vein access scale at visit 1 (appendix 2). 5. subject is willing to maintain a stable body weight and follow his/her habitual diet and physical activity patterns throughout the trial, except for the substitution of the study foods. 6. subject is willing to consume the study foods provided throughout the duration of the study. 7. subject has no plans to change smoking habits or other nicotine use during the study period and is willing to refrain from nicotine use for 1 h prior to and during all test visits. 8. subject is willing to refrain from alcohol and vigorous physical activity 24 hours prior to test days (visits 2, 3, 4 and 5). 9. subject is judged by the investigator to be in general good health on the basis of medical history. 10. subject understands the study procedures and signs forms documenting informed consent to participate in the study and authorization for release of relevant protected health information to the study investigator and is willing to complete study procedures. exclusion criteria: 1. subject has a fasting capillary glucose of ≥126 mg/dl and/or a hba1c ≥6.5 % based on the capillary blood draw at visit 1. 2. subject has a history or presence of atherosclerotic cardiovascular disease, chronic inflammatory disease (including irritable bowel disease, lupus, rheumatoid arthritis), or clinically important endocrine (including type 1 or type 2 diabetes mellitus), pulmonary (including uncontrolled asthma), hepatic, renal, hematologic, immunologic, dermatologic, neurologic, psychiatric, or biliary disorders. 3. subject has a history of cancer in the prior 5 years, except for non-melanoma skin cancer. 4. subject has experienced a change in body weight of ±4.5 kg (10 lbs) over the 3 months prior to visit 1. 5. subject has a known allergy, sensitivity, or intolerance to any ingredients in the study foods. 6. subject has uncontrolled hypertension (systolic bp ≥160 mm hg or diastolic bp * 100 mm hg) at visit 1. 7. subject has unstable use of any antihypertensive medication within 4 weeks prior to visit 1. unstable use is defined as initiation or dose alteration. 8. subject has used any of the following medications within 4 weeks of visit 1: 1. with the exception of the stable use of statins (defined as no initiation or dose alteration within 4 weeks of visit 1) any medications intended to alter the lipid profile, including but not limited to: bile acid sequestrants, cholesterol absorption inhibitor, fibrates, niacin (drug form), omega-3-ethyl ester drugs, and/or proprotein convertase subtilisin/kexin type 9 (pcsk9) inhibitors. 2. medications known to significantly influence carbohydrate metabolism, including, but not limited to, adrenergic receptor blockers, diuretics, and/or hypoglycemic medications. 3. weight-loss drugs (including over-the-counter medications) or weight loss programs. 4. systemic corticosteroid drugs. 9. subject has used any of the following foods or dietary supplements within 2 weeks of visit 1: 1. food/supplements known to influence lipid metabolism, including, but not limited to, omega-3 fatty acid supplements (e.g., flaxseed, fish or algal oils) or fortified foods, sterol/stanol products; dietary supplements (red rice yeast supplements; garlic supplements; soy isoflavone supplements; niacin or its analogues at doses \>400 mg/d (or others at the discretion of the investigator). 2. irregular or inconsistent use of metamucil® or other viscous fiber-containing supplements (consistent, daily use up to 1 tsp of a viscous-fiber supplement is acceptable). 10. subject has used antibiotics within 5 days of any clinic visit: for those with an active infection and/or using antibiotics, subjects must wait at least 5 d after the infection resolves or antibiotic use is complete. the test period will be extended for study completion in these cases. 11. subject is a female who is pregnant, planning to be pregnant during the study period, lactating, or is of childbearing potential and is unwilling to commit to the use of a medically approved form of contraception throughout the study period. 12. subject has extreme dietary habits (e.g. very low cho diet, vegan, etc.). 13. subject has a history of an eating disorder (e.g., anorexia nervosa, bulimia nervosa, or binge eating) diagnosed by a health professional. 14. subject is a habitual breakfast skipper (defined as skipping breakfast ≥4 times per week). 15. subject has a current or recent history (past 12 months), or strong potential, for drug or alcohol abuse. alcohol abuse is defined as \>14 drinks per week (1 drink = 12 oz beer, 5 oz wine, or 1 ½ oz distilled spirits). 16. subject has been exposed to any non-registered drug product within 30 days of visit 1. 17. individual has a condition the investigator believes would interfere with his or her ability to provide informed consent or comply with the study protocol, or which might confound the interpretation of the study results or put the person at undue risk.

Keywords: resistant starch free fatty acids potato insulin sensitivity lipid metabolism