Effect of almonds on insulin secretion and insulin resistance in nondiabetic hyperlipidemic subjects: a randomized controlled crossover trial.
Nuts appear to have a marked effect in cohort studies in reducing the risk of coronary heart disease (CHD), but their demonstrated ability to lower cholesterol can only explain a proportion of the reduction in risk. Our aim was to assess whether improvement in carbohydrate metabolism provides a further explanation for the effect of nuts in reducing CHD. The effects of whole almonds, taken as snacks, were compared with the effects of low saturated fat (<5% energy) whole-wheat muffins (control) in the therapeutic diets of hyperlipidemic subjects. In a randomized crossover study, 27 hyperlipidemic men and women consumed 3 isoenergetic (mean, 423 kcal/d) supplements each for 1 month. Supplements provided 22.2% of energy and consisted of full-dose almonds (73 +/- 3 g/d), half-dose almonds plus half-dose muffins, and full-dose muffins. Subjects were assessed at weeks 0, 2, and 4 and fasting blood samples were obtained. Twenty-four-hour urinary output was collected at the end of week 4 on each treatment. Mean body weights differed by less than 300 g between treatments. No differences were seen in baseline or treatment values for fasting glucose, insulin, C-peptide, or insulin resistance as measured by homeostasis model assessment of insulin resistance. However, 24-hour urinary C-peptide output as a marker of 24-hour insulin secretion was significantly reduced on the half-and full-dose almonds by comparison to the control after adjustment for urinary creatinine output (P = .002 and P = .004, respectively). We conclude that reductions in 24-hour insulin secretion appear to be a further metabolic advantage of nuts that in the longer term may help to explain the association of nut consumption with reduced CHD risk.
Clinical Nutrition and Risk Factor Modification Center, St Michael's Hospital, Toronto, Ontario, Canada M5C 2T2. cyril.kendall@utoronto.ca
David J A
DJ
Jenkins
Cyril W C
CW
Kendall
Augustine
A
Marchie
Andrea R
AR
Josse
Tri H
TH
Nguyen
Dorothea A
DA
Faulkner
Karen G
KG
Lapsley
William
W
Singer
D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D050260:Carbohydrate Metabolism / Q000187:drug effects; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000178:diet therapy* / Q000378:metabolism*; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D027861:Prunus / Q000737:chemistry*
D001786:Blood Glucose; D002096:C-Peptide; D008078:Cholesterol, LDL; D007328:Insulin