Two New Studies Examine the Potential Impact of Almonds in People with Type 2 Diabetes
Researchers from Asia, North America and Europe convened at the Experimental Biology (EB) Annual Meeting in New Orleans to present five new studies demonstrating the impact of one small nut on the body — the almond. Researchers got to the gut and heart of the matter, presenting emerging research that explores gut hormones and the gut’s role in nutrient and phytochemical absorption of almonds to examining the heart health impact of including almonds for individuals with type 2 diabetes. (1)(2)(3)(4)
The two studies examining the effect of almonds in people with type 2 diabetes explored the impact on cardiovascular risk factors. Cardiovascular disease is one of the leading causes of death for both men and women globally, but is of special concern for individuals with diabetes who are two to four times more likely to develop heart disease than their non-diabetic counterparts.(5)(6) Previous research including nine-clinical studies have found that almonds as part of a diet low in saturated fat and cholesterol can help maintain cholesterol levels and a healthy heart. The associated heart health effects of almonds, as well as low carbohydrate content (one-ounce of almonds contains 3g of net carbohydrates) has prompted researchers to further investigate the benefit of adding almonds and other nuts to the diets of individuals with diabetes.
Almonds Help People with Type 2 Diabetes Maintain a Healthy Heart(3)
Researchers from Taipei Medical University and Tufts University collaborated on new research presented at EB that examined the effects of almonds on risk factors for cardiovascular disease among 20 Chinese type 2 diabetic patients with mildly hyperlipidemia and treated with oral hypoglycemics. Researchers measured body fat, total cholesterol, LDL cholesterol, oxidative stress, blood sugar, insulin and inflammatory biomarkers. The 12-week clinical trial had subjects randomly assigned to receive either a NCEP Step II diet or the almond-based diet, which was the NCEP Step II diet that added almonds to replace 20 percent of the total calorie intake. At the end of the study researchers found that the almond diet led to a significant decrease in body fat by 1%, total cholesterol by 8%, and LDL cholesterol by 13%. Most importantly, researchers found that inclusion of almonds decreased blood glucose and insulin and inflammation. Alpha-Tocopherol or vitamin E levels in the blood increased, as well as the resistance of LDL cholesterol against oxidation, when tissues were tested in a laboratory environment. The NCEP Step II diet also improved cardiovascular risk factors. The changes, however, were not as clinically meaningful as those noted with the almond diet.
Dr. Oliver Chen, lead study author from Tufts University said, “The results of this study were very interesting, suggesting that more research needs to be conducted to evaluate the benefit of almonds on cholesterol and insulin resistance among individuals with type 2 diabetes from different populations.” He emphasized that more research will “provide us with a better understanding of how day-to-day diet, genetics and lifestyle factors may influence the overall contribution of almonds to the diet.”
Study at a Glance:
Subjects: Twenty Chinese type 2 diabetic patients with mild hyperlipidemia and treated with oral hypoglycemics.
Methods: A 12-week crossover clinical trial where subjects were randomly assigned to receive either a NCEP Step II diet or an Almond Diet. The Almond Diet was the NCEP Step II diet, except that almonds were added to replace 20 percent of the total caloric intake. Researchers measured body fat, glucose, insulin, total cholesterol, LDL cholesterol, oxidative stress and inflammatory biomarkers.
Results: Researchers found that the almond diet led to a significant decrease in body fat by 1%, total cholesterol by 8%, LDL cholesterol by 13%, blood sugar by 6.7%, and insulin by 7.9%. Changes were also noted among the inflammatory biomarkers measured, as well as the resistance of LDL against oxidation, when tissues were tested in a laboratory environment. Researchers also found an increase in alpha-tocopherol or vitamin E levels in the blood. The NCEP Step II diet also resulted in changes in cardiovascular risk factors. The changes however were not as clinically meaningful as those noted with the almond diet.
Almonds and other Nuts May Impact HbA1c levels and Risk for Cardiovascular Disease(4)
Another new study presented at EB by Dr. Cyril Kendall and funded by the International Tree Nut Council Nutrition and Research and Education Foundation examined the impact of nuts, including almonds, on not only cardiovascular disease risk factors, but also hemoglobin A1c (HbA1c) levels. HbA1c is a test used to estimate the management of blood sugar over the past two to three months. In this three month study, 117 individuals with diabetes treated with oral medication to help manage their blood sugar levels were randomly assigned to receive one of three diets, a full-dose mixed nut diet (75g), half-dose mixed nut diet (38g) and half portion of muffins or muffin diet (control). Researchers measured HbA1c levels, serum lipids, blood pressure, oxidative stress, and inflammatory biomarkers
Researchers found that the full dose mixed nut diet resulted in a significant improvement in glycemic control as indicated by a reduction in HbA1c levels (P<0.01). There was also a significant decrease in cardiovascular risk factors, total cholesterol (P<0.022) and LDL cholesterol (P<0.027), with the full dose mixed nut group compared to the control group.
Lead study author Dr. Kendall from the University of Toronto explained, “These findings build upon previous research which has found that nuts have a beneficial role in impacting serum lipid levels, and interestingly, also suggest that nuts may have value in promoting glycemic control.” While follow-up research is needed to explore the impact of nuts on blood sugar levels, this new study reinforces the many potential contributions nuts, including almonds, may have for our diets and health.
Study at a Glance:
Subjects: 120 Non-insulin dependent subjects with diabetes mellitus treated with oral hypoglycemic agents.
Methods: In the three-month parallel study subjects were randomized to receive one of the three treatment groups: 1) Full Dose Nut Diet-raw nuts, including almonds were added to the subjects usual diet based on energy intake. 2) Half-Dose Nut Diet-half-dose of nuts and half-dose of control muffin were provided according to calorie needs. 3) Control: Whole wheat muffins were matched with energy content of nuts provided.
One week diet histories were obtained and fasting blood samples were collected at baseline weeks 2, 4, 8, 10 and 12 to measure cardiovascular risk factors and glycemic control measures.
Results: There were no significant differences in HbA1c between diets, although after the full-dose nut diet there was a significant reduction from baseline in HbA1c levels (p<0.01) compared to the half-dose nut, and the muffin alone. There were significant differences between the full-dose nut group and the muffin group for total cholesterol (p=0.022) and LDL cholesterol (p=0.027).
For more information on almonds or these studies, please visit www.AlmondsAreIn.com.
The Almond Board of California administers a grower-enacted Federal Marketing Order under the supervision of the United States Department of Agriculture. Established in 1950, the Board’s charge is to promote the best quality almonds, California’s largest tree nut crop. For more information on the Almond Board of California or almonds, visit www.AlmondsAreIn.com.
(1) Berry, S., Lapsley, K., Tydeman, E., Lewis, H., Phalora, R., Rosborough, J., Picout, D., Ellis, P. Manipulation of lipid bioaccessibility influences postprandial vitamin E concentrations in healthy human subjects: implications for implications for inflammation, oxidative stress and vascular responses.
(2) Mandalari, G., Rich, G., Bisignano, G., Parker, M., Waldron, K., Wickham, M. Almond skins digestion using an in vitro dynamic gastric model: phytochemicals release and gut health.
(3) C-Y.O., Chen, J.-F., Liu, C.-M., Chen. Almonds ameliorate risk factors of cardiovascular disease in type 2 diabetes.
(4) Kendall, C., Esfahani, A.,Parker, T., Banach, M., Mitchell, S., Jenkins, D. Longer-term effects nuts on glycemic control in type 2 diabetes.
(5) World Health Organization. www.who.org
(6) American Heart Association www.aha.org
Source: Almond Board of California