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2 Clinical Nutrition and Risk Factor Modification Center and 3 Department of Medicine, Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, Ontario M5C 2T2, Canada; Departments of 4 Nutritional Sciences and 5 Medicine, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 3E2, Canada; 6 Department of Public Health, University of Parma, Parma 43100, Italy; and 7 Biopolymers Group, School of Biomedical and Health Sciences, King's College London, University of London, London SE1 9NN, United Kingdom
* To whom correspondence should be addressed. E-mail: cyril.kendall{at}utoronto.ca.
| ABSTRACT |
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| Introduction |
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-glucosidase inhibitor, acarbose, may lower the risk of coronary heart disease (CHD)8, hypertension, and the development of diabetes in high risk individuals (6,7). Operating through similar mechanisms of slowing carbohydrate absorption, low glycemic index diets are also recommended for the treatment of diabetes and CHD (2,8–10). The mechanism by which lower postprandial glycemia is hypothesized to operate is by decreasing the generation of damaging reactive oxygen species (ROS) (11) produced in the mitochondria in response to glucose surges (12,13). In the absence of adequate antioxidant activity, ROS may damage lipids (14), proteins (15), and DNA and increase resistance in insulin sensitive tissues (16). Recently, studies have demonstrated that it is the magnitude of the glycemic excursion in diabetes, not the ambient glucose level as reflected in the hemoglobin A1c, which determines the degree of oxidative damage as indicated by isoprostane production (17). A number of cohort studies have shown a negative association between nut consumption and risk of heart disease (18–25), and analysis of almonds and their seed coats demonstrated high levels of antioxidants (26–28). Nuts, by virtue of their fat and protein content, may also depress postprandial glycemia and hence ROS production. We have therefore examined the effect on postprandial oxidative damage to serum proteins of adding almonds to a carbohydrate-rich meal.
| Methods |
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Study protocol. All subjects completed 5 study sessions, each lasting 4 h, with a minimum 1 wk washout between tests. Subjects consumed the control meal on 2 occasions, and the almond, parboiled rice, and mashed potato meals only once. On the test days, subjects were asked to attend the clinic between 0800 and 0900 after a 12-h overnight fast. They were also asked to eat the same meal the evening prior to each study day and to maintain the same level of physical activity the day prior to and the morning of the study. Body wt was taken and height was measured. Venous blood was drawn from a forearm catheter kept patent with saline and capillary blood samples for glucose analysis were obtained at the same time points with an extra capillary sample at 15 min. Following the baseline sample, a test meal was provided, which subjects were asked to consume within 10 min. Subjects assessed their satiety following each blood-draw by use of a bipolar semantic 7-point visual analogue scale (with –3 representing extremely hungry, 0 neutral, and +3 extremely satiated).
Meals. There were 4 different test meals consumed in random order, each containing 50 g of available carbohydrate (Table 1). The control meal was white bread (Wonder Bread, Interstate Bakeries), which was consumed on 2 occasions. Test meals consisted of 60 g raw, unblanched almonds (California Almonds) with white bread; parboiled rice (Uncle Bens Converted, Mars); and instant mashed potatoes (McCain, McCain Foods). The last 2 meals were balanced for fat, protein, and total energy with the almond meal by the addition of fat (unsalted butter; Gay Lea, Gay Lea Foods) and protein (medium cheddar cheese; Black Diamond, Parmalat).
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All venous blood samples were collected in serum red-top BD Vacutainer blood tubes with no additives (Oakville). Upon collection, blood tubes were wrapped in tin foil to minimize light penetration and remained at room temperature for 1 h to clot before being spun in a Beckman GPR centrifuge at 1008 x g; 15 min. After centrifugation, serum was aliquoted into light-sensitive amber Eppendorf tubes and stored at –70°C.
Venous blood was collected at 0, 30, 45, 60, 90, 120, and 240 min for insulin measurements. Serum insulin was analyzed in the St. Michael's Hospital Core Laboratory using a chemiluminescent ultrasensitive insulin immunoassay (CV 3.1–5.6%) (Access Immunoassay System; Beckman Coulter).
Venous blood was collected at 0, 90, 120, and 240 min for measuring total antioxidant capacity (TAC) and protein thiols. TAC was determined by the ferric reducing-antioxidant power assay (29,30). The CV of samples analyzed in triplicate was 3.8%. Protein oxidation was measured using the 5,5'-dithio-bis(2-nitrobenzoic acid) assay (31) to assess the loss of reduced thiol (–SH) groups as a measure of protein oxidation. Reduced glutathione standards from 100 to 1000 µmol/L were used. The CV of serum samples analyzed in triplicate was 2.2%.
Statistical analyses. Values in the text are expressed as mean ± SEM and differences were considered significant at P < 0.05. Blood glucose and insulin areas were calculated as the incremental area under the curve (IAUC) using the trapezoidal rule. Peak heights were maximal incremental rises in glucose and insulin. The glycemic indices of the 4 test meals were calculated using the bread meal as the reference food (32). The mean of the 90-, 120-, and 240-min protein thiol and TAC values expressed as postprandial change from baseline was used to assess the difference between treatments. The differences between treatments were assessed by least-squares means with a Tukey adjustment for multiple comparisons in SAS (SAS version 8.2) with treatment, treatment by sex interaction, sex and a random term representing the subject identity nested within sex as main effects, and baseline as covariate. The difference in protein thiol concentrations between almonds and the other test meals combined was assessed using the CONTRAST statement in SAS (version 8.2). The values of each individual for mean glucose and insulin IAUC and glucose and insulin peak heights were related to the mean postprandial change in protein thiols, providing in each instance 15 separate Pearson correlation coefficients. The Wilcoxon's Signed Rank test was used to test the prevalence and rank of positive or negative correlation coefficients among the 15 subjects using Pearson's product-moment correlations (SAS version 8.2). Slopes and intercepts were derived by simple linear regression of percent change in protein thiol concentration on incremental peak height to plot each subject's linear response. Student's t test was used to test the strength of slopes in the linear regressions.
| Results |
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0.003). The almond and rice meal glycemic index values did not differ (P = 0.25). Similarly, the postprandial glucose peak heights for the almond (5.9 ± 0.2 mmol/L) and rice (5.8 ± 0.1 mmol/L) meals were less than the peak height for the potato meal (6.6 ± 0.2 mmol/L) and the control white bread (6.9 ± 0.2 mmol/L) (P < 0.001).
Insulin.
Serum insulin concentrations over the 4-h testing period for each meal are shown in Figure 1B. The insulin responses for the mixed meals generally reflected the glucose responses (Fig. 1A). The insulin indices of the almond (91 ± 19) and rice meals (73 ± 9) were lower than the potato meal (171 ± 19) (P < 0.001). The insulin peak height for the almond (224 ± 24 pmol/L) and rice (239 ± 28 pmol/L) meals were both lower than for the potato meal (388 ± 30 pmol/L) (P < 0.001) and the control white bread (321 ± 36 pmol/L) (P
0.042).
Oxidative damage. Protein thiol concentration, as a marker of protein oxidative damage and serum postprandial TAC, did not differ during or among the individual treatments as assessed by the response curves over the 4 h (data not shown).
The change in the serum protein thiol concentration in response to the almond meal (15 ± 14 mmol/L) was greater (P = 0.021) than that following the control bread, potato, and rice meals when the data from these 3 treatments were combined (–10 ± 8 mmol/L). This suggests less postprandial protein damage after consuming almonds. The almond meal did not differ from the combined meals for TAC (data not shown).
Relation to glucose and insulin responses. Using the postprandial data from all 4 treatments (control white bread, almonds and bread, rice, and potatoes) resulting in 60 observations (15 subjects x 4 treatments), the 2-h postprandial incremental glucose and insulin areas were negatively related by Pearson correlation to the change in protein thiols (r = –0.26, P = 0.048 and r = –0.25, P = 0.053, respectively). Similar associations were found for the incremental peak glucose and peak insulin values with change in protein thiols (r = –0.29, P = 0.026 and r = –0.26, P = 0.046, respectively). The correlation coefficients were also assessed for each subject individually (n = 15) using the data from their 4 treatments. The majority of correlation coefficients were negative, indicating the greater the glucose and insulin responses, the greater the postprandial protein oxidative damage. The 2-h postprandial incremental glucose and insulin areas related negatively to the change in protein thiols for 13/15 subjects (for all subjects, n = 15; P = 0.001) and 12/15 subjects (for all subjects, n = 15; P = 0.008), respectively (Table 2). The peak glucose and insulin concentrations also related negatively to the change in protein thiols for 12/15 subjects (for all subjects, n = 15; P = 0.007) and 11/15 subjects (for all subjects, n = 15; P = 0.03), respectively (Table 2). Figure 2 shows the percent change from baseline in mean postprandial protein thiol concentration vs. incremental peak blood glucose concentration for the 15 subjects after the 4 meals. The lines were derived from linear regression. A negative mean gradient was observed (slope = –4.8; n = 15; P = 0.014), indicating that the higher the postprandial incremental peak blood glucose concentration, the greater the damage to protein thiols (Fig. 2). Peak insulin concentrations tended to be negatively related to the mean postprandial protein thiol concentrations (slope = –0.03; n = 15; P = 0.057) (curves not shown). TAC was not related significantly to the glucose or insulin responses.
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| Discussion |
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One way in which ROS damage proteins is by oxidizing sulfhydryl groups. Disulfide bonds are created in thiol containing molecules: cysteine, methionine and glutathione, both in intracellular and plasma proteins. Therefore, a reduction in protein thiol concentrations can be used as a marker of oxidative stress (33). Protein thiols were proposed as the most expendable source of plasma antioxidants and are preferentially consumed in the presence of free radicals (34). Studies have shown that thiols are decreased in clinical states associated with increased oxidative stress, including autoimmune diseases (35), diabetes (36), and uremia (37). Their levels were inversely correlated with disease activity in systemic lupus erythematosus (35) and were improved in diabetes after administration of an antioxidant supplement (36). Autoimmune diseases (38) and diabetes (5) are both associated with an increased risk of CHD.
Postprandial glycemia did not relate to TAC. This lack of effect on TAC has been reported in other studies where eicosapentanoic acid and docosahexanoic acid were fed to healthy subjects, despite evidence of oxidative damage ex vivo to LDL cholesterol (39). The protein thiol test may be more useful in the present situation, because the results reflect protein damage rather than antioxidant potential. This difference may be particularly relevant in view of the fact that protein thiols are preferentially consumed in situations of increased oxidative stress (34). Protein thiols are not captured by the TAC test used (40).
For over a quarter of a century, there has been an interest in postprandial lipid metabolism and the risk for cardiovascular disease (1,41). More recently, studies indicate that 2-h postprandial glycemia is a risk factor for CHD (5), a concept supported by many large cohort studies, including the Hoorn Study (42), the Honolulu Heart Study (1-h postchallenge) (43), the Diabetes Epidemiology Collaborative Analysis of Diagnostic Criteria in Europe Study (44), and the 20-y follow up of 3 European cohorts: the Whitehall Study, the Paris Protective Study, and the Helsinki Policemen Study (45). Furthermore, reports show that acarbose, the
-glucosidase inhibitor that specifically lowers postprandial hyperglycemia, also lowers the risk of CHD in individuals at high risk for type 2 diabetes (7).
In normal and diabetic subjects, postprandial hyperglycemia was associated with increased production of nitrotyrosine, as another indicator of oxidative stress (46). The importance of postprandial glycemia in generating ROS in diabetes was demonstrated by the association of the urinary marker of oxidative stress, 8-isoprostaglandin F2
, with the mean amplitude of glycemic excursions rather than with the mean 24-h glucose concentration or even hemoglobin A1c (17). As a determinant of postprandial glycemia, the association of meal glycemic index with the level of oxidative damage may therefore have important implications.
Nut consumption in the Seventh Day Adventist Study, the Nurses' Health Study, the Physicians Health Study, the Health Professionals Study, and the Iowa Women's Health Study were all associated with a protective effect of nuts on CHD (24). This study opens the possibility that, in addition to cholesterol lowering (47–52), lower postprandial glycemia, insulinemia, and oxidative stress following nut consumption may also contribute to the decreased risk of CHD.
Recent reports suggest that the effect of antioxidants given as supplements in decreasing CHD risk is largely negative (53–56), despite acute effects in improving postprandial brachial artery vasodilatation (57–60). However, it is possible that the antioxidant supplementation in these studies did not achieve the intended protection from oxidative damage. There are no intervention studies where lipid and protein markers of oxidative damage were measured in addition to the primary cardiovascular endpoint. Where long-term studies of antioxidant supplementation were undertaken and markers of oxidative damage measured, the results have been inconsistent (61,62).
Little is known of the antioxidant activity of nuts apart from their content of monounsaturated fatty acids and phenolics. But even so, data on the phenolic content of different nuts are limited. However, detailed studies on almonds have shown that almond skins contain
30 different antioxidant compounds, including catechin, epicatechin, isorhamnetin, quercetin, and kampferol (28), all of which may contribute to their antioxidant activity. Also, the type of sweet almond seed used in this study contains only trace amounts of cyanogenic compounds that may influence antioxidant enzyme expression. In contrast, the mean cyanide content of bitter almonds is
250 mg/100 g (63). The TAC of almonds, assessed by Oxygen Radical Absorbance Capacity, places almonds 5th out of 10 different types of nuts (44.5 µmol trolox equivalents [TE]/g) (64), and this may well have provided sufficient endogenous antioxidant activity to be responsible for much of the effect in preserving protein thiols. Lack of antioxidant data on the meal components of the other meals precludes a direct comparison.
The composition of the meals may also have influenced the glycemic and insulinemic responses. The higher protein content of the mashed potato and cheese meal may be responsible for the high postprandial insulin and lower blood glucose compared with the control white bread. The saturated fat from the cheese and butter in both the mashed potato and parboiled rice meals might also account for the differences in glycemia by comparison with meals containing polyunsaturated fatty acids (65). However, the major fatty acid in almonds is monounsaturated fatty acid, and that fat appears to be more similar to saturated fat (65,66) and therefore does not explain the lower insulin and glucose concentrations seen after ingesting almonds with bread compared with the other meals.
We conclude that the combination of lower glucose, insulin, and less postprandial protein oxidative damage suggests that there may be additional mechanisms, besides cholesterol lowering (47–52), by which nuts may be associated with a decreased risk of CHD (24). In the case of almonds, it may be that both the attenuated glycemic response together with their known antioxidant content (26–28) may have resulted in the antioxidant advantage of the almond meal. This finding is consistent with the decrease in oxidized LDL reported after addition of almonds to the diet (50).
| FOOTNOTES |
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8 Abbreviations used: CHD, coronary heart disease; IAUC, incremental area under the curve; ROS, reactive oxygen species; TAC, total antioxidant capacity. ![]()
Manuscript received 6 August 2006. Initial review completed 25 August 2006. Revision accepted 22 September 2006.
| LITERATURE CITED |
|---|
|
|
|---|
1. Zilversmit DB. Atherogenesis: a postprandial phenomenon. Circulation. 1979;60:473–85.
2. Liu S, Willett WC, Stampfer MJ, Hu FB, Franz M, Sampson L, Hennekens CH, Manson JE. A prospective study of dietary glycemic load, carbohydrate intake, and risk of coronary heart disease in US women. Am J Clin Nutr. 2000;71:1455–61.
3. Brand-Miller JC. Glycemic index in relation to coronary disease. Asia Pac J Clin Nutr. 2004;13 Suppl:S3.
4. Stratton IM, Adler AI, Neil HA, Matthews DR, Manley SE, Cull CA, Hadden D, Turner RC, Holman RR. Association of glycaemia with macrovascular and microvascular complications of type 2 diabetes (UKPDS 35): prospective observational study. BMJ. 2000;321:405–12.
5. Ceriello A. Postprandial hyperglycemia and diabetes complications: is it time to treat? Diabetes. 2005;54:1–7.
6. Chiasson JL, Josse RG, Gomis R, Hanefeld M, Karasik A, Laakso M. Acarbose for prevention of type 2 diabetes mellitus: the STOP-NIDDM randomised trial. Lancet. 2002;359:2072–7.[Medline]
7. Chiasson JL, Josse RG, Gomis R, Hanefeld M, Karasik A, Laakso M. Acarbose treatment and the risk of cardiovascular disease and hypertension in patients with impaired glucose tolerance: the STOP-NIDDM trial. JAMA. 2003;290:486–94.
8. Anderson JW, Randles KM, Kendall CW, Jenkins DJ. Carbohydrate and fiber recommendations for individuals with diabetes: a quantitative assessment and meta-analysis of the evidence. J Am Coll Nutr. 2004;23:5–17.
9. National Nutrition Committee, CDA. Guidelines for the nutritional management of diabetes mellitus in the new millennium: a position statement by the Canadian Diabetes Association. Can J Diabetes Care. 1999;23:56–69.
10. Perlstein R, Willcox J, Hines C, Milosavljevic M. Glycemic index in diabetes management. Austral J Nutr Dietet. 1997;54:57–63.
11. Sies H, Stahl W, Sevanian A. Nutritional, dietary and postprandial oxidative stress. J Nutr. 2005;135:969–72.
12. Brownlee M. Biochemistry and molecular cell biology of diabetic complications. Nature. 2001;414:813–20.[Medline]
13. Brownlee M. The pathobiology of diabetic complications: a unifying mechanism. Diabetes. 2005;54:1615–25.
14. Rao AV, Agarwal S. Effect of diet and smoking on serum lycopene and lipid peroxidation. Nutr Res. 1998;18:713–21.
15. Rao AV, Shen H. Effect of low dose lycopene intake on lycopene bioavailability and oxidative stress. Nutr Res. 2002;22:1125–31.
16. Kaneto H, Nakatani Y, Kawamori D, Miyatsuka T, Matsuoka TA, Matsuhisa M, Yamasaki Y. Role of oxidative stress, endoplasmic reticulum stress, and c-Jun N-terminal kinase in pancreatic beta-cell dysfunction and insulin resistance. Int J Biochem Cell Biol. 2005;37:1595–608.[Medline]
17. Monnier L, Mas E, Ginet C, Michel F, Villon L, Cristol JP, Colette C. Activation of oxidative stress by acute glucose fluctuations compared with sustained chronic hyperglycemia in patients with type 2 diabetes. JAMA. 2006;295:1681–7.
18. Fraser GE, Sabate J, Beeson WL, Strahan TM. A possible protective effect of nut consumption on risk of coronary heart disease. The Adventist Health Study. Arch Intern Med. 1992;152:1416–24.
19. Fraser GE, Lindsted KD, Beeson WL. Effect of risk factor values on lifetime risk of and age at first coronary event. The Adventist Health Study. Am J Epidemiol. 1995;142:746–58.
20. Fraser GE, Sumbureru D, Pribis P, Neil RL, Frankson MA. Association among health habits, risk factors, and all-cause mortality in a black California population. Epidemiology. 1997;8:168–74.[Medline]
21. Hu FB, Stampfer MJ, Manson JE, Rimm EB, Colditz GA, Rosner BA, Speizer FE, Hennekens CH, Willett WC. Frequent nut consumption and risk of coronary heart disease in women: prospective cohort study. BMJ. 1998;317:1341–5.
22. Brown LRB, Willett C, Sacks F. Nut consumption and risk of recurrent coronary heart disease. FASEB J. 1999;13:A538.
23. Ellsworth JL, Kushi LH, Folsom AR. Frequent nut intake and risk of death from coronary heart disease and all causes in postmenopausal women: the Iowa Women's Health Study. Nutr Metab Cardiovasc Dis. 2001;11:372–7.[Medline]
24. Kris-Etherton PM, Zhao G, Binkoski AE, Coval SM, Etherton TD. The effects of nuts on coronary heart disease risk. Nutr Rev. 2001;59:103–11.[Medline]
25. Albert CM, Gaziano JM, Willett WC, Manson JE. Nut consumption and decreased risk of sudden cardiac death in the Physicians' Health Study. Arch Intern Med. 2002;162:1382–7.
26. Sang S, Lapsley K, Jeong WS, Lachance PA, Ho CT, Rosen RT. Antioxidative phenolic compounds isolated from almond skins (Prunus amygdalus Batsch). J Agric Food Chem. 2002;50:2459–63.[Medline]
27. Dourado F, Barros A, Mota M, Coimbra MA, Gama FM. Anatomy and cell wall polysaccharides of almond (Prunus dulcis D. A. Webb) seeds. J Agric Food Chem. 2004;52:1364–70.[Medline]
28. Chen CY, Milbury PE, Lapsley K, Blumberg JB. Flavonoids from almond skins are bioavailable and act synergistically with vitamins C and E to enhance hamster and human LDL resistance to oxidation. J Nutr. 2005;135:1366–73.
29. Benzie IF, Strain JJ. The ferric reducing ability of plasma (FRAP) as a measure of "antioxidant power": the FRAP assay. Anal Biochem. 1996;239:70–6.[Medline]
30. Benzie IF, Strain JJ. Ferric reducing/antioxidant power assay: direct measure of total antioxidant activity of biological fluids and modified version for simultaneous measurement of total antioxidant power and ascorbic acid concentration. Methods Enzymol. 1999;299:15–27.[Medline]
31. Hu ML. Measurement of protein thiol groups and glutathione in plasma. Methods Enzymol. 1994;233:380–5.[Medline]
32. Wolever TM. The glycemic index. World Rev Nutr Diet. 1990;62:120–85.[Medline]
33. Frei B, Stocker R, Ames BN. Antioxidant defenses and lipid peroxidation in human blood plasma. Proc Natl Acad Sci USA. 1988;85:9748–52.
34. Ceriello A, Bortolotti N, Crescentini A, Motz E, Lizzio S, Russo A, Ezsol Z, Tonutti L, Taboga C. Antioxidant defences are reduced during the oral glucose tolerance test in normal and non-insulin-dependent diabetic subjects. Eur J Clin Invest. 1998;28:329–33.[Medline]
35. Morgan PE, Sturgess AD, Davies MJ. Increased levels of serum protein oxidation and correlation with disease activity in systemic lupus erythematosus. Arthritis Rheum. 2005;52:2069–79.[Medline]
36. Bonina FP, Leotta C, Scalia G, Puglia C, Trombetta D, Tringali G, Roccazzello AM, Rapisarda P, Saija A. Evaluation of oxidative stress in diabetic patients after supplementation with a standardised red orange extract. Diabetes Nutr Metab. 2002;15:14–9.[Medline]
37. Prakash M, Upadhya S, Prabhu R. Protein thiol oxidation and lipid peroxidation in patients with uraemia. Scand J Clin Lab Invest. 2004;64:599–604.[Medline]
38. Frostegard J. Atherosclerosis in patients with autoimmune disorders. Arterioscler Thromb Vasc Biol. 2005;25:1776–85.
39. Finnegan YE, Minihane AM, Leigh-Firbank EC, Kew S, Meijer GW, Muggli R, Calder PC, Williams CM. Plant- and marine-derived n-3 polyunsaturated fatty acids have differential effects on fasting and postprandial blood lipid concentrations and on the susceptibility of LDL to oxidative modification in moderately hyperlipidemic subjects. Am J Clin Nutr. 2003;77:783–95.
40. Pellegrini N, Serafini M, Colombi B, Del Rio D, Salvatore S, Bianchi M, Brighenti F. Total antioxidant capacity of plant foods, beverages and oils consumed in Italy assessed by three different in vitro assays. J Nutr. 2003;133:2812–9.
41. Siri PW, Krauss RM. Influence of dietary carbohydrate and fat on LDL and HDL particle distributions. Curr Atheroscler Rep. 2005;7:455–9.[Medline]
42. de Vegt F, Dekker JM, Ruhe HG, Stehouwer CD, Nijpels G, Bouter LM, Heine RJ. Hyperglycaemia is associated with all-cause and cardiovascular mortality in the Hoorn population: the Hoorn Study. Diabetologia. 1999;42:926–31.[Medline]
43. Donahue RP, Abbott RD, Reed DM, Yano K. Postchallenge glucose concentration and coronary heart disease in men of Japanese ancestry. Honolulu Heart Program. Diabetes. 1987;36:689–92.[Abstract]
44. DECODE. Glucose tolerance and mortality: comparison of WHO and American Diabetes Association diagnostic criteria. The DECODE study group. European Diabetes Epidemiology Group. Diabetes epidemiology: Collaborative analysis of diagnostic criteria in Europe. Lancet. 1999;354:617–21.[Medline]
45. Balkau B, Shipley M, Jarrett RJ, Pyorala K, Pyorala M, Forhan A, Eschwege E. High blood glucose concentration is a risk factor for mortality in middle-aged nondiabetic men. 20-year follow-up in the Whitehall Study, the Paris Prospective Study, and the Helsinki Policemen Study. Diabetes Care. 1998;21:360–7.[Abstract]
46. Ceriello A, Quagliaro L, Piconi L, Assaloni R, Da Ros R, Maier A, Esposito K, Giugliano D. Effect of postprandial hypertriglyceridemia and hyperglycemia on circulating adhesion molecules and oxidative stress generation and the possible role of simvastatin treatment. Diabetes. 2004;53:701–10.
47. Spiller GA, Jenkins DJ, Cragen LN, Gates JE, Bosello O, Berra K, Rudd C, Stevenson M, Superko R. Effect of a diet high in monounsaturated fat from almonds on plasma cholesterol and lipoproteins. J Am Coll Nutr. 1992;11:126–30.[Abstract]
48. Spiller GA, Jenkins DA, Bosello O, Gates JE, Cragen LN, Bruce B. Nuts and plasma lipids: an almond-based diet lowers LDL-C while preserving HDL-C. J Am Coll Nutr. 1998;17:285–90.
49. Abbey M, Noakes M, Belling GB, Nestel PJ. Partial replacement of saturated fatty acids with almonds or walnuts lowers total plasma cholesterol and low-density-lipoprotein cholesterol. Am J Clin Nutr. 1994;59:995–9.
50. Jenkins DJ, Kendall CW, Marchie A, Parker TL, Connelly PW, Qian W, Haight JS, Faulkner D, Vidgen E, et al. Dose response of almonds on coronary heart disease risk factors: blood lipids, oxidized low-density lipoproteins, lipoprotein(a), homocysteine, and pulmonary nitric oxide: a randomized, controlled, crossover trial. Circulation. 2002;106:1327–32.
51. Jambazian PR, Haddad E, Rajaram S, Tanzman J, Sabate J. Almonds in the diet simultaneously improve plasma alpha-tocopherol concentrations and reduce plasma lipids. J Am Diet Assoc. 2005;105:449–54.[Medline]
52. Sabate J, Haddad E, Tanzman JS, Jambazian P, Rajaram S. Serum lipid response to the graduated enrichment of a Step I diet with almonds: a randomized feeding trial. Am J Clin Nutr. 2003;77:1379–84.
53. de Gaetano G. Low-dose aspirin and vitamin E in people at cardiovascular risk: a randomised trial in general practice. Collaborative Group of the Primary Prevention Project. Lancet. 2001;357:89–95.[Medline]
54. Heart Protection Study Collaborative Group. MRC/BHF Heart Protection Study of antioxidant vitamin supplementation in 20,536 high-risk individuals: a randomised placebo-controlled trial. Lancet. 2002;360:23–33.[Medline]
55. Lonn E, Yusuf S, Hoogwerf B, Pogue J, Yi Q, Zinman B, Bosch J, Dagenais G, Mann JF, et al. Effects of vitamin E on cardiovascular and microvascular outcomes in high-risk patients with diabetes: results of the HOPE study and MICRO-HOPE substudy. Diabetes Care. 2002;25:1919–27.
56. GISSI. Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial. Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto miocardico. Lancet. 1999;354:447–55.[Medline]
57. Plotnick GD, Corretti MC, Vogel RA. Effect of antioxidant vitamins on the transient impairment of endothelium-dependent brachial artery vasoactivity following a single high-fat meal. JAMA. 1997;278:1682–6.
58. Title LM, Cummings PM, Giddens K, Nassar BA. Oral glucose loading acutely attenuates endothelium-dependent vasodilation in healthy adults without diabetes: an effect prevented by vitamins C and E. J Am Coll Cardiol. 2000;36:2185–91.
59. Beckman JA, Goldfine AB, Gordon MB, Garrett LA, Keaney JF Jr, Creager MA. Oral antioxidant therapy improves endothelial function in Type 1 but not Type 2 diabetes mellitus. Am J Physiol Heart Circ Physiol. 2003;285:H2392–8.
60. Plotnick GD, Corretti MC, Vogel RA, Hesslink R Jr, Wise JA. Effect of supplemental phytonutrients on impairment of the flow-mediated brachial artery vasoactivity after a single high-fat meal. J Am Coll Cardiol. 2003;41:1744–9.
61. Huang HY, Appel LJ, Croft KD, Miller ER III, Mori TA, Puddey IB. Effects of vitamin C and vitamin E on in vivo lipid peroxidation: results of a randomized controlled trial. Am J Clin Nutr. 2002;76:549–55.
62. Meagher EA, Barry OP, Lawson JA, Rokach J, FitzGerald GA. Effects of vitamin E on lipid peroxidation in healthy persons. JAMA. 2001;285:1178–82.
63. Dicenta F, Martinez-Gomez P, Grane N, Martin ML, Leon A, Canovas JA, Berenguer V. Relationship between cyanogenic compounds in kernels, leaves, and roots of sweet and bitter kernelled almonds. J Agric Food Chem. 2002;50:2149–52.[Medline]
64. Wu X, Beecher GR, Holden JM, Haytowitz DB, Gebhardt SE, Prior RL. Lipophilic and hydrophilic antioxidant capacities of common foods in the United States. J Agric Food Chem. 2004;52:4026–37.[Medline]
65. Xiao C, Giacca A, Carpentier A, Lewis GF. Differential effects of monounsaturated, polyunsaturated and saturated fat ingestion on glucose-stimulated insulin secretion, sensitivity and clearance in overweight and obese, non-diabetic humans. Diabetologia. 2006;49:1371–9.[Medline]
66. Mekki N, Charbonnier M, Borel P, Leonardi J, Juhel C, Portugal H, Lairon D. Butter differs from olive oil and sunflower oil in its effects on postprandial lipemia and triacylglycerol-rich lipoproteins after single mixed meals in healthy young men. J Nutr. 2002;132:3642–9.
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D. J. A. Jenkins, C. W. C. Kendall, A. Marchie, A. R. Josse, T. H. Nguyen, D. A. Faulkner, K. G. Lapsley, and J. Blumberg Almonds Reduce Biomarkers of Lipid Peroxidation in Older Hyperlipidemic Subjects J. Nutr., May 1, 2008; 138(5): 908 - 913. [Abstract] [Full Text] [PDF] |
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J. H. O'Keefe, N. M. Gheewala, and J. O. O'Keefe Dietary Strategies for Improving Post-Prandial Glucose, Lipids, Inflammation, and Cardiovascular Health J. Am. Coll. Cardiol., January 22, 2008; 51(3): 249 - 255. [Abstract] [Full Text] [PDF] |
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