Nutrition in Diabetes
Yüklə 0,75 Mb. Pdf görüntüsü
|
|
N u t r i t i o n i n D i a b e t e s Osama Hamdy, MD, PhD a , * , Mohd-Yusof Barakatun-Nisak, PhD b
c INTRODUCTION Nutrition therapy is keystone of diabetes prevention and management and its impor- tance has long been recognized before the era of modern scientific medicine. 1 Before
insulin discovery, a starvation diet of very low caloric content (400–500 calories/day), known as the Allen diet, was commonly used to treat diabetes. 2 Another diet with extreme carbohydrate restriction to approximately 2% and very high fat to approxi- mately 70% was used by Elliot P. Joslin for managing diabetes in the 1920s. 3 Although
there was no clear distinction between what is known now as type 1 and type 2 dia- betes (T2D), those eccentric diets were remarkably successful in managing diabetes and for even keeping patients with type 1 diabetes alive for a few years. 2,4
At that time, diabetes was commonly defined as carbohydrate-intolerance disease. 5 After insulin discovery, the amount of carbohydrates in the diabetes diet was increased to a maximum of 35% to 40% of the total daily caloric intake. By the late 1970s, a strong claim to reduce total fat and dietary saturated fat (SFAs) intake was made due to increased incidence of cardiovascular death, particularly in patients with diabetes. 6 Reduction of fat intake by approximately 10% required a compensatory increase in Disclosure Statement: O. Hamdy is on the advisory board of Novo-Nordisk, Metagenics Inc, Astra Zeneca Inc, and Boeringher Inglehiem Inc, and is a consultant to Merck Inc. B.-N. Yusof has nothing to disclose. a Department of Endocrinology, Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, MA 02481, USA; b Joslin Diabetes Center, Harvard Medical School, Boston, MA 02215, USA; c Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia * Corresponding author. E-mail address: Osama.hamdy@joslin.harvard.edu KEYWORDS Medical nutrition therapy Nutrition Diet Glycemic index Diabetes KEY POINTS Medical nutrition therapy is effective in improving glycemic control, promoting weight loss, and modifying cardiovascular risk factors in patients with diabetes. Reduction of carbohydrate load, selection of low glycemic index food, and balancing macronutrients improve postprandial blood glucose levels. Selection of healthful dietary patterns, such as the Mediterranean diet or DASH diet, are beneficial in managing diabetes. Endocrinol Metab Clin N Am 45 (2016) 799–817 http://dx.doi.org/10.1016/j.ecl.2016.06.010 endo.theclinics.com 0889-8529/16/ ª 2016 Elsevier Inc. All rights reserved. other nutrients, and in this case it was dietary carbohydrates, which went up to approximately 55% to 60% ( Fig. 1 ).
Although a high carbohydrate diet has been frequently questioned as a major contributing factor to poor diabetes control and weight gain, little has changed for the past 3 decades. 8 Recently, the importance of specific foods and overall dietary patterns rather than a single isolated nutrient for managing diabetes and cardiovascu- lar diseases (CVD) has emerged. 9,10 This review article discusses the current evidence around the role of nutrition in diabetes management. MEDICAL NUTRITION THERAPY FOR DIABETES MANAGEMENT In 1994, the American Dietetic Association used the term “medical nutrition therapy” (MNT) to better articulate appropriate nutrition care and process in diabetes manage- ment. 11
that helps in changing the eating behavior of patients with diabetes. Despite recent progress in pharmacologic management of diabetes, MNT remains a crucial tool for achieving optimal glycemic control. 12 Although MNT is widely recognized by major diabetes organizations across the world, their dietary recommendations are slightly different ( Table 1
). In principle, the prime goal of MNT is to attain and maintain optimal glycemic control and metabolic improvement through healthy food choices while considering patients’ personal needs, preferences, and lifestyle patterns. 13 Proper MNT was shown to reduce A1C by 0.5% to 2% in patients with T2D and by 0.3% to 1% in patients with type 1 dia- betes.
14 MNT was also shown to be particularly beneficial after initial diabetes diag- nosis and in patients with poor glycemic control. Nevertheless, its effectiveness is evident at any A1C level across the entire course of the disease. 13 Practically, MNT remains the most challenging component of diabetes self- management by most patients. To enhance dietary adherence, an individualized MNT should be provided by registered dietitians or by health care providers who are well versed in nutrition. Comprehensive evaluation of the individual eating pattern, needs, nutrition status, weight history, and history of previous nutrition education are required before recommending an MNT plan. 12 Fig. 1. Trend in macronutrient intake among adults with diabetes in the United States be- tween 1988 and 2004. (Data from Oza-Frank R, Cheng YJ, Narayan KMV, et al. Trends in nutrient intake among adults with diabetes in the United States: 1988-2004. J Am Diet Assoc 2009;109(7):1173–8.) Hamdy & Barakatun-Nisak 800
Table 1 A comparison of key recommendation of medical nutrition therapy for people with type 2 diabetes ADA 2014/2016 1,12 CDA 2013
17 Joslin Guideline 16 Calorie intake Recommend reduced energy intake to promote weight loss in overweight/obese adults.
Recommend a nutritionally balanced calorie- reduced diet. Recommend reduce daily caloric intake between 250 and 500 calories for overweight/obese individuals. Meal replacement that matches the nutrition guideline can be used to initiate and maintain weight loss. Macronutrient distribution No recommendation on specific macronutrient distribution. It should be individualized to meet calorie intake and metabolic goals. Recommend 44%–60% carbohydrate, 15%–20% protein, 20%–35% total fat with consideration for individualization Recommend 40%–45% carbohydrate, 20%–30% protein, and <35% total fat with adjustment should be made to meet the cultural and food preference of individual. Eating pattern Recommend a variety of eating patterns with consideration of personal preference. Recommend a variety of dietary patterns with consideration on personal preference, values, and abilities. Not available. Dietary
carbohydrate Recommend carbohydrate intake from whole grains, vegetables, fruits, legumes, and dairy products with emphasis on foods lower in glycemic load. Recommend food with a low GI value. Recommend foods with a low GI value, such as whole grains, legumes, fruits, green salad with olive oil–based dressing and most vegetables. Limit consumption of refined carbohydrates, processed grains, and starchy foods, especially most pastas, white bread, white rice, low-fiber cereal, and white potatoes. Dietary fiber Emphasis on foods with higher fiber. Recommend higher fiber/whole grains than general population (25–50 g per day or 15–25 per 1000 kcal). Recommend w14 g fiber/ 1000 calories (20–35 g) per day. If tolerated, w50 g/
d is effective in improving postprandial hyperglycemia and should be encouraged. Sucrose and fructose
Recommend to limit intake of sucrose- containing foods and to avoid sugar-sweetened beverages. Added sugar can be substituted for other carbohydrates in mixed meals up to maximum of 10% total caloric intake. Recommend to limit consumption of sugar and sugary beverages. (continued on next page) Nutrition in Diabetes 801
Table 1 (continued ) ADA 2014/2016 1,12
CDA 2013 17 Joslin Guideline 16 Protein
Do not recommend reducing protein intake below daily allowance of 0.8 g/kg body weight including those with diabetes or kidney disease. Recommend as for general population (1.0–1.5 g/kg body weight). Consider restricting to 0.8 g kg/body weight for those with chronic kidney disease.
Recommend protein intake of not <1.2 g/kg of adjusted body weight a for overweight/obese patients. Patients with signs of kidney disease should get a consult from nephrologist before increasing protein intake. Protein can be modified but not lowered to a level that may increase the risk of malnutrition or hypoalbuminemia. Dietary fat Recommend intake of total fat, SFA, cholesterol, and transfat as for the general population (total fat between 20% and 35%,
SFA <10%). Support eating plan with key element of a Mediterranean- style diet over low in total fat and high in
carbohydrates. Encourage eating food rich in long- chain omega 3 fatty acids but no support for omega-3 supplements. Recommend SFA restriction to <7% and limit transfat to a minimum level. Encourage food rich in MUFA and PUFA up to 20% and 10%, respectively. Emphasis on quality of fat rather than quantity. Recommend SFA to <7% and limit foods high in transfats. PUFA and MUFA should comprise the rest of fat intake. Micronutrient supplements No support for vitamin and mineral
supplements. No support for routine vitamin and mineral supplements. No support for routine vitamin and mineral supplements. Alcohol
Advised to drink in moderation. As alcohol may increase the risk for delayed hypoglycemia, education and awareness should be emphasized. Advised as per general population with consideration on the same precautions. Advise for moderate consumption. If consumed, no more than 1 drink b for women and no more than 2 drinks per day for men. (continued on next page) Hamdy & Barakatun-Nisak 802
Macronutrient Recommendations Dietary carbohydrates There is no final or conclusive evidence for an ideal macronutrient proportion for all pa- tients with T2D, but rather there is an emphasis on individualization of eating plan (see Table 1 ). 1,12,15 The Canadian Diabetes Association and the Joslin Nutrition Guidelines for overweight and obese patients with T2D provide some specific macronutrient dis- tribution. Both point to the prime importance of macronutrient composition in a dia- betes nutrition plan because carbohydrates, proteins, and fat have differential impact on blood glucose levels. They recommended reduction in the total glycemic load (GL) of carbohydrates and their glycemic index (GI) (see Table 1
). 16,17
Others also made a strong case for reducing carbohydrates in a diabetes diet. 8 Meanwhile, a recent randomized controlled study showed that A1C and weight reduction were comparable between calorie-restricted low-carbohydrate and high-carbohydrate diets at 24 and 52 weeks, but a low-carbohydrate diet, which was also high in unsaturated fat and low in satu- rated fat, achieved greater improvements in the lipid profile, blood glucose stability, and reductions in diabetes medications, suggesting it as an effective strategy for the optimizing T2D management. 18 Lowering GL by modest restriction of total carbo- hydrates to approximately 40% to 45% of the total daily caloric intake with favoring carbohydrates of lower GI also showed better effect on blood glucose levels in pa- tients with T2D in comparison with conventional high-carbohydrate meal plans. 19,20
In the real world, foods with low GI property are often high in dietary fiber and whole grains, which also improve overall diet quality. 21 Increased dietary fiber intake has been strongly recommended as part of diabetes management due to its benefit in inducing satiety, 22 increasing gastrointestinal transit time, and improving overall blood glucose level. 23 Approximately 14 g of fiber per 1000 calories or approximately 20 to 35 g per day is recommended (see Table 1
). Approxi- mately 50 g fiber per day, if tolerated, is effective in improving postprandial hyperglyce- mia. 16,17
Dietary fiber from unprocessed food, such as vegetables, fruits, seeds, nuts, and legumes, is preferred, but if needed, fiber supplement, such as psyllium, resistant starch, and b-glucan can be added to reach the total dietary fiber requirement. 16 Limiting added sugars has been consistently recommended by most organizations (see Table 1
). 12,16,17
Excessive intake of high-fructose sweetened beverages Table 1
(continued ) ADA 2014/2016 1,12 CDA 2013
17 Joslin Guideline 16 Sodium
Recommend as for the general population (<2300 mg/d) with further reduction is to be
individualized. No specific cutoffs recommended but emphasized on DASH eating plan. Recommend <2300 mg ( w1 tsp of salt) per day. Abbreviations: ADA, American Diabetes Association; CDA, Canadian Diabetes Association; DASH, Dietary Approach to Stop Hypertension; GI, glycemic index; MUFA, monounsaturated fatty acids; PUFA, polyunsaturated fatty acids; SFA, saturated fatty acids. a Adjusted body weight 5 IBW (Ideal Body Weight) 1 0.25 (Current Weight IBW).
16 b 1 drink is equal to 12 ounces of regular beer, 5 ounces of wine, or 1.5 ounces of 80-proof distilled alcohol. 16 Nutrition in Diabetes 803 adversely influenced visceral fat deposition, lipid metabolism, blood pressure, insulin sensitivity, and de novo lipogenesis, in particular among overweight and obese pa- tients. 24 The use of non-nutritive sweeteners may provide short-term benefits, but their long-term effects warrant future investigation. 25 Dietary fats In general, the type of fat is more important than the amount of fat intake. Now, it is clear that putting a limit on total fat (eg, <30%) and dietary cholesterol (<300 mg/d) have no substantial benefit on cardiovascular risk. This is in line with the recent recom- mendations of the Dietary Guideline for Americans, 26 American Diabetes Associa- tion, 12 and American Heart Association. 27 Although these organizations strongly support reduction in transfat from industrial hydrogenation of oils, the extent to which dietary saturated fatty acids (SFAs) increase CVD risk has become a controversial issue. Recent meta-analyses performed by De Sauza and colleagues, 28 and included 72 studies involving more than 600,000 participants from 18 countries, found no asso- ciations between dietary SFAs and all-cause mortality, CVD mortality, ischemic stroke, or T2D. Interestingly, O’Sullivan and colleagues 29 observed that food high in SFAs, including whole milk, cheese, butter, and other dairy products, were not asso- ciated with increased risk of mortality. Increased consumption of fatty fish and long-chain omega 3 polyunsaturated fatty acids (PUFA) from vegetable oils (eg, canola, corn) and walnut were found to be pro- tective against CVD mortality in patients with T2D. They improve lipid profile and modify platelet aggregation despite their lack of effect on glycemic control. 30 It was
also found that supplementation of omega 3 PUFA does not offer any additional car- diovascular protection. 31 Dietary protein Dietary protein is important in nutrition management of diabetes. The current recom- mendations do not support protein restriction for adults with T2D. 12,16,17 Patients with diabetes, especially when they are poorly controlled, lose significant amount of their lean muscle mass as they age, and they lose it at a faster pace than individuals without diabetes. 32,33
Restricting protein intake, especially with lack of strength exercise, speeds lean muscle loss and may lead to profound sarcopenia. 34,35 Currently, several organizations do not recommend significant protein restriction below the recommen- ded dietary allowance of 0.8 g/kg per day for patients with diabetic kidney disease who are not on dialysis. 12,16,17,36,37 In the Modification of Diet in Renal Disease (MDRD) study, assignment to a low- protein diet of approximately 0.6 g/kg per day compared with the average protein diet of approximately 1.3 g/kg per day in patients with advanced kidney disease did not prevent the progressive decline in glomerular filtration rate (GFR) over 3 years. 38 Early findings from a meta-analysis of randomized clinical studies also did not show any beneficial renal effects from protein restriction in patients with diabetic nephropa- thy.
39 However, this is contradicted by another recent meta-analysis by Nezu and col- leagues. 40 In the latter study, which has several limitations that may affect its quality, the effectiveness of a low-protein diet was mostly dependent on dietary adherence. 40 For patients on a hypocaloric weight reduction diet, increasing absolute protein intake is important. Using fixed percentage (eg, 15%–20%) to estimate protein requirement in a hypocaloric diet may cause inadequate protein intake and put pa- tients at risk of protein malnutrition and significant lean muscle mass loss during weight reduction. Joslin guidelines advocate a daily protein intake of not less than 1.2 g/kg of adjusted body weight, which is approximately equivalent to 20% to 30% Hamdy & Barakatun-Nisak 804
of total daily calories. 16 A higher protein intake reduces hunger, improves satiety, and minimizes lean muscle mass loss during weight reduction. 41 Micronutrient recommendations There is no specific vitamin and mineral supplemen- tation to recommend for patients with diabetes except for those with suspected defi- ciencies. 1 However, nutrient adequacy is important and should be achieved through a balance of high-quality dietary intake because poor glycemic control is usually asso- ciated with micronutrient deficiencies. 42 There are specific patients with diabetes who require additional supplementation, including those on calorie-restricted diets, elderly individuals, vegetarians, and pregnant and lactating women. 1 Low serum vitamin D, measured as serum 25-hydroxy vitamin D, is common among the US population, 43 including patients with diabetes. 44,45 Vitamin D may modify diabetes risk through its effect on glucose homeostasis. 46 Longitudinal studies have universally shown an inverse association of vitamin D status with diabetes risk 44 and A1C level. 47 Low serum vitamin D concentration was shown to be associated with increased risk of macrovascular and microvascular complications in patients with T2D. 45 However, recent systematic review and meta-analyses that included 35 clinical trials reported that vitamin D 3 supplementation did not show any beneficial effect on glycemic outcomes or insulin sensitivity in the short term. 48 Longer clinical trials are lacking. Patients who selected to have gastric bypass surgery for weight reduction are particularly at higher risk for vitamin and mineral deficiencies postsurgery. 49 Even before surgery, some patients were found to be depleted in iron, ferritin, and folic acid, to have anemia, and to have a high level of parathyroid hormone, indicating a low level of vitamin D. 50,51
Therefore, it is important to routinely screen patients before and after bariatric surgery for potential micronutrient deficiencies and supplement them with iron, vitamin B12, folic acid, and vitamin D in addition to adequate protein intake.
Diabetes-specific nutrition formula Diabetes-specific nutrition formula (DSNF) is usually used as part of MNT to facilitate initial weight reduction while improving glyce- mic control. 52,53 DSNFs provide approximately 190 to 350 calories per serving. They have balanced macronutrient composition, including fiber, and they are frequently fortified with vitamins and minerals. As these products are specifically designed for patients with diabetes, they contain low GI/GL carbohydrates, higher whey protein than casein, and contain unique blends of amino acids. 54–56 This combination has been consistently shown to improve postprandial plasma glucose and insulin response than standard formulas. In a meta-analysis by Elia and colleagues, 52 DSNF lowered postprandial plasma glucose by 18.5 mg/dL, reduced peak glucose excursion by 28.6 mg/dL, and reduced insulin requirement by 26% to 71% compared with standard formulas. Attenuating postprandial plasma glucose excursion is always a major clinical challenge and was found to contribute to cardiovascular complication in patients with diabetes. 57 DSNF also improves glucagonlike peptide-1 (GLP-1) secretion. In response to food, patients with T2D frequently have lower GLP-1 response than healthy individuals. 58 GLP-1 hormone plays an important role in glucose homeostasis through stimulating insulin secretion, suppressing glucagon production, delaying gastric emptying, and enhancing satiety. 59 Using DSNFs for tube feeding in hospitalized patients with diabetes was found to improve metabolic parameters, to reduce hospital length of stay, and to decrease the overall hospital cost in comparison with standard formulas. 60,61 As DSNFs are Nutrition in Diabetes 805
also fortified with vitamins and several micronutrients, their use for malnourished pa- tients with T2D, especially for elderly patients, was found to improve overall nutritional status and optimize diabetes control. 61,62
Dietary pattern Dietary pattern is an overall combination of beneficial foods that are habitually consumed, which together produce synergistic health effects. 26 Healthy dietary patterns are commonly rich in fruits, vegetables, nuts, legumes, fish, dairy products, and vegetable oils and low in red meat, processed red meat, refined grains, salt, and added sugar ( Table 2
). 9,10
This pattern is usually high in fiber, vitamins, an- tioxidants, minerals, polyphenols, and unsaturated fatty acids and is lower in GI/GL, sodium, and transfat. 15,63
Ajala and colleagues 64 examined 20 RCTs that investigated the effect of different dietary patterns on glycemic control, lipid profile, and body weight in patients with T2D for 6 months or more. Six dietary patterns were included in this analysis: low carbohydrates, low GI, high fiber, high protein, vegetarian/vegan, and Mediterranean dietary patterns in comparison with the commonly used diabetes nutrition guide- lines. 65
were found to be the most effective in diabetes management. The ultimate benefit on glycemic control was achieved with the Mediterranean dietary pattern ( Fig. 2 ). These
observations were also seen in 2 recent meta-analyses in which the Mediterranean di- etary pattern reduced A1C by 0.30% to 0.47%. 66,67 The Mediterranean dietary pattern also has beneficial effects on cardiovascular risk factors. 64,67,68
In the PREDIMED trial, the subgroup of participants with T2D who followed a Mediterranean diet, even without caloric restriction, had a lower incidence of CVD after a median duration of 4.8 years when compared with those who followed a low-fat diet. 69 The combination of nutrient-rich foods in the Mediterranean diet might collectively induce favorable changes in cardio-metabolic risk factors, improve insulin sensitivity, and reduce oxidation and inflammation. 70 Such CVD benefits were not seen in the Women’s Health Initiative study among participants who followed a low-fat diet, 71 which further supports the emerging role of dietary patterns in the primary prevention of CVD in pa- tients with T2D. The Dietary Approaches to Stop Hypertension (DASH) may be an ideal cardio- protective dietary pattern for patients with T2D. 72 Although the benefits of the DASH diet have been documented for hypertension management and for CVD risk reduction, little research was done in patients with T2D. In an 8-week small RCT of 44 partici- pants withT2D, the DASH diet significantly improved glycemic control and cardio- metabolic parameters, and reduced inflammation markers. 73 Dietary quality also improved in those who followed the DASH diet in comparison with the control group. Their consumption of some minerals (calcium and potassium), fiber, fruits, vegetables, dairy, and whole grains were significantly increased. 73 Vegetarian or vegan diets have also been tested in patients with diabetes. A recent meta-analysis of controlled clinical studied in patients with T2D for 4 weeks or more (n 5 225) found a significant reduction in A1C by an average of 0.39%, but with no ef- fect on fasting plasma glucose. 74 However, this beneficial effect is difficult to separate from the effect of weight loss, as many of these trials used calorie restriction, reduced dietary fat, or changed diabetes medications. 74–76 SPECIFIC NUTRITION PLANS FOR PATIENTS WITH DIABETES Nutrition Strategies for Weight Reduction in Type 2 Diabetes Yüklə 0,75 Mb. Dostları ilə paylaş:
|