Table 1. (continued)
(combined with MUFA: 60-70%) GI important Fiber: no quantitative recommendation Sucrose <10%
SAFA + trans-FAs: <10% n-6 PUFA <10% n-3 PUFA: twice weekly MUFA 10-20% (MUFA combined with CHO: 60-70%)
The ADA have, in their most recent clinical practice recommendations , changed their guidelines regarding the carbohydrate content of the diet. In their previous recommendations [13, 14] they stated that carbohydrate and monounsaturated fat combined should provide 60-70% of the total daily energy intake (based on an expert consensus statement), without giving specific individual figures for the carbohydrates or the monounsaturated fat. (They recommend that contribution of carbohydrates and monounsaturated fat in energy intake should be individualized, based on nutrition assessment, metabolic profiles and weight and treatment goals.) In their 2005 recommendations , however, the amount of carbohydrate in the diet is specified as 45-65% of total energy intake, with the provision that the absolute quantity of carbohydrate is at least 130g/day, due to the absolute requirement of the brain and the central nervous system for glucose as an energy source. The recommendations for protein and fat intake are not mentioned in the new guidelines of the ADA and are assumed to be the same as the previous ones, based on the 2002 Technical Review . Protein intake is recommended at 15-20% of total energy (provided that renal function is normal) and total fat should be reduced to facilitate weight loss. The primary dietary fat goal in persons with diabetes is mentioned as a decrease in saturated fat intake to <10% of total energy (<7% if low density lipoprotein cholesterol is >100mg/dl) and dietary cholesterol to <300mg/day (<200mg/day if low density lipoprotein cholesterol is >100mg/dl). It is still considered as desirable that monounsaturated fat should replace saturated fat. Trans-unsatu-rated fat intake should be minimized and polyunsaturated fat reduced to —10% of total energy.
A great deal of scientific debate was generated over the previous years regarding the utility and importance of the glycemic index (GI) and its incorporation in the dietary recommendations [15-20]. The ADA, in their previous practice guidelines [13, 14], did not consider that there was sufficient data of long enough duration, to justify the incorporation of the GI into the nutritional guidelines. The total amount of carbohydrates in meals and snacks was considered more important than their source or type. In their most recent guidelines however , based on a review of new evidence , the ADA concludes that both the amount (grams) of carbohydrate as well as the type of carbohydrate in a food influence the blood glucose level, and that the use of the GI can provide an additional benefit over that observed when total carbohydrate is considered alone. The GI concept is adopted by the DNSG of the EASD, the Joslin Diabetes Center and Joslin Clinic, the Canadian Diabetes Association and Diabetes UK as well and is considered able to discriminate foods in quite a satisfactory way .
In conclusion, as regards macronutrient composition of the diet (table 1), all scientific organizations agree that very low carbohydrate diets are not appropriate for people with diabetes. The recommended proportion varies slightly among them (from 40 to 65%), being lowest in the Joslin Diabetes Center recommendation (~40%). The concept of the GI is stressed as important in almost all guidelines now. Fiber intake is advised up to an amount of 50g/day, as long as it can be tolerated. Foods containing carbohydrates from whole grains, fruits, fresh vegetables, legumes and low-fat milk should be preferred, because of their high fiber and low GI contents. If desired, and if blood glucose levels are satisfactory, moderate intakes of free sugars (up to 50 g/day of sucrose) may be incorporated in the diet of individuals with diabetes as well. It should be noted that the recommended range of carbohydrate intake (40-65% total energy for most experts) is based on the limits for total fat and protein intakes. For patients with persistently raised triglyceride levels a trial of carbohydrate intake at the lower end of the recommended intake range may be appropriate. Carbohydrate-rich, low GI foods are suitable as carbohydrate-rich choices provided the other attributes of the foods are appropriate .
Protein intake (for people with normal kidney function) is advised to range from 10 to 20% of total energy, with the exception of the Joslin Clinic that recommends 20-30% of total caloric intake to be provided by protein (although not based on strong scientific evidence). According to the Joslin Clinic recommendations, emerging data suggest that these diets aid in the sensation of fullness, whereas low protein meal plans are associated with increased hunger. Thus, lean protein together with healthy fats may serve to reduce appetite and assist patients in achieving and maintaining a lower calorie level . For type-1 diabetic persons with established nephropathy (proteinuria) a lower amount of protein intake (0.8g/kg/day) is recommended by the ADA and the DNSG of the EASD. In individuals with microalbuminuria, the ADA recommends 0.8-1.0 g/kg/day of protein intake, whereas the DNSG of the EASD state that there is not sufficient evidence to make a firm recommendation for them, as well as for type-2 diabetic persons with macroalbu-minuria. The Joslin Clinic recommends that patients with nephropathy should consult a nephrologist before they increase total or percentage protein in their diet.
Regarding fat intake, a low fat diet (<30-35%) is recommended by all scientific organizations. There is an unanimous consensus that saturated fat and trans-fatty acids should be restricted to <10% of total energy intake and dietary cholesterol to <300mg/day. Monounsaturated fatty acids (MUFA) are generally considered beneficial and should replace saturated fat or carbohydrates in low fat diets. Olive oil consumption (the richest MUFA-containing fat and an indispensable component of the Mediterranean diet ) is equivalent to polyunsaturated fatty acids (PUFA) when compared as regards blood glucose and blood lipid levels . PUFA should comprise about 10% of total caloric intake with the n-3 PUFA (from oily fish and plant sources) being more beneficial, especially for high triglyceride levels. It should also be noted that no controlled intervention studies in subjects with diabetes mellitus having sufficient power to demonstrate that effects of dietary fat on cardiovascular or other disease endpoints exist. We only have very limited data from observational studies. These recommendations are mainly based on studies in nondiabetic subjects. The percentage of people who actually adhere to these recommendations of nutrient intake is very limited in the various countries .
Was this article helpful?