University of Toronto - Faculty of Medicine

 

Author
The revision of this chapter was prepared by Margaret De Melo, RD, CDE, BSc

 

Overall goals of medical nutrition therapy (MNT) are to improve or maintain quality of life, nutritional status and physiological health, and to reduce the risk or treat the acute and long-term complications of diabetes and the associated co-morbidities. MNT can reduce A1C by an absolute 1 to 2% with the greatest impact at the initial stages of diabetes; and its effects are apparent anywhere between 6 weeks to 3 months of initiation. Effective MNT:

• Is an integral part of diabetes self-management education and should be coordinated by a registered dietitian in collaboration with the client and the diabetes health care team.
• Is adapted to the individual's nutrition needs for stage of life, lifestyle, culture, pharmacological management of DM and concomitant medical conditions.
• Takes a client-centred approach recognizing what is important to the individual, and empowering the individual to gain a sense of control, maximize quality of life and well being. MNT involves family members or significant others who are involved in supporting the individual.
• Maintains blood glucose as near normal as is safely possible, and blood pressure, and serum lipid levels to target levels that reduce the risk for vascular-related complications.
• Provides adequate calories for maintenance/achievement of a reasonable weight for adults, and normal growth and development for children and adolescents.
• Is based on Canada's Guidelines for Healthy Eating: http://www.hc-sc.gc.ca/fn-an/food-guide-aliment/index-eng.php

 

A nutrition assessment involves a thorough evaluation of the following:

• Usual eating pattern - kinds and amounts of food and beverages consumed, and times of eating including meal and snack distribution throughout the day, current energy and macronutrient intake, and micronutrient intake
• Weight history, Body Mass Index (BMI), target weight, and estimated energy requirements,
• Waist circumference
• Food, nutrition, and diabetes knowledge
• History of diets followed in the past and success attained
• Food preparation and handling skills, food preparation facilities
• Food allergies, intolerances, and personal food preferences
• Food insecurity, cultural, ethnic, socioeconomic considerations
• Current method of coordinating eating and glycemic control
• Review of results of SMBG (Self monitoring blood glucose)
• Client readiness for change and client's personal priorities

 

Meal Planning & Food Selection

• Meal planning requires inclusion of these foods in order to achieve a well-balanced diet as per Canada's Food Guide to Healthy Eating. Establishing a healthy eating pattern of regular meals, and snacks if necessary, facilitates improved glycemic control, overall health and weight management. Nutrition trends show that more than a third of Canadians skip breakfast and or lunch, and most are distracted by other activities during meals which leads to overeating. Actual intakes of fruit, vegetables and calcium-rich foods are often less than the amounts recommended to ensure optimal health.
• Effective meal planning is taught in the context of the client's culture and preferred food choices. The use of culturally and individually tailored nutrition education materials enable clients to learn to incorporate appropriate portions of culturally preferred foods.
• In some cases such as food intolerances, allergies, or inadequate intake, specific vitamin or mineral supplements may be warranted.
• Nutrition education approaches generally emphasize lower fat, higher fibre, lower sodium food choices and foods that have health-promoting properties such as omega-3 fatty acid rich fish, soy products, fresh or frozen fruits and vegetables.

Macronutrients

Carbohydrate

• Carbohydrate being the body's primary source of energy, should represent at least 45% of total daily caloric intake; this ensures a macronutrient diet composition that does not exceed 35% of total energy intake as fat. The acceptable macronutrient distribution range is 45-65%; notably high carbohydrate intakes raise triaclyglycerol and lower HDL cholesterol especially if the source of carbohydrate is monosaccharide.
• Consistency in the amount of carbohydrate, and distribution throughout the day through reasonably regular meal timing and spacing are encouraged. Avoiding high CHO loads at any one eating episode helps to facilitate glycemic control.
• For persons who take multiple injections of rapid-acting insulins, flexibility in CHO loads per eating episode is possible without compromising glycemic control. To achieve this, teaching carbohydrate counting is a key component of self-management education.
• Maintaining practice of matching meal insulin dose to carbohydrate is emphasized. Positive attitudes and proactive decisions around nutrition self-management are key to healthy eating and safe management of blood glucose levels.
• Overcompensation of carbohydrate for fear of hypoglycemia is common and needs to be addressed on an individual basis. In this way, goals towards healthy weight management and improved quality of life whilst successfully preventing and managing hypoglycemia may be achieved.
• High fibre cereals, breads, and other grain products, legumes, vegetables, fruit, and lower fat dairy products are recommended sources of carbohydrate.
• Serving sizes of CHO containing foods on the market are highly variable - up to 5 fold greater than a standard or reference portion. Persons with diabetes advised how to use food product labels, and other nutrient database sources to evaluate and control portion sizes.

Added Sugars

• Sucrose: Up to 10% of daily energy from added sugar as sucrose may be incorporated into a healthy eating pattern without impairing glycemic control and lipid profiles.
• Fructose may be used in place of sucrose as it suppresses hepatic gluconeogenesis in type 2 diabetes; recommended daily intake should not exceed 60g fructose as it may raise TG.

Dietary Fibre and Glycemic Index (GI)

• In general, the adequate intake of total daily fibre is 14 grams/1000 kcal intake for children and adults. For adults with diabetes 25-50g/day is recommended; however, most patients achieving this level of fibre into the meal plan will benefit from education and counseling.
• Insoluble dietary fibres such as bran are recommended especially as bulking agents since they have a laxative effect. In contrast, the soluble fibre sources such as barley, psyllium, oats, okra, eggplant, beans and lentils, reduce gastric emptying and slow down the absorption of glucose from the small intestine and are considered as low glycemic index food choices. Foods with soluble fiber typically have low GI.
• Replacing high-glycemic-index (GI) foods with low-glycemic-index foods in mixed meals helps slow glucose absorption from the gut and thus, reduce BG excursions, and optimize glycemic control in both Type 1 DM and Type 2 DM. Increasing the use of low-glycemic-index foods helps to optimize glycemic control in children and adults with type 1diabetes by reducing A1C and the number of hypoglycemic episodes.
• As well, diets high in fibre and low glycemic index foods also reduce total and LDL cholesterol levels. Replacing meat choices more often with low glycemic index carbohydrate-protein alternative food choices such as beans and lentils is recommended (except where dietary potassium and or phosphorous restrictions are warranted).

Protein

• Protein restriction below the usual 15 to 20% of energy intake is not recommended for most people with diabetes.
• Sources of vegetable protein may be a desirable alternate to animal protein as they contain more soluble fibre and less saturated fat and cholesterol than animal proteins and may help in decreasing serum cholesterol.

Fat

• Total fat < 35% of daily energy requirements.
• Saturated restricted to <7%, polyunsaturated fatty acids (PUFAs) to <10% with the remainder of fat from monounsaturated sources (MUFAs).
• Alerting patients to the harmful effects and encouraging as little consumption as possible of trans fatty acids as most Canadians are not aware of their negative effects on LDL cholesterol.
• Higher than 30% of energy as fat intake may be justified if fat sources are primarily MUFAs and PUFAs, and low in trans-FA.
• Consumption of fish recommended at least two servings per week as a main source of omega-3 fatty acids to help lower TGs and raise HDL.
• As well, plant stanols and sterols (2 to 3 g/ day) can help lower LDL cholesterol by up to 20%.
• Such cardio-protective fats can improve lipid profile, and for maximum benefit are encouraged in combination with a calorie restriction set to achieve a desirable weight.

Alcohol

• Light to moderate amounts of alcohol ingested with food containing carbohydrate do not affect blood glucose or blood pressure. If individuals choose to drink, alcohol intake should be limited to a light to moderate amount which represents ≤ 2 standard drinks/day or ≤ 14 drinks/week for men, and ≤ 1 drink/day or 9 drinks/week for women. A standard drink is defined as 12oz (340mL) beer, 5oz (145mL) wine, or 1.5oz (45mL) distilled spirits.
• When having 1-2 drinks/d, the alcohol does not need to substitute another food choice in the usual meal plan.
• Individuals taking insulin should be advised to eat a CHO containing food when drinking alcohol to help avoid alcohol-induced hypoglycemia.
• As with the general population, abstinence from alcohol is advised during pregnancy and lactation. As well, individuals with medical conditions such as severe hypertriglyceridemia, pancreatitis, advanced neuropathy, liver disease, and a history alcohol abuse should also avoid alcohol.
• Chronic excessive intakes (>3-4 standard drinks/day) raise blood pressure and in both men and women.
• Alcohol is a concentrated source of energy (7kcal/g of ethanol) and may contribute to weight gain.

Micronutrients

• Vitamin and mineral requirements should be met through a healthy diet including richly colored fruits and vegetables especially the orange and dark green colored choices.
• Overwhelming evidence supports the use of a daily vitamin D supplement in men and women over the age of 50 years, and in pregnancy, 400 g /day folic acid.
• Other examples wherein vitamin mineral supplements are warranted include clients on low caloric diets that do not allow them to meet the daily recommended intakes, those on vegan diets, the elderly with poor appetite, others who are do not meet their daily recommended intakes through diet despite nutritional counseling (calcium and vitamin D deficient diets are commonly encountered).
• Regular use of antioxidant supplements are not recommended and can be harmful especially in the long-term.

Weight Management

• Weight management has high priority as 80-90% of persons with type 2 diabetes are overweight or obese. Weight loss of 5-10% of initial weight can lead to significant improvement in glycemic, lipid and blood pressure control.
• Waist circumference (WC) of ≥ 102 cm (40 inches) for men, and ≥ 88 cm (35 inches) for women is an independent and practical indicator of abdominal obesity which is associated with insulin resistance, hyperinsulinemia, hypertension, and lipid abnormalities. These WC cutoffs are known to be less for persons of Asian descent (94cm and 80cm respectively) and may vary for other ethnic groups. A reduction in waist circumference for an overweight client (BMI > 25) increases insulin sensitivity and improves the lipid profile.
• Estimated energy requirement is calculated taking into account activity level. Increased regular physical activity is advantageous for energy balance and independent effect on glycemic control. (Refer to Chapter 15 Diabetes Mellitus and Exercise)
• Obese people frequently under report food intake or eat less during reporting days.
• Gradual weight loss advised, typically 1 to 2 kg/month is a reasonable target rate. Establish a mutually agreed upon short term goal with client e.g. 5 kg in 3 months with regular monitoring and counseling to support behavioural changes towards healthy eating, physical activity, and weight loss.
• Maintenance of weight loss and avoidance of weight gain are more important than quick temporary weight reduction.
• Adjustments in hypoglycemic medication may be required as weight loss progresses.
• Currently, one in five Canadians are on a weight reducing diet. Several popular diets restrict carbohydrate intake. The long-term effects of very low carbohydrate diets in people with diabetes has yet to be ascertained. Clients who follow low carbohydrate diets for weight loss should be made aware of this. Based on current guidelines, healthy eating practices should include an adequate carbohydrate intake. Precaution with use of insulin or an insulin secretagogue needs to be emphasized as the dose may need to be reduced to avoid hypoglycemia when carbohydrates are restricted.
• Continued weight gain despite MNT, for clients requiring insulin secretagogues or insulin, may suggest overcompensation with food. Repeated episodes of hypoglycemia, or fear of hypoglycemia may result in overeating. Discuss proper methods for prevention and treatment of hypoglycemia. Adjustments in medication may be warranted to enable weight loss.

 

Infants, Children and Teenagers

• Adequate nutrition to support growth and development is recommended. Regular heights and weight should be plotted on pediatric growth charts to ensure normal growth along a growth curve.
• Avoidance of hypoglycemia is the primary goal for infants and children.
• Macronutrient and micronutrient intake is the same as for children without diabetes; fat restriction ( 30% of total energy) is contraindicated in children under 2 years.
• Infants and toddlers should be encouraged to adopt normal infant/toddler feeding practices emphasizing consistency with timing of meals and snacks and avoidance of concentrated carbohydrate foods.
• Meal plans focusing on stable amounts of carbohydrate are acceptable for the school aged child.
• Older children and teenagers may benefit from Multiple Daily Injections (MDI) of insulin or Continuous Subcutaneous Insulin Infusion (CSII) to increase flexibility in lifestyle including the amount of carbohydrate consumed at each meal/snack time and timing of meals.

Children with Type 2 Diabetes Mellitus

• Children with Type 2 DM should receive care in conjunction or consultation with an interdisciplinary pediatric diabetes team.
• Adult management principles apply equally to this population, including consideration of the sociocultural environment associated with obesity.
• Intensive lifestyle intervention in obese youth with Type 2 DM should be the first line of therapy unless there is severe metabolic decompensation at which time, both lifestyle and pharmacological interventions are initiated simultaneously.

Pregnancy

• Goal is to achieve normoglycemia while consuming a nutritionally adequate diet. Preconception counseling is highly recommended.
• During pregnancy, weight reducing diets should be avoided to prevent ketosis. Rate of weight gain is monitored and is same as in pregnancy in the absence of diabetes.
• Supplementation with 400 g /day folic acid prior to conception and during pregnancy is recommended.
• Food choices divided into 6 small meals through the day to reduce peak glycemic excursions, and prevent hypoglycemia. An evening snack is often necessary to reduce nocturnal hypoglycemia and fasting ketosis in women requiring insulin during pregnancy.
• Promote breastfeeding and ensure energy requirements for breastfeeding are met.
• Postnatal MNT facilitates attainment of a healthy body weight and a healthy lifestyle to reduce risk of development or to manage Type 2 DM.

Elderly

• Social situation and co-existing medical conditions must be taken into account in nutrition care planning.
• Causes of involuntary weight loss or weight gain should be evaluated (e.g. loss of appetite, poor dentition, depression, physical disability). Appropriate referral should be made to enable client to address psychosocial or physical barriers to self-management.
• Loss of lean mass may be an undetected sign of poorly controlled diabetes and or malnutrition in the elderly reduced muscle mass also occurs with the process of aging.
• Falls prevention intervention is an important component to health maintenance of the elderly and in those with diabetes should include thorough assessment of nutritional intake and frequency of hypoglycemia.
• A daily multivitamin mineral supplement may be warranted in elderly with poor nutritional intake, or with drug-nutrient interactions.

 

Hypertension

As per usual adult guidelines for diabetes management with the following exceptions and additional considerations:

• Sodium restriction to 1.5-2.4 g/day
• Limit alcohol intake to less than 2 drinks per day in men, and no more than one drink/d in women, elderly men (>65y), and lighter-weight men.
• Incorporate the 'DASH Diet' (Dietary Approaches to Stop Hypertension) on an individualized basis, considering medication regime. The DASH diet is rich in minerals such as magnesium, potassium, and calcium, fibre, low in fat, cholesterol, and sodium

Dyslipidemia

• MNT in dyslipidemia is principally directed at reducing LDL by using the same guidelines for modifying dietary fats with an emphasis on reducing saturated fats, eliminating trans-FA, reinforcing cardioprotective food choices described above, and coaching clients towards healthier lifestyle and successful weight management.
• With persistently elevated triglycerides, if severe, abstinence from alcohol is recommended and a safe marine source of omega-3 supplement may considered if the client dislikes fish.

Nephropathy

Nutritional recommendations depend on the degree of nephropathy and the severity of co-existing cardiovascular disease and concurrent treatments:

• Priorities for MNT is to achieve the best possible glycemic and blood pressure control in order to help delay progression of nephropathy.
• during early stages of renal disease a 0.8-1g protein /kg/day restricted diet is initiated. In children: limit protein intake to recommended nutrient intake for age and gender.
• In the presence of anemia, emphasize heme-iron (lean red meat) choices of protein while maintaining a 0.8-1g/kg/day protein restriction. Otherwise, substitute some animal protein with high quality non-meat protein sources. Protein restrictions of 0.8 g of body weight per day at later stages of kidney disease have been shown to improve renal function measures such as GFR.
• Individualized sodium, potassium and phosphorus restriction based on results of lab tests.

Neuropathy

Gastroparesis refers to various disorders of upper gastrointestinal motility which delays absorption of carbohydrates and slows gastric emptying thus, predisposing postprandial hypoglycemia.

• Bloating, and nausea are common symptoms that may reduce food intake and further increase risk of hypoglycemia.
• Dietary strategies include: Chewing food thoroughly; having small frequent low-fat meals; increasing intake of foods of higher liquid consistency; eating solids as tolerated; maintaining a low fibre diet to discourage the development of bezoars. If solid foods are not tolerated, liquid diet may be warranted. Nutritional supplements and multivitamin/minerals may be necessary to meet nutrient requirements.

 

• Client-centered and meeting client's preferred learning style and stage of change.
• Maintain ongoing contact with patient and review at least annually progress with and major lifestyle changes that have impacted nutrition self-management.
• Modifying diet/ eating behaviour change is one of the most challenging components of diabetes self-management. Behavioural therapy may be beneficial in combination with nutrition therapy for persons wherein psychosocial factors prevent the person from achieving positive eating behaviour changes.

References

1. American Diabetes Association. Nutrition recommendations and interventions for diabetes. Diabetes Care: 31: S61-78, 2008
2. Canadian Diabetes Association Clinical Practice Guidelines Expert Committee. Canadian Diabetes Association 2008 clinical practice guidelines for the prevention and management of diabetes in Canada. Can J Diabetes 2008; 32 (suppl 1):S25-28, S40-45, S77-81, S107-118.
3. Canadian Food Information Council and the National Institute of Nutrition. Tracking Nutrition Trends VII; August, 2008. www.ccfn.ca
4. Daneman D, Frank M, Perlman K. When a Child has Diabetes. Toronto, Key Porter Book Limited, 2002.
5. Jenkins DJA, Kendall CWC, Augustin LSA, Vuksan V. Food frequency and carbohydrate metabolism. Canadian Journal of Diabetes Care 1999;23:(Suppl 2): S71-6.
6. Health Canada, Nutrition Policy and Promotion. Canadian Guidelines for Body Weight Classification in Adults. 2003 www.healthcanada.ca/nutrition Young L, Nestle M. Variation in perception of a 'medium' food portion: implications for dietary guidance. J Am Diet Assoc 1998;98:458-9.
7. Institute of Medicine of the National Academies. Dietary Reference Intakes: the Essential Guide to Nutrient Requirements. Washington, D.C., The National Academies Press, 2006.
8. Franz, M J, Boucher, JL, Green-Pastors J, Powers MA. Evidence-Based Nutrition Practice Guidelines for Diabetes and Scope and Standards of Practice. J Am Diet Assoc. 2008; 108:S52-S58.