The incidence of type II diabetes has increased world wide resulting from an interaction between a genetic predisposition fueled by behavior and environmental factors. Diet and exercise are considered important components of the treatment for type II diabetes. Together they can improve insulin sensitivity and potentially reduce the need for oral medication or exogenous insulin.
The consensus on dietary interventions is to increase consumption of fruit and vegetables, decrease consumption of saturated fat, and engage in regular physical activity. These modifiable lifestyle factors are certainly not exclusive to an individual with Type II diabetes rather are appropriate for anyone just with a desire to live a healthy life (1).
Data from The Third National Health and Nutrition Related Examination Survey explored common lifestyle factors specifically those living with type II Diabetes to uncover the amount of people engaging in these basic common habits to reduce their symptoms related to Type II Diabetes. The national survey examined the self-reports of 1,480 adults ages 18+ diagnosed with type II diabetes and analyzed diet and exercise habits. Of those with type II, nearly one-half reported no regular physical activity while 38% reported insufficient levels of activity based on the CDC’s recommendations. The majority of those surveyed reported a diet that was high in saturated fat and consumed fewer than the minimum recommended servings of fruits and vegetables (1).
Perhaps this large sample population needs some supportive evidence to encourage them to take advantage of there free interventions to control their diabetes?
Tuomiletho, J et al examined the positive effect moderate lifestyle changes had on the likelihood of developing Type II Diabetes. The design of the intervention took place during a 6-year period. Subjects were recruited based on risk factors including overweight (25BMI+), impaired fasting glucose (defined as 140-100mg/dl), and age 40-65 years old (2).
A total of 523 subjects were randomly assigned to two treatment groups. The intervention group was asked to achieve a reduction in weight of 5% or more, consume less than 30% of their energy as fat, less than 10% saturated fat, increase fiber to 15gm per 1000cal, and increase consumption of whole grains vegetables, fruits, low fat dairy and low-fat meat. Subjects were supported over the course of the first year with supervised individually tailored resistance training and nutrition counseling. They then participated in an annual follow up meeting. The control group did not receive any intervention and instead maintained their normal lifestyle.
During the first year the mean weight decreased by 4.2kg +/- 5.1kg in the intervention group and at 2 year follow up weight loss remained significantly greater in the intervention group compared to the control. Fasting plasma glucose concentration decreased 2+/-12mg/deciliter for the intervention group where the control group showed an increase of 3+/-14mg/deciliter. Serum insulin concentration decreased at a faster rate in those that engaged in diet and exercise compared to those that did not. Over the experiment, the control group with no dietary or physical intervention had twice the incidence of diabetes diagnosis compared to the intervention group: the cumulative incidence of diabetes after 4 years was 11% compared to 23% in the control group. During the 1st year trial, the risk of diabetes was reduced by 58% in those that received support with dietary and physical activity interventions (2). Maintaining a healthy weight, limiting saturated fat, and engaging in weekly physical activity are rules everyone should live by, so it comes as no surprise that adults at risk for type II diabetes show improvement just by engaging in some healthy lifestyle choices.
It seems rather obvious that eating fruits and vegetables, exercising, and limiting saturated fat are simple modifiable lifestyle habits and these studies confirm what we already know. Obviously, the purpose of this article is to equip you with the tools to aid someone with Type II diabetes and telling a client “eat your vegetables” most certainly won’t’ elicit an epiphany moment for a client; crediting you as a great oracle that saved their disease.
Is there anything more specific one can suggest for a type II diabetic outside the scope of the same recommendations the rest of us should follow?
2 interventions that show the greatest promise for beneficial affects include a
- high dietary fiber intake and
- participating in the Mediterranean diet.
The latest recommendations from the American Diabetes Association advises against diets high in saturated fats and instead encourages consumption of mono and polyunsaturated fats as well as lean protein, low fat dairy; and fruits vegetables and whole grains that are rich in dietary fiber. The recommendation for fiber intake increased from 20 to 35gm a day because of the cholesterol lowering effects of soluble fiber.
Chandalia, M et al explored the effects of increasing intake on dietary fiber on glycemic control in patients with type II diabetes. 13 patients were randomly assigned to follow two diets for 6 weeks each. One diet contained 24gm of fiber, 8 soluble; the minimum recommended by the ADA. The experimental group consumed a high fiber diets totaling 50gm daily including 25gm of soluble fiber Macronutrient content and energy content were kept consistent with the diets and no fiber supplements were used. All fiber came solely from food (3).
Biochemical analysis included total cholesterol, lipoprotein cholesterol, triglycerides, glucose, and glycosylated hemoglobin.
- The mean plasma glucose was lower by 13mg/dL for those in the high fiber diet, and daily mean urinary glucose excretion was lower as well.
- High fiber group had 10% lower plasma glucose concentrations
- Plasma insulin was 12% lower in the high fiber group.
- A1C was slightly lower (although not statistically significant) in the high fiber group.
- High fiber diet resulted in lower fasting plasma cholesterol by 6.7%,
- High fiber group had lower plasma triglyceride by 10.2%
- High fiber group had lower fasting LDL by 6.3%. (3)
This study not only displayed the feasibility of eating a high fiber diet without added supplements, but the health benefits of the soluble fiber improved glycemic control and lowered cholesterol by binding bile acids; preventing them from being recycled for use required the body to pull from the body’s existing stores.
The foods used to reach this daily fiber goal included: Cantaloupe, grapefruit, orange, papaya, raisins, lima beans, okra, sweet potato winter squash, zucchini, granola, oat brain.
In addition to additional soluble fiber, the Mediterranean diet has had significant positive effects on preventing further progression of Type II Diabetes. The traditional Mediterranean diet is characterized by high consumption of fruits, vegetables, nuts, grains, legumes, moderate consumption of fish and wine, and low consumption of red meat and full fat dairy.
A recent clinical trial showed that a Mediterranean diet had greater glycemic control and delayed the need for antidiabetic drugs in those newly diagnosed.
Adult men and women age 55-80 years having hypertension, dyslipidemia, and overweight (risk factors for type II diabetes) were asked to consume a Mediterranean style diet meeting the following criteria: 1) Abundant use of olive oil for cooking 2) Increased consumption of fruit, vegetables, legumes, nuts, and fish 3) reduce total meat consumption 4) prepare homemade sauces with tomatoes onions and garlic, and 5) avoid butter, cream, fast foods, and sweets (4).
Weight and fasting blood glucose were recorded. The primary outcome was the onset of Type II Diabetes. 418 non-diabetics participated in the study with an average follow up of 4 years.
The incidence of diabetes was reduced by over 50% in the participants who attained at least 4 of the dietary goals over the course of the study (4). And the likely hood of developing diabetes reduced with each additional goal met. A non-calorie restricted diet enriched with high fat foods of vegetable origin decreased the incidence of diabetes in individuals at high cardiovascular risk and these risk reductions occurred in the absence of significant weight changes or implementation of physical activity. The protective effects of a Mediterranean diet with high mono and poly unsaturated fats improved fasting glucose and decreased insulin resistance (4). Specific to this study, participants were given freedom to consume up to 1 liter of olive oil each week.
Beyond the most obvious interventions- fruits vegetables and exercise; we now have supportive evidence for more specified recommendations including: 1. Fiber intake of 25grams or more and 2. High consumption of mono and poly unsaturated oils.
But what specifically about fruits and vegetables, besides their fiber content, make them so beneficial specifically to the management of type II diabetes?
Two enzymes responsible for digesting starch molecules include α-amylase and α-glucosidase. Starch molecules are first broken into smaller pieces by the enzyme amylase, and those smaller carbohydrates require glucosidase to be broken into units of glucose to enter the bloodstream for energy. Some research suggests that the phenol compounds in fruits and vegetables have an inhibiting effect on these two enzymes which would delay the carbohydrates from rapidly entering the blood stream; beneficial for treatment of type II diabetes. These natural amylase and glucosidase inhibitors from fruits and vegetables could be a helpful strategy to control post prandial hyperglycemia. “The polyphenol components of berries inhibit α-glucosidase and α-amylase enzymes, resulting in reduced blood glucose levels after starch-rich meals…potential inhibitory activity of strawberries, raspberries, blueberries and black currants on α-glucosidase and α-amylase enzymes. These authors reported that blueberries and black currants had the highest α-glucosidase inhibitory activity, and strawberries and raspberries had the highest α-amylase inhibitory activity (5).” Additionally, the leaves and fruit of avocado inhibit both alpha- amylase and alpha-glucosidase activities and can aid in the prevention of blood sugar spikes (5).
Cooked beans can protect against pancreatic beta-cell damage due to an alpha amylase inhibitor that will delay or inhibit digestion of effect carbohydrate absorption (5).
Specifically, coffee may offer some benefits to type II due to the presence of a compound called chlorogenic acid. It’s possible this acid might interact with the absorption of glucose from the intestine by inhibiting sodium dependent glucose transporters; reducing glucose’s rapid transport to the blood stream (5).
- So, fruits and vegetables, yes. But more specifically: strawberries, blueberries, black currants, cooked beans and avocados. You can even tell a client a fancy answer to further your credibility as a coach citing their potential inhibitory effects on α-glucosidase and α-amylase enzymes.
- High fiber, yes. But more specifically, a minimum 25grams with a desirable goal of 50 including 25 soluble using cantaloupe, grapefruit, orange, papaya, raisins, lima beans, okra, sweet potato winter squash, zucchini, granola, oat brain.
- Reducing intake of saturated fat, yes. Or, replacing it with liberal use of mono and polyunsaturated fats through the use of Olive Oil by up to 1 liter per week.
- Lose weight? Sure. Or how about, reducing your weight by 5% to potentially improve fasting glucose by several mg/dL and reduce glycosylated hemoglobin to lower risk of type II diabetes advancement by upwards of 58%.
Those are some specifics to get behind and certainly pack more credibility to diabetes specific suggestions than “lifestyle modification” habits. SMART (Specific Measurable Attainable Reasonable and Time Bound) goals are a great tool to help people make changes.
“Increase consumption of fruits and vegetables” may sound overwhelming but “try having a ½ cup of strawberries with breakfast this morning” with the science to back it up will help make these blurry lifestyle modifications and attainable reality while fighting a disease that affects nearly 30 million people.
References
- Nelson KM, Reiber G, Boyko EJ. Diet and Exercise Among Adults With Type 2 Diabetes: Findings from the Third National Health and Nutrition Examination Survey (NHANES III). Diabetes Care. 2002;25(10):1722-1728
- Tuomilehto J, Lindström J, Eriksson JG, et al. Prevention of Type 2 Diabetes Mellitus by Changes in Lifestyle among Subjects with Impaired Glucose Tolerance. New England Journal of Medicine. 2001;344(18):1343-1350
- Chandalia M, Garg A, Lutjohann D, Bergmann KV, Grundy SM, Brinkley LJ. Beneficial Effects of High Dietary Fiber Intake in Patients with Type 2 Diabetes Mellitus. New England Journal of Medicine. 2000;342(19):1392-1398
- Salas-Salvado J, Bullo M, Babio N, et al. Reduction in the Incidence of Type 2 Diabetes With the Mediterranean Diet: Results of the PREDIMED-Reus nutrition intervention randomized trial. Diabetes Care. 2010;34(1):14-19
- Lin D, Xiao M, Zhao J, et al. An Overview of Plant Phenolic Compounds and Their Importance in Human Nutrition and Management of Type 2 Diabetes. Molecules. 2016;21(10):1374.