Diet, Diabetes, and Wound Management: How Important is Glycemic Control?

Advances in Skin & Wound Care, May 2004 by Posthauer, Mary Ellen

Mr J is a 50-year-old patient admitted with type 2 diabetes melIitus, depression, a nonhealing wound on his foot, and chronic urinary tract infections. He takes Humalog insulin in the morning and Lantus in the evening, plus sliding scale coverage with Humulin R if his blood glucose level rises (150 to 200 mg/dL, 2 units; 21.0 to 250 mg/dL, 4 units; 251 to 300 mg/dL, 6 units; and 301 to 400 mg/dL, 8 units).

During the dietitian's visit with Mr J, he admits that he often skips meals and doesn't monitor his blood glucose level on a daily basis. He refuses the hospital meals and has his family bring in regular sodas, milkshakes, cookies, and chips, along with fast food items.

The dietitian completes a nutritional assessment, including a history of the patient's food preferences and meal times (Table 1). Blood is drawn for a glycosylated hemoglobin (hemoglobin A^sub IC^.) and blood glucose tests, and the results confirm Mr J's dietary nonadherence and the effect on his overall health status: hemoglobin A^sub IC^, 10.7% (normal, 4.6% to 6.4%), fasting blood glucose, 350 mg/dL (normal,

Risks from Hyperglycemia

A patient like Mr J who has a poorly controlled blood glucose level and poor eating habits is at risk for numerous physiologic problems.1 An elevated blood glucose level creates a negative effect on the wound healing process, causing wounds to heal slowly.2-8 This is especially a problem for patients with diabetes. Combined with medication, dietary intake plays a significant role in the repair of wounds because the diet also provides protein, calories, fluids, and other nutrients.

When the blood glucose level is elevated, glucose docs not diffuse easily through the pores of the cell membrane. This creates a dehydrating effect: The increased osmotic pressure in the extracellular fluids causes water to transfer out of the cells. Loss of glucose in the urine causes osmotic diuresis, increasing urinary losses of electrolytes and water. Both extracellular and intracellular dehydration can occur, which affects the healing time of the skin.9

An elevated blood glucose level also damages both the blood vessels and the nerves. In addition, it places the patient at risk for developing peripheral vascular disease. Several studies show the importance of optimal insulin control in diabetes to lower the incidence of neuropathy.10

The Evidence Is In

Research shows that several biochemical pathways associated with hyperglycemia, including glucose antioxidation, polyol pathway, prostanial synthesis, and protein glycation, can increase the production of free radicals.3 Free radicals generated by the autoxidation reactions of sugar and sugar adducts to protein are possible sources of oxidation stress and damage to protein in patients with diabetes. Glycoxidation products accumulate in tissue collagen at an accelerated rate in patients with diabetes.4 This oxidative stress leads to complications in diabetes, such as tissue damage and cell death, which are reversed by antioxidants.

Controlling the blood glucose level has also been related to the rate of infection. Poor glycemic control-which impairs the body's ability to eliminate bacteria-leads to an increase in infections.5, 11-14 Urinary tract,15 respiratory,16 and soft tissue infections arc particularly common in people with diabetes.17,18 Soft tissue infections of the lower extremities and gangrene are serious complications.19

In addition, hyperglycemia decreases oxygen to the tissues. Delivery of leukocytes and antibiotic agents to the wound is impaired because of the lack of blood flow. Oxygen is necessary for macrophage mobility and growth of granulation tissue during wound healing.

Hyperglycemia can cause neuropathy or damage to the intestinal nerves, causing diarrhea, vomiting, or bloating, all of which affect the overall nutritional status of the patient with diabetes.20

Nutrition Strategies

Because Mr J has had problems adhering to his diet and monitoring his blood glucose level, his health care provider schedules a consult for Mr J and his family with the dietitian and a registered nurse, both certified diabetes educators. They meet and establish treatment goals that include diet, medication management, blood glucose monitoring, and appropriate skin care.

The diet plan prepared for Mr J compliments his lifestyle and includes frequent blood glucose monitoring. The diet plan encourages a selection of:

* complex carbohydrates, cereals, vegetables, bread, and legumes high in fiber, which arc beneficial for glucose control; they also help to maintain normal bowel function21

* whole fruits instead of juice because of their fiber and their effect on the blood glucose level

* an oral supplement formulated for people with diabetes containing fructose, which promotes removal of glucose from the blood, to be taken during the day. 22,23 Supplements with a high rate of monosaturated fatty acids are also beneficial for blood glucose and serum lipid control. Monounsaturated fatty acids (MUFAs) have positive effects on blood glucose and lipid levels.24