Defeating Diabetes
Defeating Diabetes
Brenda Davis, RD
Type 2 diabetes is rising to epidemic proportions in North America. It is estimated that 8% of all North Americans have type 2 diabetes, and 15 to 25% have a pre-diabetes condition called metabolic syndrome. It is estimated that 80 to 97 percent of all type 2 diabetes is induced by overconsumption (leading to overweight) and insufficient physical activity. The risk of diabetes is estimated to be double for those who are moderately overweight (with a body mass index above 25), and triple for those who are obese (body mass index above 30). Among the most alarming trends is the rise in type 2 diabetes in children and teens. Until recently, the disorder was known as “adult-onset diabetes” because it occurred mostly in people over fifty years of age. Today, it is estimated that approximately one-third of all newly diagnosed diabetes in children and teens in North America is type 2. Untreated, type 2 diabetes can lead to numerous debilitating health problems, including blindness, premature heart attack and stroke, kidney failure, nerve damage, and amputations.
While excess body fat plays a strong role in this disease, the way the fat is distributed is perhaps even more significant. Weight concentrated around the abdomen and in the upper part of the body (apple-shape) increases risk far more than weight that settles around the legs and hips (pear-shape). In addition, fat accumulated in and around vital organs (intra-abdominal or visceral fat) is significantly more damaging than fat that accumulates close to the skin’s surface (subcutaneous fat).
The lowest rates of type 2 diabetes in the world occur in populations consuming whole foods, plant-based diets. When such populations adopt a North American diet and lifestyle (high-fat, low-fiber, processed food diet and sedentary lifestyle) the incidence of diabetes quickly escalates. If they revert back to their traditional diet and lifestyle, diabetes rates drop.
Studies show that vegetarians are less likely to develop type 2 diabetes than nonvegetarians. In the Seventh-day Adventist Health Study, rates of type 2 diabetes were 53 percent lower for male vegetarians and 55 percent lower in female vegetarians than in nonvegetarians. People aged fifty to sixty-nine showed the greatest difference in diabetes rates, with 76 percent less diabetes in vegetarians.
Many dietary factors can help to explain the vegetarian advantage. First, vegetarians are leaner than nonvegetarians. They have significantly higher fiber intakes and lower intakes of saturated fat, both of which may improve insulin sensitivity. There is also some evidence to suggest that the absence of meat, especially processed meat, may provide additional benefit.
The risk of developing type 2 diabetes or complications from the disease can be minimized by eating a healthful diet, engaging in regular physical activity, and achieving and maintaining a BMI below 25 (preferably 20-23). The following nutrition guidelines provide powerful, practical direction for achieving these goals.
Nutrition Guidelines for People with Type 2 Diabetes
1. Make whole, unprocessed plant foods the foundation of the diet – legumes, vegetables, whole grains, fruits, nuts and seeds.
- Aim for at least 5 servings of vegetables each day. Your best choices are green leafy vegetables such as kale, broccoli and Chinese greens, and colorful red, yellow and orange vegetables such as carrots, squash, red peppers and beets.
- Select 2 or more servings of fresh fruits each day. Whole fruits are best. Citrus fruits, berries, melons, apples, peaches, plums and kiwi are excellent choices.
- Include at least 2 servings of legumes each day. Your most healthful choices are whole beans, peas and lentils. While tofu, gluten and meat analogs are reasonable options, these should be chosen less often as they lack the fiber of beans, and meat analogs are often high in sodium and fat.
- Choose 5 or more servings of whole grains each day. Intact whole grains such as barley, kamut, spelt, rye or wheat berries, oat groats, quinoa and brown rice are best. If you use foods made of processed grains, select those made with the whole grain such as bread made with whole-wheat flour.
- Select a serving of nuts and seeds each day. Nuts and seeds are rich in fat and calories, so keep serving sizes small – an ounce or two a day is plenty. Nuts and seeds provide a wonderful array of essential fatty acids, trace minerals, phytochemicals, plant sterols and plant protein. Nuts are also rich in arginine, which is converted by the body to nitric oxide, a potential vasodilator (helps increase blood flow).
2. Limit total fat intake to approximately 20-25% of total calories.
This level of fat appears to support glycemic control and weight loss, although fat can be slightly lower if triglycerides do not rise. The very best sources of fat are whole plant foods such as nuts, seeds, avocados and soybeans. Concentrated oils should be limited, as they provide little nutritional value.
3. Minimize intake of refined carbohydrates – both starches and sugars.
Refined carbohydrates tend to have a high glycemic load. They impair glycemic control, and increase insulin resistance. In addition, they increase triglycerides and reduce good HDL cholesterol. Refined carbohydrates include all added sugars, white flour and white rice products. When we refine carbohydrate-rich plant foods, we are essentially removing most of what is of value to human health, then adding damaging components such as salt, hydrogenated fat, additives, preservatives, and artificial colors and flavors. For example, if we turn a kernel of wheat into white flour, we remove approximately 90% of the fiber, 95% of the protective phytochemicals, and 70-80% of the vitamins and minerals. Keep all refined carbohydrates to a minimum.
4. Limit intake of foods rich in saturated fats to less than 7% of total calories.
Saturated fats reduce glucose tolerance and insulin sensitivity. It increases total and cholesterol, triglycerides and certain clotting factors. Saturated fats also contribute to narrowing of the blood vessels and kidney disease. The most concentrated sources of saturated fat in the diet are meat, poultry, dairy products, eggs, and tropical oils. Less than 7% of calories from saturated fat amounts to less than 8 grams per 1000 calories consumed. For someone eating 1500 calories a day, that is less than 12 grams of saturated fat. One cheeseburger or two ounces of cheese provides 12 grams of saturated fat.
5. Avoid trans fatty acids.
Trans fatty acids increase risk of heart disease, interfere with liver function, increase insulin resistance, and interfere with essential fatty acid metabolism. Trans fatty acids are formed primarily by the hydrogenation of liquid oils to turn them into hard fats. Hydrogenated fats were developed to improve shelf life of foods, increase melting point of fat (good for deep-frying), and permit high temperature cooking. Our most concentrated sources of trans fatty acids are processed foods containing hydrogenated or partially-hydrogenated vegetable oils such as margarine, shortening, crackers, cookies, granola bars, chips, snack foods and baked goods, and deep-fried foods cooked in hydrogenated oils (most deep-fried fast foods). The World Health Organization recommends that trans fatty acids be under 1% of calories to reduce risk of disease. This amounts to 1.1 grams per 1000 calories, or about 1.65 grams in a 1500 calorie diet. A single donut or a medium order of fries contain about 5 grams of trans fatty acids.
6. Include at least 35-50 grams of fiber in the daily diet.
While the American Diabetes Association currently recommends 20-35 grams of fiber per day, recent evidence suggests that this amount provides only modest benefits for people with diabetes. To improve hyperinsulinemia and glycemic control, significantly higher intakes are required – in the range of 35-50 grams per day. Fiber is found only in plant foods; animal foods are essentially fiber-free. There are two classes of dietary fiber: soluble fiber and insoluble fiber. While both types provide health benefits, soluble fiber has the greatest impact on blood sugar and blood cholesterol levels. Legumes, flaxseeds, oats, barley and peas are rich sources of soluble fiber.
7. Keep sodium intake under 2,400 mg (6 grams or 1 teaspoon salt) per day, and 1500 mg per day if salt-sensitive.
Excess sodium can contribute to high blood pressure and risk of osteoporosis. Seventy-five percent of the sodium in the North American diet comes from processed foods, while 20% comes from salt added at the table or in cooking, and just 5% is naturally present in whole foods. Table salt is not pure sodium – it is about 60% sodium and 40% chloride. Some foods that do not taste salty are actually very high in salt. For example, an ounce of flaked corn cereal or a slice of bread contains more sodium than an ounce of potato chips or an ounce of salted peanuts. The best ways to keep sodium intakes in the healthful range are to minimize use of processed foods, avoid the use of salt at the table, and moderate use of salt and salty seasonings such as tamari, soy sauce and Bragg Liquid Aminos in cooking.
8. Ensure a healthful balance and intake of essential fatty acids in the diet.
It is easy to achieve sufficient omega-6 fatty acids on almost any varied, plant-based diet, even one that is fairly low in fat. Omega-6 fatty acids are abundant in many plant foods, including grains, sunflower, safflower, soy, sesame, cottonseed, walnut and corn oil. It is considerably more difficult to achieve sufficient omega-3 fatty acids, as they are less prevalent in today’s food supply. The richest plant sources of omega-3 fatty acids are flaxseeds and flaxseed oil, hempseed and hempseed oil, dark green leafy vegetables (especially purslane), canola oil, walnuts and soy products. The recommended balance of omega-6 to omega-3 fatty acids is 2:1 to 4:1. On a 2000-calorie diet, one would require approximately 3-4.5 grams of omega-3 fatty acids. This amount of omega-3’s could be supplied by 2-3 servings of the following (each contains about 1.5 grams of alpha-linolenic acid): 0.5 tsp flaxseed oil, 2 tsp flaxseeds (ground), 2 tsp hempseed oil, 3 tbsp hempseeds,15 cups raw dark greens, 1 tbsp canola oil, 2 heaping tbsp walnuts (0.5 oz.). Some people with diabetes may also wish to consider supplemental fatty acids, including GLA (250-500 mg/day) and DHA (100-300 mg/day). The best source of DHA for vegetarians comes from a special type of microalgae that is cultured and sold in veg caps (O-Mega-Zen3 by NuTru or Dr. Fuhrman’s DHA Purity).
9. Aim for 10-20% of calories as protein, with plant protein predominating.
Several studies suggest that plant protein may be preferable to animal protein for people with diabetes. First, plant protein sources such as legumes are packaged with protectors such as fiber and phytochemicals. Plant protein also reduces blood cholesterol levels and protects kidney function. By contrast, animal protein comes packaged with potentially damaging dietary components such as saturated fats and cholesterol. The protein in animal products raises blood cholesterol levels and tends to compromise kidney function. Despite the significant advantages of plant protein, people with diabetes are frequently advised to consume generous amounts of lean animal protein. While most people with type 2 diabetes have normal protein requirements, there are two exceptions. Those with poor blood sugar control (e.g. frequent high blood sugar or hyperglycemia), and those who are losing weight may need about 20% more protein than others or about 1 gram of protein per kilogram (kg) of body weight (1 kg = 2.2 pounds).
10. If you use nutritional supplements, consider a multi-vitamin-mineral supplement containing chromium, magnesium and vanadium.
Multi-vitamin/mineral supplements can help to compensate for gaps in the diet, and provide a boost of trace minerals that may provide some benefit in terms of insulin sensitivity. A single multi-vitamin/mineral supplement is adequate for most people.
For a much more comprehensive look at type 2 diabetes and its management, read Defeating Diabetes by Brenda Davis and Thomas Barnard with recipes by Barb Bloomfield (Summertown, TN: The Book Publishing Co., 2003).
