Vegan for Life - Jack Norris [71]
• The lower rates of hypertension in vegans can be important, too, in controlling some of the complications of diabetes.
LOW-FAT VEGAN DIETS FOR TREATING HEART DISEASE AND DIABETES: THE RESEARCH
Dr. Nathan Pritikin was an early advocate of a vegan diet that limited all fats. His approach was effective in reducing cholesterol, blood sugar, and blood pressure levels.
A few years later and using a similar although not-quite-vegan diet, Dr. Dean Ornish launched a study called the Lifestyle Heart Trial.5 The subjects were people with moderate to severe coronary heart disease. Some followed the usual diet that was recommended for heart disease and others adopted a comprehensive lifestyle plan which included a 10 percent fat vegetarian diet (consisting almost entirely of whole plant foods with the addition of nonfat dairy), aerobic exercise, stress management, support groups, and smoking cessation.
The subjects who followed a standard cholesterol-lowering plan actually got worse over the course of the study (atherosclerosis increased by nearly 28 percent after five years), but the health of subjects in the lifestyle group improved. Atherosclerosis in this group decreased by nearly 8 percent after five years.
More recently, researchers with the Physicians Committee for Responsible Medicine (PCRM) looked at the effects of a low-fat vegan diet on type-2 diabetes.6 Subjects in the test group were instructed to follow a low-fat vegan diet based on whole plant foods with no limits on carbohydrates, calories, or portion sizes. Those in the control group followed a typical American Diabetes Association (ADA) diet, which uses portion control and carbohydrate counting and includes animal foods.
With their higher carbohydrate intake, it might seem like those on the low-fat vegan diet would get worse, but they didn’t. They lost more weight, even though they didn’t count calories or measure their food, and their blood glucose was better controlled.
These effective approaches for reversing heart disease and controlling diabetes have two things in common. First, they are based on whole plant foods rather than refined carbohydrates. And second, they are very low in fat—as low as 10 to 15 percent of calories in some cases.
It’s likely that many of the benefits of these diets are explained by weight loss (which reduces blood cholesterol), reduced intake of saturated fat, and perhaps protective compounds in plants. It may be that simply eating a vegan diet—based mostly on whole, unprocessed foods—and reducing calorie intake is enough to achieve therapeutic results. We’ll see below that whether or not these diets need to be low in total fat is an issue of much debate.
FAT AND CHRONIC DISEASE
Reducing intake of saturated fat is important for reducing LDL-cholesterol levels, but it’s possible that including some higher-fat plant foods in the diet is better for managing disease. In Chapter 12, we talked about the ideal cholesterol profile for reducing heart disease: low LDL-cholesterol and high HDL-cholesterol. When all types of fat in the diet are replaced with mostly carbohydrates, both LDL-and HDL-cholesterol drop.7 But replacing saturated fat with healthful plant fats lowers LDL-cholesterol without affecting the good HDL-cholesterol. Monounsaturated fat also improves glucose control in people with diabetes when it replaces saturated fat or carbohydrates in the diet.8
This has led some researchers to conclude that the healthiest diet is one that is very low in saturated fat but not too low in total fat.9 The traditional Mediterranean diet is an example of a healthful eating pattern that includes good fats, especially the monounsaturated fats found in nuts, olives, and avocado.
How much this matters for people following vegan diets is still up for debate. But low HDL levels seem to be an important risk factor for women in particular and for those with type-2 diabetes.10 HDL levels also matter a great deal for people who are overweight and sedentary. For example, in the EPIC-Norfolk study,