Does A Vegetarian Diet Help Diabetes?

Do you want a tasty diet fare that helps you to lose unwanted pounds, and lower your risk for type 2 diabetes, hypertension, and cardiovascular and chronic kidney disease? Or if you already have type 2 diabetes or atherosclerosis, would you try a delicious diet regimen that will improve and many times reverse the disease processes? We have one!

Several diets are touted for type 2 diabetes. In this blog, we examine the data supporting the use of vegetarian diets to prevent and treat type 2 diabetes. Both the American and Canadian Diabetes Associations include vegetarian and vegan eating patterns among those shown to improve glucose control, body weight, and cardiovascular risk factors.¹

First, a caveat: Being vegetarian or plant-based is not going to help you if you frequently eat refined grains, ultra-processed foods, and meat analogs. However, vegetarian or vegan diets help to prevent, improve, and even reverse type 2 diabetes if they are primarily whole-plant food diets, are well balanced, and provide all the essential nutrients. Evidence, please!

Reduces Risk for Diabetes

The consumption of red meat is positively associated with incidence of type 2 diabetes.^{2 3}  People consuming any processed meats have a one third higher likelihood of developing diabetes compared with those who do not consume any.⁴

Observational studies show that the prevalence of type 2 diabetes is 1.6 to 2 times lower in vegetarians than in the general population, even after adjustment for differences in body mass index (BMI).⁵ 

The Adventist Health Study 2 followed 15,200 men and 26,187 women (17% Black) who did not have diabetes at baseline. Those who ate vegan and lacto-ovo vegetarian diets had a 77% and 54% reduction in risk of developing diabetes, respectively. After controlling for body mass index and other lifestyle factors, the risk for diabetes declined by 62% for vegans and 38% for those committed to following a a lacto-ovo- vegetarian diet. The reduced risk was particularly pronounced among Black vegans who, in the adjusted analysis, had a 70% reduced risk, and Black lacto-ovo vegetarians had a 52% reduced risk, compared with non-vegetarians.⁶

The Tzu Chi Health Study found significant reductions in diabetes risk among vegetarian Buddhists. The 2900 omnivores consumed a little meat and fish and 2900 vegetarians consumed more soy, leafy greens, nuts, whole grains, a little fruit, and milk. Compared with the omnivore group, the vegetarian group had a 51% lower risk in men. The vegetarian postmenopausal women had a 75% lower risk for type 2 diabetes after controlling for BMI (body mass index) and other lifestyle factors.⁷

Effective Treatment for Type 2 Diabetes

Improves Weight Loss!

There is strong evidence supporting the use of a plant-based eating pattern in clinical practice for individuals with type 2 diabetes.⁸

Approximately 85% of individuals with type 2 diabetes are obese. When it comes to fat loss, a calorie does not always equal a calorie. Consider this interesting study. Dieters who adopted a low-calorie vegetarian diet not only lost weight more efficiently than those on conventional low-calorie diets. but also improved their metabolism by reducing muscle fat. Both groups in this study had reduced fat under the skin. Compared to a standard low-calorie diet, vegetarians, however, experienced more reduction in the fat that lines the muscles and a considerable reduction of stored fat inside the muscles.⁹ Losing muscle fat improves glucose and lipid metabolism; so this finding is particularly significant for people with pre-diabetes and type 2 diabetes.

In a randomized trial of individuals with type 2 diabetes, a low-fat vegan diet was prescribed with no calorie restriction. This low-fat vegan diet was linked to greater weight loss at 22 weeks compared with a conventional diet that had energy intake restrictions.¹⁰  At 74 weeks, weight loss remained significant within each diet group but not significantly different between groups (–4.4 kg in the vegan group and –3.0 kg in the conventional diet group).¹¹

Better Blood Glucose Control!

A meta-analysis of 6 randomized controlled trials–a total of 255 participants—found that vegetarian diets were associated with a 0.4% greater reduction in glycated hemoglobin (HbA1c) when compared with other prescribed diets for diabetes.¹²

Improved Measurements

In a 6 month randomized study, ¹³ researchers took seventy-four patients with type 2 diabetes and randomly assigned them to receive a vegetarian diet or a conventional diabetic diet (CDD). Both diets had similar calorie values and were calorie-restricted (-500 kcal/day). The conventional diabetic diet contains about 45% of energy in the form of carbohydrates, 30% of fats, and 25% of proteins. The upper limit for the intake of cholesterol was 200 mg daily. The vegetarian diet contained about 15% more carbohydrates, less fat, and the intake of cholesterol was up to 50 mg a day.  After 12 weeks, exercise was added to their dietary regimens. At 12 and 24 weeks, researchers measured their insulin sensitivity and their antioxidant status. MRI imaging revealed the volume of visceral and subcutaneous fat. What were the results?

Medication Use: Forty-three percent of participants in the vegetarian group and 5% of participants in the conventional diabetic diet group reduced blood glucose-lowering medication.

Weight Loss: The vegetarian group experienced almost twice the weight loss when compared to the CDD. (-6.2 kg versus -3.2 kg)

Inches: Waist circumference also decreased in both groups but more in the vegetarian group than in the CDD group.

Fat volume: The vegetarian group participants also experienced a greater reduction in both visceral and subcutaneous fat than the CDD group participants did. The volume of subcutaneous fat decreased in both groups after the dietary interventions. After the addition of exercise, it further decreased in the vegetarian group by 2%, whereas it insignificantly increased in the control group by 2%. The volume of visceral fat decreased in both groups after the dietary interventions. After the addition of exercise, it further decreased in the vegetarian group by 4%, whereas it remained unchanged in the CDD group.

Hormone optimization: In obesity and type 2 diabetes, the fat-burning, insulin-sensitizing hormone, adiponectin decreases.  Although there was no change in adiponectin in those participants who ate the CDD, the adiponectin levels in the vegetarian participants increased. This increase in adiponectin benefits vegetarians because it makes the muscles more sensitive to insulin and reduces the production and release of glucose from the liver.¹⁴ Excess production of glucose in the liver from high levels of glucagon contributed to high blood glucose levels in type 2 diabetes.

Both groups experienced approximately an equal reduction in leptin, a satiety hormone. Obesity creates leptin resistance in which leptin cannot bind to its respective receptors. Consequently, the level of leptin increases. High levels of leptin increase hunger, inflammation, and risk for cardiovascular disease and certain cancers.

Antioxidant capacity: A healthful vegetarian diet provides superior antioxidant defense. Both diabetes and obesity create free radicals and overwhelm the antioxidant defenses. Superoxide dismutase 1 (SOD1) is an enzyme that protects cells from damage from free radicals. In the vegetarian group this antioxidant increased in successive steps by 49%, whereas in the CDD group, this antioxidant enzyme gradually decreased by 30%. Reduced glutathione (GSH) is a crucial antioxidant that supports healthy liver function.  Reduced glutathione increased in the vegetarian group gradually by 27%, but it decreased in the control group by 11%. Both groups, however, had a boost in the antioxidant enzyme catalase and a reduction of free radicals overall.

LDL: LDL cholesterol decreased by 8% after the dietary intervention in the vegetarian group and remained reduced after exercise was added while the LDL level did not change in the CDD group.

Extended 74-Weeks Study

It should be noted after 6 months, the vegetarian group and the CDD participants made personal adjustments to their diet but kept generally to non-prescribed vegetarian or conventional diabetic diets. At the end of six months of free-lancing their diet and exercise regimens, the vegetarian group experienced positive effects on cardiovascular risk factors. In terms of weight loss, blood glucose, and the reduction of subcutaneous and visceral fat, there was no difference between the two groups.

Oral hyperglycemic agents, which were reduced by 43% in the vegetarian group and by 5% in the CDD group during the original intervention, had to be increased by 14% (for 3 of 21) vegetarian participants). In contrast, 26% (6 out of participants) in the CDD group during 1 year after the end of the intervention had to increase their use of blood glucose-lowering medications. Five percent  participants (1 out of 21) in vegetarian group and in thirteen percent (3 out of 23) in the CDD group were put on insulin.¹⁵ Part of the discrepancy of the last 6 months may have been from incorrect recall or perhaps liberalization of certain aspects of one’s diet, or naturally occurring plateaus.

Less Kidney Disease

One in seven Americans are at risk for chronic kidney disease. Diabetes accounts for nearly half of CKD cases. In the Nurses’ Health Study, meat consumption was associated with a significantly greater reduction in kidney function over 11 years in women who already had mild CKD.¹⁶ A 24-year follow-up of 14,868 adults in the Atherosclerosis Risk and Communities Study found that higher adherence to a healthful, plant-based diet was linked to a lower risk of chronic kidney disease.¹⁷ More studies have shown that a vegetarian diet can improve mild diabetic kidney disease.¹⁸, ¹⁹

Optimizes Blood Vessels Health

Approximately 75% of individuals who have diabetes will develop hypertension. About two-thirds of deaths in people with diabetes mellitus are attributable to cardiovascular disease. Here is the breakdown of this mortality rate in persons with diabetes: approximately 40% are from ischemic heart disease, 15% from other forms of heart disease, principally congestive heart failure, and about10% from stroke.²⁰

A meta-analysis of randomized control studies found that substituting red meat with high-quality plant protein sources, but not with fish or low-quality carbohydrates, leads to more favorable changes in blood lipids and lipoproteins.²¹

Another meta-analysis of 9 randomized controlled trials in patients with type 2 diabetes, a total of 665 participants, compared vegetarian interventions to control diets, and demonstrated significant improvements in CVD risk factors, including lipids, blood pressure, glycemic control, body weight, and abdominal adiposity.²²

A review study found that a healthful plant-based diet reduces the risk of cardiovascular disease and dying from it by 40%.²³

Healthful low-fat, vegetarian diets—coupled with exercise, stress management, and smoking cessation—can produce significant regression in coronary artery stenosis in patients with moderate to severe coronary artery disease.²⁴

Conclusions:

Healthful vegetarian diets offer many benefits. Work with a plant-based dietician to get you started in your menu plans. A well-balanced vegan diet has all the nutrients except vitamins B-12 and D. Many brands of nutrition yeast flakes and non-dairy milk have been fortified with B-12. Individuals prone to gout or elevated uric acid should get their B12 from a different source than yeast flakes. During the autumn and the winter, in areas where you cannot expose your face, arms, and hands to sunshine, you need to be sure to get vitamin D. The RDA  for vitamin D is 600 IU (15 mcg) for children and adults and 800 IU (20 mcg) if you are over than 71.

Both the Wildwood Lifestyle Center and the Lifestyle Outpatient clinic specializes in helping people who have diabetes, obesity, high blood pressure, and chronic conditions.

 

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