Summary of Recent Talk on Diabetes

Here is a summary of a recent talk I gave on Food as Prevention in Obesity and Diabetes (see at the bottom for references):

1. 1. Using a lifestyle intervention which addressed diet, smoking, and exercise over a period of 35 years, Finland was able to decrease all-cause mortality by 62%, cardiovascular mortality by 79% and cancer mortality by 65%. (1)
   2. In Canada the rate of obesity is rising and went from less than 6% in 1985 to 14.9% in 2001 (2)  and 25% in 2016 with another 36% being overweight (3).
   3. Body mass index (BMI) is a good measure of obesity.  Normal is 20 to 25. Overweight is 25-30 and obese is over 30.
      1. All cause mortality is increased 11% for a BMI of 25-30 and approximately two-fold for a BMI of 35 to 40.(4)
      2. Many health problems are associated with obesity (4)
         1. Two to 3 fold increased rate of coronary heart disease, hypertension, osteoarthritis (of the knee) and gout.
         2. More than 3 fold increase in type 2 diabetes, hyperlipidemia, sleep apnea and gallbladder disease.
   4. The prevalence of diabetes is increasing worldwide.  In Canada in 2014 it was 5.8% in women and 7.5% in men (5).
   5. In a randomised controlled trial (RCT) of a non-vegetarian intensive diet (‘healthy, low calorie, low fat’) and exercise intervention (goal to achieve and maintain 7% weight reduction) in subjects at risk for developing type 2 diabetes the results were as follows:
      1. At 4 years significantly lower rate of developing diabetes was 28.9% in the placebo group versus 14.4% in the lifestyle group (one case avoided for every 7 participants)(6)
      2. However, at 15 years, 52% of participants still developed diabetes.  Thus there was a ‘failure’ rate of over 50%.  We need to do better than that.(7)
   6. Weight training (lowers risk by 34%) and aerobic exercise (lowers risk by 52%) are effective at preventing diabetes (a combination of both with a total time of 150 min/week or more is best)(8)
   7. A low glycemic index diet is effective at treating type 1 and type 2 diabetes in adults and children (9)  Free database at www.glycemicindex.com
   8. In a prospective cohort study (10) (37,000 men & 166,000 women followed for 22-28 years), individuals with a high (for men 2 portions per day.  Note that a portion of meat is 83 grams which is smaller than a pack of playing cards) intake of red meat have
      1. A 44% increased risk of developing diabetes
      2. Increased total mortality (13% increased for unprocessed meat; 20% for processed meat)
      3. Increased cardiovascular mortality (17% for unprocessed meat; 22% for processed meat)
      4. Increased cancer mortality (10% for unprocessed meat, 16% for processed meat)
      5. These observations are supported by multiple studies.
   9. A cross-sectional study (11) of 71,751 patients analysed the diet of omnivore, semi-vegetarians, fish eaters, egg and dairy eaters and vegans.
      1. Everyone got more than enough protein
      2. Despite all taking approximately the same number of calories, only the vegans had a normal BMI (body mass index) of < 25.
   10. In a randomised controlled trial, the mediterranean diet plus olive oil (4 tablespoon per day) or nuts (1 oz of almonds + walnuts + hazelnuts) produced a 7% lower rate of developing diabetes than advice to reduce dietary fat.(12) This means that for every 13 people treated, one case of diabetes can be avoided.
   11. In a 74 week randomised controlled trial (13), it was found that in comparison to the American Diabetes Association diet (which is the current gold standard), a low fat vegan diet was able to:
       1. Produce a significantly lower glycosylated hemoglobin (HbA1c)(by 0.4%)
       2. Result in more weight loss and a lower body mass index.
       3. Result in significantly larger decreases in total and LDL cholesterol.
       4. These results were confirmed in a meta-analysis (14) (statistical summary of multiple studies) of vegetarian diets and diabetes control.  In addition, the data suggested that vegan diets (ie no animal products such as milk or cheese) were superior to vegetarian diets (which allow milk, cheese and eggs).
   12. In a large prospective cohort study (15) (40,000 men & 165,000 women followed for more than 20 years), high animal protein intake was associated with a 49% higher rate of type 2 diabetes; conversely, a high plant protein intake was associated with a 9% lower rate of diabetes.
   13. A prospective cohort study of older people of multiple different ethnicities found that the only food group which predicted longer survival was beans/legumes/lentils.  They found that each 20 grams/day intake was associated with a 7-8% lower mortality (16).

References

1. The North Karelia Project: 30 years successfully preventing chronic disease. P Puska. Diabetes Voice 2008:53:26-29 (out of print – see reference here)
2. The Canadian Obesity Epidemic, 1985-1998. CMAJ 2002:166(8):1039-40
3. Obesity in Canada Report of the Standing Senate Committee on Social Affairs, Science and Technology. March 2016
4. Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective. World Cancer Research Fund. 2007.
5. Diabetes, 2014. Statistics Canada
6. Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin.  Knowler WC et al.  NEJM 2002:346(6):393-403.
7. Long-term Effects of lifestyle intervention or metformin on diabetes development and microvascular complications over 15 year follow-up: the Diabetes Prevention Program Outcomes Study. DM Nathan Lancet Diabetes Endocrinology 2015:3:866-875.
8. A Prospective Study of Weight Training and Risk of Type 2 Diabetes Mellitus in Men.  A Grontved et al.  Arch Intern Med 2012:172(17):1306-1312.
9. Low glycemic index or low glycemic load diets for diabetes mellitus. Thomas D et al. Cochrane 2009(1)
10. Red Meat Consumption and Risk of Type 2 Diabetes: 3 Cohorts of US Adults and an Updated Meta-analysis. A Pan et al. Am J Clin Nutr 2011:94:1088-96
11. Nutrient Profiles of Vegetarian and Nonvegetarian Dietary Patterns. Rizzo NS. J Acad Nutr Diet 2013:113(12):1610-1619.
12. Reduction in the Incidence of Type 2 Diabetes with the Mediterranean Diet. J Salas-Salvado. Diabetes Care 2011:34:14-19.
13. A low-fat vegan diet and a conventional diabetes diet in the treatment of type 2 diabetes: a randomized, controlled, 74-wk clinical trial. ND Barnard et al. Am J Clin Nutrition 2009:89 sup: 1588S-1596S.   
14. Vegetarian diets and glycemic control in diabetes: a systematic review and meta-analysis. Y Yokoyama.  Cardiovasc Diagn Ther 2014:4(5):373-382.
15. Dietary Protein Intake and Risk of Type 2 Diabetes in US Men and Women.  VS Malik Am J Epidemiol 2016:183(8):715-728.
16. Legumes: the most important dietary predictor of survival in older people of different ethnicities. K Horie. Asia Pacific J Clin Nutrition 2004:13(2):217-220.