The Most Accurate Test to Determine Your Risk for Heart Disease
By Cyrus Khambatta
在Joel Fuhrman博士的书《Eat to Live》中，我看到了一个让我流泪的统计数字:
The Most Accurate Test to Determine Your Risk for Heart Disease
On this blog, we talk a lot about the causes of insulin resistance, and my mission is to provide you with strategies to reverse it through diet and exercise. Over time, I have come to realize that insulin resistance is highly misunderstood, and is one of the most neglected health conditions of our time. Most importantly, insulin resistance is directly related to your risk for heart disease.
I like to think of insulin resistance as the central lynch pin that elevates your risk for all chronic metabolic disease. Studies have shown that insulin resistance greatly accelerates the development of heart disease, cancer, type 2 diabetes and obesity, four of our leading killers, and that insulin resistance is often detectable years before metabolic dysfunction begins (1).
What does that mean for you? It’s simple: measuring, controlling and reversing insulin resistance now can prevent or delay the onset of chronic metabolic disease for you in the future.
Prevention is a practice that Americans don’t do very well. Perhaps this article will shed some light on the necessity of preventing insulin resistance to preserve your most important organ – your heart.
Heart Disease is No Joke
Heart disease is the largest killer of people worldwide, and is responsible for the deaths of 65-70% of people with diabetes (2,3). In 2015, more than 600,000 people died from heart disease in the United States alone, which represents about 25% of all deaths in this country.
Current estimates indicate that more than 1,600 people die from coronary artery disease every day, at a rate of one death every 52 seconds (4).
Over the course of the last 30 years, the rate of death from heart disease has increased exponentially, claiming more lives every year. But still, the search for the dietary causes of heart disease becomes increasingly confusing, as an overabundance of conflicting information hits consumers on a daily basis.
To say that diabetes and heart disease are closely related is an understatement. On a population-wide scale, people with diabetes experience 400% more heart attacks than those without diabetes. Heart disease kills more people with diabetes than any other cause.
Diabetes Won’t Kill You, Heart Disease Will
It is important to understand that heart disease is not selective. Even though people with type 1 diabetes are generally less overweight than those living with type 2 diabetes, elevated heart disease risk applies to both the type 1 and type 2 diabetes populations.
Insulin resistance is present in a vast majority of people living with type 1 diabetes, and understanding this can revolutionize your knowledge of the detrimental aspects of a high-fat, low-carbohydrate diet over the long-term.
In Dr. Joel Fuhrman’s book Eat to Live, I read a statistic that scared me to tears:
More than 30% of all people with type 1 diabetes will die of heart disease before the age of fifty (5).
Many people with type 1 diabetes assume that just because they are normal weight, that their risk for heart disease is very low. This is not the case, and this conventional wisdom must be rewritten.
Researchers are always on the lookout for variables that are strong predictors of heart disease. Scientists design thousands of studies to determine which variables are the strongest predictors of heart disease, then measure those markers repeatedly in an effort to educate the public about what to eat and how to exercise to reduce the chances of experiencing a life-threatening cardiac event. The truth is that there are many variables that may forewarn of impending heart disease, including, but not limited to: fasting blood glucose, A1c, insulin, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, BMI, waist-to-hip ratio and blood pressure.
There is substantial evidence that simply being overweight increases your risk for heart disease, and that carrying excess fat in your abdomen is more dangerous for your cardiovascular health than any other area (6–11).
However, being overweight or obese by itself is not always enough to raise your risk for heart disease. In fact, a large proportion of the obese population is at a surprisingly low risk for heart disease, whereas an increasingly large proportion of normal weight individuals is at a surprisingly high risk for heart disease. How could this be the case?
Insulin Resistance Predicts Heart Disease
It turns out that insulin resistance strongly predicts your risk for a heart attack. To test this, in 1981 researchers at the University of Parma, Italy designed a brilliant study to determine the relationship between insulin resistance and heart disease. They investigated nearly 650 healthy, non-obese individuals between 1981-1996 in order to understand which health markers could predict heart disease later in life.
What they found was incredible – in 1981 they found that about 25% of these individuals exhibited hyperinsulinemia – meaning that they secreted excess insulin after drinking a solution containing sugar dissolved in water. By 1996, this same 25% of subjects were three times as likely to suffer from heart disease, eight times as likely to develop type 2 diabetes and twice as likely to develop high blood pressure. More than any other marker, insulin resistance was the strongest predictor of heart disease.
Their conclusion was straightforward: aside from all other variables, simply knowing which individuals secreted excess insulin was enough information to predict who would develop heart disease in the upcoming 15 years (12,13).
Several other research groups have come to the same conclusion – high amounts of insulin appears to be the most accurate predictor of heart disease, and is a more accurate variable than BMI, fasting blood glucose or A1c (14–21).
Insulin Resistance Predicts Heart Disease Better Than Obesity
What this means is profound: insulin resistance is a stronger predictor of heart disease than obesity. This evidence shows that it’s possible to be overweight or obese and have a low risk for heart disease – the trick is that you must be insulin sensitive.
If your pancreas secretes a normal amount of insulin, your risk for heart disease is low. If your pancreas secretes a large amount of insulin, your risk for heart disease is high. It’s just that simple.
How to Test Your Level of Insulin Resistance
To test your level of insulin resistance, ask your doctor may for a glucose tolerance test (GTT). A GTT is a simple test that involves you drinking a solution of glucose dissolved in water, then measuring both your blood glucose and the amount of insulin produced over the course of the next 3 hours.
Outcome #1: Normal Insulin, Normal Glucose
If the amount of insulin secreted is within normal limits and your blood glucose is also within the normal range, then research indicates that your risk for future heart disease is low.
Outcome #2: Normal Insulin, High Glucose
If the amount of insulin secreted is within normal limits, but your blood glucose is high, then your pancreas is having trouble secreting insulin. This may be an indicator that you have either type 1 or type 2 diabetes.
Outcome #3: High Insulin, Normal Glucose
If the amount of insulin secreted is higher than normal but your blood glucose remains in the normal range, you are insulin resistant. This state is called hyperinsulinemia, which simply means that your pancreas is secreting excess insulin behind-the-scenes, and this is what elevates your risk for heart disease significantly. This is exactly why insulin resistance is considered invisible – often times your blood glucose remains normal even though your beta cells are stressed and working in overdrive. Your risk for heart disease is high.
Outcome #4: High Insulin, High Glucose
If the amount of insulin you secreted is higher than normal and your blood glucose is out of range, then you are severely insulin resistant and your pancreas is secreting excess insulin behind-the-scenes. Your risk for heart disease is high.
Take Home Messages
Understanding that your risk for heart disease is weakly related to your degree of “fatness,” and instead is strongly tied to your level of insulin resistance is a complete game-changer when thinking about how to minimize your risk for a heart attack in the future.
Eating a low fat, plant based whole foods diet teaches you how to prioritize insulin sensitivity for total body health, significantly reducing your risk for an unexpected and life-threatening cardiac event.
Ask your doctor for a glucose tolerance test to assess your risk for heart disease
Heart disease and “fatness” are weakly correlated with each other
Even if you are normal weight or skinny, your risk for heart disease is high if you over secrete insulin
33% of all people living with type 1 diabetes die of heart disease. Don’t be fooled into thinking that your weight determines your heart disease risk
- Haffner SM, Valdez RA, Hazuda HP, Mitchell BD, Morales PA, Stern MP. Prospective Analysis of The Insulin-Resistance Syndrome (Syndrome X). Diabetes. 1992 Jun 1;41(6):715–22.
- WHO | The top 10 causes of death [Internet]. WHO. [cited 2016 Apr 26]. Available from: http://www.who.int/mediacentre/factsheets/fs310/en/
- Cardiovascular Disease & Diabetes [Internet]. [cited 2016 Apr 26]. Available from: http://www.heart.org/HEARTORG/Conditions/Diabetes/WhyDiabetesMatters/Cardiovascular-Disease-Diabetes_UCM_313865_Article.jsp/#.Vx6w2jArLIU
- Kochanek, Kenneth, M.A.; Jiaquan Xu, M.D.; Sherry L. Murphy, B.S.; Arialdi M. Minin˜o, M.P.H., Hsiang-Ching Kung, Ph.D., Division of Vital Statistics. National Vital Statistics Report [Internet]. [cited 2016 Apr 26]. Available from: http://www.cdc.gov/nchs/data/nvsr/nvsr60/nvsr60_03.pdf
- Fuhrman J. Eat to live the amazing nutrient-rich program for fast and sustained weight loss. New York: Little, Brown and Co.; 2011.
- Liu J, Fox CS, Hickson DA, May WD, Hairston KG, Carr JJ, et al. Impact of abdominal visceral and subcutaneous adipose tissue on cardiometabolic risk factors: the Jackson Heart Study. J Clin Endocrinol Metab. 2010;95(12):5419–5426.
- Amati F, Pennant M, Azuma K, Dubé JJ, Toledo FGS, Rossi AP, et al. Lower thigh subcutaneous and higher visceral abdominal adipose tissue content both contribute to insulin resistance. Obes Silver Spring Md. 2012 May;20(5):1115–7.
- McLaughlin T, Lamendola C, Liu A, Abbasi F. Preferential fat deposition in subcutaneous versus visceral depots is associated with insulin sensitivity. J Clin Endocrinol Metab. 2011;96(11):E1756–E1760.
- Kim S, Cho B, Lee H, Choi K, Hwang SS, Kim D, et al. Distribution of abdominal visceral and subcutaneous adipose tissue and metabolic syndrome in a Korean population. Diabetes Care. 2011;34(2):504–506.
- Fox CS, Massaro JM, Hoffmann U, Pou KM, Maurovich-Horvat P, Liu C-Y, et al. Abdominal visceral and subcutaneous adipose tissue compartments association with metabolic risk factors in the Framingham Heart Study. Circulation. 2007;116(1):39–48.
- Demerath EW, Reed D, Rogers N, Sun SS, Lee M, Choh AC, et al. Visceral adiposity and its anatomical distribution as predictors of the metabolic syndrome and cardiometabolic risk factor levels. Am J Clin Nutr. 2008;88(5):1263–1271.
- Zavaroni I, Bonini L, Gasparini P, Barilli AL, Zuccarelli A, Dall’Aglio E, et al. Hyperinsulinemia in a normal population as a predictor of non-insulin-dependent diabetes mellitus, hypertension, and coronary heart disease: the Barilla factory revisited. Metabolism. 1999 Aug;48(8):989–94.
- Ninomiya JK, L’Italien G, Criqui MH, Whyte JL, Gamst A, Chen RS. Association of the Metabolic Syndrome With History of Myocardial Infarction and Stroke in the Third National Health and Nutrition Examination Survey. Circulation. 2004 Jan 6;109(1):42–6.
- Facchini FS, Hua N, Abbasi F, Reaven GM. Insulin resistance as a predictor of age-related diseases. J Clin Endocrinol Metab. 2001 Aug;86(8):3574–8.
- Yip J, Facchini FS, Reaven GM. Resistance to insulin-mediated glucose disposal as a predictor of cardiovascular disease. J Clin Endocrinol Metab. 1998 Aug;83(8):2773–6.
- Després JP, Lamarche B, Mauriège P, Cantin B, Dagenais GR, Moorjani S, et al. Hyperinsulinemia as an independent risk factor for ischemic heart disease. N Engl J Med. 1996 Apr 11;334(15):952–7.
- Ducimetiere P, Eschwege E, Papoz L, Richard JL, Claude JR, Rosselin G. Relationship of plasma insulin levels to the incidence of myocardial infarction and coronary heart disease mortality in a middle-aged population. Diabetologia. 1980 Sep;19(3):205–10.
- Pyörälä K. Relationship of Glucose Tolerance and Plasma Insulin to the Incidence of Coronary Heart Disease: Results from Two Population Studies in Finland. Diabetes Care. 1979 Mar 1;2(2):131–41.
- Reaven G. Insulin resistance and coronary heart disease in nondiabetic individuals. Arterioscler Thromb Vasc Biol. 2012 Aug;32(8):1754–9.
- McLaughlin T, Abbasi F, Lamendola C, Reaven G. Heterogeneity in the prevalence of risk factors for cardiovascular disease and type 2 diabetes mellitus in obese individuals: effect of differences in insulin sensitivity. Arch Intern Med. 2007 Apr 9;167(7):642–8.
- Emerging Risk Factors Collaboration, Wormser D, Kaptoge S, Di Angelantonio E, Wood AM, Pennells L, et al. Separate and combined associations of body-mass index and abdominal adiposity with cardiovascular disease: collaborative analysis of 58 prospective studies. Lancet Lond Engl. 2011 Mar 26;377(9771):1085–95.