A Lifestyle Issue
By Asian Food and Information Centre
The term metabolic syndrome may be new to many, but it has almost certainly been around for thousands of years. It was only in 1988, when it was named “Syndrome X” by Dr Gerald Reaven, a professor of medicine at Stanford University School of Medicine, that we really began to hear about it and how lifestyle can work for or against individual risk of developing this syndrome.
Metabolic syndrome (also sometimes referred to as “insulin resistance syndrome”) is diagnosed when a person has three or more of the following conditions: abdominal obesity, high triglyceride levels, low high-density lipoprotein in (HDL) levels, high blood pressure, and high fasting blood glucose levels.
Together, the symptoms of metabolic syndrome place a person at high risk of developing Type 2 diabetes and cardiovascular disease.1
Who is at risk?
Genetics: According to Dr Gerald Reaven, about 50% of a person’s degree of insulin resistance can be attributed to genetics and 50% can be attributed to lifestyle factors.1 A study conducted at the National Taiwan University Hospital in Taipei, found that metabolic syndrome is heritable in Chinese and Japanese hypertensive families.2 Interestingly, there appears to be some differences in the way men and women respond to heritable risk factors: a study conducted in 11 provinces in China found that the most significant risk factors of metabolic syndrome in men were waist circumference and a family history of diabetes mellitus; in women, primary risk factors were waist circumference and a family history of high blood pressure.3
Obesity: Obesity, especially abdominal obesity, is fundamental to metabolic syndrome. It is believed that free fatty acids and their metabolites from abdominal fat, play a role in triggering insulin resistance.2 Scientists still aren’t sure what gene gives rise to metabolic syndrome, but believe there is a link with those genes which predispose to obesity and overweight.
Physical inactivity: Physical inactivity goes hand in hand with obesity, and is an important risk factor for the development of metabolic syndrome. Physical in-activity not only increases the risk of developing metabolic syndrome, but further increases health risks associated with metabolic syndrome because of its negative effect on cardiovascular fitness.
Age: A study in the US has revealed that cases of metabolic syndrome increase significantly with age, from 6.7% in 20 to 29 year olds, to about 43.5% and 42.0% for those aged 60 to 69 years, respectively. The age adjusted prevalence was similar for men (24.0%) and women (23.4%).4
Prevention and treatment
As weight gain and sedentary lifestyles are both common factors in the development of metabolic syndrome, the American Heart Association recommends that treatment and prevention of metabolic syndrome should include achieving ideal body weight and increasing physical activity. Both are also time-tested
methods of improving insulin sensitivity, blood pressure and lipoprotein levels.
Overweight and obesity are always a direct result of calorie intake exceeding calorie output. It follows therefore, that weight loss can only be achieved by creating a calorie deficit. To achieve a calorie deficit, calorie intake from food must be reduced and/or calorie output in the form of physical activity must be increased. An obvious statement perhaps, but worth repeating given the clear difficulty many have in controlling body weight.
A moderately high carbohydrate (45-55% of the daily calories), low fat diet (10-15% of total daily calories) is the best option for weight loss and prevention of weight gain. Choosing complex, starchy carbohydrate foods such as wholegrain cereals and plenty of fruit and vegetables will help to keep hunger pangs at bay and brings other health benefits such as reduced bowel cancer risk.
Similarly, limiting fat intake is a sensible option to reduce daily calorie consumption (fat is the most energy dense food type, but is less satiating than protein and carbohydrates), and replacing saturated fats with unsaturated fats will help to reduce the risk of cardiovascular disease, associated with metabolic syndrome.
Gradual weight loss, and small sustainable changes to diet are keys to long-term success in weight loss or prevention of weight gain. Finding ways to make healthy eating enjoyable and as easy as possible are essential ingredients in developing lifelong healthy lifestyle habits.
For example, learning to balance occasional energy-dense foods with lower calorie, nutrient-dense foods, adjusting portion sizes and enjoying occasional treats without feeling guilty can help to sustain motivation to adopt a balanced diet for life.
A study in Finland found that men who exercised more than three hours per week decreased their risk of developing metabolic syndrome by about 50%, compared with the men who exercised no more than 60 minutes per week.5 Regular physical activity has also been seen to reduce VLDL and LDL cholesterol, while raising HDL cholesterol, lowering blood pressure, and reducing insulin resistance.4
Current guidelines vary, but a reasonable goal, would seem to be at least 30 minutes per day of exercise which uses some or all major muscle groups, and increases heart and respiration rate significantly, but comfortably. Some individuals may prefer to complete 30 minutes of activity in one session, but two or three individual chunks lasting between 10 and 15 minutes each is also okay and may be more manageable for some people. Taking the stairs instead of the elevator, taking 10-minute activity breaks at work are examples of the varied ways in which activity can be incorporated into a daily regime.
A final word
Metabolic syndrome is predicted to become a major public health problem in many developed, as well as developing countries. Individual and community-wide efforts to change health behaviours are vital. Given the importance of establishing lifelong healthy lifestyle habits, and the emerging evidence that metabolic syndrome is at least partly hereditary, it is never too early for not only adults, but children too, to adopt healthy lifestyles habits.
1Reaven G. & Strom T.K. and Fox B. (2000) Syndrome X: Overcoming the Silent Killer That Can Give You a Heart Attack.
2Wu KD, Hsiao CF, Ho LT, Sheu WH, Pei D, Chuang LM, Curb D, Chen YD, Tsai HJ, Dzau VJ, Cox D, Tai TY. Clustering and heritability of insulin resistance in Chinese and Japanese hypertensive families: a Stanford-Asian Pacific Program in Hypertension and Insulin Resistance sibling study. Hypertens Res. 2002 Jul; 25(4):529-36.
3Wu G. Zhonghua Yu Fang Yi Xue Za Zhi. The prevalence of metabolic syndrome in an 11 provinces cohort in China. Further Study of Risk Factors for Stroke and Coronary Heart Disease 2002 Sep; 36 (5):298-300.
4Ford ES, Giles WH, Dietz WH. Prevalence of the metabolic syndrome among US adults: Findings from the Third National Health and Nutrition Examination Survey. JAMA. 2002 Jan 16; 287(3):356-9.
5Diabetes in Control Dot Com: Diabetes Care 2002; 25:1612-1618.