DR. SRIKANT SHARMA,
THE MONTH OF SEPTEMBER IS KNOWN AS THE FOOD SAFETY EDUCATION MONTH, AS WELL AS THE CHILDHOOD OBESITY AWARENESS MONTH.
There can be little doubt about the influence of nutritional factors on human health and disease. In developed countries, inappropriate dietary intakes had been linked with diseases such as coronary heart disease and cancer. Deficiency of simple vitamins can lead to unavoidable conditions such as blindness in children.
Proper understanding of nutrition is essential, so that decisions of public policy makers will be better for individuals as per nutrition is concerned. For good health, we require energy providing nutrients (proteins, fat, and carbohydrates), vitamins, minerals, and water. Requirement for organic nutrients include nine essential amino acids, several fatty acids, glucose, four fat soluble vitamins, 10 water soluble vitamins, dietary fibers and choline. Several inorganic substances, including 4 minerals, 7 trace minerals, 3 electrolytes, and the ultra-trace elements, must also be supplied by diet.
Body mass index (BMI) is measured for a person in kilograms of weight divided by the persons height in meters squared. Normal BMI is between 18.5 to 25. If BMI is <18.5, the individual is considered underweight, >25 is considered as overweight, >30 is obese and >40 is extremely obese. Changes of body weight reflect the water or energy balance. If there is no unusual loss of water, each kilogram loss corresponds to 6000 to 7000 kcal of energy loss.
Energy building nutrients are primarily carbohydrate, fat and protein. Protein has a profoundly negative effect on appetite and its use as an energy substrate should not be contemplated. Carbohydrate and fat are the most important energy substrates and have additional functional roles. Daily requirement of energy is about 30 to 35 kcal per kg of body weight. For females, the daily calorie requirement at rest, at light work and at heavy work is 1600, 2000, 2250 kcal respectively. Similarly, for males, the daily requirement of energy for rest, light work and heavy work is 2000, 2700 and 3500 kcal respectively.
Carbohydrates are in the form of free sugar (monosaccharides, disaccharide), short chain carbohydrates, starch, non-starch polysaccharides (NSP, like Cellulose and pectin).Carbohydrate is not an essential nutrient as the body can make it for itself from protein. However, if available carbohydrate is less than hundred grams per day, ketosis is likely to occur. Daily requirement of carbohydrate is 55 to 75% of daily calorie requirement.
Refined sugar consumption may lead to dental caries. Excessive sugar consumption leads to hyperinsulinemia, which may lead to development of hyperlipoproteinemia, atherosclerosis and formation and increased growth of breast and colonic carcinomas. This is the reason why refined sugar has been set between zero percent to 10% of total energy intake.
Dr. Srikant Sharma, MBBS, MD (Medicine), Senior Consultant medicine, MCKR Hospital, New Delhi, published many national and international papers and chapters in books.
Dr. Sharma, an eminent medicine specialist with decades of experience in health care management with a holistic perspective having researched on sub systems of health care presents his article on Dengue Awareness – Key to Dengue Prevention.
The glycaemic index quantifies the effect of different carbohydrates on the blood glucose after a meal. The glycaemic index may be useful in constructing therapeutic diets for diabetes patients (low glycaemic index preferred). High glycaemic index foods are bread, potatoes and glucose; and low glycaemic index foods are pastas, legumes and whole-grain cereals. Small percentage of starch may completely escape digestion in small intestine, and passes unchanged to large intestine, where it is fermented by the resident bacteria, conferring beneficial effect on the intestinal mucosa, like dietary fibers.
NSP are defined as those parts of food, which are not digested by human enzymes. Hemicellulose of wheat increases the water holding capacity of colonic contents and the bulk feces. They relieve simple constipation, appear to prevent diverticulosis and may reduce the risk of colon cancer. Guar Gum and pectin have greater effect to slow gastric emptying, hence contribute to satiety, and may flatten glucose tolerance curve and reduce plasma cholesterol concentration. Daily recommended dose of NSP is 16-24 grams.
Fats are having high energy which is useful to people requiring large energy, but on the other hand high-energy density makes an insidious cause of obesity in sedentary people. Fats are saturated if no double bonds between any carbon atoms are present. Monounsaturated and polyunsaturated fatty acids contain single or multiple double bonds respectively between carbon atoms. Omega-3 series of polyunsaturated fatty acids occur in fish oil and in the lipids of retina and human brain. They may reduce thrombosis in people with coronary artery disease. They also lower plasma triglycerides levels. Excessive fat intake may lead to the development of coronary heart disease, obesity and increased risk of cancers. Total daily requirement of fat is 15 to 30% of the total calorie requirement. Saturated fat required is 0 to 10% of the total required calories.
Proteins form the main structural component of the body cells and are essential for health. There are 20 different amino acids, of which nine are indispensable or essential for normal synthesis of different proteins in the body, and for maintaining nitrogen balance. The biological value of proteins depends upon the proteins, which contain different essential amino acids. Proteins of animal origin particularly eggs, milk and meat are generally of higher biological value then proteins from vegetable origin. However, when two different vegetable proteins are eaten together, their amino acids pattern can complement one another and produce a mix of essential amino acid with an adequate protein nutritive value. Daily recommendation for proteins is 10 to 15% of the total calories, that is minimum of 40 g of high biological value protein. If adequate calories are provided, most people can be given 1 g of protein per KG body weigh per day.
Actual weight should be used for normal and underweight patients and ideal body weight for patient with significant Obesity. Obesity is an increasing problem in the developed world and has substantially health effect. Obesity starts between ages 20 to 40 years, and peaks around middle age. Specific causes may be endocrine (hypothyroidism, Cushing syndrome, hypothalamic tumour and insulinoma), drugs (tricyclic antidepressants, oral contraceptive pill, corticosteroid, sodium valproate etc), genetic and interplay of behavioral factors. A reduction in physical activity accounts for higher prevalence of obesity, rather than increase in food intake. Obesity may be due to multi snacking, consumption of energy dense foods like drinks which is high in fat and sugar but low in bulk, alcohol consumption, and high refined carbohydrates.
Phenotypically obesity maybe abdominal type or generalised obesity type.
Abdominal obesity is recognised by measuring high waist circumference or waist:hip ratio(>1); this subgroup is strong predictor of development of coronary artery disease, insulin resistance and type 2 diabetes mellitus. For individuals aged between 30 and 42 years, the risk of death increases by 1% for each 0.5 KG weight rise. For individuals between the ages of 50 and 62, this figure becomes 2% for each 0.5 KG weight rise. Coronary heart disease is the major cause of death but cancer rates have also increased especially in colorectal cancer in males, and cancer of gallbladder, biliary tract, breast, endometrium and cervix in females. Other medical complications of weight gain are hypertension, diabetic, stroke (paralysis), hyperlipidaemia, gallstone disease, menstrual abnormalities, hirsutism, pregnancy complications, musculoskeletal disorders, arthritis, stress incontinence, breathlessness, respiratory diseases, and obstructive sleep apnoea.
In obese individuals, there is considerable health benefit from a moderate weight reduction. A10 KG loss in weight will lead to more than 20% fall in total deaths, more than 30% fall in diabetes related deaths, and more than 40% fall in obesity related cancer deaths. As well there is fall of 10 mm of mercury systolic BP and 20 mm mercury diastolic BP. Fasting blood sugar also falls by 50%. Total cholesterol also decreases by 10%, LDL cholesterol by 15%, triglyceride by 30% and increase in HDL cholesterol by 8%.
Weight reduction program consists of avoid alcohol, smoking and pollution. Greater weight loss is achieved using treatment in a group, than individual consultations. Starvation diets are potentially dangerous due to a risk of sudden death from heart disease, exacerbated by profound loss in muscle mass and development of arrhythmias secondary to elevated free fatty acids and deranged electrolytes.
Promotion of modest physical activity, which can be maintained in the long term, for 30 minutes daily, at least 5 days a week is essential (additional weight loss of one KG per month).Such exercise need not be over strenuous because health gain is achieved at modest level of exercise as long as these are maintained. The composition of diet should ensure a minimum of 50 g of protein each day for man and 40 g of protein for women to minimize muscle degradation. Energy content intake should be a minimum of 500 kcal daily, carbohydrates intake being minimum of 100 grams.
Hence most nutritional and metabolic diseases can be prevented by awareness, lifestyle modification, healthy dietary habits, cessation of smoking and alcohol, maintaining environmental hygiene, and last but not least positive thinking