What is Nutrition?
The process by which organisms obtain and utilize the nutrients they need to sustain life is called nutrition. All microorganisms, plants, and animals continue their lives by consuming nutrients available in their natural environments. The science of nutrition examines the role of diet in the development of certain diseases. It also investigates how these diseases can be prevented or treated through healthy nutrition.
The Role of Nutrition in the Development of Chronic Diseases
In the past, humanity’s most significant health problem was diseases and infections caused by inadequate access to essential nutrients. Today, however, humanity is struggling with chronic diseases that arise due to a sedentary lifestyle and poor dietary habits. Therefore, contemporary medical education should emphasize the importance of excessive or insufficient intake of energy and nutrients in the pathogenesis of diseases. In both developed and developing countries, the most common dietary issue is the unbalanced consumption of macronutrients and excessive calorie intake. The increasing consumption of refined foods, environmental pollution, and chemical additives are other critical factors contributing to nutrition-related chronic diseases. Just as negative dietary factors significantly impact the development of chronic diseases, adopting healthy eating habits plays an equally important role in their improvement. As a result, specific nutritional approaches tailored to different diseases are now required. These approaches are not limited to adjusting macronutrient ratios; they also involve the amount and balance of micronutrients and dietary behaviors. Thus, it is essential for all physicians dealing with chronic diseases to understand the fundamental principles of nutrition and monitor their patients' adherence to these principles.
Cancer and Carbohydrate-Based Nutrition
Hyperinsulinemia and/or insulin resistance may influence carcinogenesis. In the mid-1990s, it was demonstrated that dietary and lifestyle risk factors for insulin resistance—such as physical inactivity, obesity, and positive energy balance—were also risk factors for colorectal cancer. Low-fiber diets may also contribute to this condition.
Nutrition in Hypertension
Proper nutrition is highly important in addition to medication for hypertension patients. With a correct diet, the need for antihypertensive treatment in stage 1 hypertension patients can be delayed or even eliminated.
Nutrition in Heart Diseases
Cardiovascular diseases, which have become one of the leading causes of death today, continue to grow due to genetic predisposition as well as factors such as smoking, excessive stress, physical inactivity, and poor dietary habits. One of the most significant risk factors for cardiovascular diseases is obesity. Obese individuals are more likely to develop high blood pressure and cardiovascular diseases, whereas losing just 2 to 5 kilograms can lower blood pressure, regulate blood lipids, control insulin secretion, and protect the heart. Thus, achieving an ideal weight is crucial for preventing heart diseases. Diabetics are also at higher risk for hypertension, heart attacks, and strokes, making them particularly vulnerable. To prevent and slow the progression of cardiovascular diseases, it is essential to increase the consumption of antioxidant-rich foods such as fruits and vegetables. Replacing red meat with lower-saturated-fat options like fish, chicken, and turkey is a wise choice for maintaining balanced cholesterol levels. It is also advisable to avoid high-cholesterol foods such as organ meats and processed meats (salami, sausage, hot dogs, pastrami). Visible fat on meats, as well as the skin of poultry, should not be consumed. Instead of frying or roasting, cooking methods like boiling, grilling, steaming, or baking should be preferred. Omega-3 fatty acids found in fish help raise good cholesterol while lowering triglycerides, the precursors of bad cholesterol. Therefore, diets rich in omega-3 fatty acids, such as those found in fish, walnuts, and hazelnuts, have positive effects on heart health. Additionally, the arginine amino acid, magnesium, and vitamin E found abundantly in such oily seeds are beneficial for heart health. However, it is important not to consume them excessively and to include them in a professionally designed diet plan.
Nutrition in Diabetes
The goal of diabetes treatment is to control blood sugar levels, prevent or delay complications that may arise during the course of diabetes, and ultimately improve quality of life. This goal can be achieved through proper treatment, healthy nutrition, and exercise.
Nutrition in Liver Cirrhosis
Malnutrition is observed in 50–90% of patients with liver cirrhosis and is known to negatively affect disease prognosis. Factors contributing to malnutrition include inadequate oral intake, hypercatabolic conditions, malabsorption, and increased macronutrient metabolism. Adequate enteral nutrition is recommended for cirrhosis patients as it helps improve nutritional status, enhances liver function, reduces complication rates, and positively affects survival.
Nutritional Therapy in Chronic Kidney Disease
Nutritional therapy plays a crucial role in managing the progression of chronic kidney disease (CKD). The objectives of nutritional therapy in CKD are:
- Improving and/or maintaining the patient’s nutritional status
- Reducing uremic toxicity
- Preventing the progression of kidney dysfunction
- Lowering the risk of cardiovascular, cerebrovascular, and peripheral vascular diseases
- Minimizing protein catabolism
- Preventing dehydration and excessive fluid retention
- Correcting acidosis
- Maintaining electrolyte balance
- Managing fluid-electrolyte losses due to vomiting and diarrhea
- Preventing loss of appetite
- Controlling hypertension and bone pain
- Delaying the need for dialysis as much as possible
Assoc. Dietitian Zübeyde Semiz
Dietitian and Nutrition Specialist
