Functional Foods in Weight Management

Are nutrition and diet the same?

Food is one of the most important life needs of an inpidual. Diet refers to the total amount of food consumed by inpiduals and can be influenced by many factors such as environmental conditions, food availability, religious beliefs, socioeconomic status, etc. Nutrition is the process of using food for growth, metabolism and tissue repair, and includes the digestion, absorption, transportation, incorporation into cells and excretion of nutrients.

What is obesity?

Obesity is a complex metabolic disease caused by various genetic and non-genetic factors (such as environmental factors). Overweight and obesity are defined by the World Health Organization (WHO) as a public health problem characterized by abnormal or excessive accumulation of fat in the body, leading to serious social, physical and psychological problems.A body mass index (BMI), which is the ratio of your weight to the square of your height in meters, is considered overweight if it is over 25 kg/m2, and obese if it is over 30 kg/m2. BMI, which can be used in the diagnosis of obesity, is not a sufficient measure to determine the body fat percentage.Fat in the abdominal area is associated with various non-communicable diseases (sleep apnea, diabetes, cardiovascular diseases, reflux, fatty liver, etc.), and the more fat in the abdominal area refers to the more visceral fat. A measurement that gives an idea about the fat in this area is the waist circumference measurement. This value is required to be below 94 cm for men and 80 cm for women. Another indicator of fat in the abdominal area is neck circumference measurement. Neck circumference measured from the laryngeal protrusion is ≥37 cm in men and ≥34 cm in women can be indicated as a risk factor.

Causes of obesity

The causes of obesity include sociodemographic, behavioral (nutrition and lifestyle), and genetic factors.Sociodemographic factors can be listed as advanced age, being married, low-income level, being a woman, migration from village to city, and easy accessibility to junk food and packaged foods.

Behavioral factors include eating habits and lifestyle. Nutritional habits are an important determining factor not only for obesity, but also for our health. Confectionery, alcoholic and non-alcoholic beverages, candies, pastries, processed food consumption, monotonous diet, and consuming foods high in saturated fat may increase the risk of obesity. Increased inactivity by staying in front of a screen for a long time, short sleep periods, shift work systems, stress, smoking, and constant use of vehicles for transportation are among the causes of obesity. Stress can increase your appetite through hormonal means, resulting in the production of belly fat.

Genetic factors include family history of obesity and obesity-related genes. As a result of research conducted by Harvard Health School, it has been found that genes contribute less to the development of obesity than environmental factors.

Obesity-related health problems

Excess body weight is an important risk factor for non-communicable diseases. Excess body weight can cause diabetes, dyslipidemia (high blood fats), hypertension, cardiovascular diseases, sleep apnea, lung diseases, some types of cancer (colon, rectum, breast, ovary, etc.), stroke, menstrual irregularities, reflux, fatty liver disease, osteoporosis. In addition to these diseases, obesity is also associated with psychosocial disorders such as withdrawal from society and depression. Excess body weight during pregnancy can lead to undesirable consequences for the newborn.

Obesity prevalence

When body mass index is examined according to Türkiye Statistical Institute 2023 data;

Functional nutrition

Functional nutrition emphasizes that food is a fundamental component of health while focusing on eating habits and also considering every aspect of health, diet and overall lifestyle. Functional nutrition takes lifestyle factors such as physical activity levels, environmental factors, and the presence of chronic diseases into account that may affect an inpidual's food choices, and approaches diet from a holistic perspective.

Definition of functional foods

A food can be considered functional if it has constructive effects on target functions in the human organism, beyond nutritional effects, to improve health and well-being and/or reduce chronic diseases. Functional foods can be defined as any food that has a positive effect on an inpidual's health, physical performance, or mood, in addition to its nutritional value. Functional foods should contain a variety of ingredients to improve health or reduce/prevent disease risk and provide benefits beyond basic nutrition, and the health properties of functional foods need to be supported by scientific evidence. Functional foods can be natural food containing a functional substance (tomatoes contain lycopene), a functional substance (iodized salt), or a food from which harmful compounds have been removed (sodium-reduced salt). In addition, functional foods are produced by changing some compounds in the food, increasing bioavailability (change of lycopene in processed tomatoes), and using different combinations of these. Phenolic substances, antioxidants, dietary fibers, oligosaccharides, probiotics, prebiotics, vitamins, polyunsaturated fatty acids, sulfur-containing components, phytoestrogens, and plant sterols can be added to foods to make the food functional.Functional foods can positively affect an organism's body, meet the body's basic requirements protect the host body against malnutrition diseases, and remove various harmful particles from the body.

Functional food ingredients

Functional food ingredients are bioactive compounds used in the production of functional foods. They can be found naturally in foods or added to foods as functional ingredients. Functional food components are carotenoids, isothiocyanates, dietary fiber, phenolic acids, fatty acids, plant stanols and sterols, flavonoids, polyols, soy protein, prebiotics and probiotics, phytoestrogens, vitamins and minerals. It was assumed that functional food components came only from plant sources such as whole grains, fruits, and vegetables, but with recent studies, it has been found that animal products such as milk, fermented milk products, and cold-water fish also contain functional food components such as probiotics, prebiotics, symbiotics   (combined products of prebiotics and probiotics) and unsaturated fatty acids.

Functional foods and bioactive ingredients

Bioactive compounds are found in small amounts in foodstuffs. Bioactive ingredients can be listed as resveratrol, epigallocatechin-3-gallate, curcumin, oleuropein, sulforaphane, quercetin, ellagic acid, anthocyanins, b-glucans. Bioactive compounds is especially found in red and purple fruits such as grapes and pomegranates, green tea, turmeric, olive oil and nuts.

Functional food sources

Foods with high antioxidant content: Especially green leafy vegetables (such as brussels sprouts, broccoli, spinach) and red and purple fruits (goji berry, acai, raspberry, blueberry), sweet potatoes, carrots, peppers, spirulina, wheatgrass.

High-fiber foods: Vegetables, fresh fruits, avocados, whole grains, legumes, nuts.

Nuts and seeds: Almonds, cashews, pistachios, macadamia nuts, Brazil nuts, chia seeds, flaxseeds, hemp seeds, pumpkin seeds, walnuts.

Legumes: Black beans, chickpeas, white beans, lentils.

Whole grains: Oats, barley, buckwheat, brown rice, couscous.

Omega-3 foods: Salmon, sardines, mackerel, walnuts, chia seeds and flaxseeds.

Probiotic foods: Yogurt, kefir, kombucha, kimchi, sauerkraut, vinegar.

Prebiotic foods: Leeks, onions, garlic, bananas, potatoes, asparagus, artichokes, beans, oatmeal.

Teas, herbs and spices: Green tea, black tea, coffee, turmeric, cinnamon, ginger, cayenne pepper

Functional foods and obesity

Alternative pathways have been investigated to reduce the impact of the metabolic consequences of obesity. Obesity treatment can be beneficial by combining functional foods with a balanced diet. Frequent consumption of functional foods as part of a balanced diet may also affect anthropometric measurements such as body fat and BMI. 

• A study in 300 healthy volunteers found that BMI was reduced in those who frequently consumed gojiberries, cranberries, and pomegranates, as opposed to those who never consumed these functional foods.
• The results of a meta-analysis showed that inpiduals consuming green tea catechins along with caffeine had reduced BMI, body weight, and waist circumference.
• A meta-analysis published in 2018 found that administration of probiotics led to a significant reduction in body weight, BMI, and fat percentage compared to placebo.
• It is known that capsaicin, the bioactive component of hot pepper, stimulates thermogenesis and reduces hunger. Some studies have found that hot pepper consumption is related to decreasing BMI, body fat, waist-hip ratio and increasing muscle mass.
• Fruits are rich in polyphenols such as anthocyanidins, fiber and vitamins. Consumption of fruit, and especially pomegranate, is associated with reduced BMI. The National Health and Nutrition Examination Survey (NHANES) stated that the intake of cranberries and cranberry products has benefits such as reducing anthropometric measurements such as body weight, BMI, waist circumference, and helping to maintain a normal weight.
• Although nuts are rich in fatty compounds, they may be associated with maintaining body weight, aiding weight control, and increasing satiety.
• Moderate consumption of olive oil and avocado has been observed to reduce BMI.

In conclusion; Due to increasing obesity rates, there has been a trend towards different treatment strategies. Functional foods can help weight management only if they are included in an adequate and balanced diet, thanks to various mechanisms and the bioactive compounds they contain.

Summary

Obesity, defined by the World Health Organization as abnormal or excessive fat accumulation in the body, is a serious public health problem. Body mass index (BMI), which is used in the diagnosis of obesity, calculated by using height and weight data, is insufficient in calculating the fat percentage in the body. Waist circumference and neck circumference, which are anthropometric measurements that provide information about fatness, are required to be within certain ranges depending on gender. Obesity has sociodemographic, behavioral, and genetic causes. Obesity is an important risk factor for non-communicable diseases (hypertension, cardiovascular diseases, sleep apnea, fatty liver, depression, etc.). Functional foods are foods that have a positive effect on the inpidual's health, physical performance, and mood, in addition to their nutritional value. Although there are a wide variety of functional food components, recent studies have revealed that not only plant-based foods but also animal-derived foods can be functional foods. Functional foods are found in a wide variety of foods such as dark green leafy vegetables, fruits, probiotic prebiotic foods, fiber foods, and whole grains. When the effects of functional foods were examined for the treatment of obesity, it was found that there were improvements in anthropometric measurements such as waist circumference and BMI, and these results were only possible by including functional foods in an adequate and balanced diet. There is no single food that will be used for the treatment of obesity.