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Diet and Nutrition Prevention of Chronic Diseases

3. How are chronic diseases linked to diet and nutrition?

  • 3.1 How does diet affect health at different stages of life?
  • 3.2 What are the combined effects of different risk factors over time?
  • 3.3 How can genes and food interact?
  • 3.4 How can chronic disease be tackled throughout life?

Diet largely defines a person’s health, growth, and development. Lifestyle factors that affect individuals, such as tobacco use and physical inactivity, are increasingly recognized as playing a role in the development of chronic disease. Moreover, the social, cultural, political and economic environment can aggravate the health of populations unless healthy lifestyles are actively promoted.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
4.1 Introduction 

3.1 How does diet affect health at different stages of life?

child eating fries
Adopting habits in childhood
© Micro Application

The risks of developing chronic diseases begin in fetal life and continue into old age. Thus, adult chronic diseases reflect the combined effects of prior exposure to damaging environments. Preventive measures can, therefore, be taken at all life stages.

In the womb and in early infancy, several risk factors can influence susceptibility to the development of diet-related chronic diseases later in life. Delayed fetal growth has been associated with an increased risk of coronary heart disease, stroke, diabetes and high blood pressure. Unusually large size at birth, possibly resulting from overnutrition in the womb, has been linked to an increased risk of diseases such as diabetes and cardiovascular disease.

Breastfeeding may lower the risk of later developing obesity. In contrast, breast-milk substitutes (formula) may increase the risk of developing several chronic diseases,such as type 1 diabetes and cancer, in childhood and adolescence. The level of cholesterol and specific type of fatty acids present in the milk fed to babies are thought to affect the maintenance of cholesterol levels in later life.

During infancy and childhood, both delayed growth and excessive weight or height gain have been shown to contribute to chronic disease in later life. For instance, infants with a low weight or short stature may experience an increased risk of coronary heart disease, stroke, or diabetes. Shorter children who gain height particularly quickly have an increased risk of stroke and certain cancers.

During childhood and adolescence, the adoption of habits such as unhealthy diets, low-levels of exercise, as well as alcohol and tobacco use has been shown to increase the risk of developing certain chronic diseases.

An unhealthy diet contributes to high blood pressure in children causing changes in the body which are associated with the risk of developing cardiovascular disease and obesity. A high calorie intake in childhood is also linked to an increased risk of cancer in later life. Worryingly, not only do chronic diseases occur earlier and earlier in life, but they tend to persist throughout life.

Most chronic diseases are expressed in adulthood; therefore, it is a critical time for reducing risk factors and increasing effective treatment. Risk factors that prevail during adulthood have been strongly linked with cardiovascular disease and diabetes including tobacco use, obesity, physical inactivity, high cholesterol level, high blood pressure and alcohol consumption. An individual’s ability to take control over his or her life and to make healthy lifestyle decisions appears to be an important determinant of health.

The main burden of chronic diseases is observed in people older than 60. Cardiovascular disease, type 2 diabetes and some cancers are most common at this stage in life. This is mainly due to multiple disease processes combining with age-related losses in physiological functions. As the risk of developing disease is generally believed to be reversible at any age there is an absolute benefit for ageing individuals to eat healthily, maintain their weight, and continue to exercise.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 4.2 Diet, nutrition and the prevention of chronic diseases through the life course 

3.2 What are the combined effects of different risk factors over time?

The overall risk of developing chronic disease depends on several factors and how they interact throughout life.

Risk factors can combine, or cluster together, and increase the risk of developing disease. For instance, children and adolescents with unhealthy diets and lifestyles tend to be affected simultaneously by factors such as raised blood pressure and impaired glucose tolerance. Combinations of unhealthy habits such as excessive television viewing and low levels of exercise add to the risk. In older children and adolescents, regular alcohol and tobacco use also contributes to high blood pressure which can lead to other risk factors in early adulthood.

Chronic diseases such as obesity, and unhealthy habits such as smoking during pregnancy, can affect the health of the next generation.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 4.3 Interactions between early and later factors throughout the life course 

3.3 How can genes and food interact?

Both genetic and environmental factors are likely to have an effect on health and susceptibility to disease. Genetic factors determine how susceptible a person is to develop a disease, whilst environmental factors determine which susceptible individuals will actually develop an illness.

Changes in dietary patterns may affect people in different ways because of genetic variations between individuals. While targeted dietary advice for susceptible populations or individuals is desirable, it is more practical to focus on overall environmental changes that might reduce the number of susceptible persons that go on to develop the disease.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 4.4 Gene-nutrient interactions and genetic susceptibility 

3.4 How can chronic disease be tackled throughout life?

woman sprinting
Physical activity is part
of a healthy lifestyle
© Micro Application

Scientific evidence suggests that it is possible that maintaining a healthy lifestyle can prevent and control chronic disease. Major risk factors that have been proven to contribute to chronic diseases are unhealthy diets, lack of physical activity, and smoking.

Taking steps to reduce risk factors throughout life can have a massive impact on the control of chronic disease. For instance, 80% of cases of coronary heart disease, 90% of cases of type 2 diabetes, and about one-third of cancers could be avoided by elimination of certain risk factors.

A lifestyle combining physical activity, food variety, and social interaction is the most conducive to good health. A diet including at least 20-30 biologically distinct types of food appears to be required for optimal health. It is generally recommended to increase the consumption of fruits, vegetables, and fish, and to adjust the types of fats and oils consumed, as well as the amount of sugars and starch in the diet.

The majority of people are not complying with or not aware of current dietary guidelines resulting in only a small percentage of the population currently consuming the recommended levels of different foods. To increase awareness, national governments should produce guidelines that are simple and realistic.

There is a definite need to address risk factors in adulthood and among older people, as benefits resulting from lifestyle modification may be seen within 3-5 years. The promotion of healthy lifestyle choices should be undertaken on a national scale and reinforced on a local level to ensure that guidelines reach everybody, creating health-promoting environments particularly for those most at risk.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 4.5 Intervening throughout life 


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