Nutritional diseases , nutrition 1 , part A

Nutritional diseases

Nutrition and Nutrients
Nutrients are substances that must be supplied by the diet because they are not synthesized in the body in sufficient amounts.
The need is depend :
Age
physiological state

Nutrition and Nutrients
macronutrients
Carbohydrates
Fats
Proteins
micronutrients
Vitamins
Minerals
Water

The energy balance
The energy intake equal to energy output
The major components of energy output are:
1.resting energy expenditure (REE) (BMR) (60%)
depend on FFM (total body mass- fat mass)
2. physical activity (30%)
3. Diet induced thermo-genesis (10%)

 

The energy balance
Energy intake depend on macronutrient content
Different energy densities: carbohydrates (4 kcal/g), fat (9 kcal/g) and protein (4 kcal/g).
The average energy intake is about 2800 kcal/d (2000-3500) for men and about 1800 kcal/d(1600-2250)for women.

 

Response to under- and over-nutrition

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Carbohydrates
•Carbohydrates are the sugars and starches found in foods.
•There are two general types of carbohydrates: simple and complex.
•At least 55% of total calories should be derived from carbohydrates. ( 100-200 g/ d )
•No individual carbohydrate is an essential nutrient as carbohydrates can be synthesized de novo from protein.

Simple Carbohydrates
These sugars are fructose and glucose (found in fruits and vegetables, lactose (found in milk), and sucrose (table sugar).
•The most important to the body is glucose – the form of the sugar that goes directly to the bloodstream and
•provides quick energy. All other sugars must be changed into glucose by the body before the cells can use them. The cells use glucose as their primary source of energy. Glucose that is not needed immediately is converted by body to glycogen, a form of starch stored in the muscles and liver.

Complex Carbohydrates
•Starches are complex carbohydrates that are made up of many units of glucose. These chains must be broken down by the body into single units of glucose before they can be used. simple sugars. Breads, cereals, and potatoes contain starch.
•Dietary Fiber is another complex carbohydrate, which comes from non-digestible part of plants. There two types of dietary fiber: soluble and insoluble. Soluble fiber combines with waste to assist in their removal. ( bran, beans, apples, carrots, and other vegetables)
•Insoluble fiber absorbs water and helps to provide needed bulk to the diet. (whole grains and the skins and seeds of fruits and vegetables).

DIETARY CARBOHYDRATES
Free sugars
Monosaccharides :Glucose, fructose Disaccharides : Sucrose, lactose, maltose fruits, milks, vegetables
Starch polysaccharides : Cereals (wheat, rice), root vegetables (potato), legumes (lentils, beans, peas)
Non-starch polysaccharides : (NSP, dietary fibre)
Plants Cellulose, Hemicellulose

Fats (Lipids)
•Fats are the nutrients that contains the most concentrated form of energy.
•Fatty acids have the highest energy density of the macronutrients (9 kcal/g)
•30% of calorie should be derived from the fat
•Fats are part of many body tissues and are important as carriers of other nutrients, such as vitamins. Fats also carry the flavor of foods – making foods tastier.

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Nutrients that Regulate
•Vitamins, minerals, and water are nutrients that work with the energy-providing nutrients to be sure that the body functions properly.
•Water is the most vital nutrient because it provides the means for all other nutrients to be carry throughout the body.
•Vitamins, minerals, are not digested by our body, and they do not provide Calories. They work with carbohydrates, fats, and proteins to promote growth and regulate body processes.

Vitamins

• Vitamins are organic
substances with the key
roles in certain metabolic
pathways
they also help
change
carbohydrates and
fat into energy.
• Because the body
cannot make most
vitamins, they must
be supplied by the
foods ..