PGND 1st SEMESTER APPLIED NUTRITION-I HUMAN BODY COMPOSITION PGND 1st SEMESTER APPLIED NUTRITION-I

Body Composition is used to describe the percentages of following in the body: Water Protein Fat Minerals

Body Composition :- The %age of components may change with age & state of nutrition -under nutrition -over nutrition -starvation This composition can be used for assessing nutritional requirement during -Pregnancy -Requirement of some nutrients like calcium & proteins

We All Change in Many Ways

Two people of same sex & body weight may have different body composition. Optimal body composition are healither , move more easily and efficiently as compared to less ideal body composition. If you can achieve a better body composition goes a long way toward improving your quality of life and overall wellness

Typical body composition

Study of body composition under following heads :- Methodology Changes during life cycle Changes with rise in body wt. Effect of Exercise Data uses for assessing nutritional requirement

METHODOLOGY The different types of methods used in the determination of body composition may be discussed under the following heads:- Chemical analysis of whole body Physical measurements or nutritional anthropometry Isotope dilution methods

CHEMICAL METHOD Determination of water, fat, nitrogen and mineral content of human being. Like human infant weighing 3.5 kg have :- 82.3gm of water 2.3 gm of nitrogen 1 gm of calcium and 0.6 gm of phosphorous Total value is in 100 gms.

PHYSICAL MEASUREMENT OR NUTRITIONAL ANTROPOMETRY Nutritional anthropometry or physical measurement is the measurement of human body at various ages and levels of nutritional status. It is an important component of any nutrition survey. It is so simple, easily measurable. It provides as much information on the nutritional status of individuals.

Types of Physical Measurement :- Measurement of body density Measurement of skin fold thickness

MEASUREMENT OF SKIN FOLD THICKNESS It provides an estimated size of the subcutaneous fat deposit, which is basically the fat under skin. By estimating the thickness of this area there will be the estimation of the total body fat. The goal of this method is to provide an assessment of adiposity, which is better method than the body mass index (BMI). It could be calculated from measurement made at several sites such as the triceps, the abdomen and sub-capular and subcoastal sites.

Three calipers are mainly used :- USAMKNL Calipers Lange calipers Harpenden calipers

MEASUREMENT OF BODY DENSITY It expresses total body mass or weight related to body volume or the amount of space or area that body occupies. It is commonly used to estimate percentage of body fat, which determines how much fat you are carrying around. The density (D) is calculated by dividing the weight (W) of the subject by the body volume (V). D = W/V 

ISOTOPE DILUTION METHOD Total body water Body cell mass Extracellular fluid Types of isotope dilution method

Total Body Water This is determined by injecting deuterium oxide or trotrium oxide or antipyrin intravenously. This is injection is used for calculating the total body water. Then this body water content can be used for calculating the body fat percentage.

Extracellular Fluid This is measured by injecting a substance which remains distributed only in the extracellular fluid of the body. It is also determined by the degree of dilution of the substance. Sodium thiosulphate is commonly used. Other substances which have been used include inulin, sodium thiocyanate, mannitol, chloride Na24 and radioactive bromide.

Body Cell Mass All cells in the body contain potassium at a concenteration of 150mEq/kg cell water. The total amount of potassium present in the body is directly proportional to the body cell mass. The total potassium present in the body can be determined by intravenous injection of radioactive potassium and finding out its dilution in the cells. By dividing the total body potassium content by the potassium content of 1kg of fat free body the weight of fat free body can be obtained.

According to Moore the following formula of calculating the body cell mass is :- Body cell Mass(in gms.) = Ke X 8.33 where, Ke is total exchangeable potassium content in mEq and 8.33 is the coefficient derived from :- coefficient for wet tissue for nitrogen content/potassium and nitrogen in wet cellular tissue =25/3 mEq =8.33

COMPOSITIONAL CHANGES DURING LIFE CYCLE In view of the inherent difficulties involved in obtaining body composition during life cycle or as given below :- Adult Human body Full term baby Child 4&1/2 Years

Adult Human Body Various content of an adult human body was reported as :- The water content vary from 56.0-68.0% with average value of 63.0%. The fat free body weight ranged from 70-78% with an average value of 74.0%. The fat content was found to range from 12.5-19.6% the mean value being 16.4%. The mineral matter (ash) content varied from 4.8-6.4% the mean value being 5.7%.

FULL TERM BABY The mean value for a full term baby weighing 3.5kg are as follows: water 69% , protein 12.1% , fat 16.0%. CHILD 4 & 1/2 YRS. :- The values available for only one child as follows: water 53.8% , protein 18.5% , fat 22.7%. A slightly lower water content as compared with adult Human body may be due to dehydration of the body prior to death and to the higher body fat content.  

CHANGES IN BODY COMPOSITION WITH INCREASE BODY WEIGHT DUE TO OBESITY It is generally recognized that increase in body weight over the normal is due to fat deposition in the body. The fat is deposited in the adipose tissue which contains in addition to fat, water and body cell mass. The fat, total water and body cell mass contents of body of adult human subjects of varying age and body weights are different. Obese male indicates that the weight increment of 30kg in obese male is accounted for 51% fat , 15% extracellular water , 26% body cell mass and 8% extracellular solids and skeleton as in case of obese female it indicate that the increase of 30 kg in body weight is made up of 63% fat, 13% extracellular solids and skeleton.

EFFECT OF PHYSICAL EXERCISE IN BODY COMPOSITION The Effect of physical exercise on the body composition of gymnasts and obese children. In gymnasts undergoing physical training, the body weight did not change, while total body fat decreased by increase in body density indicating a greater proportion of lean body mass. The effects of reducing diet and physical training on body composition of obese children showed that at the end of 6-7 week period, all the children lost body weight and showed a reduction in body fat with an increase in body density.

Two Persons of equal weight can have different body composition

USE OF BODY COMPOSITION FOR ASSESSING NUTRITIONAL REQUIREMENT Nutrient content like nitrogen and calcium of human body at different ages have been used for estimating nitrogen and calcium requirement for growth. Calcium requirement calculated by calcium increment in body of human subject on the basic assumption like the calcium content of the body at birth has taken as 0.8% and for adult 1.6%. The % of calcium in the body is speedily increased from 0.8% to 1.6% during growth in proportion to increase in body weight.