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Introduction

Introduction

 

I. THE RESEARCH TOPIC

An obvious thing in developing countries is that higher income allows people to raise their nutritional status. Conversely, higher food prices generally translated into reduced nutritional status of poor people. It is expected that those are also true for Vietnam. However, effects of income and food prices on nutritional status by location (urban and rural areas), by gender (male and female), and by household head (male- and female-headed households) are not known clearly. Those questions interest the author to choose the topic "The impact of income and price factors on nutritional status in Vietnam" to examine relations between income, food prices and nutritional status by location, by gender as well as by household head, in addition to those relations in the whole country. In each disaggregated case, the author hopes to find that the positive impact of income and the negative impact of food prices are stronger on nutritional status of rural population than on that of urban population; the positive impact of income and the negative impact of food prices are stronger on nutritional status of female than on that of male; and the positive impact of income and the negative impact of food prices are stronger on nutritional status of people living in a female-headed household than on that of people living in a male-headed household.

II. THE CENTRAL RESEARCH QUESTION

1. Objectives of the research

1.1. General objective: To find out whether individual nutritional status in Vietnam is responsive to income and food prices.

1.2.  Specific objectives:

¨      To verify a nutritional situation in Vietnam, compare it with other developing countries and within the country.

¨      To examine impacts of income and food market prices on nutritional status in Vietnam.

¨      To specify the magnitude of the nutritional impact between urban and rural areas, between male and female, and between male- and female- headed households.

2. Scope of the research

Relationships between income, food prices and nutritional status are analyzed for all Vietnamese, both children and adults. Nevertheless, chapter four will focus on adults to measure the impact of income and food price factors on their nutritional status through econometric models.

III. METHODOLOGY

1. Data sources

The thesis studies the impact of income and food prices on nutritional status in Vietnam by using data from the second Vietnam Living Standards Survey (VLSS 98).

2. Study design

The thesis will employ descriptive, comparative and statistical methods to deal with the research question.

IV. STRUCTURE OF THE THESIS

The thesis consists of four chapters, following the introduction part.

Chapter 1: Theoretical framework.

Chapter 2: Empirical studies on demand theory and health outcomes in some developing countries.

Chapter 3: Nutritional status in Vietnam.

Chapter 4: The impact of income and price factors on nutritional status in Vietnam.

The thesis ends with some conclusions and recommendations to improve nutritional status in Vietnam.


 

Chapter 1: Theoretical framework

 

This chapter presents an overview of nutrition, explains nutrition problems from an aspect of individual consumption behaviors, and introduces a general model for estimating health outcomes.

I. CONCEPTUAL DEFINITION

1. Understanding malnutrition

According to Jean Mayer (1976), malnutrition is classified into four types:

- Overnutrition

- Dietary deficiency

- Secondary malnutrition

- Undernutrition

In this thesis, undernutrition is a problem that the author will concentrate on. The term 'malnutrition' is also limited to undernutrition.

2. Assessment of nutritional status

2.1 Assessment of nutritional status of children

Three indicators commonly used for the nutritional status of children are height-for-age, weight-for-height and weight-for-age. They are calculated in terms of z-scores. According to the World Health Organization's recommendations, a child who has a z-score value of minus two standard deviations or below is regarded as malnutrition.

2.2 Assessment of nutritional status of adults

For adults, the Body Mass Index (BMI) or Quételet's index is a good choice for the anthropometric assessment of nutritional status. Generally, an individual who has a BMI value of over 18.5 is considered to signify adequate nutrition or be normal. Otherwise, those who have a BMI value under or equal 18.5 give a sign of chronic energy deficiency (CED). This index is best suitable for individuals between the ages of 20 and 65 years, excluding women who are pregnant or breast-feeding.

3. The consequences of undernutrition

Undernutrition can affect almost every facet of an individual's life, and then on his family and on society. It causes reduced mental and physical activities for both children and adults, and of course leads to losses in human capital.

4. World food, income and nutrition situation

On the whole, the world produces a surplus of food. Nevertheless, serious malnutrition in developing countries is a result of food shortage. Malnutrition apparently is a problem of distribution of food and income among countries, regions, income groups, between sexes and within households. The solution to malnutrition now may be to redistribute of global income and to give the poor adequate purchasing power (to meet food needs).

II. THEORY OF CONSUMER BEHAVIOUR

1. Traditional demand theory

The theory implies that consumers always choose the commodity bundle to maximize the preference they can achieve given the budget constraint available to them.

2. Theory of Household

Some theories consider household as an individual (the unitary model) that makes decision on behalf of every member in the household. Some others analyse it as a group of individuals (the collective model) where each member has different preferences and bargains with each other over household resources. The latter offers a richer structure to behaviour than the former does. However, in assessing health outcomes (particularly, nutritional status), the former is usually preferred as there is no need to process decision-making within households.

3. Laws of economics

In history of food consumption analysis, household's reactions in its consumption decisions to changes in income and prices are formed as the economic equivalent of laws.

III. REDUCED-FORM DEMAND RELATIONS

Under the assumption of the one-period, household-firm model with constrained maximization of a join utility function, Behrman and Deolalikar (1988) give a set of reduced-form demand functions, with all of the endogenous variables for the household in the left-hand side and all of the exogenous variables to the household in the right side. Reduced-form relations are a useful guidance on the choice of endogenous and exogenous variables to estimate health and nutrition outcomes. Actually, those are a background for the author to choose income and price variables to verify the impact of them on nutritional status of the Vietnamese in chapter 4.

IV. SUMMARY

The nutritional status of a person is very closely related to his or her food consumption. Bad nutritional status results in reduced physical and mental activity, stunted growth and even death… The causes of undernutrition are various, but all of them are virtually connected to low purchasing power or poverty in broader sense.

The relationship between income, price and nutritional status may be explained through demand theory. Because of budget constraints, people must allocate their resource to food and non-food items, and to various kinds of food to maximize their satisfaction. Their choice of food, therefore, influences their nutritional status.

The impact of income and food prices on nutritional status can be estimated through a reduced demand for health outcome function despite the fact that the results may be biased.

Theoretically, the nutritional status of individuals can be made better if their incomes are raised up or food price policies are set reasonably. However, performances need to be considered carefully in practice. Some empirical studies will be mentioned more clearly in chapter 2.


 

Chapter 2: empirical studies on demand theory and health outcomes in some developing countries

 

Chapter two now is more directly concerned with empirical results of demand theory and nutritional outcomes in the household in developing countries. Some points drawn from this chapter are as follows:

- Individual nutritional status is associated with household income and entitlement to food at the household level. It is easily responsive to income and price fluctuations in developing countries. In general, household income has a positive nutritional impact on the members. However, market prices have inconsistent results: reduced prices of most of food items permit a higher nutritional status but increased prices of some kinds of food also make the nutritional status better.

- Intra-household distribution is unequal throughout developing countries. "Some members of households with inadequate aggregate food intake may not be malnourished, and not all malnourished individuals come from households with inadequate aggregate food intake". And there are, in fact, very asymmetrical treatments between men and women around the world.

- Besides policies regarding to income creation and price intervention have impacts on the nutritional status of individuals within household, policies that change the mechanisms themselves of control of household income do that as well.


 

Chapter 3: Nutritional status in Vietnam

 

This chapter analyzes nutritional status in Vietnam through descriptive and comparative methods.

I. NUTRITIONAL PROBLEMS IN VIETNAM

1. General background

The transition of Vietnam from a centrally planned to a market economy has been successful. Vietnam, however, remains one of the world's poorest countries. Nutritional status of the Vietnamese is a serious problem of the whole society.

2. Nutritional status in Vietnam

A prevalence of malnutrition in Vietnam is among the highest rate in the world. The latest surveys estimate that 36.7%, 38.7% and 9.8% of children under five are underweight, stunted and wasted, respectively, and CED prevalence among adults (from 18 years old, excluding pregnant women) is 30.25%. Moreover, malnutrition is very different by gender and age. Prevalence of malnutrition among population is presented in table 1.

Table 1: Prevalence of malnutrition in Vietnam by gender, 1997-98.

 

Underweighta

Stuntinga

Wastinga

CEDb

 

% of children under 155 months

% of adults from 18 years old

Country

40.13

41.52

8.98

30.25

  - Male

41.83

43.86

8.64

28.02

  - Female

38.34

39.08

9.39

32.28

Source: Vietnam Living Standards Survey, 1997-98.

Note:  - a: anthropometric indicators less than minus two standard deviations from the median of the NCHS sample - GSO, 2000, pp. 116, 118 & 120,

          - b: BMI  equal or less than 18.5 - author's calculation.

3. Causes of undernutrition

3.1. Immediate cause

3.2. Underlying cause

3.3. Basic cause.

4. Losses of undernutrition

Vietnam suffers enormous economic and human losses from undernutrition annually. According to an estimation of NIN, about 29 per cent of child deaths each year or 180,000 child deaths per year were related to PEM (excluding deaths of mildly malnourished children); and PEM reduced 0.3 per cent of GDP per year or 674,000 million Vietnamese Dongs per year (this figure was calculated only on reduced productivity of malnourished adults, it did not include additional losses due to cognitive impairment or custodial care related to childhood nutritional deficiencies).

II. FOOD CONSUMPTION PATTERNS

1. Demand for food

2. Food expenditure

3. Composition of food expenditure

4. Food expenditure by gender of household head

In conclusion, a larger share of household budget is spent on food (compared to other non-food items) in Vietnamese households, in which, rice consumption is largest, but milk, egg consumption is smallest. Those suggest that rice is necessity but milk and egg are luxuries for almost Vietnamese. Furthermore, when household expenditure increases, a food share will reduce but more luxury food items will rise. All these happen as in the Engel's law and Bennett's law.

III. INCOME AND NUTRITIONAL STATUS IN VIETNAM

1. Income and nutritional status by years

In recent years, Vietnam's economy has grown rapidly, accompanied with increased per capita income. In parallel, the malnutrition rate has dropped significantly. The relationship between income and child malnutrition at different points in time in Vietnam is illustrated in figure 1.


Figure 1: GDP per Capita and Child Malnutrition in Vietnam, 1992-1998

Source: Author's calculation from Appendix 3.3 (in the thesis)

It is easy to see a negative correlation between income and malnutrition from two Vietnam Living Standards Surveys presented in table 2.

Table 2: Expenditure and Malnutrition in two VLSS, 1992-93 and 1997-98

 

VLSS 92 - 93

VLSS 97 - 98

Rate of change

(times)

All Vietnam

 

 

 

Expenditure/capita/year (VND 1000 at 1/1998 price)

1,936

2,764

+ 1.4

Stunting (children aged 0-155 months)

54.6*

41.5

- 0.8

Urban areas

 

 

 

Expenditure/capita/year (VND 1000 at 1/1998 price)

3,013

4,829

+ 1.6

Stunting (children aged 0-155 months)

37.3*

22.7

- 0.6

Rural areas

 

 

 

Expenditure/capita/year (VND 1000 at 1/1998 price)

1,669

2,166

+ 1.3

Stunting (children aged 0-155 months)

57.8*

45.2

- 0.8

Source: Table 3.5 in the thesis.

2. Income and Nutritional status by expenditure quintile

The relationship between income and nutritional status is able to be examined through different expenditure quintiles. A proportion of malnourished people among quintiles is showed in figure 2.

3. Income and Nutritional status by region

Table 3: Malnutrition rate in Vietnam by urban/rural area, 1997-98.

 

Urban

Rural

Income/head/year (VND 1000, 1/1998 price)a

7,105

2,409

Stuntingb

22.68

45.24

Wastingb

 9.33

 8.91

Underweightb

24.57

43.20

CEDc

25.35

31.99

Source: Vietnam Living Standards Survey, 1997-98 (see note in the thesis).

4. Income and Nutritional status by gender of household head

Table 4: Income, expenditure and nutritional status by gender of household head, 1997-98

 

Male-headed household

Female-headed household

Income/capita/year (VND 1000 at 1/1998 price)

2,910

3,721

Expenditure/capita/year (VND 1000 at 1/1998 price)

2,712

3,345

CED

30.3

30.2

Stunting

36.7

28.3

Wasting

11.2

10.0

Underweight

37.5

28.3

Source: Vietnam Living Standards Survey 1997-98.

IV. SUMMARY

It is agreed that undernutrition is an urgent concern of Vietnam. It can impair generations of citizens mentally and physically at present and in the future. The situation is even worse in rural areas. One of underlying causes of undernutrition is food poverty or low income. A clear trend in the consumption pattern is that the higher the living standard, the higher the people's need for both quantity and quality of food; the consumption structure improves along with the increase of income.

A common conclusion from this chapter is that prevalence of undernutrition reduces as income increases. This has implications for economic policies: raising income or alleviating poverty is a necessary solution. Nevertheless, how is the magnitude of the impact of income on nutritional status in the whole country? The answer must be based on regression models and will be solved in the next chapter. In chapter four, the magnitude and direction of the impact of food prices on nutritional status of the population will also be measured. Furthermore, there are disaggregated studies on the magnitude of the impact of income and prices according to location, sex and gender of household head in that chapter.


 

Chapter 4: The impact of income and price factors on nutritional status in Vietnam

 

I. DATA AND METHODS

1. Data source

The analysis is based on data from the second Vietnam Living Standards Survey, undertaken in 1997-98. The largest sample of adults (aged 20 to 65 years) for which data on all the variables of prices (35 food items) are available is summed up in table 5.

Table 5: BMI of adults (age 20-65 years) in Vietnam, 1997-98.

 

All

Urban

Rural

Male

Female

Number of observations

2865

1073

1792

1420

1445

Mean BMI

19.96

20.55

19.70

20.01

19.92

Standard Deviation

2.36

2.82

2.06

2.17

2.53

CED (% of observations)

27.79

25.87

28.66

24.03

31.43

Source: author's calculation from data of VLSS 98.

2. Methodology

Variables on income and prices are taken into account. The author will use correlation and regression analysis, which rests on some assumptions and ways of choosing variables and methods (see the thesis).

II. RESULTS

1. Correlation analysis

 

 

2. Multivariate analysis

2.1.  A continuous model

Results of the estimated coefficients for the sample in all, by urban/rural areas and by sex are given in table 6.

- Expenditure impacts on adult's nutritional status:

In general, nutritional status of adults is positively associated with per capita expenditure in the whole country (the elasticity of BMI with respect to income/expenditure is .0077). Nevertheless, the expenditure impact on BMI is different for rural and urban areas, for men and women. The result in models for urban and rural areas is different from the author's expectation. However, the result in models for male and female happens as expected.

- Price impacts on adult's nutritional status:

Overall, market prices influence nutritional outcomes of the population. Lower food prices are correlated with higher BMI, but magnitudes of the impact rely on what kind of foods. The adverse price effects of these foods remain unchanged when the sample is stratified by gender. As expected, the coefficients of prices suggest that men's health is more protected than does women's health when prices change. Price effects, on the other hand, are not uniform when the model is estimated separately for rural and urban areas.


Table 6: Impacts of expenditure and prices on adult BMI in Vietnam, 1997-98.

 

LnBMI

All

Rural

Urban

Male

Female

Sample size

2865

1792

1073

1420