Contents - Previous - Next

This is the old United Nations University website. Visit the new site at

IFPRI abstracts

Food price subsidies

The pilot food price subsidy scheme in the Philippines: Its impact on income, food consumption, and nutritional status. Marito Garcia and Per Pinstrup Andersen. Research report no. 61. International Food Policy Research Institute, Washington, D.C., 1987.

Among the strategies used by governments to augment the nutritional status and real incomes of their populations are price discounts on selected foods. Although such subsidies may be effective in achieving their direct objectives, they may also be excessively costly. To improve the cost-effectiveness of food subsidies, governments often target them to those segments of the population most in need. Because cost-effectiveness depends on the design and implementation of a scheme, small-scale pilot programmes and feasibility studies are useful in assessing the validity of a particular plan.

In The Pilot Food Price Subsidy Scheme in the Philippines: Its Impact on Income, Food Consumption, and Nutritional Status, Marito Garcia and Per Pinstrup-Andersen present results from a pilot scheme geographically targeted to three divergent but economically depressed rural provinces, Abra in the north, Antique in the middle, and Cotabato in the south. Of 14 villages in the three provinces, half received the subsidy and half served as controls. About one-third of the households in the villages-840 households-were randomly selected to be surveyed for a study of the feasibility and cost-effectiveness of the programme, and individual members of a subsample of 140 households were interviewed to determine how food was distributed within the family. The average monthly income of the sample households, 910 pesos, was well below the average for the Philippines. On average, 71% of the expenditures of the families went to food, compared with 57% for the country as a whole.

The scheme, implemented for a one-year period beginning in mid-1983, consisted of price discounts on two calorie-rich foods, rice and cooking oil, and a nutrition-education component in the form of classes for mothers. Rice was selected because it is the major food staple in the Philippines and cooking oil because its caloric density makes it a good choice for boosting the energy consumption of small children, who may not be able to consume enough calories from a high-bulk food such as rice.

The study evaluates the effects of the subsidy on household food expenditures, food acquisition, and calorie consumption, as well as the nutritional status of the individuals surveyed, especially children aged 13 to 83 months. It provides strong evidence that the targeted pilot subsidy scheme was successful in increasing calorie consumption, mostly as a result of increases in purchasing power resulting from the price subsidies on rice and oil. In addition, it evaluates the scheme's design from the viewpoint of technical and administrative feasibility, concluding that a real advantage lies in the use of an existing infrastructure of extension workers and an existing delivery system through local stores.


The scheme

Each household in a project area was issued a ration card that guaranteed a monthly quota of rice and cooking oil at a subsidized price. The quotas were filled by private grocers in the villages, who in turn purchased rice and cooking oil from public or private wholesalers and received reimbursement for the subsidy from a special account established in the local bank.

The monthly quota was 5 kilograms of rice and 400 grams of cooking oil per household member, and the price subsidy was about 30% of the price of rice and 50% of the price of cooking oil. The value of the sub sidy was about 9% of average household incomes in the project areas. Because the discounted rice ration was only about half the amount usually consumed but the oil ration was larger. consumer rice prices were not reduced at the margin but oil prices were.

Eighty-four per cent of the cost of the scheme to the government was the subsidy itself. Administrative costs accounted for about 9% and an incentive payment to retailers was about 7%

Effects of the scheme

The study shows that the pilot subsidy increased household incomes and household food consumption by more than 9%. Adult males had the largest increase among household members (13.4%) and female preschoolers gained the least (4.7%). Although the distribution of the additional food was biased toward adults, pre-school-age children in households receiving the food subsidies showed a 12.1% improvement in their weight for age and a 22% improvement in their height for age.

It is estimated that each additional peso of income from a source other than the subsidy would expand daily calorie acquisition by 150 calories per adult equivalent unit (AEU), whereas every additional peso of purchasing power obtained from food subsidies would expand calorie acquisition by 230 calories per AEU. (The adult equivalent unit is a method used to convert people of different ages and sex to standard consumption units.) These findings show that food subsidies are more likely to increase calorie consumption than household income from other sources.

During the year that the pilot subsidy scheme was being tested, the households receiving the subsidy did not show a statistically significant increase in calorie consumption. As the result of economic factors not related to the study, however, the calorie consumption in the control households-those not receiving the subsidy-declined sharply. Thus the subsidy resulted in a significantly greater calorie consumption of about 10% above what it would have been without the subsidy.


In estimating cost-effectiveness, the study considers three main factors: the size of benefits to intended beneficiaries, the extent of benefits to those not targeted (called leakage), and fiscal programme costs. The costs for five levels of targeting are estimated, including all households in the target villages, households with calorie intake below 80% of requirements. households with malnourished preschoolers, only preschoolers, and only malnourished preschoolers.

The cost-effectiveness of the scheme is estimated in several ways, including the cost of transferring the equivalent of US$1.00 of real income and the cost of transferring 100 kilocalories per AEU per day. The fiscal cost of transferring each US$1.(N) to households in the project areas is estimated to be US$1.19. However, if only the transfers received by households with malnourished preschool children are considered a benefit, whereas transfers received by other households in the project areas are considered leakages, the cost increases to US$3.61. If only households consuming less than the 80% of estimated energy requirements are considered the target, the cost would be US$1.63. The Philippine pilot project was similar to food supplementation programmes in other countries in cost-effectiveness of transferring real income.

A different picture emerges, however, when the costs of transferring calories are compared. The cost of transferring 100 calories per day per person for a year was estimated to be US$3.38 under the Philippine pilot scheme. The study compares this cost with costs for other targeted schemes, including those in Sri Lanka, Brazil, Colombia, India, and Mexico. The Philippine scheme is quite close to the cost of a food subsidy scheme in Sri Lanka but much less than the costs of other programmes for which information is available. If only households with malnourished preschool children are targeted, the cost increases to US$6.83, which is still less than that of all the other programmes except the one in Sri Lanka.

In estimating cost-effectiveness, the study considers one other factor. If rice and cooking oil are subsidized, households are likely to buy less than usual from other sources. The net increase in food consumption will be less than the additional subsidized food obtained. In this study substitution for other foods was close to 50%. Therefore, assuring a net increase in energy consumption of 100 calories per day per person for one year would cost double US$3.38. Or US$6.76; and the cost would increase to US$13.66 if the subsidy were targeted only to households with malnourished children.

Policy implications

The purpose of the subsidy in the Philippine pilot scheme was to reduce calorie deficiencies in low-income households. If the sole goal of a subsidy scheme were to reach malnourished preschoolers, however, a second step should be added to the geographical targeting procedure. After villages with a high degree of malnourishment are selected, the subsidy should be limited to households with malnourished preschoolers, which would reduce the cost of providing benefits to this group to about half the cost of providing the subsidy to the entire village. However, calorie adequacy data indicate that older children were almost as likely to be malnourished as preschoolers, which raises the question of the validity of targeting this age group alone. A two-step targeting procedure based on growth-monitoring of all children might be more appropriate.

The study finds a strong relationship between malnutrition and low income. Families of landless farm workers, hired fishermen. and tenant farmers, for example, are much more likely to be malnourished than their neighbours in other occupations. Efforts to improve the nutritional status of preschoolers in these groups through nutrition education are unlikely to be successful unless the low-income household's purchasing power is increased. Efforts to reallocate an inadequate amount of food among household members so that preschoolers receive a larger share could reduce the energy levels of adult wage-earners to the point of impairing their capacity to work, thus limiting the household's income even more. Nonetheless, nutrition education is effective in assuring that a larger share of additional income is spent on food for the most vulnerable household members.


Commercialization of agriculture

Income and nutritional effects of the commercialization of agriculture in southwestern Kenya. Eileen T. Kennedy and Bruce Coghill. Research report no. 63. International Food Policy Research Institute, Washington, D.C., 1987.

Commercialization of agriculture is a controversial issue. While a number of studies have indicated that the effects of cash cropping on nutrition have been disastrous, others have found a positive or at least a neutral effect.

This research, which was initiated at the request of the government of Kenya and conducted jointly with the National Council for Science and Technology of Kenya and Kenyatta University, aims to evaluate the effects of a shift from maize to sugar cane on agricultural production, income, expenditures, consumption, and health and nutritional status.

The research was conducted in South Nyanza district, the area of Kenya with the highest mortality rate from birth to two years of age-216 per 1,000-of any district of Kenya. By encouraging farmers to move into commercial agriculture, the government hoped to improve the general health and well-being of low-income farm households.

A random sample of smallholder farmers in various stages of sugar-cane production was selected from those under contract to a sugar factory in South Nyanza. Non-sugar farmers (those not growing sugar under contract) with similar characteristics were randomly chosen from a mapping of next-nearest neighbours to ensure geographical similarity. A random sample of merchants and the landless were included in order to assess the total effects of cash cropping on the community.

Agriculture in the area is dominated by smallholder agriculture, with maize being the major crop. Farmers mostly use a low-input technology, relying heavily on household labour. For maize, 95% of labour is provided by household members. Only 16% of the sugar farmers and 6% of the non-sugar farmers use any inorganic fertilizer.

As sugar-cane production expands, it mainly replaces maize area. Of the plots planted in sugar cane, 95% were formerly used for maize. In 1984, a drought year, returns to land were similar for maize and sugar cane. Under normal climatic conditions, however, maize usually produces a larger return to land than sugar cane. The picture is dramatically different when the returns per day of household labour are analysed. The return to labour for sugar is three times the daily agricultural wage rate and significantly higher than the return for maize.

Incomes of the farmers participating in the sugarcane outgrowers' scheme are significantly higher than those of non-sugar farmers. Most of the difference in income comes from marketed agricultural surplus- 36% of the income in sugar-producing households compared to 20% for non-sugar farmers. Fifteen per cent of the sugar farmers' income is from participation in the outgrowers' programme.

Much of the incremental income earned by sugar farmers is spent on non-food expenditures. Merchants and sugar-producing households spend more on housing and education than other households in the sample. Although these expenditures presumably have a beneficial effect, they do not appear to produce a nutritional benefit for preschoolers-at least in the short run.

However, the increased income positively affects household calorie consumption, and the percentage of income derived from sugar has an additional positive effect above and beyond the pure income effect. For each 1% increase in sugar-cane income. household energy intake increases by 24 calories. At the mean, sugar income contributes an additional 360 kilocalories per day to household energy intake. Some fine-tuning of commercial agricultural schemes could help to maximize the potential impact of the increased income on household and preschooler nutritional status.

Illness is so prevalent in South Nyanza that 50%-70% of the children and women and sick, on average, one out of every four days at any given time. Illness tends to be most prevalent in the preharvest, rainy season. Morbidity patterns are one of the major determinants of preschooler nutritional status. The more a child is ill or has diarrhoea, the less improvement will be shown in nutritional status.

Children from households headed by females consistently have better nutritional status than preschoolers from other types of households. Girls do better than boys and older children do better than younger in many of the growth parameters. There is also some evidence that income controlled by women correlates with improved nutritional status, indicating that women are more likely to spend on food and health care.

The positive effect of the sugar-cane scheme on income is apparent and should not be understated. However, the data suggest that one of the major pathways to improving nutritional status is improvement of health and the sanitation environment. The healthcare infrastructure must be taken into consideration when policy makers are trying to anticipate the effects of agricultural policies and programmes. Low-cost, low-technology innovations with a preventive focus can have a high payoff in child health.

Book reviews and notices

Human body composition: Growth, aging, nutrition, and activity. Gilbert B. Forbes. Springer-Verlag, New York, 1987. 350 pages. US$66.

This book reviews modern knowledge concerning body composition at all ages and for all physiological states. The ways in which composition is influenced by nutrition, physical activity, hormones, trauma, and disease are described. The book provides comprehensive, authoritative, and readable coverage of the subject without redundancy and includes more than 40 pages of references and a good index. It will be valuable for those whose teaching responsibilities include this subject and for physicians and graduate students whose research involves body-composition measurement.


Recent advances in obesity research. Vol. 5. Edited by E. M. Berry, S. H. Blondheim, H. E. Eliahou, and E. Shafrir. John Libbey, London, 1987. 397 pages. 32; US$56.

The First International Congress on Obesity provided the basis for the first volume in this series in 1974; subsequent congresses were covered in additional volumes in 1977, 1980, and 1983. The present volume is based on the congress held in September 1986. Given the enormous interest in the growing problem of obesity in most industrialized countries and for the more affluent in developing countries, research progress justifies congresses with this frequency. The present volume consists of 56 short chapters grouped into sections on epidemiology, genetics, the relationship between diabetes and hypertension, regional differences in adipose tissue distribution and metabolism, bioenergetics and thermogenesis, the cellular characteristics of adipocytes, central and endocrine regulation of adiposity, energy balance in pregnancy and lactation, pharmacological intervention, and the treatment of obesity, including very-low-calorie diets and exercise. With such a diversity of chapters, the subject and author index is particularly useful.

Among the highlights of greatest interest are the following

While the chapters are of variable quality and by no means constitute a complete review of the field, the book provides a good insight into the state of current knowledge and research.

Nutritional intervention in the aging process. Edited by H. James Arnbrect, John M. Prendergast, and Rodney M. Coe. Springer-Verlag, New York, 1984. 343 pages. US$51.90.

With the proportion of elderly increasing in some developing countries and already constituting 11% to 16% of the population of industrialized countries. a book on nutrition and the aging process is timely. There are two major problems: the topic is relatively new, and much of the information is extrapolated from knowledge obtained with younger age groups or extrapolated with uncertain validity from studies in experimental animals. Nevertheless, the evidence presented in many of the chapters of this book indicates that "it is presently within the power of every healthy aging individual to delay the physiological decline and body composition change by integrating exercise into the daily routine, adjusting energy intake to maintain a youthful proportion of body fat,'' and consuming a diet that meets sound guidelines. The chapters relating to the sociologic factors, age-related changes in taste and smell, and in protein, mineral and vitamin metabolism adequately cover present knowledge. Many of the other chapters are more speculative and contribute little to the book's stated purpose of identifying nutritional interventions. The book only partially succeeds in justifying its title. but until more specific attention is paid to nutritional studies in the elderly, there will be little to add.

Nutrition and aerobic exercise. Edited by Donald K. Layman. ACS symposium series, 294E. American Chemical Society, Washington, D.C., 1986. 150 pages. USA/Canada, US$34.95; export price. US$41.95.

The potential health benefits of a combined programme of nutrition and exercise are being increasingly recognized and incorporated into national dietary goals and guidelines. Based on an American Chemical Society symposium, this book provides insight into current knowledge of nutrition and exercise for both the specialist and the non-specialist. Chapters deal with biochemical adaptations induced by exercise training, the influence of exercise on fuel utilization by skeletal muscle, effects on protein and amino-acid metabolism, lipid and protein metabolism, riboflavin requirements, trace element and calcium status, and water and electrolytes. The final chapter on aerobic exercise and body composition documents the potential of exercise at any age to conserve and increase lean body mass and increase the leanness-to-fatness ratio. Aerobic exercise is particularly important in preventing obesity and retarding osteoporosis.

The opening chapter lists a series of frequently asked questions to which the book provides answers. For example:

The book is well illustrated, and references and a useful index are provided.

Nutrition and blood pressure. Edited by Peter Bursztyn. John Libbey, London, 1987. 169 pages. 19.

A well-written and well-documented series of chapters examines the relationship between blood pressure and vegetarian diets, obesity, dietary fat, dietary fibre, alcohol, dietary sodium and potassium, and calcium. Various workers have demonstrated that hypertensive patients often respond well to, and are sensitive to, weight reduction, salt-reduced diets, abstinence from alcohol, and a reduction of saturated fat as well as combined dietary measures. Dietary changes that include increased fibre intake and reduced fat, alcohol, and salt intake coupled with weight reduction produce a clinically useful reduction in the blood pressure of moderate hypertensives. The results of the dietary approach to hypertension are comparable to those achieved by drug treatments. Peasant populations tend to have low blood pressures and little hypertension, and diet appears to be the major responsible factor. However, it is noted that the physiological links between dietary factors and blood pressure have not been demonstrated experimentally. The book is an excellent summary and source of literature on this important topic.

Vitamin A deficiency and its control. Edited by J.C. Bauernfeind. Academic Press, Orlando, Fla., USA. 1986. US$95.

There has been a new wave of concern for the continuing widespread adverse health impact of avitaminosis A. If the estimate in the foreword of "8-10 million clinical cases per year, 500,00 of whom become blind" is anywhere near correct, this renewed interest in the problem is more than justified. There are also new studies suggesting that vitamin-A deficiency increases morbidity and mortality from infectious disease.

This multi-authored hook provides a comprehensive and authoritative up-date of the major issues, beginning with global occurrence and the physiological and metabolic basis of major signs of vitamin-A deficiency. Seven chapters then deal with the control of vitamin-A deficiency by periodic oral dosing in various countries. In addition chapters deal with the vitamin-A and provitamin-A composition of foods, and with organizations involved in the effort to eradicate avitaminosis A. It is unfortunate that its price will put this valuable book out of reach for most persons in developing countries who could make the best use of it.

Gene banks and the world's food. D. L. Plucknett, N. J. H. Smith, J. T. Williams, and N. M. Anishetty. Princeton University Press, Princeton, N.J., USA, 1987. US$42.

This book provides a history of germ-plasm preservation and exchange, from botanical gardens to modern cold-storage units, and a highly readable assessment of the scientific and political ramifications of gene-bank programmes.

ACCIS guide to United Nations information sources on food and agriculture. ACCIS guides to United Nations information sources, no. 1. FAO, Rome, 1987. 124 pages.

This publication is the first in a series of subject oriented guides to United Nations information sources. It is divided into 10 chapters, dealing with food and agriculture in general; plant production and protection; animal nutrition and health; food and nutrition; land and water development and natural resources; economic and social development; trade and commodities; agro-industries and industrial development; fisheries and agriculture; and statistics. Each chapter consists of a series of brief descriptions of information sources within its subject area. Some types of sources included are libraries and other units maintaining document collections, computerized data bases, including those currently not publicly available, and publications, particularly regular serial publications such as journals, newsletters, and yearbooks and some directories. Annexes contain national contact addresses, addresses of organizations included in the guide, and addresses of commercial on-line hosts offering access to United Nations system data bases. Indexes to subjects, names of organizations and departments, publication titles, and data bases and systems are also included.

News and notes

Codex Alimentarius Commission

After 25 years, the joint FAO/WHO Codex Alimentarius Commission has grown from the original 30 countries to 130 today. The Codex system was set up to facilitate the world trade in foods and to protect consumers' health through internationally agreed standards and codes of practice.

FAO and WHO have a number of projects providing assistance to member countries to set up and improve the food control system. A clear distribution of responsibilities at the national level is necessary, together with simple rules and regulations that differ as little as possible from those of other countries. The Codex work offers a common forum for discussion between government representatives, producers, exporters, importers, and consumers. The commission agreed to establish a new committee for standardization of tropical fresh fruits and vegetables and accepted Mexico as host country. The new committee will elaborate standards and codes of practice for tropical fresh fruits and vegetables that are grown exclusively in tropical zones.

So far, more than 200 individual commodity standards have been elaborated, as well as 35 codes of practice and about 2,000 maximum residue limits for pesticides. Codex committees that have completed their work have been adjourned, and new committees have been set up. In general, the work on individual commodity standards is giving way to more "horizontal" work. For future work, Codex will concentrate on aspects of food safety-additives, contaminants, pesticide residues, food hygiene- and of food quality-labelling, nutrition information, claims, ethical problems.

The Codex Committee on Methods of Analysis and Sampling has the consideration of simple methods of analysis as a permanent item on its agenda. There is a constant need for methods that can be used in laboratories with basic facilities and equipment and that are still sufficiently accurate.

An important task for the future will be to work for the practical application and implementation of standards and codes. Standards will have to be accepted by governments and be incorporated into national regulations, and the codes of technical and hygienic practice will have to be widely applied. The Codex regional co-ordinating committees have been given an important role in the co-ordination of international and national food safety work. There are four Codex co-ordinating committees-for Africa, Asia, Europe, and Latin America and the Caribbean; the co-ordinating countries are Egypt, Indonesia, Austria, and Costa Rica respectively.

For more information about Codex work, contact the Codex contact point in your country; the contact point in most countries is located in the Ministry of Agriculture. Or write to the Codex secretariat, c/o FAO, Via delle Terme di Caracalla, Rome, Italy.

- Barbo Blomberg-Johansson
(reprinted from the Food Laboratory
Newsletter, 1987, no. 10)

Course on food and nutrition in primary health care

The fifth six-week training course on Food and Nutrition in Primary Health Care will be held in Wageningen, Netherlands, 24 October-2 December 1988. It is designed primarily for programme officers who have responsibility in implementing activities for the improvement of the food and nutrition situation of vulnerable groups. The main objective of the training will be to strengthen the capability of the participants in completing their day-to-day work-in particular, programming, data collection and analysis, the management of money, materials, and time, the supervision and motivation of personnel, reporting, and other important managerial tasks.

The course will be conducted by the International Courses in Food Science and Nutrition, under the responsibility of the International Agriculture Centre. The total fee for the course is 8,500 Netherlands guilders, which covers all costs except travel to and from the course location. The closing date for applications is 1 September 1988. Admission to the course will be on a competitive basis.

For further information, contact: International Agriculture Centre, P.O. Box 88, 6700 AB Wageningen, Netherlands; telephone 08370-90111.


Tempe newsletter

In 1986 a first course of applied research and training on tempe was held at the Nutrition Research and Development Centre, Bogor, Indonesia. The training participants were ten scientists from Asia and Africa. Funding was provided by the United Nations University.

Participants pointed out the following benefits from the training: Tempe technology is an appropriate technology for processing legumes (not only soybeans) into palatable, safe, and nutritious food. The significant health effects of soybean tempe, especially the complementary value of tempe protein for cereals and other carbohydrate sources and the high content of dietary fibre and its effect on diarrhoea, are very important for developing countries. Tempe can be used in nutrition improvement programmes.

The transfer of tempe technology to developing countries will! help promote the nutritional status of their populations. This can be achieved only if the trainees disseminate the knowledge and skill gained from the training in their own countries.

To keep the participants aware of developments in tempe technology, a Tempe Newsletter, funded by the United Nations University, is being published four times a year by the Nutrition Research and Development Centre. Those interested in further information should write to the Nutrition Research and Development Centre, Komplek Gizi Jl. Dr. Semeru, Bogor 16112, Indonesia.

Letter to the editor

Precision in naming foods

Precision in naming foodstuffs about which nutritional statements are being made is obviously important. Polacchi's article "Standardized Food Terminology" [1] calls attention to sources of error concerning fish and seed legumes. Differences in the fat contents of different cuts of meat are quoted, but these are much smaller than the differences in composition of foods often grouped together as "fresh vegetables.'' For example, the percentage of protein in the dry matter can range from I to 30 and that of beta carotene from 0.4 to 0.0001; dry matter can range from 4% to 20% Inadequate recognition of differences in dry matter is a frequent source of illusion in papers about food. There is, for example, a misleading comparison between rice and vegetables in the June 1987 issue of the Food and Nutrition Bulletin.

In many publications, and in tables showing food consumption and production in various countries, it is unusual for the categories of vegetables to be properly separated. Listing vegetables by species is not a complete answer. The leaves of an open cabbage contain much more protein and beta carotene than those of a heading cabbage. A first step would be to distinguish dark green leaves from others.

Imprecision about vegetables is an aspect of a wide spread tendency to treat them less seriously than other foods. Even dark green leaves are usually regarded as decorative adjuncts to a meal rather than as significant components of it. This is absurd: the amounts eaten in some communities supply as much protein as fish supplies in countries such as the United Kingdom, and, with reasonable skill in cultivation, leafy vegetables give an annual yield of edible protein which is three or four times as great as the yield from beans. I have commented on these points at greater length elsewhere [2-4]. The paper by Quisumbing [5] who commendably differentiates leafy and yellow vegetables from "other vegetables," suggests that vegetables supplied as much protein as eggs in the Philippines in the 1970s. That paper also shows that the cost of protein in vegetables was intermediate between the cost of protein in eggs and in poultry or meat. Although the cost was greater than the cost of protein in beans, that difference is offset by the great yield and by the beta carotene in dark green vegetables.

N. W. Pirie Rothamsted Experimental Station Harpenden AL5 2JQ United Kingdom


  1. Polacchi W. Standardized food terminology: an essential element for preparing and using food consumption data on an international basis. Food Nutr Bull 1986;8(2):66-68.
  2. Pirie NW. Restoring esteem for leafy vegelables. Appropriate Technology 1976;3:24-25.
  3. Pirie NW. The need for more information about vegetables. In: Spedding CRW. ed. Vegetable productivity. London: Macmillan 1981:6-16.
  4. Pirie NW. Comments on the importance of green vegetables. Qualitas Plantarum: Plant Food for Human Nutrition 1985;35:73-80.
  5. Quisumbing MAR. The effects of food prices and income policies on the nutrition of low-income groups: a Philippine case-study. Food Nutr Bull 1986;8(2):24-49.

Contents - Previous - Next