4. Productivity, earning and nutrition in developing countries

What do all of the measurements described above mean in real life? Will increased dietary intake increase "productivity" in populations at marginal or greater nutritional risk? Also, is there an economic advantage to the individual or his society in attempting to increase his productivity by increasing his energy intake?

The old adage that "an army marches on its stomach", attributed to Napoleon, indicates an early awareness of the relationship between nutrition and productivity, in this case the performance of soldiers. Continued interest in predicting decrements in military performance due to inadequate nutrition is evidenced by a recent workshop on the topic (Committee on Military Nutrition, 1986).

In World War II, KRAUT and MULLER (1946) studied the influence of caloric supplementation on the work output of laborers in German industries during periods of food scarcity. The productivity of one group, measured as tons of material moved per hour, increased 47% when caloric intake was increased 480 kcal/d. A group of coal miners increased their productivity from 7 to 9.6 tons/d when 400 kcal were added to their diet each day. Also, WOLGEMUTH et al. (1982) found a statistically significant increase in productivity of Kenyan road workers associated with a dietary supplementation.

SATYANARAYANA et al. (1980) have provided some interesting data on earning and employment of rural boys near Hyderabad, India. In these teen-age subjects, they found a statistically significant correlation between body size (weight) and wages earned in agricultural jobs. The correlation continued to be significant after partialing out the influence of age and height. Also, there was a greater percentage of high earners classified as nutritionally normal at age 5 years than those who had moderate to severe growth retardation at age 5. The reverse was true for those earning low wages. These data support the contention that body size is important in hard physical work such as farming because of its relationship to VO₂ max (Table 3) and that early growth retardation can affect adult productivity and earning.

The economic implications of the relationships between productivity, nutritional status and VO₂ max are beyond the scope of this paper. Certainly there has been no lack of discussion about the relationships among nutrition, disease, productivity, wages and development in Third World countries (MARTORELL, 1985; BERG, 1973; OSHIMA, 1967; BALDWIN and WEISBROD, 1974; BASTA, 1977; POPKIN, 1978; BLISS and STERN, 1978; IMMINK et al., 1981; 1982; 1984).

Perhaps the most interesting of the studies which relate nutritional status to economic impact are those which have been carried out by Immink and co-workers in Guatemalan agricultural workers (IMMINK et al., 1981; 1982; 1984). These authors also found a significant correlation between adult stature and productivity in sugar-cane cutters and concluded that "those workers who suffered most severely from deficient energy-protein intake during childhood and adolescence can expect their productivity in sugar-cane cutting to be relatively affected" (IMMINK et al., 1984 p. 370). These effects result in a differential in estimated lifetime total gross earnings of 16% with the shorter workers earning less (IMMINK et al., 1984). With energy supplementation, workers appeared to increase their total energy expenditure, but since there was no demonstrable effect on worker productivity, the additional energy expenditure may have occurred in non-work activities. Furthermore, lean body mass of the workers was related to productivity of sugar-cane cutters and weeders and of coffee pickers; low values for LBM were associated with reduced lifetime earnings which represent an economic cost and a reduced human capital formation (IMMINK et al., 1984).