In 1989 the distribution of groundnuts in the general ration for Mozambican refugees in Malawi stopped and the level of available niacin in the food basket dropped. In addition, even though the distributed general ration had included beans as a source for tryptophan, the quality was often so poor that excessive cooking was necessary to make the beans edible which was often not feasible because of fuel shortages (Berry-Koch et al., 1990). Cases of pellagra appeared four months after groundnut distribution ceased and declined once groundnuts were returned to the food basket.

Outbreaks occurred when the mean daily per capita quantity of niacin equivalents (NE) in the food distributed to the refugees was 7.9 mg NE per day (or <4.0 mg per 1000 kcal energy intake) instead of the daily amount of 12 mg niacin equivalents recommended by FAO/WHO (or 6.6 mg NE per 1000 kcal) (see Table 9b). The previously recommended ration with 60 g of groundnuts would have contained 11.4 mg NE per day which would still not have covered the basic requirements for the vitamin (see Table 9b). It should be noted that only 30% of the niacin in the maize was available so the available niacin equivalent (ANE) of maize and therefore of the whole ration was considerably less than the above mentioned NE. This is reflected in Table 9a.

Table 9a. Niacin, niacin equivalent (NE)^1, and available niacin equivalent (ANE)² of daily recommended ration for Mozambican refugees in Malawi*

* recommended by UNHCR.

¹ The sum of niacin and 1/60 of the tryptophan (by weight).

² The total amount of niacin biologically available; in maize, this is calculated by adding 30% of the niacin and 1/60 of the tryptophan. All niacin in beans and groundnuts is bioavailable.

Table 9b. Niacin, niacin equivalent (NE)¹, and available niacin equivalent (ANE)² of daily rations distributed to Mozambican refugees in Malawi in 1990

Source: Tables 9a and 9b adapted from Table 1 in CDC (1991).

¹ The sum of niacin and 1/60 of the tryptophan (by weight).

² The total amount of niacin biologically available; in maize, this is calculated by adding 30% of the niacin and 1/60 of the tryptophan. All niacin in beans and groundnuts is bioavailable.

Most of the pellagra cases registered in the outbreak in Malawi in 1990 were adults aged 15-44, the incidence rate being highest among women, i.e. the female:male ratio was almost 8:1. The overall attack rate was 11.5 per 1000, the attack rate on persons > 5 years of age was almost ten times that in children < 5 years. It was argued that as women were more likely to work outside than men, exposure to sunlight may have contributed to the higher incidence of clinical pellagra among women.

The following risk factors were identified in the 1990 outbreak of pellagra in Malawi (Toole, 1992; Centers for Disease Control, 1991):

• female sex;
• having an unemployed head of the household;
• residence in a closed camp rather than an integrated village;
• absence of groundnuts or fish in the daily diet;
• lack of a home vegetable garden or domestic poultry;
• home maize milling.

As an immediate response to the pellagra problem in Malawi, groundnuts were reintroduced into the general ration, nicotinamide was used to treat the clinical cases, and vitamin B complex tablets were distributed as a preventive measure to refugees living in camps (Centers for Disease Control, 1991).

When it became clear that dietary diversification in the form of increased groundnuts in the general ration was not being effective in eliminating pellagra in Malawi, bean meal was fortified at a level providing 100 mg of nicotinamide per 20 g of bean meal and distributed to the refugees in the general ration. Subsequently, in 1991, maize meal was fortified at local commercial mills so that approximately 70% of all maize flour distributed in the general ration in Malawi was fortified with nicotinamide, providing an average intake of 55 mg per person per day or, after cooking losses, approximately 40-45 mg per day (Toole, 1994).

Lessons learnt

• Emergency affected populations dependent upon a maize-based diet should be provided with at least one niacin-rich food commodity in the general ration.

• The niacin content of the food basket for maize-dependent emergency-affected populations should be carefully monitored and if found to be low or marginal, a surveillance system for pellagra and other micronutrient deficiency diseases should be established.

• A longer-term solution for the complete eradication of pellagra may be the fortification of maize or bean flour with nicotinamide.