NAIROBI - Conventional food aid is not enough to solve Africa's malnutrition crisis, especially in nations wracked by conflict, an international health agency said on Wednesday.

On a continent where thousands of young children suffer from acute malnutrition, the use of nutrient-dense ready-to-use foods (RUFs) needs urgent expansion, humanitarian organisation Medecins Sans Frontieres (MSF) told a Nairobi news conference.

Unlike other food aid, RUFs do not leave children vulnerable to diseases they should be able to fight off easily, it said.

"Current food aid, which focuses on fighting hunger, not treating malnutrition, is not doing enough to address the needs of young children most at risk," MSF said in a statement.

"It's not only about how much food children get, it's what's in the food that counts," said Dr Christophe Fournier, president of MSF's International Council, adding that many children are forced to live without healthy essentials like milk.

MSF estimates that of the 20 million young children worldwide suffering from acute malnutrition, only about three percent will receive RUFs in 2007. Five million children's deaths each year are related to malnutrition.

It is in conflict zones where the packages of food -- containing milk powder, sugars and vegetable fats -- are particularly applicable, the agency said.

"In insecure environments, like Somalia and Darfur, where people are often forced to flee for their lives with nothing but the clothes on their backs, they can't carry with them the means to prepare food," said MSF spokeswoman Susan Sandars.

"There is often no access to clean water for cooking, or charcoal for fires, or cooking utensils in general. But RUFs can be eaten straight from the packet and don't go off in the African heat," Sandars said.

"They are also much lighter to carry (than other food aid). You can potentially give a mother months of treatment in a single distribution, so they can feed their children as they are able without having to get to a centre," she said.

Some analysts, however, say more evidence from the field is needed on RUFs, and that food distribution is an economical question, not based purely on the virtues of available products.

"Some restrictions (on RUFs) are in place but research is ongoing, with WFP as well as in universities," U.N. World Food Programme spokesman Peter Smerdon told Reuters. "We have to balance the economic considerations of food distribution."

The cost of RUFs' base ingredients are all increasing, with the price of milk powder doubling since January, MSF said. The agency called on donors to help raise 750 million euros to rapidly expand distribution of RUFs to the most vulnerable.