To me, strengthening the partnerships and linkages among all the stakeholders named is more important than anything else because if each sector is to work independently, the the beneficiaries get more confused because at times different sectors convey contradicting messages.
For example in my country, the vehicle for dissemination of agricultural information(the extension system) uses a business lens in promoting enterprises and innovations. Infact it has 10 enterprise it considers of high value and promotes them through training on production, input supply and establishing links along the value chains. For sure, this is good probably because they think that higher income can improve access to foods through the markets. However, I imagine the resource poor farmers who may not be able to commercialise agriculture because of a number of limiting factors. How about the rural woman in some societies of Africa who has no control over cash crops, yet according to literature she is the driver to food and nutrition security? I think that promoting nutrient-rich foods such as biofortified foods- OFSP, iron-rich beans and vegetables which the woman has control over may be one of the policy level solutions to malnurition.
If also researchers in all the related sectors could do their work jointly to identify the nutritional needs of a given population, this could guide informed decisions and appropriate interventions which would help curb down the problem of malnutrition. We have seen /heard M.O.U's between the different sectors to work together only on paper, but these in most cases do not reach the grass root levels...
Links and resources: