It's interesting that when searching "malnourishment" a large amount of the articles are written about seniors. The article "Senior health: How to prevent and detect malnutrition" teaches us some of the ways senior become malnourished. Some ways being low income, reduced social contact, restricted diets, etc. If you have loved ones who start losing or gaining weight, or have a change in appetite they could be malnourished. Also, medications can make it so their bodies can't absorb the nutrients from their foods, so be aware of the side effects of their medication. Prevention comes from giving them nutrient packed foods, helping or encouraging exercise or some sort of activity, helping them budget their money, etc. Try to "identify and treat nutrition issues early. This can promote good health."
Caregivers. (n.d.). Retrieved March 23, 2015, from http://www.mayoclinic.org/healthy-living/caregivers/in-depth/senior-health/art-20044699?pg=2
"Caregivers." Senior Health: How to Prevent and Detect Malnutrition. Mayo Foundation for Medical Education and Research. Web. 23 Mar. 2015. <http://www.mayoclinic.org/healthy-living/caregivers/in-depth/senior-health/art-20044699?pg=1>.