The causes of malnutrition might seem straightforward — too little food or a diet lacking in nutrients. In reality, malnutrition is often caused by a combination of physical, social and psychological issues. For example:

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• Normal age-related changes. Changes in taste, smell and appetite generally decline with age, making it more difficult to enjoy eating and keep regular eating habits.

• Illness. Disease-related inflammation and illnesses can contribute to declines in appetite and changes in how the body processes nutrients.

• Impairment in ability to eat. Difficulty chewing or swallowing, poor dental health, or limited ability in handling tableware can contribute to malnutrition.

• Dementia. Behavioral or memory problems from Alzheimer's disease or a related dementia can result in forgetting to eat, not buying groceries or other irregular food habits.

• Medications. Some medications can affect appetite or the ability to absorb nutrients.

• Restricted diets. Dietary restrictions for managing medical conditions — such as limits on salt, fat or sugar — might also contribute to inadequate eating.

• Limited income. Older adults may have trouble affording groceries, especially if they're taking expensive medications.

• Reduced social contact. Older adults who eat alone might not enjoy meals as before and lose interest in cooking and eating.

• Limited access to food. Adults with limited mobility may not have access to food or the right types of food.

• Depression. Grief, loneliness, failing health, lack of mobility and other factors might contribute to depression — causing loss of appetite.

• Alcoholism. Too much alcohol can interfere with the digestion and absorption of nutrients. Misuse of alcohol may result in poor eating habits and poor decisions about nutrition.