Sure you could read a study to get the same information, but unless your own data screams to you what the problem is it's not always easy to convince folks you should be doing anything about it.
What would you say if the family was providing unhealthy food, and the doctor prescribed a year of vegetables from Medicaid? I agree, that would be a great program, but federal agencies can only do what they're specifically allowed to by law. I would imagine there is much data gathered on what conditions Medicare patients are suffering from, and i presume if malnutrition is common, that would be addressed in agency reports and in congress.
I'm not sure what data you're envisioning 'screaming' to responsible parties or what method they would be encountering this data by.
Or, if the adult has any property that increases their net worth over a certain amount, then they can't get the benefit at all.
If they found a medical relationship is more effective, great. But the answer is to budget and create appropriate rules for that first.