Disclaimer: This is a medical nutrition therapy-heavy post and a reflection of a day in the life of a Dietetic Intern.
Nutrition is important all throughout the life span. I felt like celebrating it's importance by sharing a bit of what I learned when treating both ends of the spectrum: the Older Adult and Pediatric/Infant populations.
Older Adult Nutrition
I'm currently interning at a long term care facility. There are two long-term care wings and a rehabilitation wing. Most of the residents are above the age 65, a lot of them are in their 80's-90's.
My preceptor stressed to me that in the older adult population, quality of life is one of the highest priorities for the residents. This could mean (nutritionally) anything from offering a liberalized salt-diet to actually withholding nutrition and hydration when end of life is near.
Withholding nutrition? Is that ethical? Is that even legal? As a matter of fact it is ethical and legal in certain cases.
It is the Academy of Nutrition and Dietetics Position that Registered Dietitians should respect the individuals right to refuse nutrition and hydration as medical treatment. Not only should RD's make recommendations on providing nutrition, but it is acceptable that RD's recommend withholding it as well, provided the individual has stated his or her preferences to the care-providers or in an advanced directive.
Withholding nutrition isn't always desired by the patient or the patient's family for multiple reasons. In this case, providing nutrition therapy that optimizes the patient's nutrient intake while meeting their taste preferences is the goal. I'm learning that a neurological conditions are most commonly affecting an older adult patient's nutrient status.
Luckily, there are tools that improve nutrition quality being developed like these utensils for Alzheimer's patients. 
On the complete opposite end of the life span is the pediatric population.
After my rotation at the long term-care center, I traveled to a lecture series given by dietitians who work with these populations. The first speaker reviewed pediatric nutrition and the second was a dietitian who works in the NICU.
When working with kids and their nutrition behaviors, it's really important to find out what's nutrition message is going to be important in their world. For example, trying to explain to a kid the physiological importance of taking his pancreatic enzyme replacement therapy (PERT)  medicine might not be as effective as telling him that if he takes them, he wouldn't have an episode of steatorrhea during basketball practice :-( .
There's also a whole lot of literature on treating children who are overweight (85th-95th%ile) or obese (above the 95th%ile) and treatment and approaches vary widely. Really, encouraging healthy eating patterns, visiting SuperTracker.gov, and adding more play time should be the main goals when intervening in childhood weight management cases. So, it's not advisable to talk to a child about counting calories. Even with the best intentions, it might not be conducive to a healthy eating patterns hen they're older, and it could lead to disordered eating.
When it comes to identifying energy needs, dietitians are the experts. Little tiny babies, like those in the NICU, need a lot of calories per kilogram of bodyweight in order to develop and grow in those critical beginning stages of life.
While the average healthy adult needs about 25-30 kcals/kg/day, well-nourished term or appropriate for gestational age (AGA) infants- defined as those who are 1-3 months old- need 90-110 kcals/kg/day . Ideally these calories come from breast milk but there are dozens of conditions where supplementation with formula is required.
The caloric needs are even higher when infants are premature (born @ 23 weeks-before 37 weeks gestation)  and their nutrition is strictly monitored. A feeding might be 3mLs of breast milk or formula...such a teeny amount but it just goes to show just how important and how precise nutrition must be at this early age.
So, this post is more academic than the rest but it was too interesting not to reflect on. I went from learning about nutrition therapy in the population that's nearing the end of the life span to those who are just at the beginning.
1. Eatright.org. Position of the academy of nutrition and dietetics: ethical and legal issues in feeding and hydration. J Acad Nutr Diet. 2013;113(6).
2.Newsy Science. This colorful dish set helps alzheimer's pateints eat. Youtube. Published August 25, 2015. Accessed March 28, 2016. https://www.youtube.com/watch?v=zRPD21h8jKU
3. Fieker A., Philpott J., Armand M. Enzyme replacement therapy for pancreativ insufficiency: present and future. Clin Exp Gastroenerol. 2011; 4: 55–73.Published online 2011 May 4. doi: 10.2147/CEG.S17634
4. Holt PR. Diarrhea and malabsorption in the elderly. Gastroenterol Clin North Am. 2001 Jun. 30(2):427-44.
5.Hoelscher DM, Kirk S, Ritchie L, Cunningham-Sabo L. Position of the Academy of Nutrition and Dietetics: interventions for the prevention and treatment of pediatric overweight and obesity. J Acad Nutr Diet. 2013 Oct;113(10):1375-94. doi: 10.1016/j.jand.2013.08.004.
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