Frontotemporal Dementia Boosts Sweet Food Preference

By David Douglas

NEW YORK - The preference for sweet foods seen in patients with frontotemporal dementia may be associated with specific brain networks, according to Australian and UK researchers.

As Dr. Rebekah M. Ahmed told Reuters Health by email, "For the first time using unique methods from obesity research we have quantified total intake and sucrose preference in frontotemporal dementia. We have also shown that complex brain networks control this eating behavior."

In a January 25 online paper in JAMA Neurology, Dr. Ahmed, of Neuroscience Research Australia, Sydney, and colleagues report findings from 49 patients with dementia (19 with behavioral variant frontotemporal dementia, 15 with semantic dementia, and 15 with Alzheimer's disease) and 25 healthy controls.

Mean ages for the four groups ranged from 62 to 66.

After a 10-hour fast, participants were offered an ad libitum breakfast test meal, and their total caloric intake and food preferences were measured. The patients with semantic dementia had rigid eating behavior, often refusing to eat the food on offer.

All patients with bvFTD had increased mean total caloric intake (1,344 calories) compared with the mean in the Alzheimer's disease (710 calories), semantic dementia (573 calories), and control groups (603 calories).

Also examined was their preference for desserts with a sucrose content of 26%, 39% or 60%. No group differences were seen in perceived sweetness but patients with bvFTD and semantic dementia had a strong sucrose preference compared with the other groups.

However, five patients with semantic dementia refused to partake, saying that they did not like the traditional English dessert (a mixture of strawberries, pieces of meringue, and cream).

All participants underwent whole-brain 3-T high-resolution T1 magnetic resonance imaging (MRI) on the day of the eating experiments.

The team found that increased caloric intake correlated with atrophy in discrete neural networks that differed between patients with bvFTD and semantic dementia but included the cingulate cortices, thalami, and cerebellum in patients with bvFTD, with the addition of the orbitofrontal cortices and nucleus accumbens in patients with semantic dementia.

The researchers pointed out that lack of involvement in the orbitofrontal cortex in the bvFTD group suggests "that eating behavior in this group is not simply related to a failure of inhibitory control."

Overall a distributed network of neural correlates was associated with sucrose preference in patients with frontotemporal dementia.

In particular, voxel-based morphometry analyses showed that in the combined bvFTD and semantic dementia groups, "preference for the most sweet dessert (60% sucrose) was associated with frontal, right insula-striatal reward structures, and nucleus accumbens, occipital, and cerebellum gray matter intensity decrease."

Summing up, Dr. Ahmed concluded, "An understanding of the changes and what controls the changes offers the potential to trial treatments that could modify eating behavior, metabolism and disease progression."

In an editorial, Dr. Jennifer L. Whitwell of the Mayo Clinic, Rochester, Minnesota, noted, "Task-free functional MRI could be used to investigate whether the regions implicated with each of these eating behaviors are indeed functionally connected and allow the assessment of how disruptions in these networks are associated with behavior."

The National Health and Medical Research Council of Australia and the Australian Research Council Center of Excellence in Cognition supported this research.

SOURCE: https://bit.ly/1NM7dJe and https://bit.ly/1QTs0Bc

JAMA Neurol 2016.

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