Pediatric hepatologist Miriam Vos is starting a new study testing the effects of a low-sugar diet in children with NAFLD (non-alcoholic fatty liver disease). The study is supported by the Nutrition Science Initiative and conducted in a partnership with UCSD/Rady Children’s Hospital, San Diego. See below for more on NUSI.
While there are no medications approved for NAFLD – a healthy diet and exercise are the standard of care – plenty of drugs are under development, as a recent article from Mitch Leslie in Science illustrates. As a reality check and benchmark, the NUSI study will address whether the low-tech intervention of altering diet can be effective.
Lab Land has delved into NAFLD and its increasing prevalence in previous posts. Plenty of correlational data shows that sugar intake is linked to NAFLD (a recent paper from the Framingham Heart Study), but Vos points out that there are no studies showing that reducing sugar is sufficient to drive improvement in the disease.
Diet is a challenge to examine in humans rigorously. In observational studies, investigators are always bumping up against the limits of memory and accurate reporting. In an interventional study with adults, it’s possible to provide them a completely defined menu for a short time in a closed environment, but that’s less practical for longer periods or with children.
The press release announcing the NUSI study says: half of the families will eat and drink what they normally do while the rest will be put on sugar-free meals and snacks, all of which will be provided for the participants and their families for eight weeks.
Miriam Vos, MD
I was curious about how this would work, especially for boys aged 11 to 16 (the participants in her study), so I asked Vos more about it for Lab Land.
“We try to provide them a diet that is otherwise similar to what the family is used to,†she says. “For example, if they’re accustomed to home-cooked meals, our team of nutritionists will work with them to find different recipes.â€
“For store-bought items, we will try to find a low-sugar alternative. If a child likes to have sweetened breakfast cereal, we will look for a similar low-sugar breakfast cereal.â€
There is a hard line, Vos says — no sweets, not even with artificial sweeteners. But participating families are able to have fruit. The boys will be given lunches to take to school.
I asked Vos whether she was concerned that the boys would stick to the regimen. She says: “Most families, if they are engaged enough to be part of a research study like this, make big efforts to comply.â€
As an example, Vos cites a small study she conducted where parents made big changes in the families’ diet once they started reading labels – so that it was difficult to isolate the effects of changing fat vs sugar vs calories.
In the current study, starting this fall, outcomes are measured by the percentage of fat in the liver measured by MRI (proton density fat fraction). A biopsy is required as part of NAFLD diagnosis, but is not part of the study itself.
Note: the Nutrition Science Initiative, a nonprofit group launched by “crusading science journalist” Gary Taubes and former physician and medical researcher Peter Attia, definitely has a point of view. See this Wired profile and Taubes’ recent New York Times op-ed.
Vos is also wrapping up a pilot study — in contrast, funded by the NIDDK — testing whether two months of treatment with losartan, a widely available and inexpensive blood pressure medication, can have positive effects in children with NAFLD. Here, success is gauged by lowering levels of alanine aminotransferase, the enzyme that is a marker for liver damage.
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