Junk food science

The Herald has a story about junk food being linked to dementia.  The story itself is fine, but the sources are interesting:

Too much fatty and sweet food can increase insulin levels causing fat, muscle and liver cells to stop responding to the hormone, Medical Daily explained.

When the brain stops responding to insulin our capacity to think and create new memories is hindered, according to the paper recently published in New Scientist magazine.

 Medical Daily is an aggregator of medical stories — it’s a good place to find interesting research with lively descriptions, but it’s not very selective.    It’s a very popular source for the mass media and for alternative-medicine blogs.   The unusual aspect of the story is the primary source, New Scientist.   New Scientist is not a research journal, it’s a popular science magazine.  It used to be the best source in the world for accessible, detailed, science journalism, and although it’s become a bit sensationalist, there’s still a lot of good material there.   It has never been a primary source, and it hasn’t suddenly started publishing new research.

In fact, the New Scientist article is well worth reading: it describes the theory that some (most?) Alzheimer’s disease is due to insulin resistance in the brain, with quotes from researchers and links to the original research.  The “Type III diabetes” theory of dementia is definitely a minority view, and the evidence for it is thought-provoking, but not definitive.  There doesn’t seem to be any reason why it couldn’t be at least partly true, but the same could have been said for the aluminium theory of dementia in its early days.

The only good thing about the diabetes theory of dementia is that while we’re not great at treating insulin resistance, we’re a lot better at it than we are at treating Alzheimer’s.