Below I am copying for you a piece out of the work Dr. Greger is doing [Nutritional research]
Indeed it seems too nice to be true.

In the past i advised people to eat regular brazil nuts but not more than 2 or 3 at once.
So, maybe we can save money now!
Because of the importance of this special e-mail I may resend it a few times.
Now keep in mind they weren’t eating Brazil nuts this whole time. They had just that single serving of Brazil nuts a month before and their cholesterol was still down 30 days later. It went down and stayed down, after eating just four nuts… That’s nuts!
And no, the study was not funded by the Brazil nut industry.
Interestingly, four nuts actually seemed to work faster than the 8 nuts to lower bad cholesterol and boost good cholesterol. These results suggest that eating just four nuts might be enough to improve the levels of LDL-c and HDL-c for up to 30 days, and maybe longer—they didn’t even test past 30.
Now normally, when a study comes out in the medical literature showing some too-good-to-be-true result like this you want to wait to see the results replicated before you change your clinical practice, before you recommend something to your patients, particularly when the study is done on only 10 people, and especially when the findings are literally just too incredible to be believed. But when the intervention is cheap, easy, harmless, and healthy—eating four Brazil nuts a month—then in my opinion, the burden of proof is kind of reversed. I think the reasonable default position is to do it until proven otherwise, so now every month I eat four Brazil nuts. In conclusion, a single serving is sufficient, without producing liver and kidney toxicity. I should hope not, but what they’re referring to is the high selenium content of Brazil nuts, so high that four eaten every day may actually bump us up against the tolerable daily limit for selenium, but not something we have to worry about it we’re just eating four once a month.