I'm pretty sure B12 is pretty hard to overdose on to the point of toxicity and health issues, for many people.
Organs have been eaten for a very long time. I don't have any information on evidence of vitamin toxicity from eating organs over the thousands of years humans have, but I am going to guess that there have not been any major issues with eating organs like liver on a regular basis. A co-worker of mine eats chicken liver a few times a week. She is 63, looks like she is 50, and has a very clean bill of health. I believe she has been on a paleo-like diet for years now and have been eating animal organs, including chicken liver, for years now.
Few times a week might be fine unless he eats a lot of it at one sitting. Caveat emptor.
Estimated UL is around 3000 ug for adults, one serving of liver provides a bit more than 2x of this. So to avoid chronic toxicity, you should eat at most one portion every three days.
That's not considering the cholesterol content.
I believe vitamin A concerns should be more focuses on the synthetic version, vitamin A palmitate. Sure, too much of any vitamin from any source can possibly cause problems. I just think the concerns over vitamin A are a overhyped and with the right balance of other vitamins and minerals, your body is well equipped to handle fairly large amounts of vitamin A from natural sources.
Which is a combination of cis-retinyl palmitate (oh, same as in most supplements
, some have cis-retinyl acetate instead) and really tiny amounts of retinol.
Eating orange/red fruits and vegetables instead is far safer and carotenoids are also anti-oxidant. (but some people eating 50000 IU is funny, I suppose they look yellowish)
I wish some of the more knowledgeable members on this topic would chime in. I think you guys are a bit too concerned about getting too much vitamins from animal organs.
You mean me. I've never said they're completely unhealthy, just that they should be eaten in moderation.
Over analysis to the point of paralysis in this thread... Organs are good for you, they have been part of our ancestral diet for hundreds if not millions of years. Use common sense, check your micro and macro nutrient intake time to time, and supplement this with regular health checkups measuring key bio markers of health. It's that simple!!!
Typical checkups say little about liver function - you need to order liver enzymes specifically, same goes for kidneys (creatinine is cheap though - and a urine test). Unless you happen to own a lab (or have far too much money) and check blood vitamin and mineral levels where it's possible. Here, the idea of standard checkup is blood panel, HbA1c + cholesterol.
The diet check involves putting a good sample of the diet into software - either you're already doing that all the time, or it's going to be real pain.