Daily Science Dose

I can’t just leave it alone. First off, I’m assuming you’ve read yesterday’s post, yes?

So, I was thinking about this whole “eating liver leads to vitamin A toxicity” deal. Why? Why would a Husky liver do this, when we eat cow and chicken livers with aplomb? (Please note: I do not support liver eating of any sort. If you were to eat a car, would you eat the filter first?)

I have found the answer, at a lovely site called “Death by Vitamin A.” I cannot quote the site here, ’cause it says so, but, to sum up, vitamin A starts out in marine algae. Various things eat the marine algae, and then various things eat these various things, until we reach the guys at the top of the food chain who, for the most part, are large, carnivorous mammals like polar bears, seals, and dogs. We’re talking arctic mammals, arctic dogs.

A person’s got about 575 IU (International Units) of vitamin A per gram of liver. Compare that against the Southern Elephant seal - 1,160 IU/g; Antarctic Husky - 10,570 IU/g; the arctic bearded seal - 12,000 - 14,000 IU/g; and the polar bear, coming in at between 24,000 and 35,000 IU/g.

And check this out - Halibut liver oil runs at about 30,000 IU vitamin A/g. If someone offers you some halibut liver oil, may I suggest that you decline their kind offer?

So, like, what happens if you have too much vitamin A?

First, you know the different between fat soluble and water soluble vitamins, right? Water soluble vitamins dissolve in water, and the excess is not stored in the body - it’s excreted in, like, pee. And stuff. Vitamin C and the B vitamins are all water soluble. This is why products such as Emergen-C are safe even when they contain over 1,000% of the recommended amount of vitamin C. This does NOT mean you can’t achieve toxic levels of vitamin C or of the various B vitamins - you can achieve toxic levels of vitamins B and C. It is, however, much more difficult than achieving toxic levels of fat soluble vitamins.

The fat soluble vitamins, vitamins A, D, E, and K, don’t pass out of the body so easily. They can accumulate in the body’s fatty tissues, leading to toxic levels. You can’t, like, pee them out in an hour or so, like you can vitamin C and B. So, you want to watch your intake of these vitamins.

What are the side effects of having too much vitamin A? What are the symptoms of vitamin A toxicity?

First, there’s a better name than vitamin A toxicity. Hypervitaminosis A! Acute hypervitaminosis occurs when too much of the vitamin is taken within a short period of time, while chronic hypervitaminosis describes too much of the vitamin being present over a longer period of time.

Ooh! In a baby, acute hypervitaminosis A can make the soft spot bulge out! Something to watch out for, should your baby be…um…eating arctic animal livers. Or multivitamins.

The symptoms of hypervitaminosis A, which can be found at MedlinePlus, also include the following: hair loss, cracks at corners of mouth, bone pain, drowsiness, vomiting, and - o! - gynecomastia!

I don’t wanna talk about gynecomastia, not tonight, honey, but you can read about it if you wanna.

Wikipedia lists the symptoms of acute toxicity as “nausea and vomiting, headache, dizziness, blurred vision, and loss of muscular coordination.”

Right now, I have the symptoms of acute way-up-past-bedtime-a-matosis. I’ve got to take care of this condition, stat.

Goodnight, goodluck, and please do keep tabs on your vitamin intake, particularly if you are taking vitamin supplements, and especially especially if you are a baby, are pregnant, have a bum liver or not great kidneys, and/or if you take medication(s).

hypervitaminosis, fat soluble vitamins, water soluble vitamins, vitamin A toxicity, marine algae, arctic mammals, liver, vitamin A

ps - I realize the title of this post is a bit misleading. If I read the title, I would expect to read about algae and its direct toxic effects on the animals that encounter it. I promise - I’ve added that subject to our to-do list.

pps - I promise to do some photoshoots this weekend so that we can look at more than just letters on a screen. I will not, however, be photographing gynecomastia.