Why do polar bears have so much vitamin A in liver?

Why do polar bears have so much vitamin A in liver?

A polar bear’s liver contains an extremely high concentration of vitamin A. This is due to their vitamin A rich diet of fish and seals.

What does vitamin A do for the liver?

The liver plays a central role in vitamin A metabolism: (1) it produces bile supporting efficient intestinal absorption of fat-soluble nutrients like vitamin A; (2) it produces retinol binding protein 4 (RBP4) that distributes vitamin A, as retinol, to peripheral tissues; and (3) it harbors the largest body supply of …

How much vitamin A is in bear liver?

One pound of polar bear liver — a fist-sized chunk and barely a meal — can contain 9 million units of vitamin A.

What liver cells store vitamin A?

HSCs (hepatic stellate cells) (also called vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells or Ito cells) exist in the space between parenchymal cells and liver sinusoidal endothelial cells of the hepatic lobule and store 50-80% of vitamin A in the whole body as retinyl palmitate in lipid …

Can eating liver cause vitamin A toxicity?

Vitamin A Toxicity It is possible, and even dangerous, to consume too much vitamin A. Eating large amounts of liver can lead to symptoms of vitamin A toxicity.

Can vitamin A toxicity be reversed?

A person can often reverse hypervitaminosis A by stopping taking excess amounts of vitamin A. This may mean that they can no longer take multivitamins or vitamin A supplements. If there are no complications, a person will usually recover quickly.

Is Vit A bad for liver?

Taking high doses of vitamin A supplements can cause liver damage. Combining high doses of vitamin A supplements with other drugs that can damage the liver could increase the risk of liver disease. Orlistat (Alli, Xenical). This weight-loss drug can decrease the absorption of food sources of vitamin A.

How long does vitamin A stay in your liver?

The liver stores vitamins and minerals for the times when they may be lacking in the diet. It can store enough vitamin A and vitamin B12 for four years, and enough vitamin D for four months.

What is the recommended intake of vitamin A?

The recommended daily amount of vitamin A is 900 micrograms (mcg) for adult men and 700 mcg for adult women.

How many units of vitamin A should you have a day?

The recommended daily allowance (RDA) for vitamin A is 900 mcg and 700 mcg per day for men and women, respectively — which can be easily reached by following a whole-foods diet ( 27 ). However, it’s important not to exceed the tolerable upper limit (UL) of 10,000 IU (3,000 mcg) for adults to prevent toxicity ( 27 ).

What are symptoms of too much vitamin A?

Taking more than 10,000 mcg a day of oral vitamin A supplements long term can cause:

• Bone thinning.
• Liver damage.
• Headache.
• Diarrhea.
• Nausea.
• Skin irritation.
• Pain in the joints and bone.
• Birth defects.

Is vitamin A stored in the liver?

Vitamin A is a fat-soluble vitamin that is stored in the liver.

How is vitamin A stored in bear liver?

The third bear liver specimen contained 13,000IU/g vitamin A. The only seal liver specimen also contained 13,000IU/g vitamin A. As a scientist, I can tell you that this is not particularly impossible. Vitamin A is stored in the liver. If it gets absorbed (and it does!), unless is utilized by the body immediately, it will be stored in the liver.

What kind of liver does a seal have?

For comparison, they also brought back a seal liver from a species of seals named Phoca barbata. This is what Rodahl and Moore reported: “On chemical and biological examination these specimens were found to be very rich in vitamin A, as also was a specimen of liver from P. barbata.

Is it safe to eat bear or seal liver?

While investigating the facts and fiction of vitamin A hypervitaminosis, I found myself able to confirm with published scientific evidence why one should NEVER eat bear or seal liver. By never I mean never-ever, even if facing starvation somewhere far away from any civilization.

Why is the liver of a polar bear dangerous?

Stay away from the liver. Polar bears, like most bears, are programmed to hibernate. This creates an intense hunger at every waking moment, causing them to consume food at unbelievable rates. They have a diet that is heavy in seals, which have high levels of vitamin A in their system.