Vitamin A Dangers

ddjd

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Risks of Consuming Too Much Vitamin A

The primary risks of too much vitamin A (either acute or chronic excess) are birth defects, liver abnormalities, central nervous system disorders, and lower bone mineral density that might increase osteoporosis risk. Since the American diet contains many fortified foods, the relationship between vitamin A and decreased bone density has become a greater concern.

Both human and animal studies show that a higher vitamin A intake interferes with bone metabolism. Specifically, excess vitamin A suppresses osteoblast (bone-building) activity, stimulates osteoclast (bone breakdown) formation, and interferes with vitamin D’s role in calcium absorption and regulation.

In one study, women consuming more than 6,660 IU daily of vitamin A as retinol in food or supplements (the daily recommendation for adult women is 2,310 IU) were found to have twice the hip fracture risk compared to those consuming 1,700 IU daily or less. Men with the highest blood levels of retinol are seven times more likely to fracture a hip than men with lower levels (study details). There is evidence that older individuals have higher blood levels of vitamin A because of a reduced ability to metabolize vitamin A as efficiently as one ages.

The chart below shows the most concentrated vitamin A sources, both animal and plant. As you can see, fortification (see blue section) makes it easy to surpass the 6,660 IU level, especially if you regularly consume liver, cod liver oil, margarine, butter, and cheese.

Note: All vitamin A toxicity issues pertain to retinol intake (in foods and supplements containing retinol, retinyl palmitate, or retinyl acetate) and NOT supplemental or food-based carotenoid intake (like beta-carotene).
 

Constatine

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What do people think about this.

Risks of Consuming Too Much Vitamin A

The primary risks of too much vitamin A (either acute or chronic excess) are birth defects, liver abnormalities, central nervous system disorders, and lower bone mineral density that might increase osteoporosis risk. Since the American diet contains many fortified foods, the relationship between vitamin A and decreased bone density has become a greater concern.

Both human and animal studies show that a higher vitamin A intake interferes with bone metabolism. Specifically, excess vitamin A suppresses osteoblast (bone-building) activity, stimulates osteoclast (bone breakdown) formation, and interferes with vitamin D’s role in calcium absorption and regulation.

In one study, women consuming more than 6,660 IU daily of vitamin A as retinol in food or supplements (the daily recommendation for adult women is 2,310 IU) were found to have twice the hip fracture risk compared to those consuming 1,700 IU daily or less. Men with the highest blood levels of retinol are seven times more likely to fracture a hip than men with lower levels (study details). There is evidence that older individuals have higher blood levels of vitamin A because of a reduced ability to metabolize vitamin A as efficiently as one ages.

The chart below shows the most concentrated vitamin A sources, both animal and plant. As you can see, fortification (see blue section) makes it easy to surpass the 6,660 IU level, especially if you regularly consume liver, cod liver oil, margarine, butter, and cheese.

Note: All vitamin A toxicity issues pertain to retinol intake (in foods and supplements containing retinol, retinyl palmitate, or retinyl acetate) and NOT supplemental or food-based carotenoid intake (like beta-carotene).
Its a tad bit silly. Many non-Western diets consume many times more vitamin A via animal fats and organ meats but are healthier. Vitamin A is only dangerous when consumed in massive amounts without the other fat solubles. Take all the fat solubles together and the side effects disappear.
 

Ella

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Not only fat solubles but other nutrient cofactors. Fortification is problematic because of lack of cofactors. As people age they become mineral deficient from poor diets or poison themselves from oversupplementation. A natural wholefoods diet is your best protection.
 

Constatine

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Not only fat solubles but other nutrient cofactors. Fortification is problematic because of lack of cofactors. As people age they become mineral deficient from poor diets or poison themselves from oversupplementation. A natural wholefoods diet is your best protection.
True.
 

TeslaFan

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add vitamin K, and all these apparent bone problems with A are suddenly non-existent.
 
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ddjd

ddjd

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Its a tad bit silly. Many non-Western diets consume many times more vitamin A via animal fats and organ meats but are healthier. Vitamin A is only dangerous when consumed in massive amounts without the other fat solubles. Take all the fat solubles together and the side effects disappear.
B
Not only fat solubles but other nutrient cofactors.
what are the other nutrient cofactors for Vit A?
 

Orius

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I think the source it's derived from matters. A lot of these studies are done on synthetic vitamin A. In traditional cultures they consumed many times the level we would consider safe. The Inuit for example would occasionally eat polar bear liver which contains 35,000 IU per gram as retinol and they are a culture whose children had robust jaw lines and straight teeth before the introduction of the western diet.

The healthy ratio of vitamin A to D is 10:1 which is verifiable in most natural food D sources where this ratio is found. If you're taking synthetic D then this ratio is irrelevant because the body barely uses the synthetic variety. If you take the natural kind as derived from lanolin or cod liver oil, then that doesn't mean you need to match it point for point with retinol. Your body will already have some stored retinol to do that. However daily intake of retinol is a must, especially in northern climates where people need to live off their fatty vitamin D stores during non-UVB months. Without the retinol the body will not convert stored D to active D.

If you follow this natural regimen then you won't have to take K2. D3 only displaces calcium when cal/mag intake is not sufficient. The body attempts to uselessly reallocate minerals from bone in order to appease the huge influx of D3.

I'll never forget my classmate in college who started taking 10,000IU of D3 per day and within a few weeks she had so many cavities in her mouth that she had to invest thousands of dollars in dental work.
 
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stsfut

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How important is vitamin E? If not consuming pufa’s, less need? If you are, many pufa’s contain vitamin E. Am I being ignorant in thinking you just need to focus on supplementing ADK?
 

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