5 replies to this topic

[Klyde Chroma]

So upon examing my diet.... in which I am VERY limitted.... I noticed my vitamin A consumption is very high, yet I have seen no ill effects. Now I have read that consuming large amounts of vitamin A over time can cause a chronic toxicity and thus my question is am I over-doing it?

My daily sources of vitamin A are the following....

10-12 oz. spinach daily
6-9 bell peppers daily (red)
12-16 stalks of celery

Which adds up to roughly (give or a take a few hundred percent) 1800-2000 % the dairly recomendation.

So is this enough to hurt me over time, or am I alright? I have been eating this daily for quite awhile without problem.....

[1kgcoffee]

You're safe You can only overdose from fat soluble vitamin A (retinol) which those sources are not. Any excess water soluble vitamin A will be peed out.

[Chupo]

There is no such thing as water soluble vitamin A. What cronometer shows as vitamin A from plant sources is not true vitamin A but carotenoids which are only precursors. Not all of it will be converted to true vitamin A.

[okay]

For oil-based retinol supplements, daily doses of > 2 mg retinol/kg for weeks or months seemed to be needed for the induction of chronic hypervitaminosis A. When retinol was administered in a water-miscible or emulsified form, however, the threshold dose was reduced dramatically, and toxicity was evident after an intake of ≈0.2 mg retinol · kg−1 · d−1 for 1–4 wk.

→ source (external link)

I suggest you read the paper.

<500,000 IU/day is safe, basically.

Edited by okay, 20 September 2012 - 04:55 PM.

[pamojja]

<500,000 IU/day is safe, basically.

Interesting paper, thanks for posting. Wasn't aware that there are such huge differences (>10) in toxicity between oil-based and emulsified forms at all.

Conclusion

The present meta-analysis shows that it is important to take into account the physical form of retinol supplements when hypervitaminosis A is considered: water-miscible, emulsified, and dry preparations of retinol seem to be ≥ 10 times as toxic as oil-based preparations of retinol or dietary retinol in liver. Chronic hypervitaminosis seems to be induced after daily doses of 2 mg retinol/kg in oil-based preparations for many months or years. The safe upper single dose of retinol in oil or liver seems to be ≈4–6 mg/kg body wt. These thresholds do not vary considerably with age. Interestingly, vitamin D appears to protect against vitamin A toxicity.

[okay]

My daily sources of vitamin A are the following:

10-12 oz. spinach daily
6-9 bell peppers daily (red)
12-16 stalks of celery

Which adds up to roughly (give or a take a few hundred percent) 1800-2000 % the dairly recomendation.

11 oz. spinach = 311g
7.5 bell peppers (1 pepper≈70g) = 525g
14 stalks (1 medium stalk≈40g) = 560g

Vitamin A 50900 IU — 1018%
Retinol — 0.0mcg
Retinol Activity Equivalent — 2542mcg
Alpha Carotene — 98.6mcg
Beta Carotene — 29225mcg
Beta Cryptoxanthin — 2518mcg
Lycopene — 0.0mcg
Lutein+Zeaxanthin — 36667mcg (?)

→ source (external link)

Flawed, if you ask me.