By Billy Hammond (Copyright AELS)

February 17, 2020

Vitamin A is an essential vitamin and a deficiency can result in health problems. However, in this day and age of vitamin supplements, it’s quite possible to move into the range of toxicity with vitamin A.

The daily requirements are as follows:

RDA (Recommended Dietary Allowance)*

F: 700µg

M: 900µg

UL: 3,000µg (tolerable upper intake level)

You can get vitamin A from plants such as carrots, dark and leafy vegetables, sweet potatoes, squash, and broccoli. It primarily gets stored in the lipid-filled stellate cells in the liver.

The toxicity symptoms of acute vitamin A toxicity include headache, dizziness, vomiting, stupor, and blurred vision. Chronic toxicity is associated with weight loss, anorexia, nausea, vomiting, and bone and joint pain. Retinoic acid stimulates osteoclast production and activity, which lead to increased bone resorption and a greater risk of fractures. The retinoids used in common treatments for acne have not been associated with these conditions.** Note that their use in pregnancy needs to be avoided because of the well-established link between retinoids and birth defects.***

*Lieberman, Michael A.; Marks, Allan; Peet, Alisa. Marks’ Basic Medical Biochemistry (Lieberman, Marks’s Basic Medical Biochemistry) (Kindle Location 547). Lippincot (Wolters Kluwer Health). Kindle Edition.

**Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon. Robbins & Cotran Pathologic Basis of Disease, (Robbins Pathology) (Kindle Location 22367-22369). Elsevier Health. Kindle Edition.

***Fetal Retinoid Syndrome

ビタミンA毒性

ビタミンAは必要不可欠なビタミン。現在のサプリがあふれる社会ではビタミンAの飲みすぎることが考えられる。

*ビタミンAの1日あたりの推奨許容量

RDA(一日許容量)

女性:700µg

男性:900µg

上限: 3,000µg

様々な植物からビタミンAを摂取できる。ニンジン、緑色の葉もの野菜、サツマイモ、カボチャやブロッコリーには含まれている。ビタミンAは主に肝臓内の星細胞に貯蔵される。

急性中毒症状は頭痛、めまい、嘔吐、昏迷、及び目のかすみ。慢性中毒症状は体重減少、食欲不振、悪心、嘔吐及び骨と関節痛。レチノイン酸は破骨細胞形成と破骨細胞活性を加速するので骨吸収が増加し、骨折のリスクが増す。但し、ニキビ薬に通常含まれているレチノイドはそれらの症状とは関連付けていない。**しかし、レチノイドと奇形との関連は証明されているので妊娠中の過剰摂取は避けなければならない。***

*Lieberman, Michael A.; Marks, Allan; Peet, Alisa. Marks’ Basic Medical Biochemistry (Lieberman, Marks’s Basic Medical Biochemistry) (Kindle Location 547). Lippincot (Wolters Kluwer Health). Kindle Edition.

**Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon. Robbins & Cotran Pathologic Basis of Disease, (Robbins Pathology) (Kindle Location 22367-22369). Elsevier Health. Kindle Edition.

***Fetal Retinoid Syndrome

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English novels by Billy Hammond published by AELS

(AELS出版英語書籍リスト)

 

I. Majoh Gakuin and Hikari Juku – Japanese Witch Schools Trilogy

1. Majoh Gakuin & Hikari Juku – Japanese Witch Schools

2. Lost Witch (The second book)

3. Fate & Magic (The final book in the trilogy)

II. Brindle – Scryer Extraordinaire Trilogy

1. Brindle – Scryer Extraordinaire

2. Brindle – Scryer Extraordinaire – Returns

3. Brindle – Scryer Extraordinaire – Challenges (The final book in the trilogy)

III. Fantasy fiction set in Japan

1. 21st Century Ninja

2. Regressed

3. Japanese Woman

IV. Fantasy fiction set outside of Japan

1. Dimension Jumpers

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