你需要補充維A嗎

Chances are, you've seen the aisles at the drug store dedicated to supplements of all kinds. Vitamins and minerals packaged in a variety of pills, gummies, powders, and drinks are readily available. But many of these supplements just aren't necessary. And while you may think you need to supplement your diet with vitamin A to help with bodily functions like vision and immune response, chances are, you're already getting the recommended daily amount through the foods you eat.

你很有可能在藥店的貨架上看到過各種各樣的補充劑。包裝在各種藥片、軟糖、粉末和飲料中的維生素和礦物質隨處可見。但很多補充劑都是不必要的。雖然你可能認為你需要在飲食中補充維生素A，以幫助身體功能，如視力和免疫反應，但很有可能，你已經(jīng)從你所吃的食物中獲得了推薦的每日攝入量。

Vitamin A comes in two forms that humans are able to use (via the National Institutes of Health). The first is preformed vitamin A, which only comes from animal products such as dairy, meat, and fish. The second is provitamin A carotenoids. This is a group of plant pigments that the body can turn into vitamin A. The most well-known example of a provitamin A carotenoid is beta-carotene. This is the pigment that gives carrots their orange hue (via the University of Rochester Medical Center). It's also an antioxidant that helps defend cells from damage.

維生素A有兩種形式，可供人類可以使用。第一種是預制維生素A，它只來自動物產品，如乳制品、肉類和魚類。第二種是維生素原A類胡蘿卜素。這是一組植物色素，人體可以將其轉化為維生素a。維生素原a類胡蘿卜素最著名的例子是β-胡蘿卜素。羅徹斯特大學醫(yī)學中心研究發(fā)現(xiàn)，正是這種色素使胡蘿卜呈現(xiàn)出橙色。它也是一種抗氧化劑，有助于保護細胞免受傷害。

Should you bother with a supplement?

你需要補充嗎?

Your body uses vitamin A to produce rhodopsin, a protein that helps absorb light in the retina of the eye. By not getting enough vitamin A, your ability to see color and to see in low light diminishes (via Insider). Vitamin A has been linked to the reduction in the risk of developing macular degeneration in people who are more susceptible to the condition (via Mayo Clinic).

你的身體使用維生素A來產生視紫紅質，一種幫助眼睛視網(wǎng)膜吸收光線的蛋白質。由于缺乏足夠的維生素A，你看顏色和在弱光下看東西的能力會減弱。維生素A與降低更易患黃斑變性的人群患黃斑變性的風險有關。

Most people get enough vitamin A in their diet by eating a variety of foods like dairy, leafy green vegetables, carrots, and meat. But for people with eye diseases, pancreatic disease, or even measles, supplemental vitamin A can be helpful. If that's not you, it's important to make sure you're not getting too much vitamin A. The recommended daily allowance for vitamin A for healthy adults is 900 mcg of retinol activity equivalents (RAE) for men and 700 mcg of RAE for women. Allowances vary slightly depending on age and other conditions. When you look at the label on a bottle of vitamin A supplements, the units will most likely be in international units (IU), so there may be some conversions to do in order to find out the RAEs in a serving of the supplement. Because too much vitamin A can be harmful, it's always a good idea to talk to a trusted medical professional before taking a vitamin A supplement.

大多數(shù)人通過食用各種食物，如乳制品、綠葉蔬菜、胡蘿卜和肉類，從飲食中獲得足夠的維生素A。但是對于患有眼病、胰腺疾病甚至麻疹的人來說，補充維生素A是有幫助的。如果你沒有這些癥狀，那么確保你沒有攝入過多的維生素A也很重要。對于健康的成年人來說，每日維生素A的推薦攝入量是男性900微克視黃醇活動當量(RAE)，女性700微克。根據(jù)年齡和其他條件，用量略有不同。當你看一瓶維生素a補充劑的標簽時，它的單位很可能是國際單位(IU)，所以為了找到每一份補充劑的RAE值，你可能還需要進行一些轉換。因為過多的維生素A是有害的，所以在服用維生素A補充劑之前，最好先咨詢一下值得信賴的醫(yī)學專業(yè)人士。