8Signs and Symptoms of Vitamin A Deficiency

维生素A是一种脂溶性维生素，对许多身体功能很重要，包括适当的视力，强烈的免疫系统，繁殖和良好的皮肤健康。

There are two types of vitamin A found in foods: preformed vitamin A and provitamin A ( 1 ).

Preformed vitamin A is also known as retinol and commonly found in meat, fish, eggs and dairy products.

On the other hand, the body converts carotenoids in plant foods, such as red, green, yellow and orange fruits and vegetables, into vitamin A ( 2 ).

尽管发达国家很少缺乏症，但发展中国家的许多人没有获得足够的维生素A。

Those at highest risk of deficiency are pregnant women, breastfeeding mothers, infants and children. Cystic fibrosis and chronic diarrhea may also increase your risk of deficiency.

这是维生素A缺乏症的8个体征和症状。

Vitamin A is important for the creation and repair of skin cells. It also helps fight inflammation due to certain skin issues ( 3 ).

Not getting enough vitamin A may be to blame for the development of eczema and other skin problems ( 4 ).

Eczema is a condition that causes dry, itchy and inflamed skin. Several clinical studies have shown alitretinoin, a prescription medication with vitamin A activity, to be effective in treating eczema ( 3 ，，，，5，，，， 6 ).

In one 12-week study, people with chronic eczema who took 10–40 mg of alitretinoin per day experienced up to a 53% reduction in their symptoms ( 6 ).

请记住，干燥的皮肤可能有很多原因，但是慢性维生素A缺乏可能是原因。

Summary

Vitamin A plays an important role in skin repair and helps fight inflammation. A deficiency in this nutrient can lead to inflammatory skin conditions.

Eye problems are some of the most well-known issues related to vitamin A deficiency.

In extreme cases, not getting enough vitamin A can lead to complete blindness or dying corneas, which are characterized by marks called Bitot’s spots ( 7 ，，，， 8 ).

干眼或无法产生眼泪，是维生素A缺乏症的第一个迹象之一。

印度，非洲和东南亚的幼儿缺乏维生素A的饮食量最大的危险（ 9 ).

Supplementing with vitamin A can improve this condition.

一项研究发现，在服用补充16个月的婴儿和儿童中，高剂量的维生素A降低了63％的干眼患病率（ 10 ).

Summary

维生素A缺乏会导致眼睛干燥，失明或垂死的角膜，也称为Bitot的斑点。缺乏症的第一个迹象通常是无法产生眼泪。

Severe vitamin A deficiency can lead to night blindness ( 11 ).

几项观察性研究报告说，发展中国家的夜间失明率很高（ 12 ，，，， 13 ，，，， 14 ，，，， 15 ).

Due to the extent of this problem, health professionals have worked to improve vitamin A levels in people at risk of night blindness.

In one study, women with night blindness were given vitamin A in the form of food or supplements. Both forms of vitamin A improved the condition. The women’s ability to adapt to darkness increased by over 50% over six weeks of treatment ( 16 ).

Summary

Getting adequate amounts of vitamin A is crucial for eye health. Some of the first signs of vitamin A deficiency are dry eyes and night blindness.

Vitamin A is necessary for reproduction in both men and women, as well as proper development in babies.

如果你有麻烦怀孕，缺乏维生素A可能是原因之一。维生素A缺乏症可能导致男性和女性不孕。

研究表明，维生素A缺乏症的雌性大鼠难以怀孕，并且可能患有出生缺陷的胚胎（17).

Other research suggests that infertile men may have a greater need for antioxidants due to higher levels of oxidative stress in their bodies. Vitamin A is one of the nutrients that acts as an antioxidant in the body ( 18 ).

Vitamin A deficiency is also related to miscarriages.

A study that analyzed the blood levels of different nutrients in women who had recurrent miscarriages found that they had low levels of vitamin A ( 19 ).

Summary

Both men and women who do not get adequate vitamin A can have fertility issues. Low vitamin A in parents may also lead to miscarriages or birth defects.

没有足够的维生素A的孩子可能会遭受发育迟缓的生长。这是因为维生素A对于人体的正常发展是必要的。

Several studies have shown that vitamin A supplements, alone or with other nutrients, can improve growth. Most of these studies were conducted in children in developing nations ( 20 ，，，， 21 ，，，， 22 ，，，， 23 ).

In fact, a study in over 1,000 children in Indonesia found that those with vitamin A deficiency who took high-dose supplements over four months grew 0.15 inches (0.39 cm) more than children who took a placebo ( 20 ).

然而，对研究的综述发现，补充维生素A与其他营养素结合使用可能对生长产生比补充维生素A的影响更大（ 22 ).

例如，在南非接受多种维生素和矿物质的南非发育迟缓的儿童的年龄长度分数比仅接受维生素A的患者一半好（ 23 ).

Summary

Vitamin A deficiency can cause stunted growth in children. Supplementing with vitamin A in combination with other nutrients may improve growth more than supplementing with vitamin A alone.

Frequent infections, especially in the throat or chest, may be a sign of vitamin A deficiency.

Vitamin A supplements may help with respiratory tract infections, but research results are mixed.

对厄瓜多尔儿童的一项研究表明，每周服用10,000 IU维生素的体重不足儿童的呼吸道感染少于接受安慰剂的儿童（ 24 ).

On the other hand, a review of studies in children found that vitamin A supplements may increase the risk of developing throat and chest infections by 8% ( 25 ).

作者建议只有真正缺乏症的人只能给予补充剂（ 25 ).

Furthermore, according to one study in elderly people, high blood levels of the provitamin A carotenoid beta-carotene may protect against respiratory infections ( 26 ).

Summary

Vitamin A supplements may protect underweight children from infections but increase the risk of infection in other groups. Adults with high blood levels of vitamin A may experience fewer throat and chest infections.

受伤或手术后无法愈合的伤口可能与低维生素A水平有关。

这是因为维生素A促进了胶原，，，，an important component of healthy skin. Research suggests that both oral and topical vitamin A can strengthen skin.

A study in rats found that oral vitamin A improved collagen production. The vitamin had this effect even though the rats were taking steroids, which can inhibit wound healing ( 27 ).

Additional research in rats found that treating skin with topical vitamin A appeared to prevent wounds associated with diabetes ( 28 ).

Research in humans shows similar results. Elderly men who treated wounds with topical vitamin A had a 50% reduction in the size of their wounds, compared to men who did not use the cream ( 29 ).

Summary

Oral and topical forms of vitamin A can promote wound healing, especially in populations that are prone to wounds.

由于维生素A会促进皮肤发育并抗击炎症，因此可能会有所帮助prevent or treat acne.

多项研究已将低维生素A水平与痤疮的存在联系起来（ 30 ，，，， 31 ).

In one study in 200 adults, vitamin A levels in those with acne were over 80 mcg lower than in those without the condition ( 30 ).

Topical and oral vitamin A may treat acne. Research shows that creams containing vitamin A can reduce the number of acne lesions by 50% ( 32 ).

用于治疗痤疮的口服维生素A的最著名形式是异维诺蛋白或accutane。这种药物可以非常有效地治疗痤疮，但可能会有许多副作用，包括情绪变化和出生缺陷（ 33 ).

Summary

Acne has been associated with low vitamin A levels. Both oral and topical forms of vitamin A are often effective at treating acne but may have unwanted side effects.

Vitamin A is valuable to overall health. However, too much of it can be dangerous.

Hypervitaminosis A, or vitamin A toxicity, typically results from taking high-dose supplements over long periods of time. People rarely get too much vitamin A from diet alone ( 34 ).

过量的维生素A是储存在肝脏和勒ad to toxicity and problematic symptoms, such as vision changes, swelling of the bones, dry and rough skin, mouth ulcers and confusion.

Pregnant women should be especiallycareful not to consume too much vitamin Ato prevent possible birth defects.

在开始维生素A补充剂之前，请务必与您的医疗保健提供者联系。

People with certain health conditions may need a higher amount of vitamin A. However, most healthy adults need 700–900 mcg per day. Women who are nursing need more, while children need less ( 1 ).

Summary

Vitamin A toxicity usually results from taking too much of the vitamin in supplement form. It can cause serious issues, including vision changes, mouth ulcers, confusion and birth defects.

Vitamin A deficiency is prevalent in developing nations but rare in America and other developed nations.

太少的维生素A会导致皮肤发炎，夜盲，不育症，生长延迟和呼吸道感染。

患有伤口和痤疮的人可能具有较低的血液水平维生素A，并受益于较高剂量的维生素的治疗。

Vitamin A is found in meat, dairy and eggs, as well as red, orange, yellow and green plant foods. To make sure you get enough vitamin A, eat a variety of these foods.

如果您怀疑自己患有维生素A缺乏症，请与您的医生或医疗保健提供者交谈。与正确的食物补充剂，解决不足可能很简单。