Quick version
Retinol (vitamin A) is vital for the body and affects much more than just the surface of the skin. It is needed to form the protein that allows us to see in the dark, and a deficiency therefore often first manifests itself as night blindness. The vitamin is also crucial for the immune system because it keeps the mucous membranes in the respiratory tract and intestines intact so that they can protect against infections. For the skin, retinol is necessary for the cells to mature normally; without it, the skin becomes dry, rough and lumpy.
Serious deficiency is uncommon in Sweden but can affect people with intestinal diseases or impaired nutrient absorption. At the same time, too high doses from dietary supplements can be harmful and lead to poisoning. Since the symptoms of both deficiency and excess are diffuse, a comprehensive assessment and blood tests are often required to check the body's actual levels.
Retinol is often mentioned in skincare, but in the body, retinol is about much more than just the surface of the skin. It's a form of vitamin A that's needed for you to see in low light, for mucous membranes to act as a barrier against infection, and for the skin to mature and repair itself normally. When levels become too low, it is often first noticed in the eyes, skin or by making you more susceptible to infections.
More than skin care - retinol affects your vision, skin and immune system
Retinol is one of the biologically active forms of vitamin A. The body obtains vitamin A either directly from animal foods such as liver, eggs and dairy products, or indirectly from carotenoids in, for example, carrots, sweet potatoes and dark green leafy vegetables, which can then be converted into vitamin A. Vitamin A is stored mainly in the liver, which means that deficiency can develop slowly but also that overdose can become a problem with high supplements.
Retinol and vision - why deficiency is often first noticed in the dark
Retinol is needed to form rhodopsin, a light-sensitive protein in the retina that allows the eye to adapt to darkness. In case of deficiency, this process becomes worse, and an early symptom can be night blindness – for example, it takes an unusually long time to get used to when you go from a bright room into the evening darkness.
If the deficiency becomes more pronounced, the surfaces of the eye are also affected. The conjunctiva and cornea can become dry, and in severe cases, so-called xerophthalmia can develop, a collective name for eye changes caused by vitamin A deficiency that, in the worst case, can threaten vision. This is uncommon in Sweden, but the risk increases with long-term disturbances in the body's nutritional status or diseases that impair the absorption of fat-soluble vitamins.
Retinol and the immune system – more than just “resistance”
Vitamin A helps the immune system on several levels. It helps to keep the mucous membranes in the respiratory tract, intestines and eyes intact and functions as the body's first defense against bacteria and viruses. It also affects immune cells such as T cells and B cells, which are important for recognizing and fighting infections.
When there is a deficiency, the barrier function becomes weaker and the immune system becomes less effective. This can lead to increased susceptibility to respiratory infections and diarrheal diseases, especially in children and people with malnutrition. Even mild deficiency can increase the risk of more serious disease progression in infections.
For adults in Sweden, pronounced vitamin A deficiency is uncommon, but it does occur. Typical risk groups are people with inflammatory bowel disease, celiac disease, cystic fibrosis, chronic pancreatic disease or previous bariatric surgery, where the absorption of fat and fat-soluble vitamins may be impaired. Very restrictive dietary patterns or alcohol-related liver disease can also contribute.
Retinol and the skin – when dryness is not just a skin problem
The skin is one of the body's largest organs, and vitamin A is needed for skin cells to mature at the right rate. When there is a deficiency, the skin can become dry, rough and scaly. A classic finding is follicular hyperkeratosis, where small hair follicles are clogged with keratin and the skin feels lumpy, often on the upper arms or thighs.
This explains why some people with vitamin deficiencies describe that their skin “never recovers” despite emollient creams. If the underlying problem is nutritional status or malabsorption, skin care is rarely enough as the only solution. This can also affect mucous membranes, which can cause dryness in the eyes and respiratory tract.
At the same time, more is not better. High doses of preformed vitamin A, i.e. retinol from dietary supplements or certain medications, can also cause skin symptoms – including dry skin, chapped lips and hair loss. When someone has both skin problems and takes several supplements at the same time, you therefore need to think about both deficiency and excess.
When should you suspect a deficiency or excess of retinol?
Suspicion of deficiency is raised above all when there is a combination of symptoms and risk factors. A person who sees worse in the dark, often has dry skin and at the same time has a disease that affects intestinal absorption should be assessed differently than someone who only has dry hands in the winter. Signs that may indicate vitamin A deficiency are: Reduced night vision or night blindness Dry eyes Dry, scaly or lumpy skin Repeated infections Malnutrition or diseases with malabsorption Excess is more often seen with long-term intake of high doses of retinol than through regular diet. Symptoms may include headache, nausea, blurred vision, joint and muscle pain, dry skin and abnormal liver tests. This is especially important during pregnancy, since excessive intake of preformed vitamin A can harm the fetus. Beta-carotene from food does not have the same known risk of birth defects.
When should you get tested?
Vitamin A deficiency cannot be assessed with certainty based on symptoms alone, as dry eyes, skin changes and susceptibility to infection have many possible causes. Blood tests can be indicative, but the interpretation needs to be put in context with diet, liver function, inflammation and any diseases of the intestine or pancreas. Therefore, the overall clinical picture is important.
Sample testing is particularly relevant if you have symptoms that match a deficiency or excess, if you have had surgery on your stomach or intestine, live with a chronic intestinal disease or use several dietary supplements at the same time.
Retinol shows how closely vision, barrier function and immune defense are actually related. When the body lacks the right building blocks, it is often noticeable where we are most exposed to the outside world: in the eyes, in the skin and in the mucous membranes. This is precisely why early testing can provide answers before the problems become obvious enough to seriously disrupt everyday life.
