If you have searched for vitamin A D E K deficiency, you have probably met the same warning list on a dozen pages: dry eyes, soft bones, nerve trouble, easy bruising. What those pages almost never give you is the part that decides whether any of it applies to you, which is the numbers. How low does a blood level have to drop before it counts as a deficiency? How common is each one in a healthy woman over 40? And which of these four vitamins is worth testing for at all?
Vitamins A, D, E and K are the four fat-soluble vitamins. They are grouped together because the body absorbs and stores them the same way, using dietary fat, which means they share one risk: when fat absorption goes wrong, all four can fall at once. But in a well-fed adult, three of the four are rare to the point of being almost theoretical, and only one turns up often enough to justify a blood test. This guide goes vitamin by vitamin with the thresholds, the research doses and the honest limits of what a supplement can fix.
What vitamin A D E K deficiency actually means
The phrase vitamin A D E K deficiency is a shorthand for four separate problems that happen to travel together. Each vitamin does a different job. Vitamin A keeps the surface of the eye and the immune system working. Vitamin D moves calcium into bone. Vitamin E protects cell membranes from oxidative damage. Vitamin K lets the liver build the proteins that clot blood and the proteins that steer calcium into bone rather than arteries.
They are stored, not flushed. Water-soluble vitamins like vitamin C leave in the urine within hours, so a low day is quickly fixed and an overdose is hard. Fat-soluble vitamins sit in the liver and body fat for weeks or months. That is why a true shortage usually takes a long time to build, and why taking large doses of A, D or E is riskier than people assume. The body cannot simply rinse the excess away. That shared storage is also why vitamin A D E K deficiency tends to show up as a cluster, when it shows up at all, rather than as one isolated gap.
How common is vitamin A D E K deficiency, really?
This is the question the warning lists skip. For a woman eating a normal mixed diet in a high-income country, the honest answer is that vitamin A D E K deficiency is uncommon for three of the four, and the one that shows up is vitamin D.
Vitamin A deficiency is rare in the United States: fewer than 1 percent of people have a blood retinol level low enough to count. Vitamin E and vitamin K deficiency in healthy adults are rarer still. The National Institutes of Health notes that in people eating a varied diet, getting vitamin K low enough to change a clotting test is almost impossible. Vitamin D is the exception. In national survey data, about 5 percent of people were at risk of deficiency and another 18 percent at risk of inadequacy.
| Vitamin | Daily target, women over 40 | Deficiency blood level | Classic sign |
|---|---|---|---|
| A | 700 mcg RAE | Serum retinol 20 mcg/dL or below | Night blindness, dry eyes |
| D | 600 IU to age 70, 800 IU after | 25(OH)D below 12 ng/mL (30 nmol/L) | Soft bones, osteomalacia |
| E | 15 mg | Alpha-tocopherol below 12 micromoles/L | Nerve damage, poor balance |
| K | 90 mcg (adequate intake) | Prolonged clotting time | Bleeding, easy bruising |
Vitamin A: night blindness, and why the cap matters
Women over 40 need 700 micrograms of retinol activity equivalents a day, and the average American woman already eats about 616, close enough that outright deficiency is unusual. The first sign of a real shortage is night blindness, the loss of vision in dim light, followed by drying and damage to the surface of the eye. Worldwide, vitamin A deficiency is a leading cause of preventable blindness in children, but that is a problem of poverty and limited diets, not of a woman who eats eggs, dairy and orange vegetables.
The number that matters more for this audience is the ceiling. The tolerable upper limit for preformed vitamin A is 3,000 micrograms a day, and more is not better. In the CARET trial of over 18,000 smokers and people exposed to asbestos, a daily supplement of beta-carotene plus 7,500 micrograms of retinyl palmitate did not protect anyone. It raised lung cancer risk by 28 percent, death from lung cancer by 46 percent and all-cause death by 17 percent, and the trial was stopped early. High-dose vitamin A also causes birth defects, so anyone who is or might become pregnant should stay well under that cap. If you take a daily multivitamin for women over 40, check that its vitamin A is mostly beta-carotene rather than a large retinol dose.
Vitamin D: the one that actually shows up
Vitamin D is the fat-soluble vitamin most women will genuinely be low on, because the body makes it from sunlight and that supply falls with age, darker skin, time spent indoors and the shorter days of winter. The recommended intake is 600 international units a day up to age 70 and 800 after, where 1 microgram equals 40 units.
Blood levels are measured as 25-hydroxyvitamin D. Below 12 ng/mL (30 nmol/L) is deficiency, which softens bone and causes osteomalacia in adults. Between 12 and 20 ng/mL is a grey zone of possible inadequacy, and 20 ng/mL (50 nmol/L) or above is enough for most people. Risk is not even across groups: in the same national survey, 17.5 percent of non-Hispanic Black adults were at risk of deficiency, against 2.1 percent of non-Hispanic White adults. If a test comes back low, our guide on vitamin D deficiency symptoms in women and the walk-through of how to read a vitamin D blood test explain what the number means. One caution: the Endocrine Society does not recommend routine vitamin D testing in healthy adults aged 19 to 74, so test because of a reason, such as a fracture, a bone condition or a malabsorption problem, rather than out of habit.
Vitamin E: rare, and easy to confuse
Adults need 15 milligrams of vitamin E a day, and the average blood level in the United States is about 30 micromoles per liter, more than double the deficiency cut-off of 12. True vitamin E deficiency almost never happens from diet alone in a healthy person. When it does occur, through a fat-absorption disorder or a rare inherited condition, it damages nerves: numbness, muscle weakness, poor balance and, over time, problems with vision and the immune response.
Those nerve symptoms are the catch. They look a lot like other shortfalls, and vitamin E deficiency is sometimes mistaken for the far more common problem of low B12, which also causes numbness and balance trouble. If you have those symptoms, the useful first step is not an expensive vitamin E test but checking the usual suspects, including the signs covered in vitamin B12 deficiency signs in women. Note also that most vitamin E only supplements contain 67 milligrams or more, several times the daily target, and high doses have been linked to a higher risk of bleeding stroke.
Vitamin K: bleeding, bones and warfarin
Vitamin K has an adequate intake rather than a firm recommended amount, set at 90 micrograms a day for women. It comes in two forms: K1 from green leafy vegetables and K2 from fermented foods, with gut bacteria making some of the supply. The classic sign of a serious shortage is bleeding, because the liver cannot build its clotting factors without it. In healthy adults this is very rare and is usually limited to people with malabsorption. It is a real concern in newborns, which is why babies are given a vitamin K shot at birth.
Two points matter for women over 40. First, vitamin K also activates the protein that keeps calcium in bone and out of artery walls, which is why it is often paired with vitamin D; our explainer on vitamin D3 and K2 benefits together covers that partnership. Second, if you take warfarin or a similar blood thinner, vitamin K works against the drug. The goal there is not to avoid it but to keep your intake steady from week to week, so do not start a high-dose vitamin K supplement without telling the clinician who manages your medication.
Who is actually at risk after 40
Because all four vitamins need dietary fat to be absorbed, the people who really develop vitamin A D E K deficiency are those whose fat absorption is impaired, not those who simply eat imperfectly. The main groups are people with celiac disease, Crohn’s disease, ulcerative colitis, cystic fibrosis or chronic pancreatitis, and anyone who has had bariatric (weight-loss) surgery, which changes how the gut takes up fat and fat-soluble nutrients.
Two diet patterns raise the odds without any medical condition. Very low-fat eating limits how much of these vitamins you absorb from food, and long-term very low-calorie dieting can leave total intake short. If you are cutting calories hard, it is worth making sure the basics are covered: a mix of whole foods, some fat with meals so the vitamins can be absorbed, and enough protein, which you can size with our protein intake calculator. For a broader view of what a sensible regimen looks like at this age, the supplements hub collects the evidence by nutrient. Low magnesium often travels with poor overall diet quality too, which is covered in signs of magnesium deficiency in women.
Should you take a fat-soluble supplement?
The decision about supplementing for vitamin A D E K deficiency is narrower than the supplement aisle suggests. For most healthy women over 40, the answer for A, E and K is no, because diet already covers them and the storage effect makes high doses a liability rather than an insurance policy. Vitamin D is the reasonable exception, especially in winter, with darker skin or with little sun exposure, and a modest daily dose in the range of the recommended intake is cheap and safe. The pattern that keeps proving out in the research is that correcting a real, measured shortfall helps, while topping up a level that is already fine does nothing and, for vitamin A and vitamin E, can do harm.
So the practical path through vitamin A D E K deficiency is narrow and specific. Eat a varied diet with some fat. If you have a gut condition or weight-loss surgery, ask to have your fat-soluble vitamins monitored, because that is where real deficiencies cluster. Test vitamin D if you have a reason to. And treat any supplement that promises large doses of stored vitamins as something to question, not to trust.
Frequently asked questions
What are the symptoms of fat-soluble vitamin deficiency?
They differ by vitamin. Low vitamin A causes night blindness and dry eyes. Low vitamin D softens bone and causes aching bones and muscle weakness. Low vitamin E damages nerves, causing numbness and poor balance. Low vitamin K causes easy bruising and bleeding. Because several of these overlap with other problems, symptoms alone cannot confirm which vitamin, if any, is low.
Which of vitamins A, D, E and K is a woman most likely to be low on?
Vitamin D by a wide margin. In national survey data about 5 percent of people were at risk of vitamin D deficiency and 18 percent at risk of inadequacy, while fewer than 1 percent were low in vitamin A, and vitamin E and K deficiency are rarer still in healthy adults. Sun exposure, skin tone, age and season all push vitamin D down.
Can you take too much of the fat-soluble vitamins?
Yes, and this is the real risk for most people rather than deficiency. Because A, D, E and K are stored in the body, excess builds up. The upper limit is 3,000 micrograms a day for preformed vitamin A and 4,000 international units for vitamin D. High-dose vitamin A supplements raised cancer and death rates in smokers in the CARET trial, and high-dose vitamin E has been linked to bleeding stroke. Vitamin K has no set upper limit but interacts with blood thinners.
Do I need a blood test for vitamin A, E and K?
Usually not. Vitamin A, E and K status is not routinely tested in healthy adults because deficiency is uncommon and the tests are hard to interpret. Vitamin D is the one worth testing if you have a specific reason, such as a fracture, a bone condition or a gut problem that affects absorption. If you have a malabsorption condition or have had weight-loss surgery, ask your clinician to monitor all four.
Sources
- Vitamin A and Carotenoids: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2022
- Vitamin D: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2024
- Vitamin E: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2021
- Vitamin K: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements, 2021
This article is general health information for adults and not medical advice. It does not know your history, your medication or your results. For a decision about your own health, talk to a doctor or another qualified clinician who does.
