Vitamin A Overload: When Too Much of a Good Thing Turns Toxic!

Vitamin A supplements and cod liver oil (which is high in vitamins A and D) have been in the headlines – touted as a treatment or even a cure for the measles. Reported measles cases in the U.S. are approaching 500 and it has spread from Texas to 18 other states. There are likely more cases as not all are reported. The Health and Human Services (HHS) Secretary, Robert Kennedy Jr, has botched the measles outbreak response by failing to promote vaccination and by encouraging vitamin A and cod liver oil supplementation to treat measles. Not only is this approach ineffective, it is downright dangerous.

One circulating myth leads people to believe that these supplements can even prevent measles. Sadly, this is not true and has led to some cases of vitamin A overdose with dangerous side effects such as liver damage. High doses of vitamin A should only be given under the close supervision of a doctor.

How did these myths take hold? There is a nugget – albeit a small one – of truth. When someone is deficient in vitamin A, supplementation can improve outcomes if they have measles. Studies in lower income countries where vitamin A deficiency is common, show that vitamin A supplementation in people with measles can help prevent the disease from getting severe and can lower the risk of death. But vitamin A deficiency is rare in the U.S. - below 1%. Sometimes doctors in this country do give measles patients high doses of vitamin A supplements but they give two doses over the course of two days. Vitamin A supplements are not a cure, and they won’t prevent measles. Only the measles vaccine can do that.

Here's what you need to know about vitamin A:

• Vitamin A plays an important role in the immune system, reproduction, eyesight, growth & development.

• Adults Need: 900 mcg (300 IU’s) a day

• Fewer than 1% of Americans are vitamin A deficient; 2% are at risk for toxicity.
  

Notice vitamin A is expressed in two different measurement units – mcg’s (micrograms) and IU’s (International Units). When you read supplement labels, make sure you’re paying attention to which unit of measure is on the label.

We get vitamin A from a wide variety of foods:

Animal Foods:

• Good sources of the active form of vitamin A

• Liver, fatty fish like salmon and herring, fortified milk, cheese, eggs

Plant foods:

• Fruits and vegetables don’t have any vitamin A in them. What they do have is beta-carotene. Your body easily turns beta-carotene into vitamin A. So, you don’t have to eat animal foods to get your daily dose of vitamin A.

• The best plant sources of beta-carotene are sweet potatoes, spinach, carrots, broccoli, red peppers, and mangoes.

  
  

Fortified Foods:

• Milk and plant milks are usually fortified with vitamin A.

• Cereals often have added vitamin A.

  
  

How Much is Too Much? For all vitamins and minerals, more is not necessarily better. Everything has an upper limit.  If you get over that upper limit, particularly for a long time, you could start to see symptoms of toxicity. For water soluble vitamins, you can usually go far over the daily value (your daily need) before you get to toxicity. You’d have to get 22 times your daily need for vitamin C to reach the upper limit. For fat soluble vitamins like vitamins A and D, it’s a lot easier to get toxic levels because they are stored in our fat tissue. You would only have to get a little over 3 times the daily value for vitamin A to reach the upper limit.  It’s rare to get toxic levels of vitamins or minerals from foods. Most toxicity happens when people take supplements – especially mega doses. And it’s easy to get high dose supplements over the counter.

How easy is it to overdose on Vitamin A?

Upper Limit:

• 3,000 micrograms (1000 IU’s) for adults

• 600 -1700 micrograms for children, teens

  
  

Toxic levels can cause dry skin, painful muscles and joints, fatigue, depression, and liver damage. Remember, it’s the supplements that are the problem. So, if you’re taking a vitamin A supplement or cod liver oil, read the label carefully and pay attention to those measurement units to make sure you’re looking at the right one! Many of the supplements in stores are either at or over the upper limit.

Take a look at this sample label of cod liver oil and you can it is right at the upper limit. The % daily value is 333% of your daily need!

The bottom line? You probably don’t need a vitamin A supplement. But if you're taking one or decide to take one, tell your doctor and take a safe dose.

Safe Supplementing!

Beth Kitchin PhD RDN