The Dangers of Fat-Soluble Vitamins

You could be killing yourself and not even know it...

Research shows nearly 80% of people take supplements occasionally. Close to 60% of people think supplements are safer than prescription or over-the-counter medications and that supplements sold in "health" stores and online are proven safe...

That's a dangerous – and potentially fatal – assumption.

Water-soluble vitamins – like vitamins B and C – are relatively safe. It's hard to overdose on them. Most times, if you take too much of a water-soluble vitamin, you'll simply urinate it out.

But fat-soluble vitamins... common vitamins like A, D, E, and K... build up over time in your fatty tissues. This is far more dangerous...

At high concentrations, these vitamins create serious health problems. That means you could easily be overdosing on what's marketed as a perfectly safe supplement.

Fat-soluble vitamins do have some benefits, but they can also have dangerous consequences if levels become too high in the body... especially if you take them in concentrated pill forms. Here's the good and the bad...

Vitamin A

The Good News: Vitamin A helps promote bone and tooth growth, as well as improving night vision. Vegetables like carrots and sweet potatoes contain a naturally occurring form of vitamin A called beta-carotene. You can also get vitamin A from dairy products, leafy green vegetables, and several other foods.

The Bad News: An overdose of vitamin A can cause blurred vision, hair loss, headaches, and even bone pain. In infants and young children, too much of it causes growth retardation.

Proper Portions: An adult needs about 2,300-3,000 international units (IU) a day of vitamin A. A carrot has 4,000 IU of vitamin A. Throw a carrot in your lunch bag every day, and you'll be fine. Unless you're a starving African villager, you have no reason to supplement your diet with this fat-soluble vitamin. The dangers far outweigh the benefits.

Vitamin D

The Good News: Your body naturally converts sunlight to vitamin D, which hardens bones and teeth and helps you absorb calcium (also critical to bone structure and function).

The Bad News: Too much vitamin D can cause kidney failure, kidney stones, and painful muscle spasms. Worse, a recent review in The New England Journal of Medicine (NEJM) linked vitamin D to an increased risk of pancreatic and esophageal cancers.

It's being touted as the cure for depression, osteoporosis, and cancers alike. People with little knowledge of the science are making the recommendations. In fact, the NEJM study showed no indication that higher serum concentrations warded off some of the more common cancers like endometrial, esophageal, gastric, kidney, and ovarian, as well as lymphomas.

Proper Portions: The maximum amount of vitamin D you need is 800 IU a day. You can get most of this amount by spending a few minutes outside. Even better, your body self-regulates this process... So you can spend hours outside and still get just the right amount.

It's true that people who live in areas that don't get much sun in the winter can become deficient in vitamin D. In those cases, dietary supplements are warranted. But be careful...

Several commercial vitamins are stuffed with 600-1,000 IU in each pill. Also, you can find vitamin D in dairy products "fortified" with it, as well as over-the-counter fish-oil pills. In the past month, two friends showed me bottles of vitamin D pills with a 5,000 IU megadose. They were taking them for a variety of touted benefits (some proven, most not).

If you're vulnerable to vitamin D deficiency, be mindful of the dosage you're taking and give your body the time to process the chemicals you're feeding it. You only need 800 IU, so I wouldn't take that 5,000 IU pill more than once every six days (5,000 divided by 800). And that assumes you don't get any sunlight or eat any foods with it for those days – an absurd assumption. One bottle should last about four years.
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Vitamin E

The Good News: Vitamin E is found in whole grains, nuts, and leafy green vegetables. It's a well-known antioxidant that prevents damage to cell membranes.

The Bad News: Studies are mixed on the benefits. This is due in part to the fact that vitamin E exists in eight different structures in nature. That makes designing reliable studies tricky at best.

Proper Portions: The most an adult needs is around 22.4 IU per day. Vitamin E in high doses can be deadly. If you take too much, you can experience fatigue, muscle weakness, headaches, and excessive bleeding. Some people are taking 1,000-2,000 IU a day at great risk to their health.

Vitamin zealots claim E is the fountain of youth. It isn't. And no amount of name-calling or anecdotal claims should convince you otherwise.

Vitamin K

The Good News: Vitamin K is critical in blood clotting as well as bone metabolism. A shot of it is given to every U.S. infant at birth to prevent a rare but fatal brain bleed. (Only five in 100,000 infants now experience such a brain bleed.) New research shows vitamin K is important for bone health.

The Bad News: Not much... Vitamin K taken orally – even in large doses – is rarely toxic.

Proper Portions: The human body uses about 100 micrograms per day. You can easily get most of the vitamin K you need in a single serving of green vegetables. A cup of broccoli has 629 micrograms. A teaspoon of parsley carries 75 micrograms. One study showed eating lettuce once a day cuts your risk of hip fractures in half. And vitamin K is readily recycled in the body's cells.

With an adequate diet, you don't need extra supplementation. Megadosing hasn't shown any ill effects... but it is unnecessary.

If you're concerned about a vitamin deficiency, do what I do...

My diet is varied, and I eat nuts and green, leafy vegetables regularly for natural doses of vitamin E. For my vitamin A, I eat carrots, sweet potatoes, and green leafy vegetables. When you consume these vitamins in whole foods, you're getting much lower doses and avoiding the risks of toxicity and the long-term dangers of cancer.

Of course, I'm human... Like anyone, I fall short of those dietary goals from time to time. To cover myself in those cases, I take a multivitamin about once per week. Most people don't need to take a supplement containing fat-soluble vitamins any more often than that.

Your body needs small amounts of these vitamins to function well. If you're getting greens and colored fruits and vegetables weekly, you're putting all the fat-soluble vitamins you need into your system. Your liver and the fat in your body store these vitamins and can get them when they're needed.

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