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The Fantastic Four: Fat Soluble Vitamins That Work Together to Fight For Your Health

You know your body and your bones need certain vitamins like C and D in order to properly function.

But did you know that in order to properly absorb and use those vitamins it takes a team effort?

Let me explain.

Vitamins are generally classified into two categories: water soluble and fat soluble.

Water-soluble vitamins include all of the B vitamins and vitamin C. These vitamins are dissolved in water and if there is excess in your system, your body flushes them out.

Fat-soluble vitamins on the other hand, such as vitamins A, D, E and K, are similar to oil and don’t dissolve in water.

Unlike water-soluble vitamins, any excess of these vitamins in your system will be stored in your liver and fatty tissues until the body needs them.

The Fat-Soluble Balancing Act

Vitamins and minerals work together in your body which means you need adequate amounts of each in order for the others to properly benefit you.

For instance, numerous animal studies have shown that vitamin A reduces the toxicity of vitamin D and vitamin D reduces the toxicity of vitamin A. Not only has research demonstrated an interaction between vitamin A and vitamin D, but also interactions between all of the fat-soluble vitamins.

When researchers fed rats vitamin A at 10 times the normal amount, serum levels of vitamins E and D drop; when they feed rats vitamin A at 50 times the normal amount, serum levels of vitamin K also drop. One symptom of both vitamin A and vitamin E toxicity in the rat – internal hemorrhaging – resembles a major symptom of vitamin K deficiency, suggesting that part of the toxicity of vitamins A and E may be due to an imbalance with vitamin K,” as stated on

How well vitamin E works depends on the other fat-soluble vitamins and vice versa. Vitamins A, D, E and K have an important synergistic relationship where they balance and enhance each other. They are also crucial in promoting bone health and ensuring proper absorption and utilization of the calcium we eat.

The Fat Four: Four Fat-Soluble Vitamins You Need for Optimal Health

Vitamin A:

Vitamin A is a family of compounds that plays an important role in your vision, reproduction and bone growth. The two most common sources of vitamin A are retinol and beta-carotene. Beta-carotene is actually a precursor to vitamin A, meaning that the body needs to convert it for use.

You may think you can get all the vitamin A you need from dark leafy greens and orange plant foods such as carrots, and sweet potatoes. The problem with this is that most people are only able to convert a tiny amount of the vitamin A they consume for use. That’s why retinol is known as ‘true’ vitamin A because it is readily available and the body can process it easily. Retinol is found in animal foods such as eggs, fatty fish and liver.

Vitamin D:

We’ve all heard extensively about vitamin D and it’s importance for strong, healthy bones. But what is even more important is the type of vitamin D, as one is far superior than the other .

The two distinct forms of vitamin D are ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Initially, the two forms were regarded as interchangeable of equivalent, but this was based on studies on rickets prevention conducted over 70 years ago. With the emergence of 25-hydroxyvitamin D as a measurement to test vitamin D status, it has proven that vitamin D3 is the more potent form in humans.

One reason may be that Vitamin D3 is the more natural form of the two. Vitamin D3  is produced by your skin when you are exposed to sunlight or through fish consumption. Vitamin D2, on the other hand, is technically not ‘natural’ as it is produced through ultraviolet exposure of foods, which has been patented and licensed to pharmaceutical companies for synthetic production.

The American Journal of Clinical Nutrition has even stated that, “Vitamin D2, or ergocalciferol should not be regarded as a nutrient suitable for supplementation or fortification.”

Vitamin E:

Vitamin E is known for its antioxidant qualities and has been labeled fat-soluble vitamins’ most potent antioxidant. Vitamin E helps protects vitamin C, vitamin A, red blood cells and essential fatty acids from being destroyed.

In addition, there have been consistent studies stating that low vitamin E levels may be related to osteoporosis. In one study specifically, lower vitamin E serum levels were associated with osteoporosis in early postmenopausal women. The study showed that, “these findings highlight that vitamin E may increase BMD in healthy postmenopausal women.” However, vitamin E needs to be studied further as there are limited human studies.

Vitamin K:

Most people make the common connection between vitamin K and blood clotting, but there is more to vitamin K than just coagulation, like bone health support.

Specifically, vitamin K can protect against bone loss and arterial calcification. There has been a misunderstanding that high calcium intake is one of the reasons for arterial calcification, but this is misleading. A significant number of studies have actually shown that insufficient vitamin K2 levels accelerates arterial calcification. One of vitamin K’s functions is to direct the calcium straight to your bone and prevent it from building up in your arteries.

Like vitamin D, one form of vitamin K is far superior. You can read about it on this AlgaeCal blog post.

The RDI for Fat-Soluble Vitamins

For these vitamins to work together, they must be present in optimal amounts for your age and gender. Below are the Recommended Daily Intakes (RDI) of each.

Vitamin A: 700 mcg/day for adult females and 900 mcg//day for adult males.

Vitamin D: 800 IU, which is the recommended amount for maintenance of healthy bone for adults over age 50.

Vitamin E: 15 mcg of alpha-tocopherol/day for females and males over the age of 14. Taking more in excess does not results in any added benefits.

Vitamin K: 90 mcg/day for females 50 and older and 120 mcg/day for males 50 and older.

Conclusion? You Need to Balance Your Vitamins

Simply put, the vitamins covered today are unable to do their proper jobs without enough fat soluble vitamins in your system for them to work with. Each requires a balance of the other. So when you’re reviewing your diet and supplement protocol, make sure you’re getting a balanced amount of these crucial vitamins daily.





Author: Monica Straith, BS

Monica is the PR and Outreach Manager and Fitness Lead at AlgaeCal. She’s an ACE Certified Personal Trainer and Nutrition Specialist, and has a B.S. and B.A. from the University of Wisconsin-Madison, where she played varsity soccer for four years. Monica pulls from her experience in athletics and health to contribute to AlgaeCal and has also been featured on myfitnesspal blog, Prevention, and Huffington Post.