What are Fat-Soluble Vitamins? What They Are and How to Take Them

When we think about the building blocks of nutrition, we often only consider macronutrients (protein, fat, and carbohydrates), vitamins, and minerals. Of course, we can break macronutrients down and talk about the different types (trans-fats, saturated fat, and so on) and how we should – or shouldn’t – consume them. However, few people know there is also a difference between types of vitamins. 

Vitamins can be differentiated based on their solubility. Most vitamins dissolve in water (water-soluble vitamins) but there are also fat-soluble vitamins.


What Are Fat-Soluble Vitamins?

Fat-soluble vitamins are vitamins that require fat to “dissolve” and be usable in the body. These are vitamins that require the addition of food – either the meal they “arrived” in, or in addition to their taking – to be turned into something transportable. 

Most vitamins are water-soluble, but there are four fat-soluble vitamins_ A, D, E, and K. 

While there are relatively few fat-soluble vitamins, these are vitamins that are absolutely crucial for our well-being. If we fail to consume these vitamins adequately, we often start to feel fatigued and sluggish, are more likely to be in a bad mood, and our immune system can be compromised. 

If we want to look and feel our best we need to consume a full spectrum of vitamins on a daily or weekly basis, depending on their requirements.  


Which Vitamins are Fat-Soluble Vitamins? 

There are four fat-soluble vitamins, these are_ 

Vitamin A

Vitamin A isn’t technically a single compound; rather it is a group of fat-soluble compounds collectively known as retinoids. The most common dietary form of vitamin A is retinol. Other forms – retinal and retinoic acid - can be found in the body, but are rare or even absent in foods. 


What does vitamin A do? 

Vitamin A is vital in maintaining vision, hair growth, immune function, cell growth, and reproductive function. 


Where is vitamin A found? 

You’ll find trace amounts of vitamin A in a range foods, but the richest dietary sources of vitamin A is in foods such as fish liver oil, butter, carrots, and spinach. 


Are vitamin A deficiencies common? 

Vitamin A deficiencies are rare, and although it is found in many vegetables, “preformed” vitamin A is only found in animal-sourced foods. A deficiency in vitamin A may lead to hair loss, poor immune function, and skin conditions such as hyperkeratosis. Most people get a sufficient amount of Vitamin A from their diets, but a supplement is often beneficial, especially for those who eat largely or completely plant-based diet, but don’t always eat as many unprocessed vegetables as they should! 


Vitamin D 

This vitamin is also known as calciferol, or more colloquially, the sunshine vitamin, because it is produced by the skin when exposed to sunlight. Like vitamin A, vitamin D is actually a collective term that is used to describe a few related fat-soluble compounds.


What does vitamin D do?

Vitamin D is responsible for regulating and strengthening the immune system. It also works to regulate the circulating levels of calcium and phosphorus, which are vital minerals for bone growth and maintenance. It also promotes the absorption of these minerals from the diet.


Where can I find vitamin D?

Vitamin D comes in two main dietary forms_ vitamin D2 (ergocalciferol) which is found in mushrooms and some plants, and vitamin D3 (cholecalciferol), which can be found in animal-sourced foods, such as eggs and fish oil, and produced by your skin when exposed to sunlight. Due to its appearance in animal-based foods, it is not uncommon for vegans to take a combination supplement of Vitamin B12 and D3. 


Are vitamin D deficiencies common? 

Just like vitamin A, deficiencies in vitamin D are uncommon. Factors that may increase likelihood of being deficient include old age, dark skin colour, obesity, low sun exposure, and diseases that impair fat absorption.


Vitamin E

This is also not only one vitamin in itself, rather it is a family of eight structurally similar antioxidants that are divided into two groups_ tocopherols and tocotrienols. Alpha-tocopherol is a tocopherol and is the most common form of vitamin E, making up around 90% of vitamin E in the blood.


What does vitamin E do?

The main role of Vitamin E in the body is to act as an antioxidant, preventing oxidative stress and protecting fatty acids in your cell membranes from free radicals. These antioxidant properties are more effective when taken in addition to other nutrients like vitamin C, selenium, and vitamin B3.


Where can I find vitamin E?

Good sources of vitamin E include vegetable oils, avocados, seeds, nuts, and nut butters.


Are vitamin E deficiencies common? 

Just like the other vitamins, we have looked at, it is very uncommon to be deficient in vitamin E. Symptoms of  true vitamin E deficiency include weakened immune function, difficulty walking as a result of muscle weakness, tremors, vision problems, and numbness in the hands and feet. 


Vitamin K

Again, this vitamin is broken down into two groups known as Vitamin K1, which is found in plant-based foods, and Vitamin K2, which is primarily found in animal-products. Technically there are an additional 3 compounds, vitamins K3, K4 and K5, but they are synthetic (and so aren’t found naturally in our diets). 


What does vitamin K do?

The K in actually stands for “koagulation”, which is the Danish word, similar to the English word which basically means “to clot”. Besides helping to keep your blood clotting as it should, vitamin K also aids in supporting bone health and helping prevent the calcification of blood vessels, potentially reducing the risk of heart disease.


Where can I find Vitamin K?

Vitamin K1 (phylloquinone) can be found in leafy green vegetables, whereas vitamin K2 (menaquinone) is mainly found in animal-sourced foods and fermented soy products, such as tofu and natto.


Are vitamin K deficiencies common? 

Unlike other fat-soluble vitamins, Vitamin K is not stored in the body easily. In fact, it can take as little as 7 to 10 days for an average adult to become deficient in Vitamin K if they do not ingest it regularly in their diet. Due to vitamin K’s support of the body’s ability to clot blood, any small wound to a Vitamin K deficient body would cause continual bleeding. Despite this, Vitamin K deficiency is very rare. 


Should I Take Fat-Soluble Vitamins Differently to Other Vitamins?

No – fortunately, fat-soluble vitamins should be taken as recommended on any multivitamin packaging, which is with a meal. This will ensure your body can utilise all the vitamins and minerals you have consumed from your food or supplements. 

A healthy, balanced diet should provide you with all the fat-soluble vitamins you need. However, if you are dieting, eat a specialised diet, or worry you won’t get all your nutrients in your meals, a multivitamin is the best way to support your body. Our multivitamin contains all the vitamins you need to stay healthy, from natural sources. If you’d like to find out more about how we can help you maintain your health, click here. If you’d like to learn more about what vitamins and foods you should be consuming for optimum health, continue reading with 8 Top Vitamins and Nutrients for Glowing, Clear, Healthy Skin.