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Fat-Soluble Vitamins vs. Water-Soluble Vitamins: What’s The Difference?

Fat-Soluble Vitamins vs. Water-Soluble

You may have heard the words “fat-soluble” and “water-soluble” before when talking about vitamins. These terms are used to distinguish between the two different types of vitamins. But what is the difference, and which is better for our bodies? In this article, we’ll break down the difference between fat-soluble and water-soluble vitamins, as well as their importance to our health. 

Why Is It Important To Understand The Difference Between Fat-Soluble And Water-Soluble Vitamins?

Simply put, fat-soluble and water-soluble refers to the vitamin’s method of absorption as well as where and how long they are stored in our bodies. This is an essential distinction because it helps determine how much of each vitamin we need daily and prevents us from overconsuming them, which can result in toxicity if there is an excess intake over time. 

We can also use this information to optimize our intake because it gives insight into how to use, store, and pair these vitamins properly. To break it down:

  • There are four fat-soluble vitamins: vitamins A, D, E & K.
  • There are nine water-soluble vitamins: vitamin C and B vitamins: B1, B2, B3, B5, B6, B7, B9, & B12. 

Let’s dive into each one!

What Are Fat-Soluble Vitamins?

Fat-soluble vitamins, as the name implies, need fat to be absorbed. This means that they are absorbed along with dietary fat sources. For this reason, and among many others, getting enough healthy fats in your diet is extremely important. Conversely, if you aren’t eating enough fats in your diet, you will likely not be getting enough of the fat-soluble vitamins. This means that you won’t be absorbing them effectively, either. 

The absorbability of the fat-soluble vitamins is higher than their water-soluble counterparts, sitting at about 40-90% in optimal conditions. However, since these vitamins are absorbed with fat, absorption also depends on the efficient use of bile and pancreatic lipase, which are two digestive chemicals secreted in our bodies that are used to break down fats. 

As a whole, fat-soluble vitamins are essential for the proper functioning of our bodies. Their deficiencies have been linked to many different health disorders. However, since they are readily stored in our liver and adipose (fatty) tissue, they can also cause toxicity if consumed excessively over a long period. This is why it’s essential to continuously monitor your intake when taking these vitamins in supplement form. 

Vitamin A

Vitamin A is very important for growth & development, cell differentiation, vision, and immune function. You typically find it in yellow or orange fruits and vegetables like carrots, mangos, cantaloupe, sweet potatoes, and squash, but also in other foods such as leafy green vegetables, tomatoes, eggs, chicken, and liver. So if you eat a well-rounded diet with plenty of fruits and vegetables, you should have no problem getting enough vitamin A. 

Vitamin D

The next fat-soluble vitamin, vitamin D, is different from other vitamins. Our primary source is actually from the sun! When our skin is exposed to sunlight, we can synthesize a more stable form of this vitamin, known as vitamin D3. This enters our bloodstream and is transported to the liver and kidneys, where it is turned into its bioactive form: calcitriol. 

Vitamin D is essential for the development, growth, and maintenance of your bones, the prevention of certain diseases, general cellular function, muscle and nerve contraction, as well as the proper functioning of the immune system. 

Unfortunately, you’ll find limited dietary sources of vitamin D, such as fatty fish, liver, and fortified foods. 

Vitamin E

Vitamin E is an essential part of our body’s antioxidant network. This helps maintain the integrity of cell membranes by stopping chain reactions caused by free radicals. It also helps in the formation of blood vessels and plays a role in immune function. 

Deficiencies are rare in humans, so like vitamin A, if you eat a well-rounded diet with plenty of plant foods, you should be able to get enough of this vitamin too. Some of the best sources are sunflower seeds, almonds, whole grains, eggs, liver, peanuts, broccoli, avocado, and soybeans. 

Vitamin K 

The last fat-soluble vitamin, Vitamin K, is most known for its role in blood clotting. Vitamin K comes from the word “koagulation” (the Danish spelling for coagulation), which is the formation of a blood clot. It also plays a role in bone metabolism and the regulation of blood calcium levels. 

Vitamin K is often found in leafy greens like kale, spinach, broccoli & lettuce and other green foods like asparagus, cabbage, peas, and soybeans. Just another reason to eat something green every day! 

What Are Water-Soluble Vitamins?

Water-soluble vitamins differ from fat-soluble vitamins for a few reasons. First, they dissolve in water, which means they pass through our body much faster and are less likely to accumulate in our tissues. For this reason, toxicity is rare, and we need to ingest much higher amounts than fat-soluble vitamins. 

Another thing to note about water-soluble vitamins is that they are susceptible to heat, so they are most likely to be lost when foods are cooked. Because of this, including raw vegetables and fruits in your diet is very important! However, they can also be sensitive to air, light, and the passage of time. So, to maximize your intake, be sure to choose fresh and locally-grown produce.

Vitamin C

Vitamin C is among the most popular vitamins, best known for its role in immune health. Research has shown that it stimulates the immune system to help prevent and treat many infections and other diseases.

Like vitamin E, vitamin C is a powerful antioxidant. It also plays a role in collagen production, wound healing, and maintaining healthy blood vessels. Vitamin C is in fruits and vegetables. Therefore, the best sources are the citrus fruits such as oranges & lemons, as well as strawberries, cantaloupe, tomatoes, and green vegetables like green peppers, broccoli, and brussels sprouts. 

B Vitamins 

We collectively refer to B vitamins as the B-complex vitamins. Because we find them commonly in foods and they function similarly, we will address them all together. In fact, they often need each other to perform best. 

The B vitamins are coenzymes in our bodies that catalyze many biochemical reactions like converting carbohydrates to glucose and fat & protein metabolism. They are also essential for the optimal functioning of the nervous system and are often helpful for boosting energy levels in stressed or fatigued people. 

B vitamins are in animal proteins such as liver, seafood, poultry, eggs, whole grains, legumes, leafy greens, and seeds. However, vitamin B12 is typically in animal products or fortified foods. This is why many vegans or vegetarians take this supplement to meet the recommended daily intake or RDI.  

Wrapping It Up

As you can see, there are many differences between fat-soluble and water-soluble vitamins. We absorb fat-soluble vitamins through fat, as they do not dissolve in water. They have a higher absorbability and will be more available in our bodies than water-soluble vitamins.

On the other hand, water-soluble vitamins will dissolve in water, so they tend to be excreted more efficiently. Overall, they have less potential for toxicity. Because of these factors, our diet needs water-soluble vitamins in higher quantities to meet our nutritional requirements. 

Additionally, the water-soluble vitamins are more fragile regarding heat, light, air, and the passage of time. To optimize your intake of fat-soluble and water-soluble vitamins, choose fresh, whole foods. Eat plenty of fruits and vegetables, ideally those from local farmers. For more information or to find a vitamin that fits your needs, take our online assessment today.

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