What are Water-Soluble and Fat-Soluble Vitamins?

In this article, we’re going to explain the main difference between water-soluble and fat-soluble vitamins. We'll also look at their implications for human health. Discover more!
What are Water-Soluble and Fat-Soluble Vitamins?

Last update: 09 February, 2021

Below, we invite you to learn more about water-soluble and fat-soluble vitamins, their main differences, and the functions they perform in the human body. This way, you’ll become aware of the importance of consuming enough vitamins on a daily basis and the causes of possible deficiencies.

Vitamins belong to the group of micronutrients. Foods contain them in small amounts. Nevertheless, this doesn’t mean that they aren’t important. In fact, it’s quite the opposite! These macronutrients play a role in several essential processes for the functioning of the human body.

Water-soluble vitamins

These are the vitamins that dissolve in water. You ingest them daily through your diet, as they can be found in many different foods. They carry out various functions: they can catalyze reactions, have antioxidant properties, and play a role in nutrient metabolism. They’re excreted through the urine. You need to supply your body with them regularly to avoid deficiencies, as this can negatively impact your health.

B vitamins and vitamin C belong to the group of water-soluble vitamins. The latter is very important to the human body, thanks to their ability to improve immune response and due to the fact that they play a role in collagen synthesis, as evidenced by a study published in The American Journal of Clinical Nutrition.

Water-soluble vitamins aren’t stored in the body. A continued deficiency of water-soluble vitamins can lead to acute health problems, such as scurvy. Fortunately, many foods, especially plant foods, contain these macronutrients.

Kiwi is a fruit rich in vitamins.

Fat-soluble vitamins

For their part, fat-soluble vitamins are absorbed in fats. Thus, these nutrients can build up in the body, meaning they can make up for insufficient intakes during a certain period of time.

Fat-soluble vitamins also play a role in key processes in the human body, many of them relate to inflammation, oxidative balance, and immune function.

Vitamins A, D, E, and, also, vitamin K belong to the group of fat-soluble vitamins. Vitamin D stands out among all of them since many people suffer from its deficiency.

This vitamin can be synthesized endogenously through sunlight exposure and people usually don’t get enough of it through food. It’s found in oily fish, eggs, and fortified dairy products. However, the body usually doesn’t assimilate it well, and it’s present in foods in small quantities.

However, vitamin D plays a role in crucial health preservation functions. One of them is bone metabolism since this nutrient can boost intestinal calcium absorption.

In addition, a lot of scientific evidence, such as this study published by The New England Journal of Medicine, links high vitamin D levels with a reduced risk of developing complex conditions, such as cancer.

Eat a varied diet to meet your water-soluble and fat-soluble vitamin needs

One of the basic principles of any diet is its food variety. This makes it possible to ensure an optimal intake of both water-soluble and fat-soluble vitamins.

Nevertheless, even in these optimal conditions, deficiencies may occur due to a possible increase in daily requirements. This is why vitamin supplements, whose goal is satisfying nutritional needs, exist on the market.

In addition, experts recommend frequent sunlight exposure to avoid low vitamin D levels, which they’ve related to an increased risk of developing complex conditions. Talk to your doctor to see if you need to include a supplement that contains this vitamin in your diet.

Water and fat-soluble vitamins: essential nutrients

As you’ve seen, water-soluble and fat-soluble vitamins are necessary nutrients that ensure proper bodily functioning. Although they differ in the medium where they’re soluble, they’re all essential.

Only fat-soluble vitamins are stored in the body. For this reason, the body can compensate for a possible lack of these vitamins in the diet for a certain period of time.

In short, to ensure that you’re getting the vitamins you need every day, you need to eat a balanced and varied diet that includes foods of all groups. However, even if you do this, you might need vitamin supplements in certain situations of increased nutritional needs.

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  • Shaw G., Lee Barthel A., Ross ML, Wang B., et al., vitamin C enriched gelatin supplementation before intermittent activity augments collagen synthesis. Am J Clin Nutr, 2017. 105 (1): 136-143.
  • Manson JE., Cook NR., Lee IM., Christen W., et al., Vitamin D supplements and prevention of cancer and cardiovascular disease. N Engl J Med, 2019. 380 (1): 33-44.