The Difference Between Water-Soluble and Fat-Soluble Vitamins

When it comes to vitamins and types of vitamins, it’s easy to get lost in all the jargon. But having a grip on concepts like water-soluble vitamins and fat-soluble vitamins can help you avoid vitamin deficiencies and get the most out of your foods, the right way. Whether you’re looking to buy multivitamins, reading the back of a cereal box, or just curious about what vitamins are soluble in fat and which are for water, this guide will break it down for you simply, so you can better understand your food and diet.

As the name suggests, these are the vitamins that dissolve in water. They’re absorbed directly into your bloodstream during digestion and used by your body straight away. But they’re also more easily washed out and don’t really get stored. So if you take more than you need, the surplus is simply flushed out in your urine. That’s why it’s important to regularly top up your water-soluble vitamins. There are actually 9 vitamins in this category – all eight B vitamins and vitamin C. Maybe it’s easier to think of it as just two vitamin groups.

These obviously dissolve in fat rather than water. They’re absorbed along with dietary fats in your digestive tract, so eating them with meals containing healthy fats (like olive oil, nuts, or oily fish) helps your body use them efficiently. Fat soluble vitamins get stored in your body’s fatty tissues and liver for later use, so you don’t need to consume them every day. There are only four fat-soluble types of vitamins – Vitamins A, D, E, and K.

	Water Soluble	Fat Soluble
Types	Vitamin B-complex, Vitamin C	Vitamins A, D, E, K
Functions	Energy production  Nervous system health  Immune function  Healthy skin and red blood cells  Metabolism of carbs, proteins, and fats	Vision and skin health (vit. A)  Bone health and immune support (vit. D)  Antioxidant protection (vit. E)  Blood clotting (vit. K)
Absorption	Directly into bloodstream with water	With dietary fat, via lymphatic system
Storage	Not stored, excess flushed out in urine	Stored in liver and fatty tissues
Toxicity	Low risk (excess flushed out)	Higher risk (can build up in body)
Deficiency	Develops quickly	Develops slowly
Daily Need	Yes, must be consumed regularly	No, can be consumed less often

These vitamins mostly promote energy metabolism, which means they help break down foods better to convert it into energy. But apart from this basic function, some of them also have other roles in the body :

1. Vitamin B1 (Thiamine): Thiamine is essential for keeping your nervous system and heart working properly. Since our bodies can’t make thiamine, we have to get its fill from foods.

Food Sources: Pork, whole grains, legumes like beans and peas, organ meats like liver.

2. Vitamin B2 (Riboflavin): This is probably the most interesting vitamin to talk about. Named after its colour – “flavus” is Latin for yellow – it’s a naturally fluorescent yellow-orange vitamin, making it look like it glows sometimes. So it can be used practically as a food colouring agent. It also maintains immune system functioning and supports healthy skin and hair.

Food Sources: Eggs, organ meats like kidney and liver, lean meats, dark green veggies, milk.

(Fun fact: UV light can destroy riboflavin, that’s why milk cartons are always opaque.)

3. Vitamin B3 (Niacin): This vitamin can be produced by the body with the help of another nutrient (tryptophan). Niacin is involved in digestion, maintaining healthy skin, making and repairing DNA, and it boosts brain function.

Food Sources: Liver, fish, poultry, meat, peanuts, whole grains.

4. Vitamin B5 (Pantothenic Acid): This one’s also got an interesting origin story for its name. It’s derived from the word “pantos”, which is Greek for everywhere. That’s because small quantities of pantothenic acid are found in mostly all foods (1). This vitamin is crucial for hormone production.

Food Sources: Liver, kidney, meats, seeds like sunflower seeds, eggs, whole grains, legumes.

5. Vitamin B6 (Pyridoxine): Pyridoxine is crucial for the formation of red blood cells and the production of insulin and haemoglobin. It also contributes to normal brain development and nervous and immune systems health.

Food Sources: Pork, poultry, whole grains and cereals, legumes, and green leafy

vegetables, potatoes, chickpeas, bananas.

6. Vitamin B7 (Biotin): You’ll mostly hear of biotin in the context of hair. Yes, it does support hair health, along with skin and nails. So it can be used to address problems related to these, like hair loss and brittle nails.

Food Sources: Egg yolks, most fresh vegetables, nuts and seeds, liver, fish.

7. Vitamin B9 (Folate): This vitamin is crucial for DNA and RNA synthesis. Folate is particularly important during periods of rapid cell growth, such as infancy and pregnancy. This way, it reduces the risk of birth defects. It’s named after the Latin word for leaf, “folium”, because cruciferous veggies make the best source for folate.

Food Sources: Broccoli, brussel sprouts, cabbage, kale, spinach. Also peas, chickpeas, and kidney beans.

8. Vitamin B12 (Cobalamin): The name “cobalamin” comes from cobalt that this vitamin contains. It helps make red blood cells, supports the nervous system and neurological functions, and maintains brain functions.

Food Sources: Shellfish like oysters and clams, organ meats, fish, dairy products.

9. Vitamin C (Ascorbic Acid): We need vitamin C for several functions in the body – bone development, collagen synthesis, wound healing, immune system. But being a water soluble vitamin, we can’t store it for long, so constantly replenishing its content is important for the regular functioning of our body.

Food Sources: Citrus fruit, peppers, berries like strawberries and blackcurrants, broccoli, potatoes.

Unlike water soluble ones that share a common function (apart from their own benefits), fat soluble vitamins are involved in more distinct roles in the body (2):

1. Vitamin A: This vitamin is made up of a group of fat-soluble compounds called “retinoids”. It plays an important role in supporting our eyesight, especially in the dark. And when you hear of “retinol” in a lot of skin products, that’s also vitamin A. It’s also needed for cell growth, so it supports proper growth of children.

Food Sources: Liver, fish, eggs, dairy products, sweet potatoes, carrots, spinach.

2. Vitamin D: We’re all familiar with this sunshine vitamin, but not many know about its two forms. Vitamin D2 is found in mushrooms and plants, while vitamin D3 is what our skin produces when it’s exposed to sunlight. Vitamin D is extremely important for bone health, as it helps absorb calcium, which is what our bones are basically made of. And it supports the immune system.

Food Sources: Not a lot of dietary sources for vitamin D except for fatty fish and some mushrooms. Some foods like bread and dairy products are often fortified with vitamin D, so check for those.

3. Vitamin E: This vitamin’s main role is to be our body’s antioxidant – so it basically protects our cells from damage by free radicals. It also prevents blood clotting in the heart as it thins out our blood, and supports immune function.

Food Sources: Wheat germ oil, sunflower oil, nuts and seeds like sunflower seeds, almonds, peanuts, and some fruits like mangoes and avocado.

4. Vitamin K: This vitamin derives its name from the word “koagulation”, which is German for blood clotting. So of course, it’s the “K”ey to prevent blood clotting. It also plays a part in supporting bone health and prevents calcium build-up in blood vessels. This way, it reduces the risk of heart problems.

Food Sources: Veggies like spinach, parsley, broccoli, cabbage, avocado and kiwi, nuts and seeds like cashew nuts, chestnuts and pine nuts.

• Eat the rainbow: A varied diet with plenty of fruit, vegetables, whole grains, and healthy fats will cover most of your vitamin needs.

• Pair fat-soluble vitamins with healthy fats: Add some olive oil to your salad to boost absorption of vitamins A, D, E, and K.

• Store and cook wisely: Water-soluble vitamins can be lost during cooking, especially boiling. Steam or microwave veggies to keep more nutrients in.

• Don’t overdo supplements: More isn’t always better – especially for fat-soluble vitamins. Stick to recommended daily amounts unless advised by a healthcare professional.

Both water-soluble and fat-soluble vitamins are essential for good health, but they work differently in the body and have unique roles. Understanding these differences helps you make smarter choices about your diet and supplements, so you get all the benefits without the risks. And remember – there’s no better substitute for a balanced diet. Just make sure you’re eating well, and let your food do the work!

These are the vitamins that get dissolved in fats. They’re absorbed into your digestive system through dietary fats and get stored for later use. These are vitamins A, D, E, and K.

These are vitamins that get dissolved in water, so they get absorbed directly into your bloodstream. They’re not stored easily so we need to keep refilling our store of these vitamins. They include all the B vitamins and vitamin C.

Water-soluble vitamins (B and C) can be taken at any time of day, either with or without meals. But it might be better to take them on an empty stomach with some water.

These vitamins are best absorbed with food. Take your supplements with a meal, especially one containing healthy fats.