Water-soluble vs fat-soluble vitamins

Buthina Khalil

Dec 23, 2022

A brief history of the vitamins

The incident behind the discovery of the organic food substance “Vitamin” is worth knowing. The discovery of vitamins opened the door wide, to getting to know more about nutrition in food and how it affects one’s health and fights diseases.

The book titled Advanced Human Nutrition describes well how the “Vitamins” were discovered in the early 1900s by the biochemist Casimir Funk. Casimir tried to describe a newly discovered substance or stuff contained in the food that is vital or important to the health and function of the human body. Casimir gave the term or name “vital amine” to this new food substance. This “vital amine” is called after that “ vita-mines”. Thus, since the scientists realized that not all the newly discovered substances contain nitrogen, the letter “e” was dropped from the word “vita-mine” to become the present familiar name “vitamin” (Medeiros & Wildman).

In essence, there is a special rule for a substance to be recognized as a vitamin:

1. The vitamin must be organic 
2. The vitamin must be essential in at least one necessary process of chemical reaction in the human body
3. The vitamin can not be made in the human body either, at all, or in adequate quantities in order to meet what the body needs to function properly
4. The vitamin has no calories (0 calories)
5. The vitamins are required only in small amounts usually in milligrams or micrograms

Vitamins classification

As mentioned above, the vitamin can not be made in the human body either, by all, or inadequate quantities. For example, vitamin D, niacin (B3), K, and biotin (B7) are the only ones the body can synthesize, but sometimes not in adequate quantities.

The vitamins are commonly classified based on their water solubility due to the fact that water is the main principle component of the human body. Water is part of the blood, digestive juices, and urine which all represent the route of food transport, absorption, and excretion. 

So, fat-soluble vitamins are soluble only in organic solvents which are not water (water is an inorganic solvent because it does not contain carbon). whereas water-soluble vitamins do dissolve in water. 
Water-soluble and fat-soluble vitamins also can be classified according to other body functions such as digestion, absorption, transport, storage, or the timing of deficiency or toxicity  (Medeiros & Wildman).

Water-soluble vs fat-soluble vitamins

There are more compounds or vitamins in water-soluble than fat-soluble vitamins. Water-soluble vitamins include the B-vitamins group (8 vitamins) vitamin C, and choline. whereas fat-soluble have only four vitamins, A, D, E, and K. 

both vitamins are required in small amounts for:

1. healthy eyesight
2. healthy skin
3. to support the immune system
4. to convert food to energy
5. promote growth and reproduction. 

There are more compounds or vitamins in water-soluble than fat-soluble vitamins. Water-soluble vitamins include the B-vitamins group (8 vitamins) and vitamin C. whereas fat-soluble have only four vitamins, A, D, E, and K. 

Vitamins are required in small amounts for the benefit of:

1. healthy eyesight
2. healthy skin
3. to support the immune system
4. to convert food to energy
5. promote growth and reproduction.    

Water and fat-soluble vitamins existed in almost all types of food, but the amounts are varied. They exist in fruit and vegetables; in animal meats, organs, and products; in whole grains and nuts. The key knowledge here is for individuals to have balanced meals throughout the week which have a mix of various food, to ensure the proper function of their body. 

For example, having a bowl of salad each day full of fruit, vegetables, any kind of meat, and nuts with healthy dressing will guarantee to have a complete set of all vitamins. The exception here is for individuals who have any metabolic disorders in the stomach, colon, gallbladder, liver, etc…, or any kind of disease or history that affects the metabolism and digestion of food. 

On the other hand, too much of fat-soluble vitamins can be toxic because it’s stored in the body and take longer time than water-soluble to exit the body. But, the toxicity commonly comes from supplements and not food. For water-soluble vitamins, the risk of toxicity is far less than for fat-soluble ones, because they exit the body faster and don’t store in the body.

(You should always Consult your healthcare provider if you need specific amount and kind of food or if you need supplements whenever you have any health condition.). 

water soluble food sources:

• B vitamin groups: Fruits and vegetables, Whole grain, meats, Animal products , Nuts
• Vitamin C: fruits and vegetables 
• Choline: egg yolks, salmon, peanuts, milk

Fat-soluble food sources:

• Vitamin A: eggs, liver, dairy products
• Vitamin D: butter, fatty fish, whole and fortified milk and cereals, meat, and nuts
• Vitamin E: seeds, nuts, healthy oils
• Vitamin K: broccoli, leafy green vegetables, and dairy products

The deficiency in water-soluble vitamins is as follows:

• Disease such as beriberi (B1), ariboflavinosis (B2), or pellagra (B3)
• Neurological disorders or disturbance (B5)
• Dermatitis, anemia, depression, or weakness (B6)
• Hair loss, dermatitis, depression, neurological abnormal (B7)
• Anemia, neural tube defects, diarrhea, malabsorption (B9)
• Scurvy disease: gum bleeding, bruising, severe joint pain, loose teeth, poor wound healing (vitamin C)
• Liver damage (choline)

The deficiency in fat-soluble vitamins is as follows:

• Any decrease in bile production from the liver will decrease digestion or absorption 
• Any blockage in the way of bile to the small intestine that will decrease digestion or absorption
• Any health or digestion problem in the small intestine will decrease digestion or absorption
• Deficencincy in vitamin A might increase the risk of infection and night blindness
• A deficiency in vitamin D can cause osteoporosis and weak bones
• A deficiency in vitamin E can cause muscle weakness and damage the nerves
• A deficiency in vitamin K can cause a bleeding disorder

Referrals

Medeiros, D. M., & Wildman, R. E. C. (n.d.). Advanced Human Nutrition (4th ed.).