Niacin, B5, B6 & B7: Water-Soluble Vitamin Deficiency & Toxicity

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  • 0:02 Water-Soluble Vitamins
  • 1:35 Niacin (B3)
  • 2:28 Pantothenic Acid (B5)
  • 3:14 Pyridoxine (B6)
  • 4:32 Biotin (B7)
  • 5:31 Lesson Summary
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Lesson Transcript
Instructor: Rebecca Gillaspy

Dr. Gillaspy has taught health science at University of Phoenix and Ashford University and has a degree from Palmer College of Chiropractic.

Water-soluble vitamins, which include niacin, B5, B6 and B7, are easily flushed from the body, making them prone to deficiencies. Learn about these B vitamins and symptoms associated with consuming too few as well as too many of them.

Water-Soluble Vitamins

Just like you have to fill up your car with gasoline on a regular basis, you have to fill up your body with vitamins. In fact, water-soluble vitamins are a type of vitamin that dissolves in water and easily flushes out of your system, so you need to replenish these vitamins on a daily basis to avoid deficiencies. Water-soluble vitamins include B-complex vitamins and vitamin C. The different types of B vitamins were originally thought to be one vitamin, but later it was discovered that they were a group of vitamins with different characteristics, so they were assigned individual numbers and names.

In this lesson we will focus on four of the eight B-complex vitamins: B3, or niacin; B5, also called pantothenic acid; B6, or pyridoxine; and B7, or biotin. We'll also take a look at symptoms that can arise if you take in too few or too many of these vitamins.

One thing to keep in mind as we learn about vitamin deficiencies is that they are not always caused by a lack of vitamin-rich foods. For example, we know that water-soluble vitamins flush out of your system when you visit the restroom, so it is reasonable to think that consuming a diuretic that makes you go to the bathroom more frequently, such as alcohol, could deplete these vitamins. Because of this, we see that alcoholics are a group of people who suffer from the B-vitamin deficiencies discussed in this lesson.

Niacin (B3)

Niacin deficiency results from not having enough B3. This is associated with a disorder called pellagra, which is characterized by three symptoms that start with the letter D: dermatitis, diarrhea and dementia.

As a memory jogger you can recall that 'Low B3 = the 3 D's of pellagra.' Niacin is needed for many metabolic processes throughout your body; that's why a deficiency can lead to widespread problems with the skin, digestion and brain function.

Niacin toxicity results from consuming too much B3. However, it's rare unless you take a supplement that contains the vitamin; overdo it on the niacin supplements, and you could end up with a flushing of the skin, nausea and tingling in the hands and feet.

Pantothenic Acid (B5)

Pantothenic acid (B5) deficiency is rare, yet if it does occur you might experience some fatigue, digestive disturbances or numbness in the hands and feet. These symptoms are due to B5's role in energy metabolism and proper nerve function.

The fact that pantothenic acid deficiency is rare might be explained by its name, which is Greek for 'from everywhere.' Indeed, this B vitamin is found in every food group. Even though it is easy to obtain, your body uses it for many processes, so the B5 you consume gets put to good use. This means that pantothenic acid toxicity is also rare, with no toxic level that causes concern.

Pyridoxine (B6)

Pyridoxine, which is one of the B-complex vitamins that is more commonly referred to by its number, B6, helps out with protein metabolism, so you can remember the two P's to help you recall this vitamin's job. Proteins are used in many ways within your body, from growth and immune function to the making of hemoglobin in the blood.

So many of the symptoms of pyridoxine deficiency involve these processes, and we see poor growth, decreased immune function and anemia. We also see neurological symptoms, such as numbness and tingling in the hands and feet, depression and convulsions when B6 is deficient.

This can be explained by the fact that B6 is needed to help make the myelin coatings of your nerves. Without myelin, nerves have a hard time transmitting their messages.

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