Vitamin classification, function, deficiency

Avitaminosis:
is a disease that develops in the absence of a particular vitamin. Currently avitaminosis are not commonly found
Hypovitaminosis:
a disease caused by partial deficiency of a vitamin. Since only a few vitamins can be stored in the body (A, D, E, B12).
Hypervitaminosis (vitamin toxicity)
is a condition that occurs when there is an excessive accumulation of one or more vitamins in the body. This can happen when someone takes vitamin supplements in high doses, either intentionally or inadvertently, over an extended period of time.
1-Poor Diet
Lack of variety in food
Insufficient intake of fruits and vegetables

2-Malabsorption
Digestive disorders (e.g., Crohn’s disease, celiac disease)
Surgical removal of parts of the digestive tract

3-Increased Requirements
Pregnancy and breastfeeding
Growth spurts in children
1-Poor Diet
Lack of variety in food
Insufficient intake of fruits and vegetables

2-Malabsorption
Digestive disorders (e.g., Crohn’s disease, celiac disease)
Surgical removal of parts of the digestive tract

3-Increased Requirements
Pregnancy and breastfeeding
Growth spurts in children
1-Poor Diet
Lack of variety in food
Insufficient intake of fruits and vegetables

2-Malabsorption
Digestive disorders (e.g., Crohn’s disease, celiac disease)
Surgical removal of parts of the digestive tract

3-Increased Requirements
Pregnancy and breastfeeding
Growth spurts in children

1. Biochemistry of Vitamins
SCBC 217

2. Lecture 1Lecture 1
IIntended L Learning O Outcomes
By the end of this lecture, You should be able to:
1.Describe the definition of vitamins
2.Recognize Vitamins discovery
3.Identify the function of vitamins
4.Outline the characters of vitamins
5.Define provitamin .

3. Definition of vitamins
Vitamins are a group of organic nutrients of
various nature required in small quantities for
multiple biochemical reactions for the growth,
survival and reproduction of the organism, and
which, generally, cannot be synthesized by the
body and must therefore be supplied by the diet

4. Vitamins discovery
The discovery of the vitamins began with experiments
performed by Hopkins at the beginning of the twentieth
century; he fed rats on a defined diet providing the then
known nutrients: fats, proteins, carbohydrates, and
mineral salts. The animals failed to grow, but the
addition of a small amount of milk to the diet both
permitted the animals to maintain normal growth and
restored growth to the animals that had previously been
fed the defined diet. He suggested that milk contained
one or more accessory growth factors , essential
nutrients present in small amounts, because the addition
of only a small amount of milk to the diet was sufficient
to maintain normal growth and development

5. Vitamins discovery
The first of the accessory food factors to be isolated and
identified was found to be chemically an amine;
therefore, in 1912, Funk coined the term vitamine, from
the Latin vita for life and amine, for the prominent
chemical reactive group. Although subsequent
accessory growth factors were not found to be amines,
the name has been retained– with the loss of the final
‘e’ to avoid chemical confusion. The decision as to
whether the word should correctly be pronounced
vitamin or veitamin depends in large part on which
system of Latin pronunciation one learned – the Oxford
English Dictionary permits both.

6. Function of vitamins
•Metabolic Functions:
–Many vitamins serve as cofactors or coenzymes for
various metabolic processes in the body.
–They help facilitate the conversion of food into
cellular energy (e.g. B vitamins, vitamin C).
•Antioxidant Functions:
–Vitamins like C, E, and carotenoids (pro-vitamin A)
can act as antioxidants, protecting cells from
oxidative damage.
–They help neutralize free radicals and reactive
oxygen species.

7. Function of vitamins
•Regulatory Functions:
–Vitamins like A, D, and K have important regulatory
roles in gene expression, cell differentiation, and
signaling.
•Structural Functions:
–Vitamins contribute to the structural integrity of tissues,
such as vitamin C's role in collagen synthesis.
•Immune Functions:
–Vitamins C, D, and E help support the proper
functioning of the immune system.
•

8. Function of vitamins
•Vision and Skin Health:
–Vitamins A and C are important for maintaining
healthy vision, skin, and mucous membranes.
•Blood and Bone Health:
–Vitamins K and D are crucial for proper blood
clotting and bone mineralization, respectively.
•Nervous System Functions:
–B vitamins like B1, B6, and B12 are important for
neurological function and nerve conduction.

9. Characters of vitamins
1-Vitamins are not synthesized by the body and must
come from food. An exception are vitamin B
3 (PP),
which active form NADH (NADPH) can be
synthesized from tryptophan and vitamin D
3
(cholecalciferol), synthesized from 7-
dehydrocholesterol in the skin. Amount of those ones
and vitamins partially synthesized by intestinal
microflora (В
1, В
2, В
3, B
5, В
6, К, and others) is
normally not sufficient to cover the body's need them.

10. Characters of vitamins
2-Vitamins are not an energy source.
3-Vitamins are essential for all vital processes
and biologically active already in small quantities.
4-They influence biochemical processes in all
tissues and organs, i.e. they are not specific to
organs.
5-They can be used for medicinal purposes as a
non-specific tools in high doses for: diabetes
mellitus - B
1, B
2, B
6; colds and infectious diseases
- vitamin C; bronchial asthma - vitamin PP;
gastrointestinal ulcers

11. Characters of vitamins
6-Organic Compounds:
–Vitamins are organic molecules, meaning they are
carbon-based compounds.
–They differ in their chemical structure and properties,
which contribute to their diverse functions.
7-Micronutrients:
–Vitamins are required in relatively small amounts
compared to macronutrients like proteins,
carbohydrates, and fats.

12. Characters of vitamins
8-Diversity:
–There are 13 essential vitamins, each with unique
chemical structures and functions.
9-Physiological Functions:
–Vitamins play crucial roles in various physiological
processes, including metabolism, antioxidant
defense, cell signaling, and structural integrity.
10-Deficiency and Toxicity:
–Insufficient intake of vitamins can lead to specific
deficiency diseases, while excessive intake can
result in toxicity.
–Maintaining the appropriate balance of vitamin
intake is essential for health.

13. Characters of vitamins
11-Dietary Sources:
–Vitamins are obtained primarily through the diet, with different
foods providing varying amounts and types of vitamins.
–Some vitamins can also be synthesized in the body (e.g.,
vitamin D from sun exposure).
12-Interactions and Bioavailability:
–The bioavailability and utilization of vitamins can be influenced
by factors such as other nutrients, medications, and individual
metabolism.
–Vitamins may also interact with each other, either synergistically
or antagonistically.
.

14. Characters of vitamins
13-Regulation and Homeostasis:
–Vitamin levels in the body are tightly regulated
through absorption, storage, and excretion
mechanisms to maintain homeostasis.
.

15. provitamin
A provitamin is a compound that can be converted or transformed into an active
vitamin in the body.
The main characteristics of a provitamin are:
•Structural Similarity:
–Provitamins have a similar chemical structure to the active vitamin form, but
they are not yet in the fully active state.
•Metabolic Conversion:
–Provitamins undergo enzymatic or chemical reactions in the body to be
converted into the biologically active vitamin.
–This conversion process typically takes place in specific tissues or organs.
•Vitamin Precursors:
–Provitamins serve as precursors or "precursor compounds" that can be
transformed into the active vitamin.

16. provitamin
•Examples of common provitamins include:
•Provitamin A (Carotenoids):
–Carotenoids like beta-carotene, alpha-carotene, and beta-cryptoxanthin
can be converted into the active form of vitamin A (retinol) in the body.
•Provitamin D (7-Dehydrocholesterol):
–7-Dehydrocholesterol is a precursor that is converted into vitamin D3
(cholecalciferol) when exposed to ultraviolet B (UVB) radiation from
sunlight.
•Provitamin K (Phylloquinone and Menaquinones):
–Certain plant-derived compounds like phylloquinone (vitamin K1) and
bacterial-derived menaquinones (vitamin K2) can be converted into the
active forms of vitamin K.
.